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Cashen BA, Morse M, Rouzina I, Karpel RL, Williams MC. C-terminal Domain of T4 gene 32 Protein Enables Rapid Filament Reorganization and Dissociation. J Mol Biol 2024; 436:168544. [PMID: 38508303 DOI: 10.1016/j.jmb.2024.168544] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2024] [Revised: 02/27/2024] [Accepted: 03/14/2024] [Indexed: 03/22/2024]
Abstract
Bacteriophage T4 gene 32 protein (gp32) is a single-stranded DNA (ssDNA) binding protein essential for DNA replication. gp32 forms stable protein filaments on ssDNA through cooperative interactions between its core and N-terminal domain. gp32's C-terminal domain (CTD) is believed to primarily help coordinate DNA replication via direct interactions with constituents of the replisome. However, the exact mechanisms of these interactions are not known, and it is unclear how tightly-bound gp32 filaments are readily displaced from ssDNA as required for genomic processing. Here, we utilized truncated gp32 variants to demonstrate a key role of the CTD in regulating gp32 dissociation. Using optical tweezers, we probed the binding and dissociation dynamics of CTD-truncated gp32, *I, to an 8.1 knt ssDNA molecule and compared these measurements with those for full-length gp32. The *I-ssDNA helical filament becomes progressively unwound with increased protein concentration but remains significantly more stable than that of full-length, wild-type gp32. Protein oversaturation, concomitant with filament unwinding, facilitates rapid dissociation of full-length gp32 from across the entire ssDNA segment. In contrast, *I primarily unbinds slowly from only the ends of the cooperative clusters, regardless of the protein density and degree of DNA unwinding. Our results suggest that the CTD may constrain the relative twist angle of proteins within the ssDNA filament such that upon critical unwinding the cooperative interprotein interactions largely vanish, facilitating prompt removal of gp32. We propose a model of CTD-mediated gp32 displacement via internal restructuring of its filament, providing a mechanism for rapid ssDNA clearing during genomic processing.
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Affiliation(s)
- Ben A Cashen
- Department of Physics, Northeastern University, 360 Huntington Avenue, Boston, MA 02115, USA
| | - Michael Morse
- Department of Physics, Northeastern University, 360 Huntington Avenue, Boston, MA 02115, USA
| | - Ioulia Rouzina
- Department of Chemistry and Biochemistry, Center for Retroviral Research and Center for RNA Biology, Ohio State University, 281 W Lane Avenue, Columbus, OH 43210, USA
| | - Richard L Karpel
- Department of Chemistry and Biochemistry, University of Maryland Baltimore County, 1000 Hilltop Circle, Baltimore, MD 21250, USA
| | - Mark C Williams
- Department of Physics, Northeastern University, 360 Huntington Avenue, Boston, MA 02115, USA.
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2
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Sampathkumar A, Zhong C, Tang Y, Fujita Y, Ito M, Shinohara A. Replication protein-A, RPA, plays a pivotal role in the maintenance of recombination checkpoint in yeast meiosis. Sci Rep 2024; 14:9550. [PMID: 38664461 DOI: 10.1038/s41598-024-60082-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Accepted: 04/18/2024] [Indexed: 04/28/2024] Open
Abstract
DNA double-strand breaks (DSBs) activate DNA damage responses (DDRs) in both mitotic and meiotic cells. A single-stranded DNA (ssDNA) binding protein, Replication protein-A (RPA) binds to the ssDNA formed at DSBs to activate ATR/Mec1 kinase for the response. Meiotic DSBs induce homologous recombination monitored by a meiotic DDR called the recombination checkpoint that blocks the pachytene exit in meiotic prophase I. In this study, we further characterized the essential role of RPA in the maintenance of the recombination checkpoint during Saccharomyces cerevisiae meiosis. The depletion of an RPA subunit, Rfa1, in a recombination-defective dmc1 mutant, fully alleviates the pachytene arrest with the persistent unrepaired DSBs. RPA depletion decreases the activity of a meiosis-specific CHK2 homolog, Mek1 kinase, which in turn activates the Ndt80 transcriptional regulator for pachytene exit. These support the idea that RPA is a sensor of ssDNAs for the activation of meiotic DDR. Rfa1 depletion also accelerates the prophase I delay in the zip1 mutant defective in both chromosome synapsis and the recombination, consistent with the notion that the accumulation of ssDNAs rather than defective synapsis triggers prophase I delay in the zip1 mutant.
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Affiliation(s)
- Arivarasan Sampathkumar
- Institute for Protein Research, University of Osaka, 3-2 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Chen Zhong
- Institute for Protein Research, University of Osaka, 3-2 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Yuting Tang
- Institute for Protein Research, University of Osaka, 3-2 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Yurika Fujita
- Institute for Protein Research, University of Osaka, 3-2 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Masaru Ito
- Institute for Protein Research, University of Osaka, 3-2 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Akira Shinohara
- Institute for Protein Research, University of Osaka, 3-2 Yamadaoka, Suita, Osaka, 565-0871, Japan.
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3
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Mao EYC, Yen HY, Wu CC. Structural basis of how MGME1 processes DNA 5' ends to maintain mitochondrial genome integrity. Nucleic Acids Res 2024; 52:4067-4078. [PMID: 38471810 DOI: 10.1093/nar/gkae186] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Revised: 02/29/2024] [Accepted: 03/05/2024] [Indexed: 03/14/2024] Open
Abstract
Mitochondrial genome maintenance exonuclease 1 (MGME1) helps to ensure mitochondrial DNA (mtDNA) integrity by serving as an ancillary 5'-exonuclease for DNA polymerase γ. Curiously, MGME1 exhibits unique bidirectionality in vitro, being capable of degrading DNA from either the 5' or 3' end. The structural basis of this bidirectionally and, particularly, how it processes DNA from the 5' end to assist in mtDNA maintenance remain unclear. Here, we present a crystal structure of human MGME1 in complex with a 5'-overhang DNA, revealing that MGME1 functions as a rigid DNA clamp equipped with a single-strand (ss)-selective arch, allowing it to slide on single-stranded DNA in either the 5'-to-3' or 3'-to-5' direction. Using a nuclease activity assay, we have dissected the structural basis of MGME1-derived DNA cleavage patterns in which the arch serves as a ruler to determine the cleavage site. We also reveal that MGME1 displays partial DNA-unwinding ability that helps it to better resolve 5'-DNA flaps, providing insights into MGME1-mediated 5'-end processing of nascent mtDNA. Our study builds on previously solved MGME1-DNA complex structures, finally providing the comprehensive functional mechanism of this bidirectional, ss-specific exonuclease.
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Affiliation(s)
- Eric Y C Mao
- Department of Chemistry, College of Science, National Cheng Kung University, Tainan City 701, Taiwan
| | - Han-Yi Yen
- Department of Biochemistry and Molecular Biology, College of Medicine, National Cheng Kung University, Tainan City 701, Taiwan
| | - Chyuan-Chuan Wu
- Department of Biochemistry and Molecular Biology, College of Medicine, National Cheng Kung University, Tainan City 701, Taiwan
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4
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Joo JH, Hong S, Higashide MT, Choi EH, Yoon S, Lee MS, Kang HA, Shinohara A, Kleckner N, Kim KP. RPA interacts with Rad52 to promote meiotic crossover and noncrossover recombination. Nucleic Acids Res 2024; 52:3794-3809. [PMID: 38340339 DOI: 10.1093/nar/gkae083] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2023] [Revised: 01/24/2024] [Accepted: 01/27/2024] [Indexed: 02/12/2024] Open
Abstract
Meiotic recombination is initiated by programmed double-strand breaks (DSBs). Studies in Saccharomyces cerevisiae have shown that, following rapid resection to generate 3' single-stranded DNA (ssDNA) tails, one DSB end engages a homolog partner chromatid and is extended by DNA synthesis, whereas the other end remains associated with its sister. Then, after regulated differentiation into crossover- and noncrossover-fated types, the second DSB end participates in the reaction by strand annealing with the extended first end, along both pathways. This second-end capture is dependent on Rad52, presumably via its known capacity to anneal two ssDNAs. Here, using physical analysis of DNA recombination, we demonstrate that this process is dependent on direct interaction of Rad52 with the ssDNA binding protein, replication protein A (RPA). Furthermore, the absence of this Rad52-RPA joint activity results in a cytologically-prominent RPA spike, which emerges from the homolog axes at sites of crossovers during the pachytene stage of the meiotic prophase. Our findings suggest that this spike represents the DSB end of a broken chromatid caused by either the displaced leading DSB end or the second DSB end, which has been unable to engage with the partner homolog-associated ssDNA. These and other results imply a close correspondence between Rad52-RPA roles in meiotic recombination and mitotic DSB repair.
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Affiliation(s)
- Jeong H Joo
- Department of Life Sciences, Chung-Ang University, Seoul 06974, South Korea
| | - Soogil Hong
- Department of Life Sciences, Chung-Ang University, Seoul 06974, South Korea
| | - Mika T Higashide
- Institute for Protein Research, Graduate School of Science, Osaka University, Osaka 565-0871, Japan
| | - Eui-Hwan Choi
- Department of Life Sciences, Chung-Ang University, Seoul 06974, South Korea
- New Drug Development Center, Daegu-Gyeongbuk Medical Innovation Foundation, Deagu 41061, South Korea
| | - Seobin Yoon
- Department of Life Sciences, Chung-Ang University, Seoul 06974, South Korea
| | - Min-Su Lee
- Department of Life Sciences, Chung-Ang University, Seoul 06974, South Korea
| | - Hyun Ah Kang
- Department of Life Sciences, Chung-Ang University, Seoul 06974, South Korea
| | - Akira Shinohara
- Institute for Protein Research, Graduate School of Science, Osaka University, Osaka 565-0871, Japan
| | - Nancy Kleckner
- Department of Molecular and Cellular Biology, Harvard University, Cambridge 02138, USA
| | - Keun P Kim
- Department of Life Sciences, Chung-Ang University, Seoul 06974, South Korea
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5
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Sun K, Pu L, Chen C, Chen M, Li K, Li X, Li H, Geng J. An autocatalytic CRISPR-Cas amplification effect propelled by the LNA-modified split activators for DNA sensing. Nucleic Acids Res 2024; 52:e39. [PMID: 38477342 DOI: 10.1093/nar/gkae176] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Revised: 01/25/2024] [Accepted: 03/01/2024] [Indexed: 03/14/2024] Open
Abstract
CRISPR-Cas systems with dual functions offer precise sequence-based recognition and efficient catalytic cleavage of nucleic acids, making them highly promising in biosensing and diagnostic technologies. However, current methods encounter challenges of complexity, low turnover efficiency, and the necessity for sophisticated probe design. To better integrate the dual functions of Cas proteins, we proposed a novel approach called CRISPR-Cas Autocatalysis Amplification driven by LNA-modified Split Activators (CALSA) for the highly efficient detection of single-stranded DNA (ssDNA) and genomic DNA. By introducing split ssDNA activators and the site-directed trans-cleavage mediated by LNA modifications, an autocatalysis-driven positive feedback loop of nucleic acids based on the LbCas12a system was constructed. Consequently, CALSA enabled one-pot and real-time detection of genomic DNA and cell-free DNA (cfDNA) from different tumor cell lines. Notably, CALSA achieved high sensitivity, single-base specificity, and remarkably short reaction times. Due to the high programmability of nucleic acid circuits, these results highlighted the immense potential of CALSA as a powerful tool for cascade signal amplification. Moreover, the sensitivity and specificity further emphasized the value of CALSA in biosensing and diagnostics, opening avenues for future clinical applications.
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Affiliation(s)
- Ke Sun
- Department of Laboratory Medicine, State Key Laboratory of Biotherapy and Clinical Laboratory Medicine Research Center, West China Hospital, Sichuan University, Chengdu, 610041 Chengdu, China
- Tianfu Jincheng Laboratory, City of Future Medicine, Chengdu 641400, China
| | - Lei Pu
- Department of Laboratory Medicine, State Key Laboratory of Biotherapy and Clinical Laboratory Medicine Research Center, West China Hospital, Sichuan University, Chengdu, 610041 Chengdu, China
| | - Chuan Chen
- Department of Laboratory Medicine, State Key Laboratory of Biotherapy and Clinical Laboratory Medicine Research Center, West China Hospital, Sichuan University, Chengdu, 610041 Chengdu, China
- School of Pharmacy, North Sichuan Medical College, 637000 Nanchong, China
| | - Mutian Chen
- Department of Laboratory Medicine, State Key Laboratory of Biotherapy and Clinical Laboratory Medicine Research Center, West China Hospital, Sichuan University, Chengdu, 610041 Chengdu, China
| | - Kaiju Li
- Department of Laboratory Medicine, State Key Laboratory of Biotherapy and Clinical Laboratory Medicine Research Center, West China Hospital, Sichuan University, Chengdu, 610041 Chengdu, China
| | - Xinqiong Li
- Department of Laboratory Medicine, State Key Laboratory of Biotherapy and Clinical Laboratory Medicine Research Center, West China Hospital, Sichuan University, Chengdu, 610041 Chengdu, China
| | - Huanqing Li
- Department of Laboratory Medicine, State Key Laboratory of Biotherapy and Clinical Laboratory Medicine Research Center, West China Hospital, Sichuan University, Chengdu, 610041 Chengdu, China
| | - Jia Geng
- Department of Laboratory Medicine, State Key Laboratory of Biotherapy and Clinical Laboratory Medicine Research Center, West China Hospital, Sichuan University, Chengdu, 610041 Chengdu, China
- Tianfu Jincheng Laboratory, City of Future Medicine, Chengdu 641400, China
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6
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Shen K, Flood JJ, Zhang Z, Ha A, Shy BR, Dueber JE, Douglas SM. Engineering an Escherichia coli strain for production of long single-stranded DNA. Nucleic Acids Res 2024; 52:4098-4107. [PMID: 38499480 DOI: 10.1093/nar/gkae189] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2024] [Revised: 03/01/2024] [Accepted: 03/05/2024] [Indexed: 03/20/2024] Open
Abstract
Long single-stranded DNA (ssDNA) is a versatile molecular reagent with applications including RNA-guided genome engineering and DNA nanotechnology, yet its production is typically resource-intensive. We introduce a novel method utilizing an engineered Escherichia coli 'helper' strain and phagemid system that simplifies long ssDNA generation to a straightforward transformation and purification procedure. Our method obviates the need for helper plasmids and their associated contamination by integrating M13mp18 genes directly into the E. coli chromosome. We achieved ssDNA lengths ranging from 504 to 20 724 nt with titers up to 250 μg/l following alkaline lysis purification. The efficacy of our system was confirmed through its application in primary T-cell genome modifications and DNA origami folding. The reliability, scalability and ease of our approach promise to unlock new experimental applications requiring large quantities of long ssDNA.
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Affiliation(s)
- Konlin Shen
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA, 94158 USA
| | - Jake J Flood
- Department of Bioengineering, University of California, Berkeley, Berkeley, CA, 94720 USA
| | - Zhihuizi Zhang
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA, 94158 USA
| | - Alvin Ha
- Department of Laboratory Medicine, University of California, San Francisco, San Francisco, CA, 94143 USA
- Gladstone-UCSF Institute of Genomic Immunology, San Francisco, CA, 94158 USA
- Department of Medicine, University of California, San Francisco, San Francisco, CA, 94143 USA
| | - Brian R Shy
- Department of Laboratory Medicine, University of California, San Francisco, San Francisco, CA, 94143 USA
- Gladstone-UCSF Institute of Genomic Immunology, San Francisco, CA, 94158 USA
- Department of Medicine, University of California, San Francisco, San Francisco, CA, 94143 USA
| | - John E Dueber
- Department of Bioengineering, University of California, Berkeley, Berkeley, CA, 94720 USA
- Biological Systems & Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720 USA
| | - Shawn M Douglas
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA, 94158 USA
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7
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Sandler SJ, Bonde NJ, Wood EA, Cox MM, Keck JL. The intrinsically disordered linker in the single-stranded DNA-binding protein influences DNA replication restart and recombination pathways in Escherichia coli K-12. J Bacteriol 2024; 206:e0033023. [PMID: 38470036 PMCID: PMC11025327 DOI: 10.1128/jb.00330-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2023] [Accepted: 02/21/2024] [Indexed: 03/13/2024] Open
Abstract
Tetrameric single-stranded (ss) DNA-binding proteins (SSBs) stabilize ssDNA intermediates formed during genome maintenance reactions in Bacteria. SSBs also recruit proteins important for these processes through direct SSB-protein interactions, including proteins involved in DNA replication restart and recombination processes. SSBs are composed of an N-terminal oligomerization and ssDNA-binding domain, a C-terminal acidic tip that mediates SSB-protein interactions, and an internal intrinsically disordered linker (IDL). Deletions and insertions into the IDL are well tolerated with few phenotypes, although the largest deletions and insertions exhibit some sensitivity to DNA-damaging agents. To define specific DNA metabolism processes dependent on IDL length, ssb mutants that lack 16, 26, 37, or 47 residues of the 57-residue IDL were tested for synthetic phenotypes with mutations in DNA replication restart or recombination genes. We also tested the impact of integrating a fluorescent domain within the SSB IDL using an ssb::mTur2 insertion mutation. Only the largest deletion tested or the insertion mutation causes sensitivity in any of the pathways. Mutations in two replication restart pathways (PriA-B1 and PriA-C) showed synthetic lethalities or small colony phenotypes with the largest deletion or insertion mutations. Recombination gene mutations del(recBCD) and del(ruvABC) show synthetic phenotypes only when combined with the largest ssb deletion. These results suggest that a minimum IDL length is important in some genome maintenance reactions in Escherichia coli. These include pathways involving PriA-PriB1, PriA-PriC, RecFOR, and RecG. The mTur2 insertion in the IDL may also affect SSB interactions in some processes, particularly the PriA-PriB1 and PriA-PriC replication restart pathways.IMPORTANCEssb is essential in Escherichia coli due to its roles in protecting ssDNA and coordinating genome maintenance events. While the DNA-binding core and acidic tip have well-characterized functions, the purpose of the intrinsically disordered linker (IDL) is poorly understood. In vitro studies have revealed that the IDL is important for cooperative ssDNA binding and phase separation. However, single-stranded (ss) DNA-binding protein (SSB) variants with large deletions and insertions in the IDL support normal cell growth. We find that the PriA-PriB1 and PriA-C replication restart, as well as the RecFOR- and RecG-dependent recombination, pathways are sensitive to IDL length. This suggests that cooperativity, phase separation, or a longer spacer between the core and acidic tip of SSB may be important for specific cellular functions.
