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Fijen C, Drogalis Beckham L, Terino D, Li Y, Ramsden DA, Wood RD, Doublié S, Rothenberg E. Sequential requirements for distinct Polθ domains during theta-mediated end joining. Mol Cell 2024; 84:1460-1474.e6. [PMID: 38640894 PMCID: PMC11031631 DOI: 10.1016/j.molcel.2024.03.010] [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: 03/29/2023] [Revised: 01/10/2024] [Accepted: 03/12/2024] [Indexed: 04/21/2024]
Abstract
DNA polymerase θ (Polθ) plays a central role in a DNA double-strand break repair pathway termed theta-mediated end joining (TMEJ). TMEJ functions by pairing short-sequence "microhomologies" (MHs) in single-stranded DNA at each end of a break and subsequently initiating DNA synthesis. It is not known how the Polθ helicase domain (HD) and polymerase domain (PD) operate to bring together MHs and facilitate repair. To resolve these transient processes in real time, we utilized in vitro single-molecule FRET approaches and biochemical analyses. We find that the Polθ-HD mediates the initial capture of two ssDNA strands, bringing them in close proximity. The Polθ-PD binds and stabilizes pre-annealed MHs to form a synaptic complex (SC) and initiate repair synthesis. Individual synthesis reactions show that Polθ is inherently non-processive, accounting for complex mutational patterns during TMEJ. Binding of Polθ-PD to stem-loop-forming sequences can substantially limit synapsis, depending on the available dNTPs and sequence context.
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Affiliation(s)
- Carel Fijen
- Department of Biochemistry and Molecular Pharmacology, NYU Grossman School of Medicine, New York, NY 10016, USA.
| | - Lea Drogalis Beckham
- Department of Microbiology and Molecular Genetics, University of Vermont, Burlington, VT 05405, USA
| | - Dante Terino
- Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Yuzhen Li
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, TX 77230, USA
| | - Dale A Ramsden
- Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Richard D Wood
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, TX 77230, USA
| | - Sylvie Doublié
- Department of Microbiology and Molecular Genetics, University of Vermont, Burlington, VT 05405, USA
| | - Eli Rothenberg
- Department of Biochemistry and Molecular Pharmacology, NYU Grossman School of Medicine, New York, NY 10016, USA.
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2
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Smalheiser NR. Mobile circular DNAs regulating memory and communication in CNS neurons. Front Mol Neurosci 2023; 16:1304667. [PMID: 38125007 PMCID: PMC10730651 DOI: 10.3389/fnmol.2023.1304667] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Accepted: 11/14/2023] [Indexed: 12/23/2023] Open
Abstract
Stimuli that stimulate neurons elicit transcription of immediate-early genes, a process which requires local sites of chromosomal DNA to form double-strand breaks (DSBs) generated by topoisomerase IIb within a few minutes, followed by repair within a few hours. Wakefulness, exploring a novel environment, and contextual fear conditioning also elicit turn-on of synaptic genes requiring DSBs and repair. It has been reported (in non-neuronal cells) that extrachromosomal circular DNA can form at DSBs as the sites are repaired. I propose that activated neurons may generate extrachromosomal circular DNAs during repair at DSB sites, thus creating long-lasting "markers" of that activity pattern which contain sequences from their sites of origin and which regulate long-term gene expression. Although the population of extrachromosomal DNAs is diverse and overall associated with pathology, a subclass of small circular DNAs ("microDNAs," ∼100-400 bases long), largely derives from unique genomic sequences and has attractive features to act as stable, mobile circular DNAs to regulate gene expression in a sequence-specific manner. Circular DNAs can be templates for the transcription of RNAs, particularly small inhibitory siRNAs, circular RNAs and other non-coding RNAs that interact with microRNAs. These may regulate translation and transcription of other genes involved in synaptic plasticity, learning and memory. Another possible fate for mobile DNAs is to be inserted stably into chromosomes after new DSB sites are generated in response to subsequent activation events. Thus, the insertions of mobile DNAs into activity-induced genes may tend to inactivate them and aid in homeostatic regulation to avoid over-excitation, as well as providing a "counter" for a neuron's activation history. Moreover, activated neurons release secretory exosomes that can be transferred to recipient cells to regulate their gene expression. Mobile DNAs may be packaged into exosomes, released in an activity-dependent manner, and transferred to recipient cells, where they may be templates for regulatory RNAs and possibly incorporated into chromosomes. Finally, aging and neurodegenerative diseases (including Alzheimer's disease) are also associated with an increase in DSBs in neurons. It will become important in the future to assess how pathology-associated DSBs may relate to activity-induced mobile DNAs, and whether the latter may potentially contribute to pathogenesis.
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Affiliation(s)
- Neil R. Smalheiser
- Department of Psychiatry, University of Illinois College of Medicine, Chicago, IL, United States
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3
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Kudriaeva AA, Yakubova LA, Saratov GA, Vladimirov VI, Lipkin VM, Belogurov AA. Topology of Ubiquitin Chains in the Chromatosomal Environment of the E3 Ubiquitin Ligase RNF168. Biochemistry (Mosc) 2023; 88:2063-2072. [PMID: 38462450 DOI: 10.1134/s000629792312009x] [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: 05/03/2023] [Revised: 07/19/2023] [Accepted: 09/20/2023] [Indexed: 03/12/2024]
Abstract
Genome stability is critical for normal functioning of cells, it depends on accuracy of DNA replication, chromosome segregation, and DNA repair. Cellular defense mechanisms against DNA damage are important for preventing cancer development and aging. The E3 ubiquitin ligase RNF168 of the RING superfamily is an essential component of the complex responsible for ubiquitination of the H2A/H2A.X histones near DNA double-strand breaks, which is a key step in attracting repair factors to the damage site. In this study, we unequivocally showed that RNF168 does not have the ability to directly distinguish architecture of polyubiquitin chains, except for the tropism of its two ubiquitin-binding domains UDM1/2 to K63 ubiquitin chains. Analysis of intracellular chromatosomal environment of the full-length RNF168 and its domains using the ligand-induced bioluminescence resonance energy transfer (BRET) revealed that the C-terminal part of UDM1 is associated with the K63 ubiquitin chains; RING and the N-terminal part of UDM2 are sterically close to the K63- and K48-ubiquitin chains, while the C-terminal part of UDM1 is co-localized with all possible ubiquitin variants. Our observations together with the available structural data suggest that the C-terminal part of UDM1 binds the K63 polyubiquitin chains on the linker histone H1; RING and the N-terminal part of UDM2 are located in the central part of nucleosome and sterically close to H1 and K48-ubiquitinated alternative substrates of RNF168, such as JMJD2A/B demethylases, while the C-terminal part of UDM1 is in the region of activated ubiquitin residue associated with E2 ubiquitin ligase, engaged by RNF168.
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Affiliation(s)
- Anna A Kudriaeva
- Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, 117997, Russia.
| | - Lyudmila A Yakubova
- Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, 117997, Russia
| | - George A Saratov
- Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, 117997, Russia
| | - Vasiliy I Vladimirov
- Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, 117997, Russia
| | - Valeriy M Lipkin
- Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, 117997, Russia
| | - Alexey A Belogurov
- Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, 117997, Russia
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T N, Govindarajan S, Munavar MH. trans-translation system is important for maintaining genome integrity during DNA damage in bacteria. Res Microbiol 2023; 174:104136. [PMID: 37690591 DOI: 10.1016/j.resmic.2023.104136] [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: 04/21/2023] [Revised: 08/29/2023] [Accepted: 08/31/2023] [Indexed: 09/12/2023]
Abstract
DNA integrity in bacteria is regulated by various factors that act on the DNA. trans-translation has previously been shown to be important for the survival of Escherichia coli cells exposed to certain DNA-damaging agents. However, the mechanisms underlying this sensitivity are poorly understood. In this study, we explored the involvement of the trans-translation system in the maintenance of genome integrity using various DNA-damaging agents and mutant backgrounds. Relative viability assays showed that SsrA-defective cells were sensitive to DNA-damaging agents, such as nalidixic acid (NA), ultraviolet radiation (UV), and methyl methanesulfonate (MMS). The viability of SsrA-defective cells was rescued by deleting sulA, although the expression of SulA was not more pronounced in SsrA-defective cells than in wild-type cells. Live cell imaging using a Gam-GFP fluorescent reporter showed increased double-strand breaks (DSBs) in SsrA-defective cells during DNA damage. We also showed that the ribosome rescue function of SsrA was sufficient for DNA damage tolerance. DNA damage sensitivity can be alleviated by partial uncoupling of transcription and translation by using sub-lethal concentrations of ribosome inhibiting antibiotic (tetracycline) or by mutating the gene coding for RNase H (rnhA). Taken together, our results highlight the importance of trans-translation system in maintaining genome integrity and bacterial survival during DNA damage.
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Affiliation(s)
- Nagarajan T
- Department of Molecular Biology, School of Biological Sciences, Madurai Kamaraj University, Madurai, India; Department of Biological Sciences, SRM University-AP, Amaravati, India
| | | | - M Hussain Munavar
- Department of Molecular Biology, School of Biological Sciences, Madurai Kamaraj University, Madurai, India.
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Fu Y, Sacco O, DeBitetto E, Kanshin E, Ueberheide B, Sfeir A. Mitochondrial DNA breaks activate an integrated stress response to reestablish homeostasis. Mol Cell 2023; 83:3740-3753.e9. [PMID: 37832546 DOI: 10.1016/j.molcel.2023.09.026] [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: 02/17/2023] [Revised: 08/10/2023] [Accepted: 09/21/2023] [Indexed: 10/15/2023]
Abstract
Mitochondrial DNA double-strand breaks (mtDSBs) lead to the degradation of circular genomes and a reduction in copy number; yet, the cellular response in human cells remains elusive. Here, using mitochondrial-targeted restriction enzymes, we show that a subset of cells with mtDSBs exhibited defective mitochondrial protein import, reduced respiratory complexes, and loss of membrane potential. Electron microscopy confirmed the altered mitochondrial membrane and cristae ultrastructure. Intriguingly, mtDSBs triggered the integrated stress response (ISR) via the phosphorylation of eukaryotic translation initiation factor 2α (eIF2α) by DELE1 and heme-regulated eIF2α kinase (HRI). When ISR was inhibited, the cells experienced intensified mitochondrial defects and slower mtDNA recovery post-breakage. Lastly, through proteomics, we identified ATAD3A-a membrane-bound protein interacting with nucleoids-as potentially pivotal in relaying signals from impaired genomes to the inner mitochondrial membrane. In summary, our study delineates the cascade connecting damaged mitochondrial genomes to the cytoplasm and highlights the significance of the ISR in maintaining mitochondrial homeostasis amid genome instability.
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Affiliation(s)
- Yi Fu
- Skirball Institute of Biomolecular Medicine, Cell Biology Department, NYU School of Medicine, New York, NY 10016, USA; Molecular Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Olivia Sacco
- Molecular Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Emily DeBitetto
- Molecular Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Evgeny Kanshin
- Proteomics Laboratory, NYU School of Medicine, New York, NY 10016, USA; Biochemistry and Molecular Pharmacology, NYU School of Medicine, New York, NY 10016, USA
| | - Beatrix Ueberheide
- Proteomics Laboratory, NYU School of Medicine, New York, NY 10016, USA; Biochemistry and Molecular Pharmacology, NYU School of Medicine, New York, NY 10016, USA; Department of Neurology, NYU School of Medicine, New York, NY 10016, USA; Perlmutter Cancer Center, NYU School of Medicine, New York, NY 10016, USA
| | - Agnel Sfeir
- Molecular Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA.
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Li F, Zafar A, Luo L, Denning AM, Gu J, Bennett A, Yuan F, Zhang Y. R-Loops in Genome Instability and Cancer. Cancers (Basel) 2023; 15:4986. [PMID: 37894353 PMCID: PMC10605827 DOI: 10.3390/cancers15204986] [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] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Revised: 10/04/2023] [Accepted: 10/11/2023] [Indexed: 10/29/2023] Open
Abstract
R-loops are unique, three-stranded nucleic acid structures that primarily form when an RNA molecule displaces one DNA strand and anneals to the complementary DNA strand in a double-stranded DNA molecule. R-loop formation can occur during natural processes, such as transcription, in which the nascent RNA molecule remains hybridized with the template DNA strand, while the non-template DNA strand is displaced. However, R-loops can also arise due to many non-natural processes, including DNA damage, dysregulation of RNA degradation pathways, and defects in RNA processing. Despite their prevalence throughout the whole genome, R-loops are predominantly found in actively transcribed gene regions, enabling R-loops to serve seemingly controversial roles. On one hand, the pathological accumulation of R-loops contributes to genome instability, a hallmark of cancer development that plays a role in tumorigenesis, cancer progression, and therapeutic resistance. On the other hand, R-loops play critical roles in regulating essential processes, such as gene expression, chromatin organization, class-switch recombination, mitochondrial DNA replication, and DNA repair. In this review, we summarize discoveries related to the formation, suppression, and removal of R-loops and their influence on genome instability, DNA repair, and oncogenic events. We have also discussed therapeutical opportunities by targeting pathological R-loops.
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Affiliation(s)
- Fang Li
- Department of Biochemistry & Molecular Biology, Miller School of Medicine, University of Miami, Miami, FL 33136, USA
| | - Alyan Zafar
- Department of Biochemistry & Molecular Biology, Miller School of Medicine, University of Miami, Miami, FL 33136, USA
| | - Liang Luo
- Department of Biochemistry & Molecular Biology, Miller School of Medicine, University of Miami, Miami, FL 33136, USA
| | - Ariana Maria Denning
- Department of Biochemistry & Molecular Biology, Miller School of Medicine, University of Miami, Miami, FL 33136, USA
| | - Jun Gu
- Department of Molecular and Cellular Pharmacology, Miller School of Medicine, University of Miami, Miami, FL 33136, USA
| | - Ansley Bennett
- Department of Biochemistry & Molecular Biology, Miller School of Medicine, University of Miami, Miami, FL 33136, USA
| | - Fenghua Yuan
- Department of Biochemistry & Molecular Biology, Miller School of Medicine, University of Miami, Miami, FL 33136, USA
| | - Yanbin Zhang
- Department of Biochemistry & Molecular Biology, Miller School of Medicine, University of Miami, Miami, FL 33136, USA
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Enkhbaatar T, Skoneczny M, Stępień K, Mołoń M, Skoneczna A. Live while the DNA lasts. The role of autophagy in DNA loss and survival of diploid yeast cells during chronological aging. Aging (Albany NY) 2023; 15:9965-9983. [PMID: 37815879 PMCID: PMC10599738 DOI: 10.18632/aging.205102] [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: 06/13/2023] [Accepted: 09/06/2023] [Indexed: 10/12/2023]
Abstract
Aging is inevitable and affects all cell types, thus yeast cells are often used as a model in aging studies. There are two approaches to studying aging in yeast: replicative aging, which describes the proliferative potential of cells, and chronological aging, which is used for studying post-mitotic cells. While analyzing the chronological lifespan (CLS) of diploid Saccharomyces cerevisiae cells, we discovered a remarkable phenomenon: ploidy reduction during aging progression. To uncover the mechanism behind this unusual process we used yeast strains undergoing a CLS assay, looking for various aging parameters. Cell mortality, regrowth ability, autophagy induction and cellular DNA content measurements indicated that during the CLS assay, dying cells lost their DNA, and only diploids survived. We demonstrated that autophagy was responsible for the gradual loss of DNA. The nucleophagy marker activation at the start of the CLS experiment correlated with the significant drop in cell viability. The activation of piecemeal microautophagy of nucleus (PMN) markers appeared to accompany the chronological aging process until the end. Our findings emphasize the significance of maintaining at least one intact copy of the genome for the survival of post-mitotic diploid cells. During chronological aging, cellular components, including DNA, are exposed to increasing stress, leading to DNA damage and fragmentation in aging cells. We propose that PMN-dependent clearance of damaged DNA from the nucleus helps prevent genome rearrangements. However, as long as one copy of the genome can be rebuilt, cells can still survive.
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Affiliation(s)
- Tuguldur Enkhbaatar
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw 02-106, Poland
| | - Marek Skoneczny
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw 02-106, Poland
| | - Karolina Stępień
- Institute of Medical Sciences, Rzeszów University, Rzeszów 35-959, Poland
| | - Mateusz Mołoń
- Institute of Biology, Rzeszów University, Rzeszów 35-601, Poland
| | - Adrianna Skoneczna
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw 02-106, Poland
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8
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Wang N, Xu S, Egli D. Replication stress in mammalian embryo development, differentiation, and reprogramming. Trends Cell Biol 2023; 33:872-886. [PMID: 37202286 DOI: 10.1016/j.tcb.2023.03.015] [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: 01/04/2023] [Revised: 03/24/2023] [Accepted: 03/29/2023] [Indexed: 05/20/2023]
Abstract
Duplicating a genome of 3 billion nucleotides is challenged by a variety of obstacles that can cause replication stress and affect the integrity of the genome. Recent studies show that replication fork slowing and stalling is prevalent in early mammalian development, resulting in genome instability and aneuploidy, and constituting a barrier to development in human reproduction. Genome instability resulting from DNA replication stress is a barrier to the cloning of animals and to the reprogramming of differentiated cells to induced pluripotent stem cells, as well as a barrier to cell transformation. Remarkably, the regions most impacted by replication stress are shared in these different cellular contexts, affecting long genes and flanking intergenic areas. In this review we integrate our knowledge of DNA replication stress in mammalian embryos, in programming, and in reprogramming, and we discuss a potential role for fragile sites in sensing replication stress and restricting cell cycle progression in health and disease.
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Affiliation(s)
- Ning Wang
- Division of Molecular Genetics, Department of Pediatrics and Naomi Berrie Diabetes Center, Columbia Stem Cell Initiative, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Shuangyi Xu
- Division of Molecular Genetics, Department of Pediatrics and Naomi Berrie Diabetes Center, Columbia Stem Cell Initiative, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Dieter Egli
- Division of Molecular Genetics, Department of Pediatrics and Naomi Berrie Diabetes Center, Columbia Stem Cell Initiative, Columbia University Irving Medical Center, New York, NY 10032, USA.
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9
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Zahradka K, Repar J, Đermić D, Zahradka D. Chromosome Segregation and Cell Division Defects in Escherichia coli Recombination Mutants Exposed to Different DNA-Damaging Treatments. Microorganisms 2023; 11:microorganisms11030701. [PMID: 36985274 PMCID: PMC10051365 DOI: 10.3390/microorganisms11030701] [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] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Accepted: 03/05/2023] [Indexed: 03/30/2023] Open
Abstract
Homologous recombination repairs potentially lethal DNA lesions such as double-strand DNA breaks (DSBs) and single-strand DNA gaps (SSGs). In Escherichia coli, DSB repair is initiated by the RecBCD enzyme that resects double-strand DNA ends and loads RecA recombinase to the emerging single-strand (ss) DNA tails. SSG repair is mediated by the RecFOR protein complex that loads RecA onto the ssDNA segment of gaped duplex. In both repair pathways, RecA catalyses reactions of homologous DNA pairing and strand exchange, while RuvABC complex and RecG helicase process recombination intermediates. In this work, we have characterised cytological changes in various recombination mutants of E. coli after three different DNA-damaging treatments: (i) expression of I-SceI endonuclease, (ii) γ-irradiation, and (iii) UV-irradiation. All three treatments caused severe chromosome segregation defects and DNA-less cell formation in the ruvABC, recG, and ruvABC recG mutants. After I-SceI expression and γ-irradiation, this phenotype was efficiently suppressed by the recB mutation, indicating that cytological defects result mostly from incomplete DSB repair. In UV-irradiated cells, the recB mutation abolished cytological defects of recG mutants and also partially suppressed the cytological defects of ruvABC recG mutants. However, neither recB nor recO mutation alone could suppress the cytological defects of UV-irradiated ruvABC mutants. The suppression was achieved only by simultaneous inactivation of the recB and recO genes. Cell survival and microscopic analysis suggest that chromosome segregation defects in UV-irradiated ruvABC mutants largely result from defective processing of stalled replication forks. The results of this study show that chromosome morphology is a valuable marker in genetic analyses of recombinational repair in E. coli.
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Affiliation(s)
- Ksenija Zahradka
- Laboratory for Molecular Microbiology, Division of Molecular Biology, Ruđer Bošković Institute, Bijenička 54, 10000 Zagreb, Croatia
| | - Jelena Repar
- Laboratory for Molecular Microbiology, Division of Molecular Biology, Ruđer Bošković Institute, Bijenička 54, 10000 Zagreb, Croatia
| | - Damir Đermić
- Laboratory for Molecular Microbiology, Division of Molecular Biology, Ruđer Bošković Institute, Bijenička 54, 10000 Zagreb, Croatia
| | - Davor Zahradka
- Laboratory for Molecular Microbiology, Division of Molecular Biology, Ruđer Bošković Institute, Bijenička 54, 10000 Zagreb, Croatia
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10
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Schimmel J, Muñoz-Subirana N, Kool H, van Schendel R, van der Vlies S, Kamp JA, de Vrij FMS, Kushner SA, Smith GCM, Boulton SJ, Tijsterman M. Modulating mutational outcomes and improving precise gene editing at CRISPR-Cas9-induced breaks by chemical inhibition of end-joining pathways. Cell Rep 2023; 42:112019. [PMID: 36701230 DOI: 10.1016/j.celrep.2023.112019] [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: 02/08/2022] [Revised: 05/18/2022] [Accepted: 01/09/2023] [Indexed: 01/26/2023] Open
Abstract
Gene editing through repair of CRISPR-Cas9-induced chromosomal breaks offers a means to correct a wide range of genetic defects. Directing repair to produce desirable outcomes by modulating DNA repair pathways holds considerable promise to increase the efficiency of genome engineering. Here, we show that inhibition of non-homologous end joining (NHEJ) or polymerase theta-mediated end joining (TMEJ) can be exploited to alter the mutational outcomes of CRISPR-Cas9. We show robust inhibition of TMEJ activity at CRISPR-Cas9-induced double-strand breaks (DSBs) using ART558, a potent polymerase theta (Polϴ) inhibitor. Using targeted sequencing, we show that ART558 suppresses the formation of microhomology-driven deletions in favor of NHEJ-specific outcomes. Conversely, NHEJ deficiency triggers the formation of large kb-sized deletions, which we show are the products of mutagenic TMEJ. Finally, we show that combined chemical inhibition of TMEJ and NHEJ increases the efficiency of homology-driven repair (HDR)-mediated precise gene editing. Our work reports a robust strategy to improve the fidelity and safety of genome engineering.
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Affiliation(s)
- Joost Schimmel
- Department of Human Genetics, Leiden University Medical Center, Leiden, the Netherlands
| | - Núria Muñoz-Subirana
- Department of Human Genetics, Leiden University Medical Center, Leiden, the Netherlands
| | - Hanneke Kool
- Department of Human Genetics, Leiden University Medical Center, Leiden, the Netherlands
| | - Robin van Schendel
- Department of Human Genetics, Leiden University Medical Center, Leiden, the Netherlands
| | - Sven van der Vlies
- Department of Human Genetics, Leiden University Medical Center, Leiden, the Netherlands
| | - Juliette A Kamp
- Department of Psychiatry, Erasmus Medical Center, Rotterdam, the Netherlands
| | - Femke M S de Vrij
- Department of Psychiatry, Erasmus Medical Center, Rotterdam, the Netherlands
| | - Steven A Kushner
- Department of Psychiatry, Erasmus Medical Center, Rotterdam, the Netherlands; Department of Psychiatry, Columbia University Irving Medical Center, New York, NY, USA
| | - Graeme C M Smith
- Artios Pharma, The Glenn Berge Building, Babraham Research Campus, Cambridge, UK
| | - Simon J Boulton
- Artios Pharma, The Glenn Berge Building, Babraham Research Campus, Cambridge, UK; The Francis Crick Institute, London, UK
| | - Marcel Tijsterman
- Department of Human Genetics, Leiden University Medical Center, Leiden, the Netherlands; Institute of Biology Leiden, Leiden University, Sylviusweg 72, 2333 BE Leiden, the Netherlands.
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Mechetin GV, Zharkov DO. DNA Damage Response and Repair in Boron Neutron Capture Therapy. Genes (Basel) 2023; 14:127. [PMID: 36672868 PMCID: PMC9859301 DOI: 10.3390/genes14010127] [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] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2022] [Revised: 12/28/2022] [Accepted: 12/29/2022] [Indexed: 01/03/2023] Open
Abstract
Boron neutron capture therapy (BNCT) is an approach to the radiotherapy of solid tumors that was first outlined in the 1930s but has attracted considerable attention recently with the advent of a new generation of neutron sources. In BNCT, tumor cells accumulate 10B atoms that react with epithermal neutrons, producing energetic α particles and 7Li atoms that damage the cell's genome. The damage inflicted by BNCT appears not to be easily repairable and is thus lethal for the cell; however, the molecular events underlying the action of BNCT remain largely unaddressed. In this review, the chemistry of DNA damage during BNCT is outlined, the major mechanisms of DNA break sensing and repair are summarized, and the specifics of the repair of BNCT-induced DNA lesions are discussed.