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Affiliation(s)
- Steven J. Sandler
- Department of Microbiology, University of Massachusetts at Amherst, Amherst, Massachusetts, USA
| | - Nina J. Bonde
- Department of Biochemistry, University of Wisconsin, Madison, Wisconsin, USA
- Department of Biomolecular Chemistry, University of Wisconsin, Madison, Wisconsin, USA
| | - Elizabeth A. Wood
- Department of Biochemistry, University of Wisconsin, Madison, Wisconsin, USA
| | - Michael M. Cox
- Department of Biochemistry, University of Wisconsin, Madison, Wisconsin, USA
| | - James L. Keck
- Department of Biomolecular Chemistry, University of Wisconsin, Madison, Wisconsin, USA
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8
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Pirojsirikul T, Lee VS, Nimmanpipug P. Unraveling Bacterial Single-Stranded Sequence Specificities: Insights from Molecular Dynamics and MMPBSA Analysis of Oligonucleotide Probes. Mol Biotechnol 2024; 66:582-591. [PMID: 38374320 DOI: 10.1007/s12033-024-01082-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Accepted: 01/10/2024] [Indexed: 02/21/2024]
Abstract
We utilized molecular dynamics (MD) simulations and Molecular Mechanics Poisson-Boltzmann Surface Area (MMPBSA) free energy calculations to investigate the specificity of two oligonucleotide probes, namely probe B and probe D, in detecting single-stranded DNA (ssDNA) within three bacteria families: Enterobacteriaceae, Pasteurellaceae, and Vibrionaceae. Due to the limited understanding of molecular mechanisms in the previous research, we have extended the discussion to focus specifically on investigating the binding process of bacteria-probe DNA duplexes, with an emphasis on analyzing the binding free energy. The role of electrostatic contributions in the specificity between the oligonucleotide probes and the bacterial ssDNAs was investigated and found to be crucial. Our calculations yielded results that were highly consistent with the experimental data. Through our study, we have successfully exhibited the benefits of utilizing in-silico approaches as a powerful virtual-screening tool, particularly in research areas that demand a thorough comprehension of molecular interactions.
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Affiliation(s)
- Teerapong Pirojsirikul
- Division of Physical Science, Faculty of Science, Prince of Songkla University, Songkhla, 90110, Thailand.
| | - Vannajan Sanghiran Lee
- Department of Chemistry, Center of Theoretical and Computational Physics, Faculty of Science, University of Malaya, 50603, Kuala Lumpur, Malaysia
| | - Piyarat Nimmanpipug
- Department of Chemistry, Faculty of Science, Chiang Mai University, Chiang Mai, 50200, Thailand
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9
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Love SD, Posey S, Burch AD, Fane BA. Disenfranchised DNA: biochemical analysis of mutant øX174 DNA-binding proteins may further elucidate the evolutionary significance of the unessential packaging protein A. J Virol 2024; 98:e0182723. [PMID: 38305183 PMCID: PMC10949513 DOI: 10.1128/jvi.01827-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2023] [Accepted: 01/10/2024] [Indexed: 02/03/2024] Open
Abstract
Most icosahedral DNA viruses package and condense their genomes into pre-formed, volumetrically constrained capsids. However, concurrent genome biosynthesis and packaging are specific to single-stranded (ss) DNA micro- and parvoviruses. Before packaging, ~120 copies of the øX174 DNA-binding protein J interact with double-stranded DNA. 60 J proteins enter the procapsid with the ssDNA genome, guiding it between 60 icosahedrally ordered DNA-binding pockets formed by the capsid proteins. Although J proteins are small, 28-37 residues in length, they have two domains. The basic, positively charged N-terminus guides the genome between binding pockets, whereas the C-terminus acts as an anchor to the capsid's inner surface. Three C-terminal aromatic residues, W30, Y31, and F37, interact most extensively with the coat protein. Their corresponding codons were mutated, and the resulting strains were biochemically and genetically characterized. Depending on the mutation, the substitutions produced unstable packaging complexes, unstable virions, infectious progeny, or particles packaged with smaller genomes, the latter being a novel phenomenon. The smaller genomes contained internal deletions. The juncture sequences suggest that the unessential A* (A star) protein mediates deletion formation.IMPORTANCEUnessential but strongly conserved gene products are understudied, especially when mutations do not confer discernable phenotypes or the protein's contribution to fitness is too small to reliably determine in laboratory-based assays. Consequently, their functions and evolutionary impact remain obscure. The data presented herein suggest that microvirus A* proteins, discovered over 40 years ago, may hasten the termination of non-productive packaging events. Thus, performing a salvage function by liberating the reusable components of the failed packaging complexes, such as DNA templates and replication enzymes.
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Affiliation(s)
- Samuel D. Love
- The BIO5 Institute, University of Arizona, Tucson, Arizona, USA
| | - Sierra Posey
- Berkshire School, Advanced Math/Science Research Program, Sheffield, Massachusetts, USA
| | - April D. Burch
- Berkshire School, Advanced Math/Science Research Program, Sheffield, Massachusetts, USA
| | - Bentley A. Fane
- The BIO5 Institute, University of Arizona, Tucson, Arizona, USA
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10
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Pangeni S, Biswas G, Kaushik V, Kuppa S, Yang O, Lin CT, Mishra G, Levy Y, Antony E, Ha T. Rapid Long-distance Migration of RPA on Single Stranded DNA Occurs Through Intersegmental Transfer Utilizing Multivalent Interactions. J Mol Biol 2024; 436:168491. [PMID: 38360091 PMCID: PMC10949852 DOI: 10.1016/j.jmb.2024.168491] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2023] [Revised: 02/04/2024] [Accepted: 02/08/2024] [Indexed: 02/17/2024]
Abstract
Replication Protein A (RPA) is asingle strandedDNA(ssDNA)binding protein that coordinates diverse DNA metabolic processes including DNA replication, repair, and recombination. RPA is a heterotrimeric protein with six functional oligosaccharide/oligonucleotide (OB) domains and flexible linkers. Flexibility enables RPA to adopt multiple configurations andis thought to modulate its function. Here, usingsingle moleculeconfocal fluorescencemicroscopy combinedwith optical tweezers and coarse-grained molecular dynamics simulations, we investigated the diffusional migration of single RPA molecules on ssDNA undertension.The diffusioncoefficientDis the highest (20,000nucleotides2/s) at 3pNtension and in 100 mMKCl and markedly decreases whentensionor salt concentrationincreases. We attribute the tension effect to intersegmental transfer which is hindered by DNA stretching and the salt effect to an increase in binding site size and interaction energy of RPA-ssDNA. Our integrative study allowed us to estimate the size and frequency of intersegmental transfer events that occur through transient bridging of distant sites on DNA by multiple binding sites on RPA. Interestingly, deletion of RPA trimeric core still allowed significant ssDNA binding although the reduced contact area made RPA 15-fold more mobile. Finally, we characterized the effect of RPA crowding on RPA migration. These findings reveal how the high affinity RPA-ssDNA interactions are remodeled to yield access, a key step in several DNA metabolic processes.
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Affiliation(s)
- Sushil Pangeni
- TC Jenkins Department of Biophysics, Johns Hopkins University, Baltimore, MD, USA; Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA, USA
| | - Gargi Biswas
- Department of Chemical and Structural Biology, Weizmann Institute of Science, Rehovot, Israel
| | - Vikas Kaushik
- Department of Biochemistry and Molecular Biology, St. Louis University School of Medicine, St. Louis, MO, USA
| | - Sahiti Kuppa
- Department of Biochemistry and Molecular Biology, St. Louis University School of Medicine, St. Louis, MO, USA
| | - Olivia Yang
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Chang-Ting Lin
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Garima Mishra
- Department of Physics, Ashoka University, Sonepet, Haryana, India
| | - Yaakov Levy
- Department of Chemical and Structural Biology, Weizmann Institute of Science, Rehovot, Israel
| | - Edwin Antony
- Department of Biochemistry and Molecular Biology, St. Louis University School of Medicine, St. Louis, MO, USA.
| | - Taekjip Ha
- TC Jenkins Department of Biophysics, Johns Hopkins University, Baltimore, MD, USA; Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA, USA; Department of Pediatrics, Harvard Medical School, Boston, MA, USA; Howard Hughes Medical Institute, Boston, MA, USA.
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11
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Umemura K, Kawamoto Y, Takahashi Y, Takakura Y. Development of a Cytosolic DNA Sensor Agonist Using GALA Peptide-Conjugated DNA and Long Single-Stranded DNA. Mol Pharm 2024; 21:1204-1213. [PMID: 38319924 DOI: 10.1021/acs.molpharmaceut.3c00840] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2024]
Abstract
Cytosolic DNA sensors (CDSs) recognize DNA molecules that are abnormally located in the cytosol, thus leading to the activation of the stimulator of interferon genes (STING) and the induction of type 1 interferon. In turn, type 1 interferon evokes defensive reactions against viral infections and activates the immune system; therefore, the use of agonists of CDSs as cancer therapeutics and vaccine adjuvants is expected. Double-stranded DNA molecules with dozens to thousands of bases derived from bacteria and viruses are agonists of CDSs. However, DNA is a water-soluble molecule with a high molecular weight, resulting in poor cellular uptake and endosomal escape. In contrast, long single-stranded DNA (lssDNA) obtained by rolling circle amplification is efficiently taken up and localized to endosomes. Here we constructed a CDS-targeting lssDNA via the facilitation of its intracellular transport from endosomes to the cytosol. An endosome-disrupting GALA peptide was used to deliver the lssDNA to the cytosol. A peptide-oligonucleotide conjugate (POC) was successfully obtained via the conjugation of the GALA peptide with an oligonucleotide complementary to the lssDNA. By hybridization of the POC to the complementary lssDNA (POC/lssDNA), the CDS-STING pathway in dendritic cells was efficiently stimulated. GALA peptide-conjugated DNA seems to be a helpful tool for the delivery of DNA to the cytosol.
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Affiliation(s)
- Keisuke Umemura
- Department of Biopharmaceutics and Drug Metabolism, Graduate School of Pharmaceutical Sciences, Kyoto University, 46-29 Shimoadachi-cho, Yoshida, Sakyo-ku, Kyoto 606-8501, Japan
| | - Yusuke Kawamoto
- Department of Biopharmaceutics and Drug Metabolism, Graduate School of Pharmaceutical Sciences, Kyoto University, 46-29 Shimoadachi-cho, Yoshida, Sakyo-ku, Kyoto 606-8501, Japan
| | - Yuki Takahashi
- Department of Biopharmaceutics and Drug Metabolism, Graduate School of Pharmaceutical Sciences, Kyoto University, 46-29 Shimoadachi-cho, Yoshida, Sakyo-ku, Kyoto 606-8501, Japan
| | - Yoshinobu Takakura
- Department of Biopharmaceutics and Drug Metabolism, Graduate School of Pharmaceutical Sciences, Kyoto University, 46-29 Shimoadachi-cho, Yoshida, Sakyo-ku, Kyoto 606-8501, Japan
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12
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Lu H, Chen Z, Xie T, Zhong S, Suo S, Song S, Wang L, Xu H, Tian B, Zhao Y, Zhou R, Hua Y. The Deinococcus protease PprI senses DNA damage by directly interacting with single-stranded DNA. Nat Commun 2024; 15:1892. [PMID: 38424107 PMCID: PMC10904395 DOI: 10.1038/s41467-024-46208-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Accepted: 02/16/2024] [Indexed: 03/02/2024] Open
Abstract
Bacteria have evolved various response systems to adapt to environmental stress. A protease-based derepression mechanism in response to DNA damage was characterized in Deinococcus, which is controlled by the specific cleavage of repressor DdrO by metallopeptidase PprI (also called IrrE). Despite the efforts to document the biochemical, physiological, and downstream regulation of PprI-DdrO, the upstream regulatory signal activating this system remains unclear. Here, we show that single-stranded DNA physically interacts with PprI protease, which enhances the PprI-DdrO interactions as well as the DdrO cleavage in a length-dependent manner both in vivo and in vitro. Structures of PprI, in its apo and complexed forms with single-stranded DNA, reveal two DNA-binding interfaces shaping the cleavage site. Moreover, we show that the dynamic monomer-dimer equilibrium of PprI is also important for its cleavage activity. Our data provide evidence that single-stranded DNA could serve as the signal for DNA damage sensing in the metalloprotease/repressor system in bacteria. These results also shed light on the survival and acquired drug resistance of certain bacteria under antimicrobial stress through a SOS-independent pathway.
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Affiliation(s)
- Huizhi Lu
- MOE Key Laboratory of Biosystems Homeostasis & Protection, Institute of Biophysics, College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Zijing Chen
- MOE Key Laboratory of Biosystems Homeostasis & Protection, Institute of Biophysics, College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Teng Xie
- MOE Key Laboratory of Biosystems Homeostasis & Protection, Institute of Biophysics, College of Life Sciences, Zhejiang University, Hangzhou, China
- Shanghai Institute for Advanced Study, Zhejiang University, Shanghai, China
| | - Shitong Zhong
- MOE Key Laboratory of Biosystems Homeostasis & Protection, Institute of Biophysics, College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Shasha Suo
- MOE Key Laboratory of Biosystems Homeostasis & Protection, Institute of Biophysics, College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Shuang Song
- MOE Key Laboratory of Biosystems Homeostasis & Protection, Institute of Biophysics, College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Liangyan Wang
- MOE Key Laboratory of Biosystems Homeostasis & Protection, Institute of Biophysics, College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Hong Xu
- MOE Key Laboratory of Biosystems Homeostasis & Protection, Institute of Biophysics, College of Life Sciences, Zhejiang University, Hangzhou, China
- Cancer Center, Zhejiang University, Hangzhou, Zhejiang, China
| | - Bing Tian
- MOE Key Laboratory of Biosystems Homeostasis & Protection, Institute of Biophysics, College of Life Sciences, Zhejiang University, Hangzhou, China
- Cancer Center, Zhejiang University, Hangzhou, Zhejiang, China
| | - Ye Zhao
- MOE Key Laboratory of Biosystems Homeostasis & Protection, Institute of Biophysics, College of Life Sciences, Zhejiang University, Hangzhou, China.
- Cancer Center, Zhejiang University, Hangzhou, Zhejiang, China.
| | - Ruhong Zhou
- MOE Key Laboratory of Biosystems Homeostasis & Protection, Institute of Biophysics, College of Life Sciences, Zhejiang University, Hangzhou, China.
- Shanghai Institute for Advanced Study, Zhejiang University, Shanghai, China.
- Cancer Center, Zhejiang University, Hangzhou, Zhejiang, China.
- Department of Chemistry, Columbia University, New York, NY, USA.
| | - Yuejin Hua
- MOE Key Laboratory of Biosystems Homeostasis & Protection, Institute of Biophysics, College of Life Sciences, Zhejiang University, Hangzhou, China.
- Cancer Center, Zhejiang University, Hangzhou, Zhejiang, China.
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13
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Du Q, Zhu L, Zhong J, Wei X, Zhang Q, Shi T, Han C, Yin X, Chen X, Tong D, Huang Y. Porcine circovirus type 2 infection promotes the SUMOylation of nucleophosmin-1 to facilitate the viral circular single-stranded DNA replication. PLoS Pathog 2024; 20:e1012014. [PMID: 38394330 PMCID: PMC10917307 DOI: 10.1371/journal.ppat.1012014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2023] [Revised: 03/06/2024] [Accepted: 01/31/2024] [Indexed: 02/25/2024] Open
Abstract
The mechanism of genome DNA replication in circular single-stranded DNA viruses is currently a mystery, except for the fact that it undergoes rolling-circle replication. Herein, we identified SUMOylated porcine nucleophosmin-1 (pNPM1), which is previously reported to be an interacting protein of the viral capsid protein, as a key regulator that promotes the genome DNA replication of porcine single-stranded DNA circovirus. Upon porcine circovirus type 2 (PCV2) infection, SUMO2/3 were recruited and conjugated with the K263 site of pNPM1's C-terminal domain to SUMOylate pNPM1, subsequently, the SUMOylated pNPM1 were translocated in nucleoli to promote the replication of PCV2 genome DNA. The mutation of the K263 site reduced the SUMOylation levels of pNPM1 and the nucleolar localization of pNPM1, resulting in a decrease in the level of PCV2 DNA replication. Meanwhile, the mutation of the K263 site prevented the interaction of pNPM1 with PCV2 DNA, but not the interaction of pNPM1 with PCV2 Cap. Mechanistically, PCV2 infection increased the expression levels of Ubc9, the only E2 enzyme involved in SUMOylation, through the Cap-mediated activation of ERK signaling. The upregulation of Ubc9 promoted the interaction between pNPM1 and TRIM24, a potential E3 ligase for SUMOylation, thereby facilitating the SUMOylation of pNPM1. The inhibition of ERK activation could significantly reduce the SUMOylation levels and the nucleolar localization of pNPM1, as well as the PCV2 DNA replication levels. These results provide new insights into the mechanism of circular single-stranded DNA virus replication and highlight NPM1 as a potential target for inhibiting PCV2 replication.