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Affiliation(s)
- Grigory V. Mechetin
- Department of Natural Sciences, Novosibirsk State University, 2 Pirogova St., 630090 Novosibirsk, Russia
- Siberian Branch of the Russian Academy of Sciences Institute of Chemical Biology and Fundamental Medicine, 8 Lavrentieva Ave., 630090 Novosibirsk, Russia
| | - Dmitry O. Zharkov
- Department of Natural Sciences, Novosibirsk State University, 2 Pirogova St., 630090 Novosibirsk, Russia
- Siberian Branch of the Russian Academy of Sciences Institute of Chemical Biology and Fundamental Medicine, 8 Lavrentieva Ave., 630090 Novosibirsk, Russia
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12
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Schimmel J, van Wezel MD, van Schendel R, Tijsterman M. Chromosomal breaks at the origin of small tandem DNA duplications. Bioessays 2023; 45:e2200168. [PMID: 36385254 DOI: 10.1002/bies.202200168] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Revised: 11/01/2022] [Accepted: 11/03/2022] [Indexed: 11/18/2022]
Abstract
Small tandem DNA duplications in the range of 15 to 300 base-pairs play an important role in the aetiology of human disease and contribute to genome diversity. Here, we discuss different proposed mechanisms for their occurrence and argue that this type of structural variation mainly results from mutagenic repair of chromosomal breaks. This hypothesis is supported by both bioinformatical analysis of insertions occurring in the genome of different species and disease alleles, as well as by CRISPR/Cas9-based experimental data from different model systems. Recent work points to fill-in synthesis at double-stranded DNA breaks with complementary sequences, regulated by end-joining mechanisms, to account for small tandem duplications. We will review the prevalence of small tandem duplications in the population, and we will speculate on the potential sources of DNA damage that could give rise to this mutational signature. With the development of novel algorithms to analyse sequencing data, small tandem duplications are now more frequently detected in the human genome and identified as oncogenic gain-of-function mutations. Understanding their origin could lead to optimized treatment regimens to prevent therapy-induced activation of oncogenes and might expose novel vulnerabilities in cancer.
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Affiliation(s)
- Joost Schimmel
- Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands
| | - Marloes D van Wezel
- Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands
| | - Robin van Schendel
- Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands
| | - Marcel Tijsterman
- Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands
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13
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Awwad SW, Darawshe MM, Machour FE, Arman I, Ayoub N. Recruitment of RBM6 to DNA Double-Strand Breaks Fosters Homologous Recombination Repair. Mol Cell Biol 2023; 43:130-142. [PMID: 36941773 PMCID: PMC10038030 DOI: 10.1080/10985549.2023.2187105] [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: 06/13/2022] [Revised: 12/20/2022] [Accepted: 02/01/2023] [Indexed: 03/23/2023] Open
Abstract
DNA double-strand breaks (DSBs) are highly toxic lesions that threaten genome integrity and cell survival. To avoid harmful repercussions of DSBs, a wide variety of DNA repair factors are recruited to execute DSB repair. Previously, we demonstrated that RBM6 splicing factor facilitates homologous recombination (HR) of DSB by regulating alternative splicing-coupled nonstop-decay of the HR protein APBB1/Fe65. Here, we describe a splicing-independent function of RBM6 in promoting HR repair of DSBs. We show that RBM6 is recruited to DSB sites and PARP1 activity indirectly regulates RBM6 recruitment to DNA breakage sites. Deletion mapping analysis revealed a region containing five glycine residues within the G-patch domain that regulates RBM6 accumulation at DNA damage sites. We further ascertain that RBM6 interacts with Rad51, and this interaction is attenuated in RBM6 mutant lacking the G-patch domain (RBM6del(G-patch)). Consequently, RBM6del(G-patch) cells exhibit reduced levels of Rad51 foci after ionizing radiation. In addition, while RBM6 deletion mutant lacking the G-patch domain has no detectable effect on the expression levels of its splicing targets Fe65 and Eya2, it fails to restore the integrity of HR. Altogether, our results suggest that RBM6 recruitment to DSB promotes HR repair, irrespective of its splicing activity.HIGHLIGHTSPARP1 activity indirectly regulates RBM6 recruitment to DNA damage sites.Five glycine residues within the G-patch domain of RBM6 are critical for its recruitment to DNA damage sites, but dispensable for its splicing activity.RBM6 G-patch domain fosters its interaction with Rad51 and promotes Rad51 foci formation following irradiation.RBM6 recruitment to DSB sites underpins HR repair.
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Affiliation(s)
- Samah W. Awwad
- Department of Biology, Technion – Israel Institute of Technology, Haifa, Israel
| | - Malak M. Darawshe
- Department of Biology, Technion – Israel Institute of Technology, Haifa, Israel
| | - Feras E. Machour
- Department of Biology, Technion – Israel Institute of Technology, Haifa, Israel
| | - Inbar Arman
- Department of Biology, Technion – Israel Institute of Technology, Haifa, Israel
| | - Nabieh Ayoub
- Department of Biology, Technion – Israel Institute of Technology, Haifa, Israel
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14
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Nath S, Welch LA, Flanagan MK, White MA. Meiotic pairing and double-strand break formation along the heteromorphic threespine stickleback sex chromosomes. Chromosome Res 2022; 30:429-442. [PMID: 35635635 DOI: 10.1007/s10577-022-09699-0] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Revised: 05/02/2022] [Accepted: 05/04/2022] [Indexed: 01/25/2023]
Abstract
Double-strand break repair during meiosis is normally achieved using the homologous chromosome as a repair template. Heteromorphic sex chromosomes share little sequence homology, presenting unique challenges to the repair of double-strand breaks. Our understanding of how heteromorphic sex chromosomes behave during meiosis has been focused on ancient sex chromosomes, where the X and Y differ markedly in overall structure and gene content. It remains unclear how more recently evolved sex chromosomes that share considerably more sequence homology with one another pair and form double-strand breaks. One possibility is barriers to pairing evolve rapidly. Alternatively, recently evolved sex chromosomes may exhibit pairing and double-strand break repair that more closely resembles that of their autosomal ancestors. Here, we use the recently evolved X and Y chromosomes of the threespine stickleback fish (Gasterosteus aculeatus) to study patterns of pairing and double-stranded break formation using molecular cytogenetics. We found that the sex chromosomes of threespine stickleback fish did not pair exclusively in the pseudoautosomal region. Instead, the chromosomes fully paired in a non-homologous fashion. To achieve this, the X chromosome underwent synaptic adjustment during pachytene to match the axis length of the Y chromosome. Double-strand break formation and repair rate also matched that of the autosomes. Our results highlight that recently evolved sex chromosomes exhibit meiotic behavior that is reminiscent of autosomes and argues for further work to identify the homologous templates that are used to repair double-strand breaks on the X and Y chromosomes.
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Affiliation(s)
- Shivangi Nath
- Department of Genetics, University of Georgia, 120 Green St, Athens, GA, 30602, USA
| | - Lucille A Welch
- Department of Genetics, University of Georgia, 120 Green St, Athens, GA, 30602, USA
| | - Mary K Flanagan
- Department of Genetics, University of Georgia, 120 Green St, Athens, GA, 30602, USA
| | - Michael A White
- Department of Genetics, University of Georgia, 120 Green St, Athens, GA, 30602, USA.
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15
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Ketley RF, Battistini F, Alagia A, Mondielli C, Iehl F, Balikçi E, Huber KVM, Orozco M, Gullerova M. DNA double-strand break-derived RNA drives TIRR/53BP1 complex dissociation. Cell Rep 2022; 41:111526. [PMID: 36288694 PMCID: PMC9638026 DOI: 10.1016/j.celrep.2022.111526] [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] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Revised: 08/11/2022] [Accepted: 09/28/2022] [Indexed: 11/25/2022] Open
Abstract
Tudor-interacting repair regulator (TIRR) is an RNA-binding protein and a negative regulator of the DNA-repair factor p53-binding protein 1 (53BP1). In non-damage conditions, TIRR is bound to 53BP1. After DNA damage, TIRR and 53BP1 dissociate, and 53BP1 binds the chromatin at the double-strand break (DSB) to promote non-homologous end joining (NHEJ)-mediated repair. However, the exact mechanistic details of this dissociation after damage are unknown. Increasing evidence has implicated RNA as a crucial factor in the DNA damage response (DDR). Here, we show that RNA can separate TIRR/53BP1. Specifically, RNA with a hairpin secondary structure, transcribed at the DSB by RNA polymerase II (RNAPII), promotes TIRR/53BP1 complex separation. This hairpin RNA binds to the same residues on TIRR as 53BP1. Our results uncover a role of DNA-damage-derived RNA in modulating a protein-protein interaction and contribute to our understanding of DSB repair.
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Affiliation(s)
- Ruth F Ketley
- Sir William Dunn School of Pathology, South Parks Road, Oxford OX1 3RE, UK
| | - Federica Battistini
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science, and Technology, Baldiri Reixac 10-12, 08028 Barcelona, Spain; Department of Biochemistry and Molecular Biology. University of Barcelona, 08028 Barcelona, Spain
| | - Adele Alagia
- Sir William Dunn School of Pathology, South Parks Road, Oxford OX1 3RE, UK
| | - Clémence Mondielli
- HTBS - Biophysics Group, Evotec (France) SAS, Campus Curie, 195 Route d'Espagne, 31036 Toulouse Cedex, France
| | - Florence Iehl
- HTBS - Biophysics Group, Evotec (France) SAS, Campus Curie, 195 Route d'Espagne, 31036 Toulouse Cedex, France
| | - Esra Balikçi
- Centre for Medicines Discovery, Nuffield Department of Medicine, Oxford OX3 7FZ, UK; Target Discovery Institute, Nuffield Department of Medicine, Oxford OX3 7FZ, UK
| | - Kilian V M Huber
- Centre for Medicines Discovery, Nuffield Department of Medicine, Oxford OX3 7FZ, UK; Target Discovery Institute, Nuffield Department of Medicine, Oxford OX3 7FZ, UK
| | - Modesto Orozco
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science, and Technology, Baldiri Reixac 10-12, 08028 Barcelona, Spain; Department of Biochemistry and Molecular Biology. University of Barcelona, 08028 Barcelona, Spain
| | - Monika Gullerova
- Sir William Dunn School of Pathology, South Parks Road, Oxford OX1 3RE, UK.
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16
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Casari E, Gnugnoli M, Rinaldi C, Pizzul P, Colombo CV, Bonetti D, Longhese MP. To Fix or Not to Fix: Maintenance of Chromosome Ends Versus Repair of DNA Double-Strand Breaks. Cells 2022; 11:cells11203224. [PMID: 36291091 PMCID: PMC9601279 DOI: 10.3390/cells11203224] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [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: 09/15/2022] [Revised: 10/07/2022] [Accepted: 10/12/2022] [Indexed: 02/08/2023] Open
Abstract
Early work by Muller and McClintock discovered that the physical ends of linear chromosomes, named telomeres, possess an inherent ability to escape unwarranted fusions. Since then, extensive research has shown that this special feature relies on specialized proteins and structural properties that confer identity to the chromosome ends, thus allowing cells to distinguish them from intrachromosomal DNA double-strand breaks. Due to the inability of conventional DNA replication to fully replicate the chromosome ends and the downregulation of telomerase in most somatic human tissues, telomeres shorten as cells divide and lose this protective capacity. Telomere attrition causes the activation of the DNA damage checkpoint that leads to a cell-cycle arrest and the entering of cells into a nondividing state, called replicative senescence, that acts as a barrier against tumorigenesis. However, downregulation of the checkpoint overcomes this barrier and leads to further genomic instability that, if coupled with re-stabilization of telomeres, can drive tumorigenesis. This review focuses on the key experiments that have been performed in the model organism Saccharomyces cerevisiae to uncover the mechanisms that protect the chromosome ends from eliciting a DNA damage response, the conservation of these pathways in mammals, as well as the consequences of their loss in human cancer.
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17
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Guo H, Stamper EL, Sato-Carlton A, Shimazoe MA, Li X, Zhang L, Stevens L, Tam KCJ, Dernburg AF, Carlton PM. Phosphoregulation of DSB-1 mediates control of meiotic double-strand break activity. eLife 2022; 11:77956. [PMID: 35758641 PMCID: PMC9278955 DOI: 10.7554/elife.77956] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Accepted: 06/23/2022] [Indexed: 12/28/2022] Open
Abstract
In the first meiotic cell division, proper segregation of chromosomes in most organisms depends on chiasmata, exchanges of continuity between homologous chromosomes that originate from the repair of programmed double-strand breaks (DSBs) catalyzed by the Spo11 endonuclease. Since DSBs can lead to irreparable damage in germ cells, while chromosomes lacking DSBs also lack chiasmata, the number of DSBs must be carefully regulated to be neither too high nor too low. Here, we show that in Caenorhabditis elegans, meiotic DSB levels are controlled by the phosphoregulation of DSB-1, a homolog of the yeast Spo11 cofactor Rec114, by the opposing activities of PP4PPH-4.1 phosphatase and ATRATL-1 kinase. Increased DSB-1 phosphorylation in pph-4.1 mutants correlates with reduction in DSB formation, while prevention of DSB-1 phosphorylation drastically increases the number of meiotic DSBs both in pph-4.1 mutants and in the wild-type background. C. elegans and its close relatives also possess a diverged paralog of DSB-1, called DSB-2, and loss of dsb-2 is known to reduce DSB formation in oocytes with increasing age. We show that the proportion of the phosphorylated, and thus inactivated, form of DSB-1 increases with age and upon loss of DSB-2, while non-phosphorylatable DSB-1 rescues the age-dependent decrease in DSBs in dsb-2 mutants. These results suggest that DSB-2 evolved in part to compensate for the inactivation of DSB-1 through phosphorylation, to maintain levels of DSBs in older animals. Our work shows that PP4PPH-4.1, ATRATL-1, and DSB-2 act in concert with DSB-1 to promote optimal DSB levels throughout the reproductive lifespan.
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Affiliation(s)
- Heyun Guo
- Graduate School of Biostudies, Kyoto University, Yoshidakonoe, Sakyo, Kyoto, Japan
| | - Ericca L Stamper
- Department of Molecular and Cell Biology, University of California, Berkeley, United States.,Howard Hughes Medical Institute, Chevy Chase, United States.,California Institute for Quantitative Biosciences, Berkeley, United States.,Division of Biological Systems and Engineering, Lawrence Berkeley National Laboratory, Berkeley, United States
| | - Aya Sato-Carlton
- Graduate School of Biostudies, Kyoto University, Yoshidakonoe, Sakyo, Kyoto, Japan
| | - Masa A Shimazoe
- Graduate School of Biostudies, Kyoto University, Yoshidakonoe, Sakyo, Kyoto, Japan.,Department of Science, Kyoto University, Kyoto, Japan
| | - Xuan Li
- Graduate School of Biostudies, Kyoto University, Yoshidakonoe, Sakyo, Kyoto, Japan
| | - Liangyu Zhang
- Department of Molecular and Cell Biology, University of California, Berkeley, United States.,Howard Hughes Medical Institute, Chevy Chase, United States.,California Institute for Quantitative Biosciences, Berkeley, United States.,Division of Biological Systems and Engineering, Lawrence Berkeley National Laboratory, Berkeley, United States
| | - Lewis Stevens
- Institute of Evolutionary Biology, Ashworth Laboratories, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - K C Jacky Tam
- Graduate School of Biostudies, Kyoto University, Yoshidakonoe, Sakyo, Kyoto, Japan
| | - Abby F Dernburg
- Department of Molecular and Cell Biology, University of California, Berkeley, United States.,Howard Hughes Medical Institute, Chevy Chase, United States.,California Institute for Quantitative Biosciences, Berkeley, United States.,Division of Biological Systems and Engineering, Lawrence Berkeley National Laboratory, Berkeley, United States
| | - Peter M Carlton
- Graduate School of Biostudies, Kyoto University, Yoshidakonoe, Sakyo, Kyoto, Japan.,Radiation Biology Center, Kyoto University, Kyoto, Japan.,Institute for Integrated Cell-Material Sciences (iCeMS), Kyoto University, Kyoto, Japan
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18
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Czajkowski D, Szmyd R, Gee HE. Impact of DNA damage response defects in cancer cells on response to immunotherapy and radiotherapy. J Med Imaging Radiat Oncol 2022; 66:546-559. [PMID: 35460184 PMCID: PMC9321602 DOI: 10.1111/1754-9485.13413] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Revised: 04/03/2022] [Accepted: 04/06/2022] [Indexed: 11/30/2022]
Abstract
The DNA damage response (DDR) is a complex set of downstream pathways triggered in response to DNA damage to maintain genomic stability. Many tumours exhibit mutations which inactivate components of the DDR, making them prone to the accumulation of DNA defects. These can both facilitate the development of tumours and provide potential targets for novel therapeutic interventions. The inhibition of the DDR has been shown to induce radiosensitivity in certain cancers, rendering them susceptible to treatment with radiotherapy and improving the therapeutic window. Moreover, DDR defects are a strong predictor of patient response to immune checkpoint inhibition (ICI). The ability to target the DDR selectively has the potential to expand the tumour neoantigen repertoire, thus increasing tumour immunogenicity and facilitating a CD8+ T and NK cell response against cancer cells. Combinatorial approaches, which seek to integrate DDR inhibition with radiotherapy and immunotherapy, have shown promise in early trials. Further studies are necessary to understand these synergies and establish reliable biomarkers.
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Affiliation(s)
| | - Radosław Szmyd
- Genome Integrity Unit, Children's Medical Research Institute, University of Sydney, Sydney, New South Wales, Australia.,Sydney West Radiation Oncology Network, Crown Princess Mary Cancer Centre Westmead, Sydney, New South Wales, Australia
| | - Harriet E Gee
- University of Sydney, Sydney, New South Wales, Australia.,Genome Integrity Unit, Children's Medical Research Institute, University of Sydney, Sydney, New South Wales, Australia.,Sydney West Radiation Oncology Network, Crown Princess Mary Cancer Centre Westmead, Sydney, New South Wales, Australia
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19
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Mallikarjun J, Gowrishankar J. Essential Role for an Isoform of Escherichia coli Translation Initiation Factor IF2 in Repair of Two-Ended DNA Double-Strand Breaks. J Bacteriol 2022;:e0057121. [PMID: 35343794 DOI: 10.1128/jb.00571-21] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
In Escherichia coli, three isoforms of the essential translation initiation factor IF2 (IF2-1, IF2-2, and IF2-3) are generated from separate in-frame initiation codons in infB. The isoforms have earlier been suggested to additionally participate in DNA damage repair and replication restart. It is also known that the proteins RecA and RecBCD are needed for repair of DNA double-strand breaks (DSBs) in E. coli. Here, we show that strains lacking IF2-1 are profoundly sensitive to two-ended DSBs in DNA generated by radiomimetic agents phleomycin or bleomycin, or by endonuclease I-SceI. However, these strains remained tolerant to other DSB-generating genotoxic agents or perturbations to which recA and recBC mutants remained sensitive, such as to mitomycin C, type-2 DNA topoisomerase inhibitors, or DSB caused by palindrome cleavage behind a replication fork. Data from genome-wide copy number analyses following I-SceI cleavage at a single chromosomal locus suggested that, in a strain lacking IF2-1, the magnitude of recombination-dependent replication through replication restart mechanisms is largely preserved but the extent of DNA resection around the DSB site is reduced. We propose that in the absence of IF2-1 it is the synapsis of a RecA nucleoprotein filament to its homologous target that is weakened, which in turn leads to a specific failure in assembly of Ter-to-oriC directed replisomes needed for consummation of two-ended DSB repair. IMPORTANCE Double-strand breaks (DSBs) in DNA are major threats to genome integrity. In Escherichia coli, DSBs are repaired by RecA- and RecBCD-mediated homologous recombination (HR). This study demonstrates a critical role for an isoform (IF2-1) of the translation initiation factor IF2 in the repair of two-ended DSBs in E. coli (that can be generated by ionizing radiation, certain DNA-damaging chemicals, or endonuclease action). It is proposed that IF2-1 acts to facilitate the function of RecA in the synapsis between a pair of DNA molecules during HR.
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20
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Peraza-Vega RI, Valverde M, Rojas E. Interactions between miRNAs and Double-Strand Breaks DNA Repair Genes, Pursuing a Fine-Tuning of Repair. Int J Mol Sci 2022; 23:3231. [PMID: 35328651 DOI: 10.3390/ijms23063231] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Revised: 03/06/2022] [Accepted: 03/09/2022] [Indexed: 02/04/2023] Open
Abstract
The repair of DNA damage is a crucial process for the correct maintenance of genetic information, thus, allowing the proper functioning of cells. Among the different types of lesions occurring in DNA, double-strand breaks (DSBs) are considered the most harmful type of lesion, which can result in significant loss of genetic information, leading to diseases, such as cancer. DSB repair occurs through two main mechanisms, called non-homologous end joining (NHEJ) and homologous recombination repair (HRR). There is evidence showing that miRNAs play an important role in the regulation of genes acting in NHEJ and HRR mechanisms, either through direct complementary binding to mRNA targets, thus, repressing translation, or by targeting other genes involved in the transcription and activity of DSB repair genes. Therefore, alteration of miRNA expression has an impact on the ability of cells to repair DSBs, which, in turn, affects cancer therapy sensitivity. This latter gives account of the importance of miRNAs as regulators of NHEJ and HRR and places them as a promising target to improve cancer therapy. Here, we review recent reports demonstrating an association between miRNAs and genes involved in NHEJ and HRR. We employed the Web of Science search query TS (“gene official symbol/gene aliases*” AND “miRNA/microRNA/miR-”) and focused on articles published in the last decade, between 2010 and 2021. We also performed a data analysis to represent miRNA–mRNA validated interactions from TarBase v.8, in order to offer an updated overview about the role of miRNAs as regulators of DSB repair.
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21
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Kwon T, Ra JS, Lee S, Baek IJ, Khim KW, Lee EA, Song EK, Otarbayev D, Jung W, Park YH, Wie M, Bae J, Cheng H, Park JH, Kim N, Seo Y, Yun S, Kim HE, Moon HE, Paek SH, Park TJ, Park YU, Rhee H, Choi JH, Cho SW, Myung K. Precision targeting tumor cells using cancer-specific InDel mutations with CRISPR-Cas9. Proc Natl Acad Sci U S A 2022; 119:e2103532119. [PMID: 35217600 DOI: 10.1073/pnas.2103532119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/21/2022] [Indexed: 11/29/2022] Open
Abstract
The targeted killing of cancer cells without affecting surrounding normal cells is the most desirable approach for cancer therapy; however, it cannot be easily achieved, owing to the shared properties of normal and cancer cells. Using CRISPR-Cas9 targeting multiple cancer-specific mutations, we developed an innovative approach called cancer-specific insertions and deletions attacker that can induce targeted cancer cell death by simultaneous and multiple DNA double-strand breaks. As demonstrated in cell lines, cancer patient–driven cells and xenografts, the concept proposed in this study may become a potential approach for personalized cancer treatments. An ideal cancer therapeutic strategy involves the selective killing of cancer cells without affecting the surrounding normal cells. However, researchers have failed to develop such methods for achieving selective cancer cell death because of shared features between cancerous and normal cells. In this study, we have developed a therapeutic strategy called the cancer-specific insertions–deletions (InDels) attacker (CINDELA) to selectively induce cancer cell death using the CRISPR-Cas system. CINDELA utilizes a previously unexplored idea of introducing CRISPR-mediated DNA double-strand breaks (DSBs) in a cancer-specific fashion to facilitate specific cell death. In particular, CINDELA targets multiple InDels with CRISPR-Cas9 to produce many DNA DSBs that result in cancer-specific cell death. As a proof of concept, we demonstrate here that CINDELA selectively kills human cancer cell lines, xenograft human tumors in mice, patient-derived glioblastoma, and lung patient-driven xenograft tumors without affecting healthy human cells or altering mouse growth.