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Affiliation(s)
- Qian Du
- College of Veterinary Medicine, Northwest A&F University, Yangling, China
- Engineering Research Center of Efficient New Vaccines for Animals, Ministry of Education, Yangling, China
- Key Laboratory of Ruminant Disease Prevention and Control (West), Ministry of Agriculture and Rural Affairs, Yangling, China
- Engineering Research Center of Efficient New Vaccines for Animals, Universities of Shaanxi Province, Yangling, China
| | - Lei Zhu
- College of Veterinary Medicine, Northwest A&F University, Yangling, China
| | - Jianhui Zhong
- College of Veterinary Medicine, Northwest A&F University, Yangling, China
| | - Xueqi Wei
- College of Veterinary Medicine, Northwest A&F University, Yangling, China
| | - Qi Zhang
- College of Veterinary Medicine, Northwest A&F University, Yangling, China
| | - Tengfei Shi
- College of Veterinary Medicine, Northwest A&F University, Yangling, China
| | - Cong Han
- College of Veterinary Medicine, Northwest A&F University, Yangling, China
| | - Xinhuan Yin
- College of Veterinary Medicine, Northwest A&F University, Yangling, China
| | - Xingqi Chen
- Department of Immunology, Genetics and Pathology, Uppsala University and Science for Life Laboratory, Uppsala, Sweden
| | - Dewen Tong
- College of Veterinary Medicine, Northwest A&F University, Yangling, China
- Engineering Research Center of Efficient New Vaccines for Animals, Ministry of Education, Yangling, China
- Key Laboratory of Ruminant Disease Prevention and Control (West), Ministry of Agriculture and Rural Affairs, Yangling, China
- Engineering Research Center of Efficient New Vaccines for Animals, Universities of Shaanxi Province, Yangling, China
| | - Yong Huang
- College of Veterinary Medicine, Northwest A&F University, Yangling, China
- Engineering Research Center of Efficient New Vaccines for Animals, Ministry of Education, Yangling, China
- Key Laboratory of Ruminant Disease Prevention and Control (West), Ministry of Agriculture and Rural Affairs, Yangling, China
- Engineering Research Center of Efficient New Vaccines for Animals, Universities of Shaanxi Province, Yangling, China
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14
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Thawani A, Ariza AJF, Nogales E, Collins K. Template and target-site recognition by human LINE-1 in retrotransposition. Nature 2024; 626:186-193. [PMID: 38096901 PMCID: PMC10830416 DOI: 10.1038/s41586-023-06933-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Accepted: 12/04/2023] [Indexed: 01/26/2024]
Abstract
The long interspersed element-1 (LINE-1, hereafter L1) retrotransposon has generated nearly one-third of the human genome and serves as an active source of genetic diversity and human disease1. L1 spreads through a mechanism termed target-primed reverse transcription, in which the encoded enzyme (ORF2p) nicks the target DNA to prime reverse transcription of its own or non-self RNAs2. Here we purified full-length L1 ORF2p and biochemically reconstituted robust target-primed reverse transcription with template RNA and target-site DNA. We report cryo-electron microscopy structures of the complete human L1 ORF2p bound to structured template RNAs and initiating cDNA synthesis. The template polyadenosine tract is recognized in a sequence-specific manner by five distinct domains. Among them, an RNA-binding domain bends the template backbone to allow engagement of an RNA hairpin stem with the L1 ORF2p C-terminal segment. Moreover, structure and biochemical reconstitutions demonstrate an unexpected target-site requirement: L1 ORF2p relies on upstream single-stranded DNA to position the adjacent duplex in the endonuclease active site for nicking of the longer DNA strand, with a single nick generating a staggered DNA break. Our research provides insights into the mechanism of ongoing transposition in the human genome and informs the engineering of retrotransposon proteins for gene therapy.
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Affiliation(s)
- Akanksha Thawani
- California Institute for Quantitative Biosciences (QB3), Berkeley, CA, USA.
- Department of Molecular and Cell Biology, University of California Berkeley, Berkeley, CA, USA.
| | - Alfredo Jose Florez Ariza
- California Institute for Quantitative Biosciences (QB3), Berkeley, CA, USA
- Biophysics Graduate Group, University of California Berkeley, Berkeley, CA, USA
| | - Eva Nogales
- California Institute for Quantitative Biosciences (QB3), Berkeley, CA, USA.
- Department of Molecular and Cell Biology, University of California Berkeley, Berkeley, CA, USA.
- Howard Hughes Medical Institute, Chevy Chase, MD, USA.
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
| | - Kathleen Collins
- California Institute for Quantitative Biosciences (QB3), Berkeley, CA, USA.
- Department of Molecular and Cell Biology, University of California Berkeley, Berkeley, CA, USA.
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Asin-Garcia E, Garcia-Morales L, Bartholet T, Liang Z, Isaacs F, Martins dos Santos VP. Metagenomics harvested genus-specific single-stranded DNA-annealing proteins improve and expand recombineering in Pseudomonas species. Nucleic Acids Res 2023; 51:12522-12536. [PMID: 37941137 PMCID: PMC10711431 DOI: 10.1093/nar/gkad1024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Revised: 10/14/2023] [Accepted: 10/30/2023] [Indexed: 11/10/2023] Open
Abstract
The widespread Pseudomonas genus comprises a collection of related species with remarkable abilities to degrade plastics and polluted wastes and to produce a broad set of valuable compounds, ranging from bulk chemicals to pharmaceuticals. Pseudomonas possess characteristics of tolerance and stress resistance making them valuable hosts for industrial and environmental biotechnology. However, efficient and high-throughput genetic engineering tools have limited metabolic engineering efforts and applications. To improve their genome editing capabilities, we first employed a computational biology workflow to generate a genus-specific library of potential single-stranded DNA-annealing proteins (SSAPs). Assessment of the library was performed in different Pseudomonas using a high-throughput pooled recombinase screen followed by Oxford Nanopore NGS analysis. Among different active variants with variable levels of allelic replacement frequency (ARF), efficient SSAPs were found and characterized for mediating recombineering in the four tested species. New variants yielded higher ARFs than existing ones in Pseudomonas putida and Pseudomonas aeruginosa, and expanded the field of recombineering in Pseudomonas taiwanensisand Pseudomonas fluorescens. These findings will enhance the mutagenesis capabilities of these members of the Pseudomonas genus, increasing the possibilities for biotransformation and enhancing their potential for synthetic biology applications. .
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Affiliation(s)
- Enrique Asin-Garcia
- Laboratory of Systems and Synthetic Biology, Wageningen University & Research, Wageningen 6708 WE, The Netherlands
- Bioprocess Engineering Group, Wageningen University & Research, Wageningen 6700 AA, The Netherlands
| | - Luis Garcia-Morales
- Laboratory of Systems and Synthetic Biology, Wageningen University & Research, Wageningen 6708 WE, The Netherlands
| | - Tessa Bartholet
- Laboratory of Systems and Synthetic Biology, Wageningen University & Research, Wageningen 6708 WE, The Netherlands
| | - Zhuobin Liang
- Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, CT 06520, USA
- Systems Biology Institute, Yale University, West Haven, CT 06516, USA
| | - Farren J Isaacs
- Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, CT 06520, USA
- Systems Biology Institute, Yale University, West Haven, CT 06516, USA
- Department of Biomedical Engineering, Yale University, New Haven, CT 06520, USA
| | - Vitor A P Martins dos Santos
- Laboratory of Systems and Synthetic Biology, Wageningen University & Research, Wageningen 6708 WE, The Netherlands
- Bioprocess Engineering Group, Wageningen University & Research, Wageningen 6700 AA, The Netherlands
- LifeGlimmer GmbH, Berlin 12163, Germany
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Chib S, Griffin WC, Gao J, Proffitt DR, Byrd AK, Raney KD. Pif1 Helicase Mediates Remodeling of Protein-Nucleic Acid Complexes by Promoting Dissociation of Sub1 from G-Quadruplex DNA and Cdc13 from G-Rich Single-Stranded DNA. Biochemistry 2023; 62:3360-3372. [PMID: 37948114 PMCID: PMC10841737 DOI: 10.1021/acs.biochem.3c00441] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2023]
Abstract
Pif1 is a molecular motor enzyme that is conserved from yeast to mammals. It translocates on ssDNA with a directional bias (5' → 3') and unwinds duplexes using the energy obtained from ATP hydrolysis. Pif1 is involved in dsDNA break repair, resolution of G-quadruplex (G4) structures, negative regulation of telomeres, and Okazaki fragment maturation. An important property of this helicase is to exert force and disrupt protein-DNA complexes, which may otherwise serve as barriers to various cellular pathways. Previously, Pif1 was reported to displace streptavidin from biotinylated DNA, Rap1 from telomeric DNA, and telomerase from DNA ends. Here, we have investigated the ability of S. cerevisiae Pif1 helicase to disrupt protein barriers from G4 and telomeric sites. Yeast chromatin-associated transcription coactivator Sub1 was characterized as a G4 binding protein. We found evidence for a physical interaction between Pif1 helicase and Sub1 protein. Here, we demonstrate that Pif1 is capable of catalyzing the disruption of Sub1-bound G4 structures in an ATP-dependent manner. We also investigated Pif1-mediated removal of yeast telomere-capping protein Cdc13 from DNA ends. Cdc13 exhibits a high-affinity interaction with an 11-mer derived from the yeast telomere sequence. Our results show that Pif1 uses its translocase activity to enhance the dissociation of this telomere-specific protein from its binding site. The rate of dissociation increased with an increase in the helicase loading site length. Additionally, we examined the biochemical mechanism for Pif1-catalyzed protein displacement by mutating the sequence of the telomeric 11-mer on the 5'-end and the 3'-end. The results support a model whereby Pif1 disrupts Cdc13 from the ssDNA in steps.
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Affiliation(s)
- Shubeena Chib
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, AR 72205
| | - Wezley C. Griffin
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, AR 72205
| | - Jun Gao
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, AR 72205
| | - David R. Proffitt
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, AR 72205
| | - Alicia K. Byrd
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, AR 72205
| | - Kevin D. Raney
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, AR 72205
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17
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Shobeiri SS, Dashti M, Pordel S, Rezaee M, Haghnavaz N, Moghadam M, Ansari B, Sankian M. Topical anti-TNF-a ssDNA aptamer decreased the imiquimod induced psoriatic inflammation in BALB/c mice. Cytokine 2023; 172:156406. [PMID: 37879125 DOI: 10.1016/j.cyto.2023.156406] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2023] [Revised: 10/08/2023] [Accepted: 10/19/2023] [Indexed: 10/27/2023]
Abstract
BACKGROUND Tumor Necrosis Factor-α (TNF-α) is a pro-inflammatory factor that plays a pivotal role in psoriasis. Due to limitations of monoclonal antibody-based therapies, it is needed to discover new anti-TNF-α factors instead of usual anti-TNF-α monoclonal antibodies. Compared to antibodies, single-stranded DNA or RNA molecules named aptamers, have advantages such as time-saving, less risk for immunogenicity and cost-effectiveness. Therefore, the aim of the present study was to assess the therapeutic effects of T1-T4 dimer anti-TNF-ɑ ssDNA aptamer topical treatment in the imiquimod (IMQ)-induced psoriasis animal model. METHODS 5% IMQ cream was prescribed on the right ear of BALB/c to induce psoriasis model. The hydrogel-containing anti-TNF-ɑ aptamer or treatment control aptamer (anti- Interleukin (IL)17A) was topically prescribed to the mice's ears 10 min before IMQ cream treatment. The psoriasis area severity index (PASI) score was used to evaluate psoriasis intensity. Histopathology analysis was done for mice ears sections. Mass, size, and cell number of mice spleens were measured. The IL-17 level was determined in culture supernatants of axillary lymph node cells using ELISA. The mRNA expression levels of IL-17A, IL-1β, STAT3, and S100a9, were evaluated in mice treated ear with quantitative Real Time-PCR. RESULTS The anti-TNF-ɑ ssDNA aptamer lower doses had significant decrease in IMQ-induced PASI score (p < 0.05). In addition, in these groups, the IL-17A, STAT3, and S100a9 mRNA levels were significantly lower than the IMQ group (p < 0.05). CONCLUSION According to our findings, this aptamer seems to be a prospective candidate for treating psoriatic inflammation especially in lower concentrations.
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Affiliation(s)
- Saeideh Sadat Shobeiri
- Immunology Research Center, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Mohammadreza Dashti
- Immunology Research Center, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Safoora Pordel
- Immunology Research Center, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - MohammadAli Rezaee
- Immunology Research Center, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran; Department of Medical Laboratory Sciences, Faculty of Paramedical, Kurdistan University of Medical Sciences, Sanandaj, Iran
| | - Navideh Haghnavaz
- Immunology Research Center, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Malihe Moghadam
- Immunology Research Center, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Bahareh Ansari
- Immunology Research Center, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Mojtaba Sankian
- Immunology Research Center, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran.
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18
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Morciano L, Elgrabli RM, Zenvirth D, Arbel-Eden A. Homologous Recombination and Repair Functions Required for Mutagenicity during Yeast Meiosis. Genes (Basel) 2023; 14:2017. [PMID: 38002960 PMCID: PMC10671739 DOI: 10.3390/genes14112017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Revised: 10/22/2023] [Accepted: 10/23/2023] [Indexed: 11/26/2023] Open
Abstract
Several meiotic events reshape the genome prior to its transfer (via gametes) to the next generation. The occurrence of new meiotic mutations is tightly linked to homologous recombination (HR) and firmly depends on Spo11-induced DNA breaks. To gain insight into the molecular mechanisms governing mutagenicity during meiosis, we examined the timing of mutation and recombination events in cells deficient in various DNA HR-repair genes, which represent distinct functions along the meiotic recombination process. Despite sequence similarities and overlapping activities of the two DNA translocases, Rad54 and Tid1, we observed essential differences in their roles in meiotic mutation occurrence: in the absence of Rad54, meiotic mutagenicity was elevated 8-fold compared to the wild type (WT), while in the tid1Δ mutant, there were few meiotic mutations, nine percent compared to the WT. We propose that the presence of Rad54 channels recombinational repair to a less mutagenic pathway, whereas repair assisted by Tid1 is more mutagenic. A 3.5-fold increase in mutation level was observed in dmc1∆ cells, suggesting that single-stranded DNA (ssDNA) may be a potential source for mutagenicity during meiosis. Taken together, we suggest that the introduction of de novo mutations also contributes to the diversification role of meiotic recombination. These rare meiotic mutations revise genomic sequences and may contribute to long-term evolutionary changes.
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Affiliation(s)
- Liat Morciano
- Department of Genetics, Hebrew University of Jerusalem, Jerusalem 91904, Israel; (L.M.); (R.M.E.)
| | - Renana M. Elgrabli
- Department of Genetics, Hebrew University of Jerusalem, Jerusalem 91904, Israel; (L.M.); (R.M.E.)
| | - Drora Zenvirth
- Department of Genetics, Hebrew University of Jerusalem, Jerusalem 91904, Israel; (L.M.); (R.M.E.)
| | - Ayelet Arbel-Eden
- Department of Genetics, Hebrew University of Jerusalem, Jerusalem 91904, Israel; (L.M.); (R.M.E.)
- The Medical Laboratory Sciences Department, Hadassah Academic College, Jerusalem 91010, Israel
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Pike AM, Friend CM, Bell SP. Distinct RPA functions promote eukaryotic DNA replication initiation and elongation. Nucleic Acids Res 2023; 51:10506-10518. [PMID: 37739410 PMCID: PMC10602884 DOI: 10.1093/nar/gkad765] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2022] [Revised: 08/14/2023] [Accepted: 09/10/2023] [Indexed: 09/24/2023] Open
Abstract
Replication protein A (RPA) binds single-stranded DNA (ssDNA) and serves critical functions in eukaryotic DNA replication, the DNA damage response, and DNA repair. During DNA replication, RPA is required for extended origin DNA unwinding and DNA synthesis. To determine the requirements for RPA during these processes, we tested ssDNA-binding proteins (SSBs) from different domains of life in reconstituted Saccharomyces cerevisiae origin unwinding and DNA replication reactions. Interestingly, Escherichia coli SSB, but not T4 bacteriophage Gp32, fully substitutes for RPA in promoting origin DNA unwinding. Using RPA mutants, we demonstrated that specific ssDNA-binding properties of RPA are required for origin unwinding but that its protein-interaction domains are dispensable. In contrast, we found that each of these auxiliary RPA domains have distinct functions at the eukaryotic replication fork. The Rfa1 OB-F domain negatively regulates lagging-strand synthesis, while the Rfa2 winged-helix domain stimulates nascent strand initiation. Together, our findings reveal a requirement for specific modes of ssDNA binding in the transition to extensive origin DNA unwinding and identify RPA domains that differentially impact replication fork function.