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22
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Mladenova V, Mladenov E, Stuschke M, Iliakis G. DNA Damage Clustering after Ionizing Radiation and Consequences in the Processing of Chromatin Breaks. Molecules 2022; 27:1540. [PMID: 35268641 DOI: 10.3390/molecules27051540] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 02/21/2022] [Accepted: 02/22/2022] [Indexed: 11/26/2022] Open
Abstract
Charged-particle radiotherapy (CPRT) utilizing low and high linear energy transfer (low-/high-LET) ionizing radiation (IR) is a promising cancer treatment modality having unique physical energy deposition properties. CPRT enables focused delivery of a desired dose to the tumor, thus achieving a better tumor control and reduced normal tissue toxicity. It increases the overall radiation tolerance and the chances of survival for the patient. Further improvements in CPRT are expected from a better understanding of the mechanisms governing the biological effects of IR and their dependence on LET. There is increasing evidence that high-LET IR induces more complex and even clustered DNA double-strand breaks (DSBs) that are extremely consequential to cellular homeostasis, and which represent a considerable threat to genomic integrity. However, from the perspective of cancer management, the same DSB characteristics underpin the expected therapeutic benefit and are central to the rationale guiding current efforts for increased implementation of heavy ions (HI) in radiotherapy. Here, we review the specific cellular DNA damage responses (DDR) elicited by high-LET IR and compare them to those of low-LET IR. We emphasize differences in the forms of DSBs induced and their impact on DDR. Moreover, we analyze how the distinct initial forms of DSBs modulate the interplay between DSB repair pathways through the activation of DNA end resection. We postulate that at complex DSBs and DSB clusters, increased DNA end resection orchestrates an increased engagement of resection-dependent repair pathways. Furthermore, we summarize evidence that after exposure to high-LET IR, error-prone processes outcompete high fidelity homologous recombination (HR) through mechanisms that remain to be elucidated. Finally, we review the high-LET dependence of specific DDR-related post-translational modifications and the induction of apoptosis in cancer cells. We believe that in-depth characterization of the biological effects that are specific to high-LET IR will help to establish predictive and prognostic signatures for use in future individualized therapeutic strategies, and will enhance the prospects for the development of effective countermeasures for improved radiation protection during space travel.
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23
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Abstract
The most common human lymphoid chromosomal translocations involve concurrent failures of the recombination activating gene (RAG) complex and Activation-Induced Deaminase (AID). These are two enzymes that are normally expressed for purposes of the two site-specific DNA recombination processes: V(D)J recombination and class switch recombination (CSR). First, though it is rare, a low level of expression of AID can introduce long-lived T:G mismatch lesions at 20-600 bp fragile zones. Second, the V(D)J recombination process can occasionally fail to rejoin coding ends, and this failure may permit an opportunity for Artemis:DNA-dependent kinase catalytic subunit (DNA-PKcs) to convert the T:G mismatch sites at the fragile zones into double-strand breaks. The 20-600 bp fragile zones must be, at least transiently, in a single-stranded DNA (ssDNA) state for the first step to occur, because AID only acts on ssDNA. Here we discuss the key DNA sequence features that lead to AID action at a fragile zone, which are (a) the proximity and density of strings of cytosine nucleotides (C-strings) that cause a B/A-intermediate DNA conformation; (b) overlapping AID hotspots that contain a methyl CpG (WRCG), which AID converts to a long-lived T:G mismatch; and (c) transcription, which, though not essential, favors increased ssDNA in the fragile zone. We also summarize chromosomal features of the focal fragile zones in lymphoid malignancies and discuss the clinical relevance of understanding the translocation mechanisms. Many of the key principles covered here are also relevant to chromosomal translocations in non-lymphoid somatic cells as well.
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Affiliation(s)
- Di Liu
- Department of Pathology & Laboratory Medicine, Department of Biochemistry & Molecular Biology, Department of Molecular Microbiology and Immunology, and Section of Computational Biology in the Department of Biological Sciences, USC Norris Comprehensive Cancer Center, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Michael R Lieber
- Department of Pathology & Laboratory Medicine, Department of Biochemistry & Molecular Biology, Department of Molecular Microbiology and Immunology, and Section of Computational Biology in the Department of Biological Sciences, USC Norris Comprehensive Cancer Center, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
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Hussmann JA, Ling J, Ravisankar P, Yan J, Cirincione A, Xu A, Simpson D, Yang D, Bothmer A, Cotta-Ramusino C, Weissman JS, Adamson B. Mapping the genetic landscape of DNA double-strand break repair. Cell 2021; 184:5653-5669.e25. [PMID: 34672952 PMCID: PMC9074467 DOI: 10.1016/j.cell.2021.10.002] [Citation(s) in RCA: 75] [Impact Index Per Article: 25.0] [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: 06/06/2021] [Revised: 08/31/2021] [Accepted: 09/29/2021] [Indexed: 12/20/2022]
Abstract
Cells repair DNA double-strand breaks (DSBs) through a complex set of pathways critical for maintaining genomic integrity. To systematically map these pathways, we developed a high-throughput screening approach called Repair-seq that measures the effects of thousands of genetic perturbations on mutations introduced at targeted DNA lesions. Using Repair-seq, we profiled DSB repair products induced by two programmable nucleases (Cas9 and Cas12a) in the presence or absence of oligonucleotides for homology-directed repair (HDR) after knockdown of 476 genes involved in DSB repair or associated processes. The resulting data enabled principled, data-driven inference of DSB end joining and HDR pathways. Systematic interrogation of this data uncovered unexpected relationships among DSB repair genes and demonstrated that repair outcomes with superficially similar sequence architectures can have markedly different genetic dependencies. This work provides a foundation for mapping DNA repair pathways and for optimizing genome editing across diverse modalities.
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Affiliation(s)
- Jeffrey A Hussmann
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA 94158, USA; Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, CA 94158, USA; Howard Hughes Medical Institute, University of California, San Francisco, San Francisco, CA 94158, USA; Whitehead Institute for Biomedical Research, Massachusetts Institute of Technology, Cambridge, MA 02142, USA
| | - Jia Ling
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA
| | - Purnima Ravisankar
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA
| | - Jun Yan
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
| | - Ann Cirincione
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA
| | - Albert Xu
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA 94158, USA; Howard Hughes Medical Institute, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Danny Simpson
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA
| | - Dian Yang
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA 94158, USA; Howard Hughes Medical Institute, University of California, San Francisco, San Francisco, CA 94158, USA; Whitehead Institute for Biomedical Research, Massachusetts Institute of Technology, Cambridge, MA 02142, USA
| | | | | | - Jonathan S Weissman
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA 94158, USA; Howard Hughes Medical Institute, University of California, San Francisco, San Francisco, CA 94158, USA; Whitehead Institute for Biomedical Research, Massachusetts Institute of Technology, Cambridge, MA 02142, USA; Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
| | - Britt Adamson
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA; Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA.
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Sharda M, Badrinarayanan A, Seshasayee ASN. Evolutionary and Comparative Analysis of Bacterial Nonhomologous End Joining Repair. Genome Biol Evol 2021; 12:2450-2466. [PMID: 33078828 PMCID: PMC7719229 DOI: 10.1093/gbe/evaa223] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/14/2020] [Indexed: 01/04/2023] Open
Abstract
DNA double-strand breaks (DSBs) are a threat to genome stability. In all domains of life, DSBs are faithfully fixed via homologous recombination. Recombination requires the presence of an uncut copy of duplex DNA which is used as a template for repair. Alternatively, in the absence of a template, cells utilize error-prone nonhomologous end joining (NHEJ). Although ubiquitously found in eukaryotes, NHEJ is not universally present in bacteria. It is unclear as to why many prokaryotes lack this pathway. Toward understanding what could have led to the current distribution of bacterial NHEJ, we carried out comparative genomics and phylogenetic analysis across ∼6,000 genomes. Our results show that this pathway is sporadically distributed across the phylogeny. Ancestral reconstruction further suggests that NHEJ was absent in the eubacterial ancestor and can be acquired via specific routes. Integrating NHEJ occurrence data for archaea, we also find evidence for extensive horizontal exchange of NHEJ genes between the two kingdoms as well as across bacterial clades. The pattern of occurrence in bacteria is consistent with correlated evolution of NHEJ with key genome characteristics of genome size and growth rate; NHEJ presence is associated with large genome sizes and/or slow growth rates, with the former being the dominant correlate. Given the central role these traits play in determining the ability to carry out recombination, it is possible that the evolutionary history of bacterial NHEJ may have been shaped by requirement for efficient DSB repair.
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Affiliation(s)
- Mohak Sharda
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bangalore, Karnataka, India.,School of Life Science, The University of Trans-Disciplinary Health Sciences & Technology (TDU), Bangalore, Karnataka, India
| | - Anjana Badrinarayanan
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bangalore, Karnataka, India
| | - Aswin Sai Narain Seshasayee
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bangalore, Karnataka, India
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Kendek A, Wensveen MR, Janssen A. The Sound of Silence: How Silenced Chromatin Orchestrates the Repair of Double-Strand Breaks. Genes (Basel) 2021; 12:1415. [PMID: 34573397 DOI: 10.3390/genes12091415] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Revised: 09/07/2021] [Accepted: 09/13/2021] [Indexed: 12/29/2022] Open
Abstract
The eukaryotic nucleus is continuously being exposed to endogenous and exogenous sources that cause DNA breaks, whose faithful repair requires the activity of dedicated nuclear machineries. DNA is packaged into a variety of chromatin domains, each characterized by specific molecular properties that regulate gene expression and help maintain nuclear structure. These different chromatin environments each demand a tailored response to DNA damage. Silenced chromatin domains in particular present a major challenge to the cell’s DNA repair machinery due to their specific biophysical properties and distinct, often repetitive, DNA content. To this end, we here discuss the interplay between silenced chromatin domains and DNA damage repair, specifically double-strand breaks, and how these processes help maintain genome stability.
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Wozny AS, Gauthier A, Alphonse G, Malésys C, Varoclier V, Beuve M, Brichart-Vernos D, Magné N, Vial N, Ardail D, Nakajima T, Rodriguez-Lafrasse C. Involvement of HIF-1α in the Detection, Signaling, and Repair of DNA Double-Strand Breaks after Photon and Carbon-Ion Irradiation. Cancers (Basel) 2021; 13:cancers13153833. [PMID: 34359734 PMCID: PMC8345054 DOI: 10.3390/cancers13153833] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 07/22/2021] [Accepted: 07/26/2021] [Indexed: 01/31/2023] Open
Abstract
Simple Summary Hypoxia-Inducible Factor 1α (HIF-1α), the main regulator of the oxygen homeostasis, promotes cancer cell survival through proliferation, angiogenesis, metastasis and radioresistance. Previously, our group demonstrated that silencing HIF-1α under hypoxia leads to a substantial radiosensitization of Head-and-Neck Squamous Cell Carcinoma (HNSCC) cells after both photons and carbon-ions, probably resulting from an accumulation of deleterious complex DNA damage. In this study, we aimed at determining the potential role of HIF-1α in the detection, signaling, and repair of DNA Double-Strand-Breaks (DSBs) in response to both irradiations, under hypoxia, in two HNSCC cell lines and their subpopulations of Cancer-Stem Cells (CSCs). Silencing HIF-1α under hypoxia led us to demonstrate the involvement of this transcriptional regulator in DSB repair in non-CSCS and CSC, thus highlighting its targeting together with radiation as a promising therapeutic strategy against radioresistant tumor cells in hypoxic niches. Abstract Hypoxia-Inducible Factor 1α (HIF-1α), which promotes cancer cell survival, is the main regulator of oxygen homeostasis. Hypoxia combined with photon and carbon ion irradiation (C-ions) stabilizes HIF-1α. Silencing HIF-1α under hypoxia leads to substantial radiosensitization of Head-and-Neck Squamous Cell Carcinoma (HNSCC) cells after both photons and C-ions. Thus, this study aimed to clarify a potential involvement of HIF-1α in the detection, signaling, and repair of DNA Double-Strand-Breaks (DSBs) in response to both irradiations, in two HNSCC cell lines and their subpopulations of Cancer-Stem Cells (CSCs). After confirming the nucleoshuttling of HIF-1α in response to both exposure under hypoxia, we showed that silencing HIF-1α in non-CSCs and CSCs decreased the initiation of the DSB detection (P-ATM), and increased the residual phosphorylated H2AX (γH2AX) foci. While HIF-1α silencing did not modulate 53BP1 expression, P-DNA-PKcs (NHEJ-c) and RAD51 (HR) signals decreased. Altogether, our experiments demonstrate the involvement of HIF-1α in the detection and signaling of DSBs, but also in the main repair pathways (NHEJ-c and HR), without favoring one of them. Combining HIF-1α silencing with both types of radiation could therefore present a potential therapeutic benefit of targeting CSCs mostly present in tumor hypoxic niches.
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Affiliation(s)
- Anne-Sophie Wozny
- Cellular and Molecular Radiobiology Laboratory, Lyon-Sud Medical School, UMR CNRS5822/IP2I, Univ Lyon, Lyon 1 University, 69921 Oullins, France; (A.-S.W.); (A.G.); (G.A.); (C.M.); (V.V.); (D.B.-V.); (N.M.); (N.V.); (D.A.)
- Department of Biochemistry and Molecular Biology, Lyon-Sud Hospital, Hospices Civils de Lyon, 69310 Pierre-Bénite, France
| | - Arnaud Gauthier
- Cellular and Molecular Radiobiology Laboratory, Lyon-Sud Medical School, UMR CNRS5822/IP2I, Univ Lyon, Lyon 1 University, 69921 Oullins, France; (A.-S.W.); (A.G.); (G.A.); (C.M.); (V.V.); (D.B.-V.); (N.M.); (N.V.); (D.A.)
- Department of Biochemistry and Molecular Biology, Lyon-Sud Hospital, Hospices Civils de Lyon, 69310 Pierre-Bénite, France
| | - Gersende Alphonse
- Cellular and Molecular Radiobiology Laboratory, Lyon-Sud Medical School, UMR CNRS5822/IP2I, Univ Lyon, Lyon 1 University, 69921 Oullins, France; (A.-S.W.); (A.G.); (G.A.); (C.M.); (V.V.); (D.B.-V.); (N.M.); (N.V.); (D.A.)
- Department of Biochemistry and Molecular Biology, Lyon-Sud Hospital, Hospices Civils de Lyon, 69310 Pierre-Bénite, France
| | - Céline Malésys
- Cellular and Molecular Radiobiology Laboratory, Lyon-Sud Medical School, UMR CNRS5822/IP2I, Univ Lyon, Lyon 1 University, 69921 Oullins, France; (A.-S.W.); (A.G.); (G.A.); (C.M.); (V.V.); (D.B.-V.); (N.M.); (N.V.); (D.A.)
| | - Virginie Varoclier
- Cellular and Molecular Radiobiology Laboratory, Lyon-Sud Medical School, UMR CNRS5822/IP2I, Univ Lyon, Lyon 1 University, 69921 Oullins, France; (A.-S.W.); (A.G.); (G.A.); (C.M.); (V.V.); (D.B.-V.); (N.M.); (N.V.); (D.A.)
| | - Michael Beuve
- Univ Lyon, Lyon 1 University, UMR CNRS5822/IP2I, 69100 Villeurbanne, France;
| | - Delphine Brichart-Vernos
- Cellular and Molecular Radiobiology Laboratory, Lyon-Sud Medical School, UMR CNRS5822/IP2I, Univ Lyon, Lyon 1 University, 69921 Oullins, France; (A.-S.W.); (A.G.); (G.A.); (C.M.); (V.V.); (D.B.-V.); (N.M.); (N.V.); (D.A.)
| | - Nicolas Magné
- Cellular and Molecular Radiobiology Laboratory, Lyon-Sud Medical School, UMR CNRS5822/IP2I, Univ Lyon, Lyon 1 University, 69921 Oullins, France; (A.-S.W.); (A.G.); (G.A.); (C.M.); (V.V.); (D.B.-V.); (N.M.); (N.V.); (D.A.)
- Department of Radiotherapy, Institute of Cancerology Lucien Neuwirth, 42270 Saint-Priest-en-Jarez, France
| | - Nicolas Vial
- Cellular and Molecular Radiobiology Laboratory, Lyon-Sud Medical School, UMR CNRS5822/IP2I, Univ Lyon, Lyon 1 University, 69921 Oullins, France; (A.-S.W.); (A.G.); (G.A.); (C.M.); (V.V.); (D.B.-V.); (N.M.); (N.V.); (D.A.)
- Department of Radiotherapy, Institute of Cancerology Lucien Neuwirth, 42270 Saint-Priest-en-Jarez, France
| | - Dominique Ardail
- Cellular and Molecular Radiobiology Laboratory, Lyon-Sud Medical School, UMR CNRS5822/IP2I, Univ Lyon, Lyon 1 University, 69921 Oullins, France; (A.-S.W.); (A.G.); (G.A.); (C.M.); (V.V.); (D.B.-V.); (N.M.); (N.V.); (D.A.)
| | - Tetsuo Nakajima
- Department of Radiation Effects Research, National Institute of Radiological Sciences, National Institute for Quantum and Radiological Science and Technology, Chiba 263-8555, Japan;
| | - Claire Rodriguez-Lafrasse
- Cellular and Molecular Radiobiology Laboratory, Lyon-Sud Medical School, UMR CNRS5822/IP2I, Univ Lyon, Lyon 1 University, 69921 Oullins, France; (A.-S.W.); (A.G.); (G.A.); (C.M.); (V.V.); (D.B.-V.); (N.M.); (N.V.); (D.A.)
- Department of Biochemistry and Molecular Biology, Lyon-Sud Hospital, Hospices Civils de Lyon, 69310 Pierre-Bénite, France
- Correspondence: ; Tel.: +33-426-235-965
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Liu D, Loh YHE, Hsieh CL, Lieber MR. Mechanistic basis for chromosomal translocations at the E2A gene and its broader relevance to human B cell malignancies. Cell Rep 2021; 36:109387. [PMID: 34260910 PMCID: PMC8327686 DOI: 10.1016/j.celrep.2021.109387] [Citation(s) in RCA: 3] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2021] [Revised: 03/31/2021] [Accepted: 06/21/2021] [Indexed: 11/22/2022] Open
Abstract
Analysis of translocation breakpoints in human B cell malignancies reveals that DNA double-strand breaks at oncogenes most frequently occur at CpG sites located within 20-600 bp fragile zones and depend on activation-induced deaminase (AID). AID requires single-stranded DNA (ssDNA) to act, but it has been unclear why or how this region transiently acquires a ssDNA state. Here, we demonstrate the ssDNA state in the 23 bp E2A fragile zone using several methods, including native bisulfite DNA structural analysis in live human pre-B cells. AID deamination within the E2A fragile zone does not require but is increased upon transcription. High C-string density, nascent RNA tails, and direct DNA sequence repeats prolong the ssDNA state of the E2A fragile zone and increase AID deamination at overlapping AID hotspots that contain the CpG sites at which breaks occur in patients. These features provide key insights into lymphoid fragile zones generally.
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Affiliation(s)
- Di Liu
- Departments of Pathology, Biochemistry & Molecular Biology, and Molecular Microbiology & Immunology, and Section of Molecular & Computational Biology (Department of Biological Sciences), USC Norris Comprehensive Cancer Center, University of Southern California and USC Keck School of Medicine, Los Angeles, CA, USA
| | - Yong-Hwee Eddie Loh
- USC Libraries Bioinformatics Services, University of Southern California and USC Keck School of Medicine, Los Angeles, CA, USA
| | - Chih-Lin Hsieh
- Department of Urology, USC Norris Comprehensive Cancer Center, University of Southern California and USC Keck School of Medicine, Los Angeles, CA, USA
| | - Michael R Lieber
- Departments of Pathology, Biochemistry & Molecular Biology, and Molecular Microbiology & Immunology, and Section of Molecular & Computational Biology (Department of Biological Sciences), USC Norris Comprehensive Cancer Center, University of Southern California and USC Keck School of Medicine, Los Angeles, CA, USA.
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Abstract
This Outlook discusses Mu et al.’s finding showing that synaptonemal complex (SC) formation between individual chromosomes provides the feedback to down-regulate Spo11 activity, thereby revealing an additional function for the SC. Proper segregation during meiosis requires that homologs be connected by the combination of crossovers and sister chromatid cohesion. To generate crossovers, numerous double-strand breaks (DSBs) are introduced throughout the genome by the conserved Spo11 endonuclease. DSB formation and its repair are then highly regulated to ensure that homologous chromosomes contain at least one crossover and no DSBs remain prior to meiosis I segregation. The synaptonemal complex (SC) is a meiosis-specific structure formed between homologous chromosomes during prophase that promotes DSB formation and biases repair of DSBs to homologs over sister chromatids. Synapsis occurs when a particular recombination pathway is successful in establishing stable interhomolog connections. In this issue of Genes & Development, Mu and colleagues (pp. 1605–1618) show that SC formation between individual chromosomes provides the feedback to down-regulate Spo11 activity, thereby revealing an additional function for the SC.
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Affiliation(s)
- Nancy M Hollingsworth
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, New York 11794, USA
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Bergero R, Ellis P, Haerty W, Larcombe L, Macaulay I, Mehta T, Mogensen M, Murray D, Nash W, Neale MJ, O'Connor R, Ottolini C, Peel N, Ramsey L, Skinner B, Suh A, Summers M, Sun Y, Tidy A, Rahbari R, Rathje C, Immler S. Meiosis and beyond - understanding the mechanistic and evolutionary processes shaping the germline genome. Biol Rev Camb Philos Soc 2021; 96:822-841. [PMID: 33615674 PMCID: PMC8246768 DOI: 10.1111/brv.12680] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [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: 11/26/2019] [Revised: 12/15/2020] [Accepted: 12/15/2020] [Indexed: 12/11/2022]
Abstract
The separation of germ cell populations from the soma is part of the evolutionary transition to multicellularity. Only genetic information present in the germ cells will be inherited by future generations, and any molecular processes affecting the germline genome are therefore likely to be passed on. Despite its prevalence across taxonomic kingdoms, we are only starting to understand details of the underlying micro-evolutionary processes occurring at the germline genome level. These include segregation, recombination, mutation and selection and can occur at any stage during germline differentiation and mitotic germline proliferation to meiosis and post-meiotic gamete maturation. Selection acting on germ cells at any stage from the diploid germ cell to the haploid gametes may cause significant deviations from Mendelian inheritance and may be more widespread than previously assumed. The mechanisms that affect and potentially alter the genomic sequence and allele frequencies in the germline are pivotal to our understanding of heritability. With the rise of new sequencing technologies, we are now able to address some of these unanswered questions. In this review, we comment on the most recent developments in this field and identify current gaps in our knowledge.
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Affiliation(s)
- Roberta Bergero
- Institute of Evolutionary BiologyUniversity of EdinburghEdinburghEH9 3JTU.K.
| | - Peter Ellis
- School of BiosciencesUniversity of KentCanterburyCT2 7NJU.K.
| | | | - Lee Larcombe
- Applied Exomics LtdStevenage Bioscience CatalystStevenageSG1 2FXU.K.
| | - Iain Macaulay
- Earlham InstituteNorwich Research ParkNorwichNR4 7UZU.K.
| | - Tarang Mehta
- Earlham InstituteNorwich Research ParkNorwichNR4 7UZU.K.
| | - Mette Mogensen
- School of Biological SciencesUniversity of East AngliaNorwich Research ParkNorwichNR4 7TJU.K.
| | - David Murray
- School of Biological SciencesUniversity of East AngliaNorwich Research ParkNorwichNR4 7TJU.K.
| | - Will Nash
- Earlham InstituteNorwich Research ParkNorwichNR4 7UZU.K.
| | - Matthew J. Neale
- Genome Damage and Stability Centre, School of Life SciencesUniversity of SussexBrightonBN1 9RHU.K.
| | | | | | - Ned Peel
- Earlham InstituteNorwich Research ParkNorwichNR4 7UZU.K.
| | - Luke Ramsey
- The James Hutton InstituteInvergowrieDundeeDD2 5DAU.K.
| | - Ben Skinner
- School of Life SciencesUniversity of EssexColchesterCO4 3SQU.K.
| | - Alexander Suh
- School of Biological SciencesUniversity of East AngliaNorwich Research ParkNorwichNR4 7TJU.K.
- Department of Organismal BiologyUppsala UniversityNorbyvägen 18DUppsala752 36Sweden
| | - Michael Summers
- School of BiosciencesUniversity of KentCanterburyCT2 7NJU.K.
- The Bridge Centre1 St Thomas Street, London BridgeLondonSE1 9RYU.K.
| | - Yu Sun
- Norwich Medical SchoolUniversity of East AngliaNorwich Research Park, Colney LnNorwichNR4 7UGU.K.
| | - Alison Tidy
- School of BiosciencesUniversity of Nottingham, Plant Science, Sutton Bonington CampusSutton BoningtonLE12 5RDU.K.
| | | | - Claudia Rathje
- School of BiosciencesUniversity of KentCanterburyCT2 7NJU.K.
| | - Simone Immler
- School of Biological SciencesUniversity of East AngliaNorwich Research ParkNorwichNR4 7TJU.K.