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Affiliation(s)
- Alexandra M Pike
- Howard Hughes Medical Institute, Massachusetts Institute of Technology, Department of Biology, Cambridge, MA 02139, USA
| | - Caitlin M Friend
- Massachusetts Institute of Technology, Department of Biology, Cambridge, MA 02139, USA
| | - Stephen P Bell
- Howard Hughes Medical Institute, Massachusetts Institute of Technology, Department of Biology, Cambridge, MA 02139, USA
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20
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Deveryshetty J, Chadda R, Mattice JR, Karunakaran S, Rau MJ, Basore K, Pokhrel N, Englander N, Fitzpatrick JAJ, Bothner B, Antony E. Yeast Rad52 is a homodecamer and possesses BRCA2-like bipartite Rad51 binding modes. Nat Commun 2023; 14:6215. [PMID: 37798272 PMCID: PMC10556141 DOI: 10.1038/s41467-023-41993-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Accepted: 09/25/2023] [Indexed: 10/07/2023] Open
Abstract
Homologous recombination (HR) is an essential double-stranded DNA break repair pathway. In HR, Rad52 facilitates the formation of Rad51 nucleoprotein filaments on RPA-coated ssDNA. Here, we decipher how Rad52 functions using single-particle cryo-electron microscopy and biophysical approaches. We report that Rad52 is a homodecameric ring and each subunit possesses an ordered N-terminal and disordered C-terminal half. An intrinsic structural asymmetry is observed where a few of the C-terminal halves interact with the ordered ring. We describe two conserved charged patches in the C-terminal half that harbor Rad51 and RPA interacting motifs. Interactions between these patches regulate ssDNA binding. Surprisingly, Rad51 interacts with Rad52 at two different bindings sites: one within the positive patch in the disordered C-terminus and the other in the ordered ring. We propose that these features drive Rad51 nucleation onto a single position on the DNA to promote formation of uniform pre-synaptic Rad51 filaments in HR.
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Affiliation(s)
- Jaigeeth Deveryshetty
- Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, St. Louis, MO, USA
| | - Rahul Chadda
- Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, St. Louis, MO, USA
| | - Jenna R Mattice
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT, USA
| | - Simrithaa Karunakaran
- Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, St. Louis, MO, USA
| | - Michael J Rau
- Center for Cellular Imaging, Washington University in St. Louis School of Medicine, St. Louis, MO, USA
| | - Katherine Basore
- Center for Cellular Imaging, Washington University in St. Louis School of Medicine, St. Louis, MO, USA
| | - Nilisha Pokhrel
- Department of Biological Sciences, Marquette University, Milwaukee, WI, USA
- Aera Therapeutics, Boston, MA, USA
| | - Noah Englander
- Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, St. Louis, MO, USA
| | - James A J Fitzpatrick
- Center for Cellular Imaging, Washington University in St. Louis School of Medicine, St. Louis, MO, USA
| | - Brian Bothner
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT, USA
| | - Edwin Antony
- Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, St. Louis, MO, USA.
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21
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Liu S, Miné-Hattab J, Villemeur M, Guerois R, Pinholt HD, Mirny LA, Taddei A. In vivo tracking of functionally tagged Rad51 unveils a robust strategy of homology search. Nat Struct Mol Biol 2023; 30:1582-1591. [PMID: 37605042 DOI: 10.1038/s41594-023-01065-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Accepted: 07/12/2023] [Indexed: 08/23/2023]
Abstract
Homologous recombination (HR) is a major pathway to repair DNA double-strand breaks (DSB). HR uses an undamaged homologous DNA sequence as a template for copying the missing information, which requires identifying a homologous sequence among megabases of DNA within the crowded nucleus. In eukaryotes, the conserved Rad51-single-stranded DNA nucleoprotein filament (NPF) performs this homology search. Although NPFs have been extensively studied in vitro by molecular and genetic approaches, their in vivo formation and dynamics could not thus far be assessed due to the lack of functional tagged versions of Rad51. Here we develop and characterize in budding yeast the first fully functional, tagged version of Rad51. Following induction of a unique DSB, we observe Rad51-ssDNA forming exceedingly long filaments, spanning the whole nucleus and eventually contacting the donor sequence. Emerging filaments adopt a variety of shapes not seen in vitro and are modulated by Rad54 and Srs2, shedding new light on the function of these factors. The filaments are also dynamic, undergoing rounds of compaction and extension. Our biophysical models demonstrate that formation of extended filaments, and particularly their compaction-extension dynamics, constitute a robust search strategy, allowing DSB to rapidly explore the nuclear volume and thus enable efficient HR.
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Affiliation(s)
- Siyu Liu
- Institut Curie, Université PSL, Sorbonne University, CNRS, Nuclear Dynamics, Paris, France
| | - Judith Miné-Hattab
- Institut Curie, Université PSL, Sorbonne University, CNRS, Nuclear Dynamics, Paris, France
| | - Marie Villemeur
- Institut Curie, Université PSL, Sorbonne University, CNRS, Nuclear Dynamics, Paris, France
| | - Raphaël Guerois
- Institute for Integrative Biology of the Cell (I2BC), University of Paris-Saclay, CEA, CNRS, Gif-sur-Yvette, France
| | - Henrik Dahl Pinholt
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Leonid A Mirny
- Institut Curie, Université PSL, Sorbonne University, CNRS, Nuclear Dynamics, Paris, France
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, USA
- Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Angela Taddei
- Institut Curie, Université PSL, Sorbonne University, CNRS, Nuclear Dynamics, Paris, France.
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22
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Lee W, Iwasaki H, Tsubouchi H, Li HW. Hop2-Mnd1 and Swi5-Sfr1 stimulate Dmc1 filament assembly using distinct mechanisms. Nucleic Acids Res 2023; 51:8550-8562. [PMID: 37395447 PMCID: PMC10484676 DOI: 10.1093/nar/gkad561] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2023] [Revised: 06/12/2023] [Accepted: 06/20/2023] [Indexed: 07/04/2023] Open
Abstract
In meiosis, Dmc1 recombinase and the general recombinase Rad51 are responsible for pairing homologous chromosomes and exchanging strands. Fission yeast (Schizosaccharomyces pombe) Swi5-Sfr1 and Hop2-Mnd1 stimulate Dmc1-driven recombination, but the stimulation mechanism is unclear. Using single-molecule fluorescence resonance energy transfer (smFRET) and tethered particle motion (TPM) experiments, we showed that Hop2-Mnd1 and Swi5-Sfr1 individually enhance Dmc1 filament assembly on single-stranded DNA (ssDNA) and adding both proteins together allows further stimulation. FRET analysis showed that Hop2-Mnd1 enhances the binding rate of Dmc1 while Swi5-Sfr1 specifically reduces the dissociation rate during the nucleation, about 2-fold. In the presence of Hop2-Mnd1, the nucleation time of Dmc1 filaments shortens, and doubling the ss/double-stranded DNA (ss/dsDNA) junctions of DNA substrates reduces the nucleation times in half. Order of addition experiments confirmed that Hop2-Mnd1 binds on DNA to recruit and stimulate Dmc1 nucleation at the ss/dsDNA junction. Our studies directly support the molecular basis of how Hop2-Mnd1 and Swi5-Sfr1 act on different steps during the Dmc1 filament assembly. DNA binding of these accessory proteins and nucleation preferences of recombinases thus dictate how their regulation can take place.
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Affiliation(s)
- Wei Lee
- Department of Chemistry, National Taiwan University, Taiwan
| | - Hiroshi Iwasaki
- Cell Biology Center, Institute of Innovative Research, Tokyo Institute of Technology, Japan
| | - Hideo Tsubouchi
- Cell Biology Center, Institute of Innovative Research, Tokyo Institute of Technology, Japan
| | - Hung-Wen Li
- Department of Chemistry, National Taiwan University, Taiwan
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23
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Cashen BA, Morse M, Rouzina I, Karpel R, Williams M. Dynamic structure of T4 gene 32 protein filaments facilitates rapid noncooperative protein dissociation. Nucleic Acids Res 2023; 51:8587-8605. [PMID: 37449435 PMCID: PMC10484735 DOI: 10.1093/nar/gkad595] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Revised: 06/26/2023] [Accepted: 07/04/2023] [Indexed: 07/18/2023] Open
Abstract
Bacteriophage T4 gene 32 protein (gp32) is a model single-stranded DNA (ssDNA) binding protein, essential for DNA replication. gp32 forms cooperative filaments on ssDNA through interprotein interactions between its core and N-terminus. However, detailed understanding of gp32 filament structure and organization remains incomplete, particularly for longer, biologically-relevant DNA lengths. Moreover, it is unclear how these tightly-bound filaments dissociate from ssDNA during complementary strand synthesis. We use optical tweezers and atomic force microscopy to probe the structure and binding dynamics of gp32 on long (∼8 knt) ssDNA substrates. We find that cooperative binding of gp32 rigidifies ssDNA while also reducing its contour length, consistent with the ssDNA helically winding around the gp32 filament. While measured rates of gp32 binding and dissociation indicate nM binding affinity, at ∼1000-fold higher protein concentrations gp32 continues to bind into and restructure the gp32-ssDNA filament, leading to an increase in its helical pitch and elongation of the substrate. Furthermore, the oversaturated gp32-ssDNA filament becomes progressively unwound and unstable as observed by the appearance of a rapid, noncooperative protein dissociation phase not seen at lower complex saturation, suggesting a possible mechanism for prompt removal of gp32 from the overcrowded ssDNA in front of the polymerase during replication.
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Affiliation(s)
- Ben A Cashen
- Department of Physics, Northeastern University, Boston, MA 02115, USA
| | - Michael Morse
- Department of Physics, Northeastern University, Boston, MA 02115, USA
| | - Ioulia Rouzina
- Department of Chemistry and Biochemistry, Center for Retroviral Research and Center for RNA Biology, Ohio State University, Columbus, OH 43210, USA
| | - Richard L Karpel
- Department of Chemistry and Biochemistry, University of Maryland Baltimore County, Baltimore, MD 21250, USA
| | - Mark C Williams
- Department of Physics, Northeastern University, Boston, MA 02115, USA
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24
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Ujaoney AK, Anaganti N, Padwal MK, Basu B. Deinococcus lineage and Rad52 family-related protein DR0041 is involved in DNA protection and compaction. Int J Biol Macromol 2023; 248:125885. [PMID: 37473881 DOI: 10.1016/j.ijbiomac.2023.125885] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Revised: 07/10/2023] [Accepted: 07/17/2023] [Indexed: 07/22/2023]
Abstract
DR0041 ORF encodes an uncharacterized Deinococcus lineage protein. We earlier reported presence of DR0041 protein in DNA repair complexes of Ssb and RecA in Deinococcus radiodurans. Here, we systematically examined the role of DR0041 in DNA metabolism using various experimental methodologies including electrophoretic mobility assays, nuclease assays, strand exchange assays and transmission electron microscopy. Interaction between DR0041 and the C-terminal acidic tail of Ssb was assessed through co-expression and in vivo cross-linking studies. A knockout mutant was constructed to understand importance of DR0041 ORF for various physiological processes. Results highlight binding of DR0041 protein to single-stranded and double-stranded DNA, interaction with Ssb-coated single-stranded DNA without interference with RecA-mediated strand exchange, protection of DNA from exonucleases, and compaction of high molecular weight DNA molecules into tightly condensed forms. Bridging and compaction of sheared DNA by DR0041 protein might have implications in the preservation of damaged DNA templates to maintain genome integrity upon exposure to gamma irradiation. Our results suggest that DR0041 protein is dispensable for growth under standard growth conditions and following gamma irradiation but contributes to protection of DNA during transformation. We discuss the role of DR0041 protein from the perspective of protection of broken DNA templates and functional redundancy.
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Affiliation(s)
- Aman Kumar Ujaoney
- Molecular Biology Division, Bhabha Atomic Research Centre, Mumbai 400085, India
| | - Narasimha Anaganti
- Molecular Biology Division, Bhabha Atomic Research Centre, Mumbai 400085, India; Homi Bhabha National Institute, Training School Complex, Anushakti Nagar, Mumbai 400094, India
| | - Mahesh Kumar Padwal
- Molecular Biology Division, Bhabha Atomic Research Centre, Mumbai 400085, India
| | - Bhakti Basu
- Molecular Biology Division, Bhabha Atomic Research Centre, Mumbai 400085, India; Homi Bhabha National Institute, Training School Complex, Anushakti Nagar, Mumbai 400094, India.
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25
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Herbert A. Flipons and small RNAs accentuate the asymmetries of pervasive transcription by the reset and sequence-specific microcoding of promoter conformation. J Biol Chem 2023; 299:105140. [PMID: 37544644 PMCID: PMC10474125 DOI: 10.1016/j.jbc.2023.105140] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Revised: 07/25/2023] [Accepted: 07/31/2023] [Indexed: 08/08/2023] Open
Abstract
The role of alternate DNA conformations such as Z-DNA in the regulation of transcription is currently underappreciated. These structures are encoded by sequences called flipons, many of which are enriched in promoter and enhancer regions. Through a change in their conformation, flipons provide a tunable mechanism to mechanically reset promoters for the next round of transcription. They act as actuators that capture and release energy to ensure that the turnover of the proteins at promoters is optimized to cell state. Likewise, the single-stranded DNA formed as flipons cycle facilitates the docking of RNAs that are able to microcode promoter conformations and canalize the pervasive transcription commonly observed in metazoan genomes. The strand-specific nature of the interaction between RNA and DNA likely accounts for the known asymmetry of epigenetic marks present on the histone tetramers that pair to form nucleosomes. The role of these supercoil-dependent processes in promoter choice and transcriptional interference is reviewed. The evolutionary implications are examined: the resilience and canalization of flipon-dependent gene regulation is contrasted with the rapid adaptation enabled by the spread of flipon repeats throughout the genome. Overall, the current findings underscore the important role of flipons in modulating the readout of genetic information and how little we know about their biology.
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Affiliation(s)
- Alan Herbert
- Discovery Division, InsideOutBio, Charlestown, Massachusetts, USA.
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26
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Xu C, Li C, Chen J, Xiong Y, Qiao Z, Fan P, Li C, Ma S, Liu J, Song A, Tao B, Xu T, Xu W, Chi Y, Xue J, Wang P, Ye D, Gu H, Zhang P, Wang Q, Xiao R, Cheng J, Zheng H, Yu X, Zhang Z, Wu J, Liang K, Liu YJ, Lu H, Chen FX. R-loop-dependent promoter-proximal termination ensures genome stability. Nature 2023; 621:610-619. [PMID: 37557913 PMCID: PMC10511320 DOI: 10.1038/s41586-023-06515-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Accepted: 08/03/2023] [Indexed: 08/11/2023]
Abstract
The proper regulation of transcription is essential for maintaining genome integrity and executing other downstream cellular functions1,2. Here we identify a stable association between the genome-stability regulator sensor of single-stranded DNA (SOSS)3 and the transcription regulator Integrator-PP2A (INTAC)4-6. Through SSB1-mediated recognition of single-stranded DNA, SOSS-INTAC stimulates promoter-proximal termination of transcription and attenuates R-loops associated with paused RNA polymerase II to prevent R-loop-induced genome instability. SOSS-INTAC-dependent attenuation of R-loops is enhanced by the ability of SSB1 to form liquid-like condensates. Deletion of NABP2 (encoding SSB1) or introduction of cancer-associated mutations into its intrinsically disordered region leads to a pervasive accumulation of R-loops, highlighting a genome surveillance function of SOSS-INTAC that enables timely termination of transcription at promoters to constrain R-loop accumulation and ensure genome stability.