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Moradi MS, Bidabadi BS. Assessment of Single-and Double-Strand Breaks in DNA Induced by Auger Electrons of Radioisotopes Used in Diagnostic and Therapeutic Applications. J Med Phys 2021; 45:240-248. [PMID: 33953500 PMCID: PMC8074716 DOI: 10.4103/jmp.jmp_79_19] [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] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2019] [Revised: 12/02/2020] [Accepted: 12/02/2020] [Indexed: 11/30/2022] Open
Abstract
Introduction: Most of the radionuclides that are used for diagnostic purposes emit Auger electrons and can thus cause damage to the DNA molecule on a nanometer scale. Therefore, the nanodosimetric calculation of these radioisotopes is necessary to achieve better understanding on their effects. Aim: The aim of this study was to calculate the mean number of DNA strand breaks (single-strand breaks and double-strand breaks) caused by direct and indirect effects for six widely used Auger electron-emitting diagnostic radioisotopes, including 123I, 125I, 99mTc, 67Ga, 201Tl, 111In and two therapeutic radioisotopes of 131I(beta + Auger + CK emitter) and 211At(alpha + Auger + CK emitter). Materials and Methods: Geant4-DNA simulation tool was used to evaluate the effects of Auger electrons, beta and alpha particles of these radioisotopes on DNA molecules. Two different DNA molecule geometric models were simulated and the results of these two models were compared with each other as well as with the results of previous studies. Results and Conclusion: The results showed that the geometric shape of the sugar-phosphate groups may have a significant effect on the number of single-strand breaks (SSBs) and double-strand breaks (DSBs) of the DNA molecule. Among the most widely used diagnostic radioisotopes, 201Tl and 125I, had the greatest impact on the number of SSBs and DSBs, respectively, while therapeutic radioisotope of 131I almost had no effect, therapeutic radioisotope of 211At had the moderate effect on the number of breaks in the DNA chain.
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Affiliation(s)
- Mahdi Seifi Moradi
- Department of Nuclear Engineering, Faculty of Physics, University of Isfahan, Isfahan, Iran
| | - Babak Shirani Bidabadi
- Department of Nuclear Engineering, Faculty of Physics, University of Isfahan, Isfahan, Iran
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Derlin T, Bogdanova N, Ohlendorf F, Ramachandran D, Werner RA, Ross TL, Christiansen H, Bengel FM, Henkenberens C. Assessment of γ-H2AX and 53BP1 Foci in Peripheral Blood Lymphocytes to Predict Subclinical Hematotoxicity and Response in Somatostatin Receptor-Targeted Radionuclide Therapy for Advanced Gastroenteropancreatic Neuroendocrine Tumors. Cancers (Basel) 2021; 13:cancers13071516. [PMID: 33806081 PMCID: PMC8036952 DOI: 10.3390/cancers13071516] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Revised: 03/16/2021] [Accepted: 03/20/2021] [Indexed: 01/11/2023] Open
Abstract
BACKGROUND We aimed to characterize γ-H2AX and 53BP1 foci formation in patients receiving somatostatin receptor-targeted radioligand therapy, and explored its role for predicting treatment-related hematotoxicity, and treatment response. METHODS A prospective analysis of double-strand break (DSB) markers was performed in 21 patients with advanced gastroenteropancreatic neuroendocrine tumors. γ-H2AX and 53BP1 foci formation were evaluated in peripheral blood lymphocytes (PBLs) at baseline, +1 h and +24 h after administration of 7.4 GBq (177Lu)Lu-DOTA-TATE. Hematotoxicity was evaluated using standard hematology. Therapy response was assessed using (68Ga)Ga-DOTA-TATE PET/CT before enrollment and after 2 cycles of PRRT according to the volumetric modification of RECIST 1.1. RESULTS DSB marker kinetics were heterogeneous among patients. Subclinical hematotoxicity was associated with γ-H2AX and 53BP1 foci formation (e.g., change in platelet count vs change in γ-H2AX+ cells between baseline and +1 h (r = -0.6080; p = 0.0045). Patients showing early development of new metastases had less γ-H2AX (p = 0.0125) and less 53BP1 foci per cell at +1 h (p = 0.0289), and demonstrated a distinct kinetic pattern with an absence of DSB marker decrease at +24 h (γ-H2AX: p = 0.0025; 53BP1: p = 0.0008). CONCLUSIONS Assessment of γ-H2AX and 53BP1 foci formation in PBLs of patients receiving radioligand therapy may hold promise for predicting subclinical hematotoxicity and early treatment response.
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Affiliation(s)
- Thorsten Derlin
- Department of Nuclear Medicine, Hannover Medical School, 30625 Hannover, Germany; (F.O.); (R.A.W.); (T.L.R.); (F.M.B.)
- Correspondence: ; Tel.: +49-(0)5115322579; Fax: +49-(0)5115323761
| | - Natalia Bogdanova
- Department of Radiation Oncology, Hannover Medical School, 30625 Hannover, Germany; (N.B.); (H.C.); (C.H.)
| | - Fiona Ohlendorf
- Department of Nuclear Medicine, Hannover Medical School, 30625 Hannover, Germany; (F.O.); (R.A.W.); (T.L.R.); (F.M.B.)
| | - Dhanya Ramachandran
- Department of Radiation Oncology, and Gynaecology Research Unit, Hannover Medical School, 30625 Hannover, Germany;
| | - Rudolf A. Werner
- Department of Nuclear Medicine, Hannover Medical School, 30625 Hannover, Germany; (F.O.); (R.A.W.); (T.L.R.); (F.M.B.)
| | - Tobias L. Ross
- Department of Nuclear Medicine, Hannover Medical School, 30625 Hannover, Germany; (F.O.); (R.A.W.); (T.L.R.); (F.M.B.)
| | - Hans Christiansen
- Department of Radiation Oncology, Hannover Medical School, 30625 Hannover, Germany; (N.B.); (H.C.); (C.H.)
| | - Frank M. Bengel
- Department of Nuclear Medicine, Hannover Medical School, 30625 Hannover, Germany; (F.O.); (R.A.W.); (T.L.R.); (F.M.B.)
| | - Christoph Henkenberens
- Department of Radiation Oncology, Hannover Medical School, 30625 Hannover, Germany; (N.B.); (H.C.); (C.H.)
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Marsella A, Gobbini E, Cassani C, Tisi R, Cannavo E, Reginato G, Cejka P, Longhese MP. Sae2 and Rif2 regulate MRX endonuclease activity at DNA double-strand breaks in opposite manners. Cell Rep 2021; 34:108906. [PMID: 33789097 PMCID: PMC8028314 DOI: 10.1016/j.celrep.2021.108906] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Revised: 01/29/2021] [Accepted: 03/04/2021] [Indexed: 11/17/2022] Open
Abstract
The Mre11-Rad50-Xrs2 (MRX) complex detects and processes DNA double-strand breaks (DSBs). Its DNA binding and processing activities are regulated by transitions between an ATP-bound state and a post-hydrolysis cutting state that is nucleolytically active. Mre11 endonuclease activity is stimulated by Sae2, whose lack increases MRX persistence at DSBs and checkpoint activation. Here we show that the Rif2 protein inhibits Mre11 endonuclease activity and is responsible for the increased MRX retention at DSBs in sae2Δ cells. We identify a Rad50 residue that is important for Rad50-Rif2 interaction and Rif2 inhibition of Mre11 nuclease. This residue is located near a Rad50 surface that binds Sae2 and is important in stabilizing the Mre11-Rad50 (MR) interaction in the cutting state. We propose that Sae2 stimulates Mre11 endonuclease activity by stabilizing a post-hydrolysis MR conformation that is competent for DNA cleavage, whereas Rif2 antagonizes this Sae2 function and stabilizes an endonuclease inactive MR conformation. Sae2 stimulates Mre11 endonuclease activity by stabilizing the MRX cutting state Rif2 inhibits Sae2-mediated stimulation of Mre11 endonuclease activity The rad50-N18S mutation escapes Rif2-mediated inhibition of Mre11 nuclease Rif2 stabilizes an endonuclease inactive MR conformation that persistently binds DSBs
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Affiliation(s)
- Antonio Marsella
- Dipartimento di Biotecnologie e Bioscienze, Università degli Studi di Milano-Bicocca, Milano 20126, Italy
| | - Elisa Gobbini
- Dipartimento di Biotecnologie e Bioscienze, Università degli Studi di Milano-Bicocca, Milano 20126, Italy
| | - Corinne Cassani
- Dipartimento di Biotecnologie e Bioscienze, Università degli Studi di Milano-Bicocca, Milano 20126, Italy
| | - Renata Tisi
- Dipartimento di Biotecnologie e Bioscienze, Università degli Studi di Milano-Bicocca, Milano 20126, Italy
| | - Elda Cannavo
- Institute for Research in Biomedicine, Faculty of Biomedical Sciences, Università della Svizzera italiana (USI), Bellinzona, Switzerland
| | - Giordano Reginato
- Institute for Research in Biomedicine, Faculty of Biomedical Sciences, Università della Svizzera italiana (USI), Bellinzona, Switzerland; Department of Biology, Institute of Biochemistry, Eidgenössische Technische Hochschule (ETH), Zürich, Switzerland
| | - Petr Cejka
- Institute for Research in Biomedicine, Faculty of Biomedical Sciences, Università della Svizzera italiana (USI), Bellinzona, Switzerland; Department of Biology, Institute of Biochemistry, Eidgenössische Technische Hochschule (ETH), Zürich, Switzerland
| | - Maria Pia Longhese
- Dipartimento di Biotecnologie e Bioscienze, Università degli Studi di Milano-Bicocca, Milano 20126, Italy.
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34
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Mu X, Murakami H, Mohibullah N, Keeney S. Chromosome-autonomous feedback down-regulates meiotic DNA break competence upon synaptonemal complex formation. Genes Dev 2020; 34:1605-1618. [PMID: 33184224 PMCID: PMC7706706 DOI: 10.1101/gad.342873.120] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [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: 07/27/2020] [Accepted: 09/29/2020] [Indexed: 01/20/2023]
Abstract
The number of DNA double-strand breaks (DSBs) initiating meiotic recombination is elevated in Saccharomyces cerevisiae mutants that are globally defective in forming crossovers and synaptonemal complex (SC), a protein scaffold juxtaposing homologous chromosomes. These mutants thus appear to lack a negative feedback loop that inhibits DSB formation when homologs engage one another. This feedback is predicted to be chromosome autonomous, but this has not been tested. Moreover, what chromosomal process is recognized as "homolog engagement" remains unclear. To address these questions, we evaluated effects of homolog engagement defects restricted to small portions of the genome using karyotypically abnormal yeast strains with a homeologous chromosome V pair, monosomic V, or trisomy XV. We found that homolog engagement-defective chromosomes incurred more DSBs, concomitant with prolonged retention of the DSB-promoting protein Rec114, while the rest of the genome remained unaffected. SC-deficient, crossover-proficient mutants ecm11 and gmc2 experienced increased DSB numbers diagnostic of homolog engagement defects. These findings support the hypothesis that SC formation provokes DSB protein dissociation, leading in turn to loss of a DSB competent state. Our findings show that DSB number is regulated in a chromosome-autonomous fashion and provide insight into how homeostatic DSB controls respond to aneuploidy during meiosis.
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Affiliation(s)
- Xiaojing Mu
- Weill Cornell Graduate School of Medical Sciences, Cornell University, New York, New York 10021, USA
- Molecular Biology Program, Memorial Sloan Kettering Cancer Center, New York, New York 10065, USA
| | - Hajime Murakami
- Molecular Biology Program, Memorial Sloan Kettering Cancer Center, New York, New York 10065, USA
| | - Neeman Mohibullah
- Molecular Biology Program, Memorial Sloan Kettering Cancer Center, New York, New York 10065, USA
- Howard Hughes Medical Institute, Memorial Sloan Kettering Cancer Center, New York, New York 10065, USA
| | - Scott Keeney
- Weill Cornell Graduate School of Medical Sciences, Cornell University, New York, New York 10021, USA
- Molecular Biology Program, Memorial Sloan Kettering Cancer Center, New York, New York 10065, USA
- Howard Hughes Medical Institute, Memorial Sloan Kettering Cancer Center, New York, New York 10065, USA
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35
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Abstract
This Outlook discusses the findings by Pérez-Calero et al. reporting that, in addition to its RNA processing role, UAP56/DDX39B is a key helicase required to eliminate harmful cotranscriptional RNA structures that otherwise would block transcription and replication. R loops arise from hybridization of RNA transcripts with template DNA during transcription. Unrepaired R loops lead to transcription–replication collisions, causing DNA damage and genomic instability. In this issue of Genes & Development, Pérez-Calero and colleagues (pp. 898–912) identify UAP56 as a cotranscriptional RNA–DNA helicase that unwinds R loops. They found that UAP56 helicase activity is required to remove R loops formed from different sources and prevent R-loop accumulation genome-wide at actively transcribed genes.