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Affiliation(s)
- Congling Xu
- Fudan University Shanghai Cancer Center, Institutes of Biomedical Sciences, State Key Laboratory of Genetic Engineering, Shanghai Key Laboratory of Medical Epigenetics, Shanghai Key Laboratory of Radiation Oncology, Human Phenome Institute, Fudan University, Shanghai, China
| | - Chengyu Li
- Zhejiang Provincial Key Laboratory for Cancer Molecular Cell Biology, Life Sciences Institute, Zhejiang University, Hangzhou, China
| | - Jiwei Chen
- Fudan University Shanghai Cancer Center, Institutes of Biomedical Sciences, State Key Laboratory of Genetic Engineering, Shanghai Key Laboratory of Medical Epigenetics, Shanghai Key Laboratory of Radiation Oncology, Human Phenome Institute, Fudan University, Shanghai, China
| | - Yan Xiong
- Fudan University Shanghai Cancer Center, Institutes of Biomedical Sciences, State Key Laboratory of Genetic Engineering, Shanghai Key Laboratory of Medical Epigenetics, Shanghai Key Laboratory of Radiation Oncology, Human Phenome Institute, Fudan University, Shanghai, China
| | - Zhibin Qiao
- Fudan University Shanghai Cancer Center, Institutes of Biomedical Sciences, State Key Laboratory of Genetic Engineering, Shanghai Key Laboratory of Medical Epigenetics, Shanghai Key Laboratory of Radiation Oncology, Human Phenome Institute, Fudan University, Shanghai, China
- Department of Radiation Oncology, Fudan University Shanghai Cancer Center, Fudan University, Shanghai, China
| | - Pengyu Fan
- Fudan University Shanghai Cancer Center, Institutes of Biomedical Sciences, State Key Laboratory of Genetic Engineering, Shanghai Key Laboratory of Medical Epigenetics, Shanghai Key Laboratory of Radiation Oncology, Human Phenome Institute, Fudan University, Shanghai, China
- Department of Thoracic Surgery, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai, China
| | - Conghui Li
- Department of Pathophysiology, School of Basic Medical Sciences, Wuhan University, Wuhan, China
| | - Shuangyu Ma
- Department of Histoembryology, Genetics and Developmental Biology, Shanghai Key Laboratory of Reproductive Medicine, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Jin Liu
- Fudan University Shanghai Cancer Center, Institutes of Biomedical Sciences, State Key Laboratory of Genetic Engineering, Shanghai Key Laboratory of Medical Epigenetics, Shanghai Key Laboratory of Radiation Oncology, Human Phenome Institute, Fudan University, Shanghai, China
| | - Aixia Song
- Fudan University Shanghai Cancer Center, Institutes of Biomedical Sciences, State Key Laboratory of Genetic Engineering, Shanghai Key Laboratory of Medical Epigenetics, Shanghai Key Laboratory of Radiation Oncology, Human Phenome Institute, Fudan University, Shanghai, China
| | - Bolin Tao
- Fudan University Shanghai Cancer Center, Institutes of Biomedical Sciences, State Key Laboratory of Genetic Engineering, Shanghai Key Laboratory of Medical Epigenetics, Shanghai Key Laboratory of Radiation Oncology, Human Phenome Institute, Fudan University, Shanghai, China
| | - Tao Xu
- Inflammation and Immune Mediated Diseases Laboratory of Anhui Province, Anhui Institute of Innovative Drugs, School of Pharmacy, Anhui Medical University, Hefei, China
| | - Wei Xu
- Department of Orthopedic Oncology, Changzheng Hospital, Second Military Medical University, Shanghai, China
| | - Yayun Chi
- Department of Breast Surgery, Fudan University Shanghai Cancer Center, Shanghai, China
| | - Jingyan Xue
- Department of Breast Surgery, Fudan University Shanghai Cancer Center, Shanghai, China
| | - Pu Wang
- Huashan Hospital, Fudan University, Shanghai Key Laboratory of Medical Epigenetics, Molecular and Cell Biology Lab, Institutes of Biomedical Sciences, Shanghai Medical College of Fudan University, Shanghai, China
| | - Dan Ye
- Huashan Hospital, Fudan University, Shanghai Key Laboratory of Medical Epigenetics, Molecular and Cell Biology Lab, Institutes of Biomedical Sciences, Shanghai Medical College of Fudan University, Shanghai, China
| | - Hongzhou Gu
- Fudan University Shanghai Cancer Center, Institutes of Biomedical Sciences, State Key Laboratory of Genetic Engineering, Shanghai Key Laboratory of Medical Epigenetics, Shanghai Key Laboratory of Radiation Oncology, Human Phenome Institute, Fudan University, Shanghai, China
| | - Peng Zhang
- Department of Thoracic Surgery, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai, China
| | - Qiong Wang
- Department of Histoembryology, Genetics and Developmental Biology, Shanghai Key Laboratory of Reproductive Medicine, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Ruijing Xiao
- Department of Pathophysiology, School of Basic Medical Sciences, Wuhan University, Wuhan, China
| | - Jingdong Cheng
- Fudan University Shanghai Cancer Center, Institutes of Biomedical Sciences, State Key Laboratory of Genetic Engineering, Shanghai Key Laboratory of Medical Epigenetics, Shanghai Key Laboratory of Radiation Oncology, Human Phenome Institute, Fudan University, Shanghai, China
| | - Hai Zheng
- Fudan University Shanghai Cancer Center, Institutes of Biomedical Sciences, State Key Laboratory of Genetic Engineering, Shanghai Key Laboratory of Medical Epigenetics, Shanghai Key Laboratory of Radiation Oncology, Human Phenome Institute, Fudan University, Shanghai, China
| | - Xiaoli Yu
- Department of Radiation Oncology, Fudan University Shanghai Cancer Center, Fudan University, Shanghai, China
| | - Zhen Zhang
- Department of Radiation Oncology, Fudan University Shanghai Cancer Center, Fudan University, Shanghai, China
| | - Jiong Wu
- Department of Breast Surgery, Fudan University Shanghai Cancer Center, Shanghai, China
| | - Kaiwei Liang
- Department of Pathophysiology, School of Basic Medical Sciences, Wuhan University, Wuhan, China
| | - Yan-Jun Liu
- Fudan University Shanghai Cancer Center, Institutes of Biomedical Sciences, State Key Laboratory of Genetic Engineering, Shanghai Key Laboratory of Medical Epigenetics, Shanghai Key Laboratory of Radiation Oncology, Human Phenome Institute, Fudan University, Shanghai, China
| | - Huasong Lu
- Zhejiang Provincial Key Laboratory for Cancer Molecular Cell Biology, Life Sciences Institute, Zhejiang University, Hangzhou, China.
| | - Fei Xavier Chen
- Fudan University Shanghai Cancer Center, Institutes of Biomedical Sciences, State Key Laboratory of Genetic Engineering, Shanghai Key Laboratory of Medical Epigenetics, Shanghai Key Laboratory of Radiation Oncology, Human Phenome Institute, Fudan University, Shanghai, China.
- Department of Radiation Oncology, Fudan University Shanghai Cancer Center, Fudan University, Shanghai, China.
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27
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Jones ML, Aria V, Baris Y, Yeeles JTP. How Pol α-primase is targeted to replisomes to prime eukaryotic DNA replication. Mol Cell 2023; 83:2911-2924.e16. [PMID: 37506699 PMCID: PMC10501992 DOI: 10.1016/j.molcel.2023.06.035] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Revised: 06/16/2023] [Accepted: 06/28/2023] [Indexed: 07/30/2023]
Abstract
During eukaryotic DNA replication, Pol α-primase generates primers at replication origins to start leading-strand synthesis and every few hundred nucleotides during discontinuous lagging-strand replication. How Pol α-primase is targeted to replication forks to prime DNA synthesis is not fully understood. Here, by determining cryoelectron microscopy (cryo-EM) structures of budding yeast and human replisomes containing Pol α-primase, we reveal a conserved mechanism for the coordination of priming by the replisome. Pol α-primase binds directly to the leading edge of the CMG (CDC45-MCM-GINS) replicative helicase via a complex interaction network. The non-catalytic PRIM2/Pri2 subunit forms two interfaces with CMG that are critical for in vitro DNA replication and yeast cell growth. These interactions position the primase catalytic subunit PRIM1/Pri1 directly above the exit channel for lagging-strand template single-stranded DNA (ssDNA), revealing why priming occurs efficiently only on the lagging-strand template and elucidating a mechanism for Pol α-primase to overcome competition from RPA to initiate primer synthesis.
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Affiliation(s)
- Morgan L Jones
- MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, UK
| | - Valentina Aria
- MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, UK
| | - Yasemin Baris
- MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, UK
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28
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Yang F, Su W, Chung OW, Tracy L, Wang L, Ramsden DA, Zhang ZZZ. Retrotransposons hijack alt-EJ for DNA replication and eccDNA biogenesis. Nature 2023; 620:218-225. [PMID: 37438532 PMCID: PMC10691919 DOI: 10.1038/s41586-023-06327-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Accepted: 06/14/2023] [Indexed: 07/14/2023]
Abstract
Retrotransposons are highly enriched in the animal genome1-3. The activation of retrotransposons can rewrite host DNA information and fundamentally impact host biology1-3. Although developmental activation of retrotransposons can offer benefits for the host, such as against virus infection, uncontrolled activation promotes disease or potentially drives ageing1-5. After activation, retrotransposons use their mRNA as templates to synthesize double-stranded DNA for making new insertions in the host genome1-3,6. Although the reverse transcriptase that they encode can synthesize the first-strand DNA1-3,6, how the second-strand DNA is generated remains largely unclear. Here we report that retrotransposons hijack the alternative end-joining (alt-EJ) DNA repair process of the host for a circularization step to synthesize their second-strand DNA. We used Nanopore sequencing to examine the fates of replicated retrotransposon DNA, and found that 10% of them achieve new insertions, whereas 90% exist as extrachromosomal circular DNA (eccDNA). Using eccDNA production as a readout, further genetic screens identified factors from alt-EJ as essential for retrotransposon replication. alt-EJ drives the second-strand synthesis of the long terminal repeat retrotransposon DNA through a circularization process and is therefore necessary for eccDNA production and new insertions. Together, our study reveals that alt-EJ is essential in driving the propagation of parasitic genomic retroelements. Our study uncovers a conserved function of this understudied DNA repair process, and provides a new perspective to understand-and potentially control-the retrotransposon life cycle.
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Affiliation(s)
- Fu Yang
- Department of Pharmacology and Cancer Biology, Duke University School of Medicine, Durham, NC, USA
| | - Weijia Su
- Department of Pharmacology and Cancer Biology, Duke University School of Medicine, Durham, NC, USA
| | - Oliver W Chung
- Department of Pharmacology and Cancer Biology, Duke University School of Medicine, Durham, NC, USA
| | - Lauren Tracy
- Department of Pharmacology and Cancer Biology, Duke University School of Medicine, Durham, NC, USA
| | - Lu Wang
- Department of Pharmacology and Cancer Biology, Duke University School of Medicine, Durham, NC, USA
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai, China
| | - Dale A Ramsden
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Z Z Zhao Zhang
- Department of Pharmacology and Cancer Biology, Duke University School of Medicine, Durham, NC, USA.
- Duke Regeneration Center, Duke University School of Medicine, Durham, NC, USA.
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29
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Xu D, Huang Y, Luo L, Tang L, Lu M, Cao H, Wang F, Diao Y, Lyubchenko L, Kapranov P. Genome-Wide Profiling of Endogenous Single-Stranded DNA Using the SSiNGLe-P1 Method. Int J Mol Sci 2023; 24:12062. [PMID: 37569439 PMCID: PMC10418711 DOI: 10.3390/ijms241512062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Revised: 07/23/2023] [Accepted: 07/25/2023] [Indexed: 08/13/2023] Open
Abstract
Endogenous single-stranded DNA (essDNA) can form in a mammalian genome as the result of a variety of molecular processes and can both play important roles inside the cell as well as have detrimental consequences to genome integrity, much of which remains to be fully understood. Here, we established the SSiNGLe-P1 approach based on limited digestion by P1 endonuclease for high-throughput genome-wide identification of essDNA regions. We applied this method to profile essDNA in both human mitochondrial and nuclear genomes. In the mitochondrial genome, the profiles of essDNA provide new evidence to support the strand-displacement model of mitochondrial DNA replication. In the nuclear genome, essDNA regions were found to be enriched in certain types of functional genomic elements, particularly, the origins of DNA replication, R-loops, and to a lesser degree, in promoters. Furthermore, interestingly, many of the essDNA regions identified by SSiNGLe-P1 have not been annotated and thus could represent yet unknown functional elements.
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Affiliation(s)
- Dongyang Xu
- Institute of Genomics, School of Medicine, Huaqiao University, 668 Jimei Road, Xiamen 361021, China; (D.X.)
| | - Yu Huang
- Institute of Genomics, School of Medicine, Huaqiao University, 668 Jimei Road, Xiamen 361021, China; (D.X.)
| | - Lingcong Luo
- Institute of Genomics, School of Medicine, Huaqiao University, 668 Jimei Road, Xiamen 361021, China; (D.X.)
| | - Lu Tang
- Institute of Genomics, School of Medicine, Huaqiao University, 668 Jimei Road, Xiamen 361021, China; (D.X.)
| | - Meng Lu
- Institute of Genomics, School of Medicine, Huaqiao University, 668 Jimei Road, Xiamen 361021, China; (D.X.)
| | - Huifen Cao
- Institute of Genomics, School of Medicine, Huaqiao University, 668 Jimei Road, Xiamen 361021, China; (D.X.)
| | - Fang Wang
- Institute of Genomics, School of Medicine, Huaqiao University, 668 Jimei Road, Xiamen 361021, China; (D.X.)
| | - Yong Diao
- Institute of Genomics, School of Medicine, Huaqiao University, 668 Jimei Road, Xiamen 361021, China; (D.X.)
| | - Liudmila Lyubchenko
- National Medical Research Center for Radiology, Ministry of Health of Russia, 125284 Moscow, Russia
| | - Philipp Kapranov
- Institute of Genomics, School of Medicine, Huaqiao University, 668 Jimei Road, Xiamen 361021, China; (D.X.)
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen 361102, China
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30
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Yoshida R, Ozaki S, Kawakami H, Katayama T. Single-stranded DNA recruitment mechanism in replication origin unwinding by DnaA initiator protein and HU, an evolutionary ubiquitous nucleoid protein. Nucleic Acids Res 2023; 51:6286-6306. [PMID: 37178000 PMCID: PMC10325909 DOI: 10.1093/nar/gkad389] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2022] [Revised: 04/18/2023] [Accepted: 05/02/2023] [Indexed: 05/15/2023] Open
Abstract
The Escherichia coli replication origin oriC contains the initiator ATP-DnaA-Oligomerization Region (DOR) and its flanking duplex unwinding element (DUE). In the Left-DOR subregion, ATP-DnaA forms a pentamer by binding to R1, R5M and three other DnaA boxes. The DNA-bending protein IHF binds sequence-specifically to the interspace between R1 and R5M boxes, promoting DUE unwinding, which is sustained predominantly by binding of R1/R5M-bound DnaAs to the single-stranded DUE (ssDUE). The present study describes DUE unwinding mechanisms promoted by DnaA and IHF-structural homolog HU, a ubiquitous protein in eubacterial species that binds DNA sequence-non-specifically, preferring bent DNA. Similar to IHF, HU promoted DUE unwinding dependent on ssDUE binding of R1/R5M-bound DnaAs. Unlike IHF, HU strictly required R1/R5M-bound DnaAs and interactions between the two DnaAs. Notably, HU site-specifically bound the R1-R5M interspace in a manner stimulated by ATP-DnaA and ssDUE. These findings suggest a model that interactions between the two DnaAs trigger DNA bending within the R1/R5M-interspace and initial DUE unwinding, which promotes site-specific HU binding that stabilizes the overall complex and DUE unwinding. Moreover, HU site-specifically bound the replication origin of the ancestral bacterium Thermotoga maritima depending on the cognate ATP-DnaA. The ssDUE recruitment mechanism could be evolutionarily conserved in eubacteria.
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Affiliation(s)
- Ryusei Yoshida
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
| | - Shogo Ozaki
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
| | - Hironori Kawakami
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
| | - Tsutomu Katayama
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
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31
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Rawal Y, Jia L, Meir A, Zhou S, Kaur H, Ruben EA, Kwon Y, Bernstein KA, Jasin M, Taylor AB, Burma S, Hromas R, Mazin AV, Zhao W, Zhou D, Wasmuth EV, Greene EC, Sung P, Olsen SK. Structural insights into BCDX2 complex function in homologous recombination. Nature 2023; 619:640-649. [PMID: 37344589 PMCID: PMC10712684 DOI: 10.1038/s41586-023-06219-w] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Accepted: 05/15/2023] [Indexed: 06/23/2023]
Abstract
Homologous recombination (HR) fulfils a pivotal role in the repair of DNA double-strand breaks and collapsed replication forks1. HR depends on the products of several paralogues of RAD51, including the tetrameric complex of RAD51B, RAD51C, RAD51D and XRCC2 (BCDX2)2. BCDX2 functions as a mediator of nucleoprotein filament assembly by RAD51 and single-stranded DNA (ssDNA) during HR, but its mechanism remains undefined. Here we report cryogenic electron microscopy reconstructions of human BCDX2 in apo and ssDNA-bound states. The structures reveal how the amino-terminal domains of RAD51B, RAD51C and RAD51D participate in inter-subunit interactions that underpin complex formation and ssDNA-binding specificity. Single-molecule DNA curtain analysis yields insights into how BCDX2 enhances RAD51-ssDNA nucleoprotein filament assembly. Moreover, our cryogenic electron microscopy and functional analyses explain how RAD51C alterations found in patients with cancer3-6 inactivate DNA binding and the HR mediator activity of BCDX2. Our findings shed light on the role of BCDX2 in HR and provide a foundation for understanding how pathogenic alterations in BCDX2 impact genome repair.
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Affiliation(s)
- Yashpal Rawal
- Department of Biochemistry & Structural Biology and Greehey Children's Cancer Research Institute, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA
| | - Lijia Jia
- Department of Biochemistry & Structural Biology and Greehey Children's Cancer Research Institute, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA
| | - Aviv Meir
- Department of Biochemistry and Molecular Biophysics, Columbia University Irving Medical Center, New York, NY, USA
| | - Shuo Zhou
- Department of Biochemistry & Structural Biology and Greehey Children's Cancer Research Institute, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA
| | - Hardeep Kaur
- Department of Biochemistry & Structural Biology and Greehey Children's Cancer Research Institute, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA
| | - Eliza A Ruben
- Department of Biochemistry & Structural Biology and Greehey Children's Cancer Research Institute, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA
| | - Youngho Kwon
- Department of Biochemistry & Structural Biology and Greehey Children's Cancer Research Institute, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA
| | - Kara A Bernstein
- Department of Biochemistry & Biophysics, University of Pennsylvania School of Medicine, Philadelphia, PA, USA
| | - Maria Jasin
- Developmental Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Alexander B Taylor
- Department of Biochemistry & Structural Biology and Greehey Children's Cancer Research Institute, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA
| | - Sandeep Burma
- Department of Biochemistry & Structural Biology and Greehey Children's Cancer Research Institute, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA
- Department of Neurosurgery, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA
| | - Robert Hromas
- Department of Medicine, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA
| | - Alexander V Mazin
- Department of Biochemistry & Structural Biology and Greehey Children's Cancer Research Institute, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA
| | - Weixing Zhao
- Department of Biochemistry & Structural Biology and Greehey Children's Cancer Research Institute, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA
| | - Daohong Zhou
- Department of Biochemistry & Structural Biology and Greehey Children's Cancer Research Institute, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA
| | - Elizabeth V Wasmuth
- Department of Biochemistry & Structural Biology and Greehey Children's Cancer Research Institute, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA
| | - Eric C Greene
- Department of Biochemistry and Molecular Biophysics, Columbia University Irving Medical Center, New York, NY, USA.
| | - Patrick Sung
- Department of Biochemistry & Structural Biology and Greehey Children's Cancer Research Institute, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA.
| | - Shaun K Olsen
- Department of Biochemistry & Structural Biology and Greehey Children's Cancer Research Institute, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA.
- Glenn Biggs Institute for Alzheimer's and Neurodegenerative Diseases, San Antonio, TX, USA.
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32
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Gan X, Zhang Y, Jiang D, Shi J, Zhao H, Xie C, Wang Y, Xu J, Zhang X, Cai G, Wang H, Huang J, Chen X. Proper RPA acetylation promotes accurate DNA replication and repair. Nucleic Acids Res 2023; 51:5565-5583. [PMID: 37140030 PMCID: PMC10287905 DOI: 10.1093/nar/gkad291] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2023] [Revised: 04/06/2023] [Accepted: 04/12/2023] [Indexed: 05/05/2023] Open
Abstract
The single-stranded DNA (ssDNA) binding protein complex RPA plays a critical role in promoting DNA replication and multiple DNA repair pathways. However, how RPA is regulated to achieve its functions precisely in these processes remains elusive. Here, we found that proper acetylation and deacetylation of RPA are required to regulate RPA function in promoting high-fidelity DNA replication and repair. We show that yeast RPA is acetylated on multiple conserved lysines by the acetyltransferase NuA4 upon DNA damage. Mimicking constitutive RPA acetylation or blocking its acetylation causes spontaneous mutations with the signature of micro-homology-mediated large deletions or insertions. In parallel, improper RPA acetylation/deacetylation impairs DNA double-strand break (DSB) repair by the accurate gene conversion or break-induced replication while increasing the error-prone repair by single-strand annealing or alternative end joining. Mechanistically, we show that proper acetylation and deacetylation of RPA ensure its normal nuclear localization and ssDNA binding ability. Importantly, mutation of the equivalent residues in human RPA1 also impairs RPA binding on ssDNA, leading to attenuated RAD51 loading and homologous recombination repair. Thus, timely RPA acetylation and deacetylation likely represent a conserved mechanism promoting high-fidelity replication and repair while discriminating the error-prone repair mechanisms in eukaryotes.
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Affiliation(s)
- Xiaoli Gan
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, TaiKang Center for Life and Medical Sciences, Frontier Science Centre of Immunology and Metabolism, Wuhan University, Wuhan, Hubei 430072, China
| | - Yueyue Zhang
- The First Affiliated Hospital of USTC, MOE Key Laboratory for Membraneless Organelles and Cellular Dynamics, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui 230001, China
| | - Donghao Jiang
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, TaiKang Center for Life and Medical Sciences, Frontier Science Centre of Immunology and Metabolism, Wuhan University, Wuhan, Hubei 430072, China
| | - Jingyao Shi
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, TaiKang Center for Life and Medical Sciences, Frontier Science Centre of Immunology and Metabolism, Wuhan University, Wuhan, Hubei 430072, China
| | - Han Zhao
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, TaiKang Center for Life and Medical Sciences, Frontier Science Centre of Immunology and Metabolism, Wuhan University, Wuhan, Hubei 430072, China
| | - Chengyu Xie
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, TaiKang Center for Life and Medical Sciences, Frontier Science Centre of Immunology and Metabolism, Wuhan University, Wuhan, Hubei 430072, China
| | - Yanyan Wang
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, TaiKang Center for Life and Medical Sciences, Frontier Science Centre of Immunology and Metabolism, Wuhan University, Wuhan, Hubei 430072, China
| | - Jingyan Xu
- Department of Hematology, Nanjing Drum Tower Hospital, the Affiliated Hospital of Nanjing University Medical School, Nanjing, China
| | - Xinghua Zhang
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, TaiKang Center for Life and Medical Sciences, Frontier Science Centre of Immunology and Metabolism, Wuhan University, Wuhan, Hubei 430072, China
| | - Gang Cai
- The First Affiliated Hospital of USTC, MOE Key Laboratory for Membraneless Organelles and Cellular Dynamics, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui 230001, China
| | - Hailong Wang
- Beijing Key Laboratory of DNA Damage Response and College of Life Sciences, Capital Normal University, Beijing 100048, China
| | - Jun Huang
- The MOE Key Laboratory of Biosystems Homeostasis & Protection, Zhejiang Provincial Key Laboratory for Cancer Molecular Cell Biology and Innovation Center for Cell Signaling Network, Life Sciences Institute, Zhejiang University, Hangzhou 310058, China
| | - Xuefeng Chen
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, TaiKang Center for Life and Medical Sciences, Frontier Science Centre of Immunology and Metabolism, Wuhan University, Wuhan, Hubei 430072, China
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33
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Henry C, Mbele N, Cox MM. RecF protein targeting to postreplication (daughter strand) gaps I: DNA binding by RecF and RecFR. Nucleic Acids Res 2023; 51:5699-5713. [PMID: 37125642 PMCID: PMC10287957 DOI: 10.1093/nar/gkad311] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Revised: 04/09/2023] [Accepted: 04/27/2023] [Indexed: 05/02/2023] Open
Abstract
In bacteria, the repair of post-replication gaps by homologous recombination requires the action of the recombination mediator proteins RecF, RecO and RecR. Whereas the role of the RecOR proteins to displace the single strand binding protein (SSB) and facilitate RecA loading is clear, how RecF mediates targeting of the system to appropriate sites remains enigmatic. The most prominent hypothesis relies on specific RecF binding to gap ends. To test this idea, we present a detailed examination of RecF and RecFR binding to more than 40 DNA substrates of varying length and structure. Neither RecF nor the RecFR complex exhibited specific DNA binding that can explain the targeting of RecF(R) to post-replication gaps. RecF(R) bound to dsDNA and ssDNA of sufficient length with similar facility. DNA binding was highly ATP-dependent. Most measured Kd values fell into a range of 60-180 nM. The addition of ssDNA extensions on duplex substrates to mimic gap ends or CPD lesions produces only subtle increases or decreases in RecF(R) affinity. Significant RecFR binding cooperativity was evident with many DNA substrates. The results indicate that RecF or RecFR targeting to post-replication gaps must rely on factors not yet identified, perhaps involving interactions with additional proteins.
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Affiliation(s)
- Camille Henry
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706-1544, USA
| | - Neema Mbele
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706-1544, USA
| | - Michael M Cox
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706-1544, USA
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34
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Pham P, Wood EA, Cox MM, Goodman MF. RecA and SSB genome-wide distribution in ssDNA gaps and ends in Escherichia coli. Nucleic Acids Res 2023; 51:5527-5546. [PMID: 37070184 PMCID: PMC10287960 DOI: 10.1093/nar/gkad263] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Revised: 03/29/2023] [Accepted: 03/30/2023] [Indexed: 04/19/2023] Open
Abstract
Single-stranded DNA (ssDNA) gapped regions are common intermediates in DNA transactions. Using a new non-denaturing bisulfite treatment combined with ChIP-seq, abbreviated 'ssGap-seq', we explore RecA and SSB binding to ssDNA on a genomic scale in E. coli in a wide range of genetic backgrounds. Some results are expected. During log phase growth, RecA and SSB assembly profiles coincide globally, concentrated on the lagging strand and enhanced after UV irradiation. Unexpected results also abound. Near the terminus, RecA binding is favored over SSB, binding patterns change in the absence of RecG, and the absence of XerD results in massive RecA assembly. RecA may substitute for the absence of XerCD to resolve chromosome dimers. A RecA loading pathway may exist that is independent of RecBCD and RecFOR. Two prominent and focused peaks of RecA binding revealed a pair of 222 bp and GC-rich repeats, equidistant from dif and flanking the Ter domain. The repeats, here named RRS for replication risk sequence, trigger a genomically programmed generation of post-replication gaps that may play a special role in relieving topological stress during replication termination and chromosome segregation. As demonstrated here, ssGap-seq provides a new window on previously inaccessible aspects of ssDNA metabolism.
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Affiliation(s)
- Phuong Pham
- Departments of Biological Sciences and Chemistry, University of Southern California, Los Angeles, CA 90089-2910, USA
| | - Elizabeth A Wood
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706-1544, USA
| | - Michael M Cox
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706-1544, USA
| | - Myron F Goodman
- Departments of Biological Sciences and Chemistry, University of Southern California, Los Angeles, CA 90089-2910, USA
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35
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Mustafi M, Kwon Y, Sung P, Greene EC. Single-molecule visualization of Pif1 helicase translocation on single-stranded DNA. J Biol Chem 2023; 299:104817. [PMID: 37178921 PMCID: PMC10279920 DOI: 10.1016/j.jbc.2023.104817] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 04/22/2023] [Accepted: 04/23/2023] [Indexed: 05/15/2023] Open
Abstract
Pif1 is a broadly conserved helicase that is essential for genome integrity and participates in numerous aspects of DNA metabolism, including telomere length regulation, Okazaki fragment maturation, replication fork progression through difficult-to-replicate sites, replication fork convergence, and break-induced replication. However, details of its translocation properties and the importance of amino acids residues implicated in DNA binding remain unclear. Here, we use total internal reflection fluorescence microscopy with single-molecule DNA curtain assays to directly observe the movement of fluorescently tagged Saccharomyces cerevisiae Pif1 on single-stranded DNA (ssDNA) substrates. We find that Pif1 binds tightly to ssDNA and translocates very rapidly (∼350 nucleotides per second) in the 5'→3' direction over relatively long distances (∼29,500 nucleotides). Surprisingly, we show the ssDNA-binding protein replication protein A inhibits Pif1 activity in both bulk biochemical and single-molecule measurements. However, we demonstrate Pif1 can strip replication protein A from ssDNA, allowing subsequent molecules of Pif1 to translocate unimpeded. We also assess the functional attributes of several Pif1 mutations predicted to impair contact with the ssDNA substrate. Taken together, our findings highlight the functional importance of these amino acid residues in coordinating the movement of Pif1 along ssDNA.
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Affiliation(s)
- Mainak Mustafi
- Department of Biochemistry & Molecular Biophysics, Columbia University, New York, New York, USA
| | - Youngho Kwon
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center at San Antonio, Texas, USA
| | - Patrick Sung
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center at San Antonio, Texas, USA
| | - Eric C Greene
- Department of Biochemistry & Molecular Biophysics, Columbia University, New York, New York, USA.
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36
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Tompkins J, Lizhar E, Shokrani A, Wu X, Berley J, Kamali D, Hussey D, Cerneckis J, Kang TH, Wang J, Tsark W, Zeng D, Godatha S, Natarajan R, Riggs A. Engineering CpG island DNA methylation in pluripotent cells through synthetic CpG-free ssDNA insertion. Cell Rep Methods 2023; 3:100465. [PMID: 37323577 PMCID: PMC10261899 DOI: 10.1016/j.crmeth.2023.100465] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Revised: 02/14/2023] [Accepted: 04/12/2023] [Indexed: 06/17/2023]
Abstract
Cellular differentiation requires global changes to DNA methylation (DNAme), where it functions to regulate transcription factor, chromatin remodeling activity, and genome interpretation. Here, we describe a simple DNAme engineering approach in pluripotent stem cells (PSCs) that stably extends DNAme across target CpG islands (CGIs). Integration of synthetic CpG-free single-stranded DNA (ssDNA) induces a target CpG island methylation response (CIMR) in multiple PSC lines, Nt2d1 embryonal carcinoma cells, and mouse PSCs but not in highly methylated CpG island hypermethylator phenotype (CIMP)+ cancer lines. MLH1 CIMR DNAme spanned the CGI, was precisely maintained through cellular differentiation, suppressed MLH1 expression, and sensitized derived cardiomyocytes and thymic epithelial cells to cisplatin. Guidelines for CIMR editing are provided, and initial CIMR DNAme is characterized at TP53 and ONECUT1 CGIs. Collectively, this resource facilitates CpG island DNAme engineering in pluripotency and the genesis of novel epigenetic models of development and disease.
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Affiliation(s)
- Joshua Tompkins
- Department of Diabetes Complications and Metabolism, Diabetes and Metabolism Research Institute, City of Hope, Duarte, CA 91010, USA
| | - Elizabeth Lizhar
- Department of Diabetes Complications and Metabolism, Diabetes and Metabolism Research Institute, City of Hope, Duarte, CA 91010, USA
| | - Alireza Shokrani
- Department of Diabetes Complications and Metabolism, Diabetes and Metabolism Research Institute, City of Hope, Duarte, CA 91010, USA
| | - Xiwei Wu
- Integrative Genomics Core, City of Hope, Duarte, CA 91010, USA
| | - Jordan Berley
- Department of Diabetes Complications and Metabolism, Diabetes and Metabolism Research Institute, City of Hope, Duarte, CA 91010, USA
| | - Diba Kamali
- Department of Diabetes Complications and Metabolism, Diabetes and Metabolism Research Institute, City of Hope, Duarte, CA 91010, USA
| | - Deborah Hussey
- Department of Diabetes Complications and Metabolism, Diabetes and Metabolism Research Institute, City of Hope, Duarte, CA 91010, USA
| | - Jonas Cerneckis
- Department of Diabetes Complications and Metabolism, Diabetes and Metabolism Research Institute, City of Hope, Duarte, CA 91010, USA
| | - Tae Hyuk Kang
- Integrative Genomics Core, City of Hope, Duarte, CA 91010, USA
| | - Jinhui Wang
- Integrative Genomics Core, City of Hope, Duarte, CA 91010, USA
| | - Walter Tsark
- Department of Diabetes Complications and Metabolism, Diabetes and Metabolism Research Institute, City of Hope, Duarte, CA 91010, USA
| | - Defu Zeng
- Department of Diabetes Complications and Metabolism, Diabetes and Metabolism Research Institute, City of Hope, Duarte, CA 91010, USA
| | - Swetha Godatha
- Department of Diabetes Complications and Metabolism, Diabetes and Metabolism Research Institute, City of Hope, Duarte, CA 91010, USA
| | - Rama Natarajan
- Department of Diabetes Complications and Metabolism, Diabetes and Metabolism Research Institute, City of Hope, Duarte, CA 91010, USA
| | - Arthur Riggs
- Department of Diabetes Complications and Metabolism, Diabetes and Metabolism Research Institute, City of Hope, Duarte, CA 91010, USA
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37
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Duckworth AT, Ducos PL, McMillan SD, Satyshur KA, Blumenthal KH, Deorio HR, Larson JA, Sandler SJ, Grant T, Keck JL. Replication fork binding triggers structural changes in the PriA helicase that govern DNA replication restart in E. coli. Nat Commun 2023; 14:2725. [PMID: 37169801 PMCID: PMC10175261 DOI: 10.1038/s41467-023-38144-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2023] [Accepted: 04/18/2023] [Indexed: 05/13/2023] Open
Abstract
Bacterial replisomes often dissociate from replication forks before chromosomal replication is complete. To avoid the lethal consequences of such situations, bacteria have evolved replication restart pathways that reload replisomes onto prematurely terminated replication forks. To understand how the primary replication restart pathway in E. coli (PriA-PriB) selectively acts on replication forks, we determined the cryogenic-electron microscopy structure of a PriA/PriB/replication fork complex. Replication fork specificity arises from extensive PriA interactions with each arm of the branched DNA. These interactions reshape the PriA protein to create a pore encircling single-stranded lagging-strand DNA while also exposing a surface of PriA onto which PriB docks. Together with supporting biochemical and genetic studies, the structure reveals a switch-like mechanism for replication restart initiation in which restructuring of PriA directly couples replication fork recognition to PriA/PriB complex formation to ensure robust and high-fidelity replication re-initiation.
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Affiliation(s)
- Alexander T Duckworth
- Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - Peter L Ducos
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI, 53706, USA
- John and Jeanne Rowe Center for Research in Virology, Morgridge Institute for Research, Madison, WI, 53715, USA
| | - Sarah D McMillan
- Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - Kenneth A Satyshur
- Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - Katelien H Blumenthal
- Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - Haley R Deorio
- Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - Joseph A Larson
- Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - Steven J Sandler
- Department of Microbiology, University of Massachusetts at Amherst, Amherst, MA, 01003, USA.
| | - Timothy Grant
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI, 53706, USA.
- John and Jeanne Rowe Center for Research in Virology, Morgridge Institute for Research, Madison, WI, 53715, USA.
| | - James L Keck
- Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, WI, 53706, USA.
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38
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Bonde NJ, Henry C, Wood EA, Cox MM, Keck J. Interaction with the carboxy-terminal tip of SSB is critical for RecG function in E. coli. Nucleic Acids Res 2023; 51:3735-3753. [PMID: 36912097 PMCID: PMC10164576 DOI: 10.1093/nar/gkad162] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Revised: 02/17/2023] [Accepted: 03/03/2023] [Indexed: 03/14/2023] Open
Abstract
In Escherichia coli, the single-stranded DNA-binding protein (SSB) acts as a genome maintenance organizational hub by interacting with multiple DNA metabolism proteins. Many SSB-interacting proteins (SIPs) form complexes with SSB by docking onto its carboxy-terminal tip (SSB-Ct). An alternative interaction mode in which SIPs bind to PxxP motifs within an intrinsically-disordered linker (IDL) in SSB has been proposed for the RecG DNA helicase and other SIPs. Here, RecG binding to SSB and SSB peptides was measured in vitro and the RecG/SSB interface was identified. The results show that RecG binds directly and specifically to the SSB-Ct, and not the IDL, through an evolutionarily conserved binding site in the RecG helicase domain. Mutations that block RecG binding to SSB sensitize E. coli to DNA damaging agents and induce the SOS DNA-damage response, indicating formation of the RecG/SSB complex is important in vivo. The broader role of the SSB IDL is also investigated. E. coli ssb mutant strains encoding SSB IDL deletion variants lacking all PxxP motifs retain wildtype growth and DNA repair properties, demonstrating that the SSB PxxP motifs are not major contributors to SSB cellular functions.
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Affiliation(s)
- Nina J Bonde
- Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Camille Henry
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Elizabeth A Wood
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Michael M Cox
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - James L Keck
- Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
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Ait Saada A, Guo W, Costa AB, Yang J, Wang J, Lobachev K. Widely spaced and divergent inverted repeats become a potent source of chromosomal rearrangements in long single-stranded DNA regions. Nucleic Acids Res 2023; 51:3722-3734. [PMID: 36919609 PMCID: PMC10164571 DOI: 10.1093/nar/gkad153] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2022] [Revised: 02/16/2023] [Accepted: 02/20/2023] [Indexed: 03/16/2023] Open
Abstract
DNA inverted repeats (IRs) are widespread across many eukaryotic genomes. Their ability to form stable hairpin/cruciform secondary structures is causative in triggering chromosome instability leading to several human diseases. Distance and sequence divergence between IRs are inversely correlated with their ability to induce gross chromosomal rearrangements (GCRs) because of a lesser probability of secondary structure formation and chromosomal breakage. In this study, we demonstrate that structural parameters that normally constrain the instability of IRs are overcome when the repeats interact in single-stranded DNA (ssDNA). We established a system in budding yeast whereby >73 kb of ssDNA can be formed in cdc13-707fs mutants. We found that in ssDNA, 12 bp or 30 kb spaced Alu-IRs show similarly high levels of GCRs, while heterology only beyond 25% suppresses IR-induced instability. Mechanistically, rearrangements arise after cis-interaction of IRs leading to a DNA fold-back and the formation of a dicentric chromosome, which requires Rad52/Rad59 for IR annealing as well as Rad1-Rad10, Slx4, Msh2/Msh3 and Saw1 proteins for nonhomologous tail removal. Importantly, using structural characteristics rendering IRs permissive to DNA fold-back in yeast, we found that ssDNA regions mapped in cancer genomes contain a substantial number of potentially interacting and unstable IRs.
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Affiliation(s)
- Anissia Ait Saada
- School of Biological Sciences and Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Wenying Guo
- School of Biological Sciences and Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Alex B Costa
- School of Biological Sciences and Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Jiaxin Yang
- Department of Computational Mathematics, Science and Engineering, Michigan State University, East Lansing, MI 48824, USA
| | - Jianrong Wang
- Department of Computational Mathematics, Science and Engineering, Michigan State University, East Lansing, MI 48824, USA
| | - Kirill S Lobachev
- School of Biological Sciences and Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA 30332, USA
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Mersch K, Sokoloski J, Nguyen B, Galletto R, Lohman T. "Helicase" Activity promoted through dynamic interactions between a ssDNA translocase and a diffusing SSB protein. Proc Natl Acad Sci U S A 2023; 120:e2216777120. [PMID: 37011199 PMCID: PMC10104510 DOI: 10.1073/pnas.2216777120] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Accepted: 03/06/2023] [Indexed: 04/05/2023] Open
Abstract
Replication protein A (RPA) is a eukaryotic single-stranded (ss) DNA-binding (SSB) protein that is essential for all aspects of genome maintenance. RPA binds ssDNA with high affinity but can also diffuse along ssDNA. By itself, RPA is capable of transiently disrupting short regions of duplex DNA by diffusing from a ssDNA that flanks the duplex DNA. Using single-molecule total internal reflection fluorescence and optical trapping combined with fluorescence approaches, we show that S. cerevisiae Pif1 can use its ATP-dependent 5' to 3' translocase activity to chemomechanically push a single human RPA (hRPA) heterotrimer directionally along ssDNA at rates comparable to those of Pif1 translocation alone. We further show that using its translocation activity, Pif1 can push hRPA from a ssDNA loading site into a duplex DNA causing stable disruption of at least 9 bp of duplex DNA. These results highlight the dynamic nature of hRPA enabling it to be readily reorganized even when bound tightly to ssDNA and demonstrate a mechanism by which directional DNA unwinding can be achieved through the combined action of a ssDNA translocase that pushes an SSB protein. These results highlight the two basic requirements for any processive DNA helicase: transient DNA base pair melting (supplied by hRPA) and ATP-dependent directional ssDNA translocation (supplied by Pif1) and that these functions can be unlinked by using two separate proteins.
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Affiliation(s)
- Kacey N. Mersch
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO63110-1093
| | - Joshua E. Sokoloski
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO63110-1093
- Department of Chemistry, Salisbury University, Salisbury, MD21801
| | - Binh Nguyen
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO63110-1093
| | - Roberto Galletto
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO63110-1093
| | - Timothy M. Lohman
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO63110-1093
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Shinn MK, Chaturvedi SK, Kozlov AG, Lohman T. Allosteric effects of E. coli SSB and RecR proteins on RecO protein binding to DNA. Nucleic Acids Res 2023; 51:2284-2297. [PMID: 36808259 PMCID: PMC10018359 DOI: 10.1093/nar/gkad084] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Revised: 01/23/2023] [Accepted: 01/25/2023] [Indexed: 02/22/2023] Open
Abstract
Escherichia coli single stranded (ss) DNA binding protein (SSB) plays essential roles in DNA maintenance. It binds ssDNA with high affinity through its N-terminal DNA binding core and recruits at least 17 different SSB interacting proteins (SIPs) that are involved in DNA replication, recombination, and repair via its nine amino acid acidic tip (SSB-Ct). E. coli RecO, a SIP, is an essential recombination mediator protein in the RecF pathway of DNA repair that binds ssDNA and forms a complex with E. coli RecR protein. Here, we report ssDNA binding studies of RecO and the effects of a 15 amino acid peptide containing the SSB-Ct monitored by light scattering, confocal microscope imaging, and analytical ultracentrifugation (AUC). We find that one RecO monomer can bind the oligodeoxythymidylate, (dT)15, while two RecO monomers can bind (dT)35 in the presence of the SSB-Ct peptide. When RecO is in molar excess over ssDNA, large RecO-ssDNA aggregates occur that form with higher propensity on ssDNA of increasing length. Binding of RecO to the SSB-Ct peptide inhibits RecO-ssDNA aggregation. RecOR complexes can bind ssDNA via RecO, but aggregation is suppressed even in the absence of the SSB-Ct peptide, demonstrating an allosteric effect of RecR on RecO binding to ssDNA. Under conditions where RecO binds ssDNA but does not form aggregates, SSB-Ct binding enhances the affinity of RecO for ssDNA. For RecOR complexes bound to ssDNA, we also observe a shift in RecOR complex equilibrium towards a RecR4O complex upon binding SSB-Ct. These results suggest a mechanism by which SSB recruits RecOR to facilitate loading of RecA onto ssDNA gaps.
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Affiliation(s)
- Min Kyung Shinn
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63110, USA
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO 63130, USA
- Center for Biomolecular Condensates (CBC), Washington University in St. Louis, St. Louis, MO 63130, USA
| | - Sumit K Chaturvedi
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63110, USA
- Department of Biophysics, University of Delhi South Campus, New Delhi 110021, India
| | - Alexander G Kozlov
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Timothy M Lohman
- To whom correspondence should be addressed. Tel: +1 314 362 4393; Fax: +1 314 362 7183;
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Torres R, Carrasco B, Alonso JC. Bacillus subtilis RadA/Sms-Mediated Nascent Lagging-Strand Unwinding at Stalled or Reversed Forks Is a Two-Step Process: RadA/Sms Assists RecA Nucleation, and RecA Loads RadA/Sms. Int J Mol Sci 2023; 24:ijms24054536. [PMID: 36901969 PMCID: PMC10003422 DOI: 10.3390/ijms24054536] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Revised: 02/14/2023] [Accepted: 02/23/2023] [Indexed: 03/02/2023] Open
Abstract
Replication fork rescue requires Bacillus subtilis RecA, its negative (SsbA) and positive (RecO) mediators, and fork-processing (RadA/Sms). To understand how they work to promote fork remodeling, reconstituted branched replication intermediates were used. We show that RadA/Sms (or its variant, RadA/Sms C13A) binds to the 5'-tail of a reversed fork with longer nascent lagging-strand and unwinds it in the 5'→3' direction, but RecA and its mediators limit unwinding. RadA/Sms cannot unwind a reversed fork with a longer nascent leading-strand, or a gapped stalled fork, but RecA interacts with and activates unwinding. Here, the molecular mechanism by which RadA/Sms, in concert with RecA, in a two-step reaction, unwinds the nascent lagging-strand of reversed or stalled forks is unveiled. First, RadA/Sms, as a mediator, contributes to SsbA displacement from the forks and nucleates RecA onto single-stranded DNA. Then, RecA, as a loader, interacts with and recruits RadA/Sms onto the nascent lagging strand of these DNA substrates to unwind them. Within this process, RecA limits RadA/Sms self-assembly to control fork processing, and RadA/Sms prevents RecA from provoking unnecessary recombination.
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Johnston CHG, Hope R, Soulet AL, Dewailly M, De Lemos D, Polard P. The RecA-directed recombination pathway of natural transformation initiates at chromosomal replication forks in the pneumococcus. Proc Natl Acad Sci U S A 2023; 120:e2213867120. [PMID: 36795748 PMCID: PMC9974461 DOI: 10.1073/pnas.2213867120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Accepted: 12/09/2022] [Indexed: 02/17/2023] Open
Abstract
Homologous recombination (HR) is a crucial mechanism of DNA strand exchange that promotes genetic repair and diversity in all kingdoms of life. Bacterial HR is driven by the universal recombinase RecA, assisted in the early steps by dedicated mediators that promote its polymerization on single-stranded DNA (ssDNA). In bacteria, natural transformation is a prominent HR-driven mechanism of horizontal gene transfer specifically dependent on the conserved DprA recombination mediator. Transformation involves internalization of exogenous DNA as ssDNA, followed by its integration into the chromosome by RecA-directed HR. How DprA-mediated RecA filamentation on transforming ssDNA is spatiotemporally coordinated with other cellular processes remains unknown. Here, we tracked the localization of fluorescent fusions to DprA and RecA in Streptococcus pneumoniae and revealed that both accumulate in an interdependent manner with internalized ssDNA at replication forks. In addition, dynamic RecA filaments were observed emanating from replication forks, even with heterologous transforming DNA, which probably represent chromosomal homology search. In conclusion, this unveiled interaction between HR transformation and replication machineries highlights an unprecedented role for replisomes as landing pads for chromosomal access of tDNA, which would define a pivotal early HR step for its chromosomal integration.
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Affiliation(s)
- Calum H. G. Johnston
- Laboratoire de Microbiologie et Génétique Moléculaires, UMR5100, Centre de Biologie Intégrative, Centre Nationale de la Recherche Scientifique, 31062Toulouse, France
- Université Paul Sabatier (Toulouse III), 31062Toulouse, France
| | - Rachel Hope
- Laboratoire de Microbiologie et Génétique Moléculaires, UMR5100, Centre de Biologie Intégrative, Centre Nationale de la Recherche Scientifique, 31062Toulouse, France
- Université Paul Sabatier (Toulouse III), 31062Toulouse, France
- Department of Life Sciences, Imperial College, SW7 2AZLondon, UK
| | - Anne-Lise Soulet
- Laboratoire de Microbiologie et Génétique Moléculaires, UMR5100, Centre de Biologie Intégrative, Centre Nationale de la Recherche Scientifique, 31062Toulouse, France
- Université Paul Sabatier (Toulouse III), 31062Toulouse, France
| | - Marie Dewailly
- Laboratoire de Microbiologie et Génétique Moléculaires, UMR5100, Centre de Biologie Intégrative, Centre Nationale de la Recherche Scientifique, 31062Toulouse, France
- Université Paul Sabatier (Toulouse III), 31062Toulouse, France
| | - David De Lemos
- Laboratoire de Microbiologie et Génétique Moléculaires, UMR5100, Centre de Biologie Intégrative, Centre Nationale de la Recherche Scientifique, 31062Toulouse, France
- Université Paul Sabatier (Toulouse III), 31062Toulouse, France
| | - Patrice Polard
- Laboratoire de Microbiologie et Génétique Moléculaires, UMR5100, Centre de Biologie Intégrative, Centre Nationale de la Recherche Scientifique, 31062Toulouse, France
- Université Paul Sabatier (Toulouse III), 31062Toulouse, France
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Maloisel L, Ma E, Phipps J, Deshayes A, Mattarocci S, Marcand S, Dubrana K, Coïc E. Rad51 filaments assembled in the absence of the complex formed by the Rad51 paralogs Rad55 and Rad57 are outcompeted by translesion DNA polymerases on UV-induced ssDNA gaps. PLoS Genet 2023; 19:e1010639. [PMID: 36749784 PMCID: PMC9937489 DOI: 10.1371/journal.pgen.1010639] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Revised: 02/17/2023] [Accepted: 01/26/2023] [Indexed: 02/08/2023] Open
Abstract
The bypass of DNA lesions that block replicative polymerases during DNA replication relies on DNA damage tolerance pathways. The error-prone translesion synthesis (TLS) pathway depends on specialized DNA polymerases that incorporate nucleotides in front of base lesions, potentially inducing mutagenesis. Two error-free pathways can bypass the lesions: the template switching pathway, which uses the sister chromatid as a template, and the homologous recombination pathway (HR), which also can use the homologous chromosome as template. The balance between error-prone and error-free pathways controls the mutagenesis level. Therefore, it is crucial to precisely characterize factors that influence the pathway choice to better understand genetic stability at replication forks. In yeast, the complex formed by the Rad51 paralogs Rad55 and Rad57 promotes HR and template-switching at stalled replication forks. At DNA double-strand breaks (DSBs), this complex promotes Rad51 filament formation and stability, notably by counteracting the Srs2 anti-recombinase. To explore the role of the Rad55-Rad57 complex in error-free pathways, we monitored the genetic interactions between Rad55-Rad57, the translesion polymerases Polζ or Polη, and Srs2 following UV radiation that induces mostly single-strand DNA gaps. We found that the Rad55-Rad57 complex was involved in three ways. First, it protects Rad51 filaments from Srs2, as it does at DSBs. Second, it promotes Rad51 filament stability independently of Srs2. Finally, we observed that UV-induced HR is almost abolished in Rad55-Rad57 deficient cells, and is partially restored upon Polζ or Polη depletion. Hence, we propose that the Rad55-Rad57 complex is essential to promote Rad51 filament stability on single-strand DNA gaps, notably to counteract the error-prone TLS polymerases and mutagenesis.
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Affiliation(s)
- Laurent Maloisel
- Université de Paris and Université Paris-Saclay, INSERM, CEA, Institut de Biologie François Jacob, UMR Stabilité Génétique Cellules Souches et Radiations, Fontenay-aux-Roses, France
- * E-mail: (LM); (EC)
| | - Emilie Ma
- Université de Paris and Université Paris-Saclay, INSERM, CEA, Institut de Biologie François Jacob, UMR Stabilité Génétique Cellules Souches et Radiations, Fontenay-aux-Roses, France
| | - Jamie Phipps
- Université de Paris and Université Paris-Saclay, INSERM, CEA, Institut de Biologie François Jacob, UMR Stabilité Génétique Cellules Souches et Radiations, Fontenay-aux-Roses, France
| | - Alice Deshayes
- Université de Paris and Université Paris-Saclay, INSERM, CEA, Institut de Biologie François Jacob, UMR Stabilité Génétique Cellules Souches et Radiations, Fontenay-aux-Roses, France
| | - Stefano Mattarocci
- Université de Paris and Université Paris-Saclay, INSERM, CEA, Institut de Biologie François Jacob, UMR Stabilité Génétique Cellules Souches et Radiations, Fontenay-aux-Roses, France
| | - Stéphane Marcand
- Université de Paris and Université Paris-Saclay, INSERM, CEA, Institut de Biologie François Jacob, UMR Stabilité Génétique Cellules Souches et Radiations, Fontenay-aux-Roses, France
| | - Karine Dubrana
- Université de Paris and Université Paris-Saclay, INSERM, CEA, Institut de Biologie François Jacob, UMR Stabilité Génétique Cellules Souches et Radiations, Fontenay-aux-Roses, France
| | - Eric Coïc
- Université de Paris and Université Paris-Saclay, INSERM, CEA, Institut de Biologie François Jacob, UMR Stabilité Génétique Cellules Souches et Radiations, Fontenay-aux-Roses, France
- * E-mail: (LM); (EC)
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Caldwell BJ, Norris AS, Karbowski CF, Wiegand AM, Wysocki VH, Bell CE. Structure of a RecT/Redβ family recombinase in complex with a duplex intermediate of DNA annealing. Nat Commun 2022; 13:7855. [PMID: 36543802 PMCID: PMC9772228 DOI: 10.1038/s41467-022-35572-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Accepted: 12/09/2022] [Indexed: 12/24/2022] Open
Abstract
Some bacteriophage encode a recombinase that catalyzes single-stranded DNA annealing (SSA). These proteins are apparently related to RAD52, the primary human SSA protein. The best studied protein, Redβ from bacteriophage λ, binds weakly to ssDNA, not at all to dsDNA, but tightly to a duplex intermediate of annealing formed when two complementary DNA strands are added to the protein sequentially. We used single particle cryo-electron microscopy (cryo-EM) to determine a 3.4 Å structure of a Redβ homolog from a prophage of Listeria innocua in complex with two complementary 83mer oligonucleotides. The structure reveals a helical protein filament bound to a DNA duplex that is highly extended and unwound. Native mass spectrometry confirms that the complex seen by cryo-EM is the predominant species in solution. The protein shares a common core fold with RAD52 and a similar mode of ssDNA-binding. These data provide insights into the mechanism of protein-catalyzed SSA.
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Affiliation(s)
- Brian J Caldwell
- Ohio State Biochemistry Program, The Ohio State University, Columbus, OH, 43210, USA
- Department of Biological Chemistry and Pharmacology, The Ohio State University, Columbus, OH, 43210, USA
| | - Andrew S Norris
- Department of Chemistry and Biochemistry and Resource for Native MS-Guided Structural Biology, The Ohio State University, Columbus, OH, 43210, USA
| | - Caroline F Karbowski
- Department of Biological Chemistry and Pharmacology, The Ohio State University, Columbus, OH, 43210, USA
| | - Alyssa M Wiegand
- Department of Biological Chemistry and Pharmacology, The Ohio State University, Columbus, OH, 43210, USA
| | - Vicki H Wysocki
- Ohio State Biochemistry Program, The Ohio State University, Columbus, OH, 43210, USA
- Department of Chemistry and Biochemistry and Resource for Native MS-Guided Structural Biology, The Ohio State University, Columbus, OH, 43210, USA
| | - Charles E Bell
- Ohio State Biochemistry Program, The Ohio State University, Columbus, OH, 43210, USA.
- Department of Biological Chemistry and Pharmacology, The Ohio State University, Columbus, OH, 43210, USA.
- Department of Chemistry and Biochemistry and Resource for Native MS-Guided Structural Biology, The Ohio State University, Columbus, OH, 43210, USA.
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Wilkinson M, Wilkinson OJ, Feyerherm C, Fletcher EE, Wigley DB, Dillingham MS. Structures of RecBCD in complex with phage-encoded inhibitor proteins reveal distinctive strategies for evasion of a bacterial immunity hub. eLife 2022; 11:e83409. [PMID: 36533901 PMCID: PMC9836394 DOI: 10.7554/elife.83409] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Accepted: 12/18/2022] [Indexed: 12/23/2022] Open
Abstract
Following infection of bacterial cells, bacteriophage modulate double-stranded DNA break repair pathways to protect themselves from host immunity systems and prioritise their own recombinases. Here, we present biochemical and structural analysis of two phage proteins, gp5.9 and Abc2, which target the DNA break resection complex RecBCD. These exemplify two contrasting mechanisms for control of DNA break repair in which the RecBCD complex is either inhibited or co-opted for the benefit of the invading phage. Gp5.9 completely inhibits RecBCD by preventing it from binding to DNA. The RecBCD-gp5.9 structure shows that gp5.9 acts by substrate mimicry, binding predominantly to the RecB arm domain and competing sterically for the DNA binding site. Gp5.9 adopts a parallel coiled-coil architecture that is unprecedented for a natural DNA mimic protein. In contrast, binding of Abc2 does not substantially affect the biochemical activities of isolated RecBCD. The RecBCD-Abc2 structure shows that Abc2 binds to the Chi-recognition domains of the RecC subunit in a position that might enable it to mediate the loading of phage recombinases onto its single-stranded DNA products.
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Affiliation(s)
- Martin Wilkinson
- Section of Structural Biology, Department of Infectious Disease, Faculty of Medicine, Imperial College LondonLondonUnited Kingdom
| | - Oliver J Wilkinson
- DNA:protein Interactions Unit, School of Biochemistry, University of BristolBristolUnited Kingdom
| | - Connie Feyerherm
- DNA:protein Interactions Unit, School of Biochemistry, University of BristolBristolUnited Kingdom
| | - Emma E Fletcher
- DNA:protein Interactions Unit, School of Biochemistry, University of BristolBristolUnited Kingdom
| | - Dale B Wigley
- Section of Structural Biology, Department of Infectious Disease, Faculty of Medicine, Imperial College LondonLondonUnited Kingdom
| | - Mark S Dillingham
- DNA:protein Interactions Unit, School of Biochemistry, University of BristolBristolUnited Kingdom
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Qian J, Zheng M, Wang L, Song Y, Yan J, Hsu YF. Arabidopsis mitochondrial single-stranded DNA-binding proteins SSB1 and SSB2 are essential regulators of mtDNA replication and homologous recombination. J Integr Plant Biol 2022; 64:1952-1965. [PMID: 35925893 DOI: 10.1111/jipb.13338] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Accepted: 08/04/2022] [Indexed: 06/15/2023]
Abstract
Faithful DNA replication is one of the most essential processes in almost all living organisms. However, the proteins responsible for organellar DNA replication are still largely unknown in plants. Here, we show that the two mitochondrion-targeted single-stranded DNA-binding (SSB) proteins SSB1 and SSB2 directly interact with each other and act as key factors for mitochondrial DNA (mtDNA) maintenance, as their single or double loss-of-function mutants exhibit severe germination delay and growth retardation. The mtDNA levels in mutants lacking SSB1 and/or SSB2 function were two- to four-fold higher than in the wild-type (WT), revealing a negative role for SSB1/2 in regulating mtDNA replication. Genetic analysis indicated that SSB1 functions upstream of mitochondrial DNA POLYMERASE IA (POLIA) or POLIB in mtDNA replication, as mutation in either gene restored the high mtDNA copy number of the ssb1-1 mutant back to WT levels. In addition, SSB1 and SSB2 also participate in mitochondrial genome maintenance by influencing mtDNA homologous recombination (HR). Additional genetic analysis suggested that SSB1 functions upstream of ORGANELLAR SINGLE-STRANDED DNA-BINDING PROTEIN1 (OSB1) during mtDNA replication, while SSB1 may act downstream of OSB1 and MUTS HOMOLOG1 for mtDNA HR. Overall, our results yield new insights into the roles of the plant mitochondrion-targeted SSB proteins and OSB1 in maintaining mtDNA stability via affecting DNA replication and DNA HR.
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Affiliation(s)
- Jie Qian
- School of Life Sciences, Southwest University, Chongqing, 400715, China
| | - Min Zheng
- School of Life Sciences, Southwest University, Chongqing, 400715, China
| | - Lingyu Wang
- School of Life Sciences, Southwest University, Chongqing, 400715, China
| | - Yu Song
- School of Life Sciences, Southwest University, Chongqing, 400715, China
| | - Jiawen Yan
- School of Life Sciences, Southwest University, Chongqing, 400715, China
| | - Yi-Feng Hsu
- School of Life Sciences, Southwest University, Chongqing, 400715, China
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Hassid RR, Kedem S, Bachar-Beck M, Shamir Y, Goldbourt A. Solid state NMR chemical shift assignment of the non-structural single-stranded DNA binding protein gVp from fd bacteriophage. Biomol NMR Assign 2022; 16:181-185. [PMID: 35460051 DOI: 10.1007/s12104-022-10076-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Accepted: 03/10/2022] [Indexed: 06/14/2023]
Abstract
The non-structural gene V protein (pV, gVp) from fd virus is a non-specific single-stranded DNA binding protein. The role of gVp is to sequester the single-stranded DNA thus reducing the generation of the replicative DNA form and leading to the formation of progeny phage. In this study, we assigned the 13C and 15N resonances of the crystalline unbound protein by magic-angle spinning solid-state NMR. The secondary structure predicted by the NMR shifts is in excellent agreement with the X-ray structure of the same 87-residue protein.
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Affiliation(s)
- Roni Rene Hassid
- School of Chemistry, Tel Aviv University, 6997801, Tel Aviv, Israel
| | - Smadar Kedem
- School of Chemistry, Tel Aviv University, 6997801, Tel Aviv, Israel
| | | | - Yoav Shamir
- School of Chemistry, Tel Aviv University, 6997801, Tel Aviv, Israel
| | - Amir Goldbourt
- School of Chemistry, Tel Aviv University, 6997801, Tel Aviv, Israel.
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Feliciello I, Đermić E, Malović H, Ivanković S, Zahradka D, Ljubić S, Procino A, Đermić D. Regulation of ssb Gene Expression in Escherichia coli. Int J Mol Sci 2022; 23:ijms231810917. [PMID: 36142827 PMCID: PMC9505508 DOI: 10.3390/ijms231810917] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Revised: 09/01/2022] [Accepted: 09/15/2022] [Indexed: 11/16/2022] Open
Abstract
Bacterial SSB proteins, as well as their eukaryotic RPA analogues, are essential and ubiquitous. They avidly bind single-stranded DNA and regulate/coordinate its metabolism, hence enabling essential DNA processes such as replication, transcription, and repair. The prototypic Escherichia coli SSB protein is encoded by an ssb gene. Although the ssb gene promoters harbor an SOS box, multiple studies over several decades failed to elucidate whether ssb gene expression is inducible and SOS dependent. The SOS regulon is comprised of about 50 genes, whose transcription is coordinately induced under stress conditions. Using quantitative real-time PCR, we determined the ssb gene expression kinetics in UV- and γ-irradiated E. coli and revealed that ssb gene expression is elevated in irradiated cells in an SOS-dependent manner. Additionally, the expression of the sulA gene was determined to indicate the extent of SOS induction. In a mutant with a constitutively induced SOS regulon, the ssb gene was overexpressed in the absence of DNA damage. Furthermore, we measured ssb gene expression by droplet digital PCR during unaffected bacterial growth and revealed that ssb gene expression was equal in wild-type and SOS- bacteria, whereas sulA expression was higher in the former. This study thus reveals a complex pattern of ssb gene expression, which under stress conditions depends on the SOS regulon, whereas during normal bacterial growth it is unlinked to SOS induction. The E. coli ssb gene is SOS regulated in such a way that its basal expression is relatively high and can be increased only through stronger SOS induction. The remarkable SOS induction observed in undisturbed wild-type cells may challenge our notion of the physiological role of the SOS response in bacteria.
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Affiliation(s)
- Isidoro Feliciello
- Department of Clinical Medicine and Surgery, University of Naples Federico II, 81031 Naples, Italy
| | - Edyta Đermić
- Department of Plant Pathology, Division for Phytomedicine, Faculty of Agriculture, University of Zagreb, 10000 Zagreb, Croatia
| | - Helena Malović
- Department of Plant Pathology, Division for Phytomedicine, Faculty of Agriculture, University of Zagreb, 10000 Zagreb, Croatia
| | - Siniša Ivanković
- Division of Molecular Medicine, Ruđer Bošković Institute, 10000 Zagreb, Croatia
| | - Davor Zahradka
- Division of Molecular Biology, Ruđer Bošković Institute, 10000 Zagreb, Croatia
| | - Sven Ljubić
- Division of Molecular Biology, Ruđer Bošković Institute, 10000 Zagreb, Croatia
| | - Alfredo Procino
- Division of Molecular Biology, Ruđer Bošković Institute, 10000 Zagreb, Croatia
| | - Damir Đermić
- Division of Molecular Biology, Ruđer Bošković Institute, 10000 Zagreb, Croatia
- Correspondence:
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50
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Wald J, Fahrenkamp D, Goessweiner-Mohr N, Lugmayr W, Ciccarelli L, Vesper O, Marlovits TC. Mechanism of AAA+ ATPase-mediated RuvAB-Holliday junction branch migration. Nature 2022; 609:630-639. [PMID: 36002576 PMCID: PMC9477746 DOI: 10.1038/s41586-022-05121-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Accepted: 07/18/2022] [Indexed: 12/12/2022]
Abstract
The Holliday junction is a key intermediate formed during DNA recombination across all kingdoms of life1. In bacteria, the Holliday junction is processed by two homo-hexameric AAA+ ATPase RuvB motors, which assemble together with the RuvA-Holliday junction complex to energize the strand-exchange reaction2. Despite its importance for chromosome maintenance, the structure and mechanism by which this complex facilitates branch migration are unknown. Here, using time-resolved cryo-electron microscopy, we obtained structures of the ATP-hydrolysing RuvAB complex in seven distinct conformational states, captured during assembly and processing of a Holliday junction. Five structures together resolve the complete nucleotide cycle and reveal the spatiotemporal relationship between ATP hydrolysis, nucleotide exchange and context-specific conformational changes in RuvB. Coordinated motions in a converter formed by DNA-disengaged RuvB subunits stimulate hydrolysis and nucleotide exchange. Immobilization of the converter enables RuvB to convert the ATP-contained energy into a lever motion, which generates the pulling force driving the branch migration. We show that RuvB motors rotate together with the DNA substrate, which, together with a progressing nucleotide cycle, forms the mechanistic basis for DNA recombination by continuous branch migration. Together, our data decipher the molecular principles of homologous recombination by the RuvAB complex, elucidate discrete and sequential transition-state intermediates for chemo-mechanical coupling of hexameric AAA+ motors and provide a blueprint for the design of state-specific compounds targeting AAA+ motors.
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Affiliation(s)
- Jiri Wald
- Institute of Structural and Systems Biology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
- Centre for Structural Systems Biology, Hamburg, Germany.
- Deutsches Elektronen Synchrotron (DESY), Hamburg, Germany.
- Institute of Molecular Biotechnology GmbH (IMBA), Austrian Academy of Sciences, Vienna, Austria.
- Research Institute of Molecular Pathology (IMP), Vienna, Austria.
| | - Dirk Fahrenkamp
- Institute of Structural and Systems Biology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
- Centre for Structural Systems Biology, Hamburg, Germany.
- Deutsches Elektronen Synchrotron (DESY), Hamburg, Germany.
| | - Nikolaus Goessweiner-Mohr
- Institute of Structural and Systems Biology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- Centre for Structural Systems Biology, Hamburg, Germany
- Deutsches Elektronen Synchrotron (DESY), Hamburg, Germany
- Institute of Molecular Biotechnology GmbH (IMBA), Austrian Academy of Sciences, Vienna, Austria
- Research Institute of Molecular Pathology (IMP), Vienna, Austria
- Institute of Biophysics, Johannes Kepler University (JKU), Linz, Austria
| | - Wolfgang Lugmayr
- Institute of Structural and Systems Biology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- Centre for Structural Systems Biology, Hamburg, Germany
- Deutsches Elektronen Synchrotron (DESY), Hamburg, Germany
- Institute of Molecular Biotechnology GmbH (IMBA), Austrian Academy of Sciences, Vienna, Austria
- Research Institute of Molecular Pathology (IMP), Vienna, Austria
| | - Luciano Ciccarelli
- Institute of Structural and Systems Biology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- Centre for Structural Systems Biology, Hamburg, Germany
- Institute of Molecular Biotechnology GmbH (IMBA), Austrian Academy of Sciences, Vienna, Austria
- Research Institute of Molecular Pathology (IMP), Vienna, Austria
- GlaxoSmithKline Vaccines, Siena, Italy
| | - Oliver Vesper
- Institute of Structural and Systems Biology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- Centre for Structural Systems Biology, Hamburg, Germany
- Deutsches Elektronen Synchrotron (DESY), Hamburg, Germany
- Institute of Molecular Biotechnology GmbH (IMBA), Austrian Academy of Sciences, Vienna, Austria
- Research Institute of Molecular Pathology (IMP), Vienna, Austria
| | - Thomas C Marlovits
- Institute of Structural and Systems Biology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
- Centre for Structural Systems Biology, Hamburg, Germany.
- Deutsches Elektronen Synchrotron (DESY), Hamburg, Germany.
- Institute of Molecular Biotechnology GmbH (IMBA), Austrian Academy of Sciences, Vienna, Austria.
- Research Institute of Molecular Pathology (IMP), Vienna, Austria.
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