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Affiliation(s)
- Jacob P Matson
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Charlestown, Massachusetts 02129, USA
| | - Lee Zou
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Charlestown, Massachusetts 02129, USA.,Department of Pathology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02114, USA
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36
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Abstract
Archaea often thrive in environmental extremes, enduring levels of heat, pressure, salinity, pH, and radiation that prove intolerable to most life. Many environmental extremes raise the propensity for DNA damaging events and thus, impact DNA stability, placing greater reliance on molecular mechanisms that recognize DNA damage and initiate accurate repair. Archaea can presumably prosper in harsh and DNA-damaging environments in part due to robust DNA repair pathways but surprisingly, no DNA repair pathways unique to Archaea have been described. Here, we review the most recent advances in our understanding of archaeal DNA repair. We summarize DNA damage types and their consequences, their recognition by host enzymes, and how the collective activities of many DNA repair pathways maintain archaeal genomic integrity.
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Affiliation(s)
| | - Thomas J. Santangelo
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO 80523, USA;
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37
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Gamble D, Shaltz S, Jinks-Robertson S. Recombinational Repair of Nuclease-Generated Mitotic Double-Strand Breaks with Different End Structures in Yeast. G3 (Bethesda) 2020; 10:3821-9. [PMID: 32826304 DOI: 10.1534/g3.120.401603] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Mitotic recombination is the predominant mechanism for repairing double-strand breaks in Saccharomyces cerevisiae. Current recombination models are largely based on studies utilizing the enzyme I-SceI or HO to create a site-specific break, each of which generates broken ends with 3′ overhangs. In this study sequence-diverged ectopic substrates were used to assess whether the frequent Pol δ-mediated removal of a mismatch 8 nucleotides from a 3′ end affects recombination outcomes and whether the presence of a 3′ vs. 5′ overhang at the break site alters outcomes. Recombination outcomes monitored were the distributions of recombination products into crossovers vs. noncrossovers, and the position/length of transferred sequence (heteroduplex DNA) in noncrossover products. A terminal mismatch that was 22 nucleotides from the 3′ end was rarely removed and the greater distance from the end did not affect recombination outcomes. To determine whether the recombinational repair of breaks with 3′ vs. 5′ overhangs differs, we compared the well-studied 3′ overhang created by I-SceI to a 5′ overhang created by a ZFN (Zinc Finger Nuclease). Initiation with the ZFN yielded more recombinants, consistent with more efficient cleavage and potentially faster repair rate relative to I-SceI. While there were proportionally more COs among ZFN- than I-SceI-initiated events, NCOs in the two systems were indistinguishable in terms of the extent of strand transfer. These data demonstrate that the method of DSB induction and the resulting differences in end polarity have little effect on mitotic recombination outcomes despite potential differences in repair rate.
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38
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Bruckbauer ST, Martin J, Minkoff BB, Veling MT, Lancaster I, Liu J, Trimarco JD, Bushnell B, Lipzen A, Wood EA, Sussman MR, Pennacchio C, Cox MM. Physiology of Highly Radioresistant Escherichia coli After Experimental Evolution for 100 Cycles of Selection. Front Microbiol 2020; 11:582590. [PMID: 33072055 PMCID: PMC7536353 DOI: 10.3389/fmicb.2020.582590] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2020] [Accepted: 08/26/2020] [Indexed: 11/13/2022] Open
Abstract
Ionizing radiation (IR) is lethal to most organisms at high doses, damaging every cellular macromolecule via induction of reactive oxygen species (ROS). Utilizing experimental evolution and continuing previous work, we have generated the most IR-resistant Escherichia coli populations developed to date. After 100 cycles of selection, the dose required to kill 99% the four replicate populations (IR9-100, IR10-100, IR11-100, and IR12-100) has increased from 750 Gy to approximately 3,000 Gy. Fitness trade-offs, specialization, and clonal interference are evident. Long-lived competing sub-populations are present in three of the four lineages. In IR9, one lineage accumulates the heme precursor, porphyrin, leading to generation of yellow-brown colonies. Major genomic alterations are present. IR9 and IR10 exhibit major deletions and/or duplications proximal to the chromosome replication terminus. Contributions to IR resistance have expanded beyond the alterations in DNA repair systems documented previously. Variants of proteins involved in ATP synthesis (AtpA), iron-sulfur cluster biogenesis (SufD) and cadaverine synthesis (CadA) each contribute to IR resistance in IR9-100. Major genomic and physiological changes are emerging. An isolate from IR10 exhibits protein protection from ROS similar to the extremely radiation resistant bacterium Deinococcus radiodurans, without evident changes in cellular metal homeostasis. Selection is continuing with no limit to IR resistance in evidence as our E. coli populations approach levels of IR resistance typical of D. radiodurans.
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Affiliation(s)
- Steven T Bruckbauer
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI, United States
| | - Joel Martin
- DOE Joint Genome Institute, Berkeley, CA, United States
| | - Benjamin B Minkoff
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI, United States.,Center for Genomic Science Innovation, University of Wisconsin School of Medicine and Public Health, Madison, WI, United States
| | - Mike T Veling
- Department of Systems Biology, Harvard Medical School, Boston, MA, United States
| | - Illissa Lancaster
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI, United States
| | - Jessica Liu
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI, United States
| | - Joseph D Trimarco
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI, United States
| | | | - Anna Lipzen
- DOE Joint Genome Institute, Berkeley, CA, United States
| | - Elizabeth A Wood
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI, United States
| | - Michael R Sussman
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI, United States.,Center for Genomic Science Innovation, University of Wisconsin School of Medicine and Public Health, Madison, WI, United States
| | | | - Michael M Cox
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI, United States
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Abstract
Three independent studies show that a protein called ZCWPW1 is able to recognize the histone modifications that initiate the recombination of genetic information during meiosis.
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Affiliation(s)
- Mathilde Biot
- Institut de Génétique Humaine, University Montpellier, Montpellier, France.,Centre National de la Recherche Scientifique, University Montpellier, Montpellier, France
| | - Bernard de Massy
- Institut de Génétique Humaine, University Montpellier, Montpellier, France.,Centre National de la Recherche Scientifique, University Montpellier, Montpellier, France
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40
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Ritter GS, Nikolin VP, Popova NA, Proskurina AS, Kisaretova PE, Taranov OS, Dubatolova TD, Dolgova EV, Potter EA, Kirikovich SS, Efremov YR, Bayborodin SI, Romanenko MV, Meschaninova MI, Venyaminova AG, Kolchanov NA, Shurdov MA, Bogachev SS. Characterization of biological peculiarities of the radioprotective activity of double-stranded RNA isolated from Saccharomyces сerevisiae. Int J Radiat Biol 2020; 96:1173-1191. [PMID: 32658564 DOI: 10.1080/09553002.2020.1793020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
THE PURPOSE OF THE ARTICLE Protection from ionizing radiation is the most important component in the curing malignant neoplasms, servicing atomic reactors, and resolving the situations associated with uncontrolled radioactive pollutions. In this regard, discovering new effective radioprotectors as well as novel principles of protecting living organisms from high-dose radiation is the most important factor, determining the new approaches in medical and technical usage of radiation. MATERIALS AND METHODS Experimental animals were irradiated on the γ-emitter (Cs137) with a dose of 9.4 Gy. Radioprotective properties of several agents (total RNA, single-stranded RNA, double-stranded RNA and B-190) were estimated by the survival/death rates of experimental animals within 30-90 d. Pathomorphological examination of internal organs end electron microscope assay was done on days 9-12 after irradiation. Cloning and other molecular procedures were performed accordingly to commonly accepted protocols. For assessment of the internalization of labeled nucleic acid, bone marrow cells were incubated with double-stranded RNA labeled with 6-FAM fluorescent dye. Cells with internalized double-stranded RNA were assayed using Axio Imager M1 microscope. In the other experiment, bone marrow cells after incubation with double-stranded RNA were stained with Cy5-labeled anti-CD34 antibodies and assayed using Axioskop 2 microscope. RESULTS In this study, several biological features of the radioprotective action of double-stranded RNA are characterized. It was shown that 160 µg of the double-stranded RNA per mouse protect experimental animals from the absolutely lethal dose of γ-radiation of 9.4 Gy. In different experiments, 80-100% of irradiated animals survive and live until their natural death. Radioprotective properties of double-stranded RNA were found to be independent on its sequence, but strictly dependent on its double-stranded form. Moreover, double-stranded RNA must have 'open' ends of the molecule to exert its radioprotective activity. CONCLUSIONS Experiments indicate that radioprotective effect of double-stranded RNA is tightly bound to its internalization into hematopoietic stem cells, which further repopulate the spleen parenchyma of irradiated mice. Actively proliferating progenitors form the splenic colonies, which further serve as the basis for restoration of hematopoiesis and immune function and determine the survival of animals received the lethal dose of radiation.
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Affiliation(s)
- Genrikh S Ritter
- Institute of Cytology and Genetics, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia.,Department of Natural Sciences, Novosibirsk State University, Novosibirsk, Russia
| | - Valeriy P Nikolin
- Institute of Cytology and Genetics, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia
| | - Nelly A Popova
- Institute of Cytology and Genetics, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia.,Department of Natural Sciences, Novosibirsk State University, Novosibirsk, Russia
| | - Anastasia S Proskurina
- Institute of Cytology and Genetics, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia
| | - Polina E Kisaretova
- Institute of Cytology and Genetics, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia
| | - Oleg S Taranov
- State Research Center of Virology and Biotechnology "Vector", Koltsovo, Russia
| | - Tatiana D Dubatolova
- Institute of Molecular and Cellular Biology, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia
| | - Evgenia V Dolgova
- Institute of Cytology and Genetics, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia
| | - Ekaterina A Potter
- Institute of Cytology and Genetics, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia
| | - Svetlana S Kirikovich
- Institute of Cytology and Genetics, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia
| | - Yaroslav R Efremov
- Institute of Cytology and Genetics, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia.,Department of Natural Sciences, Novosibirsk State University, Novosibirsk, Russia
| | - Sergey I Bayborodin
- Institute of Cytology and Genetics, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia.,Department of Natural Sciences, Novosibirsk State University, Novosibirsk, Russia
| | | | - Maria I Meschaninova
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia
| | - Aliya G Venyaminova
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia
| | - Nikolay A Kolchanov
- Institute of Cytology and Genetics, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia
| | | | - Sergey S Bogachev
- Institute of Cytology and Genetics, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia
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41
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Li Z, Kim JH, Kim J, Lyu JI, Zhang Y, Guo H, Nam HG, Woo HR. ATM suppresses leaf senescence triggered by DNA double-strand break through epigenetic control of senescence-associated genes in Arabidopsis. New Phytol 2020; 227:473-484. [PMID: 32163596 DOI: 10.1111/nph.16535] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [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: 11/28/2019] [Accepted: 02/28/2020] [Indexed: 06/10/2023]
Abstract
All living organisms are unavoidably exposed to various endogenous and environmental stresses that trigger potentially fatal DNA damage, including double-strand breaks (DSBs). Although a growing body of evidence indicates that DNA damage is one of the prime drivers of aging in animals, little is known regarding the importance of DNA damage and its repair on lifespan control in plants. We found that the level of DSBs increases but DNA repair efficiency decreases as Arabidopsis leaves age. Generation of DSBs by inducible expression of I-PpoI leads to premature senescence phenotypes. We examined the senescence phenotypes in the loss-of-function mutants for 13 key components of the DNA repair pathway and found that deficiency in ATAXIA TELANGIECTASIA MUTATED (ATM), the chief transducer of the DSB signal, results in premature senescence in Arabidopsis. ATM represses DSB-induced expression of senescence-associated genes, including the genes encoding the WRKY and NAC transcription factors, central components of the leaf senescence process, via modulation of histone lysine methylation. Our work highlights the significance of ATM in the control of leaf senescence and has significant implications for the conservation of aging mechanisms in animals and plants.
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Affiliation(s)
- Zhonghai Li
- Center for Plant Aging Research, Institute for Basic Science (IBS), Daegu, 42988, Korea
- Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, Beijing Forestry University, Beijing, 100083, China
| | - Jin Hee Kim
- Center for Plant Aging Research, Institute for Basic Science (IBS), Daegu, 42988, Korea
- Department of New Biology, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, 42988, Korea
| | - Jeongsik Kim
- Center for Plant Aging Research, Institute for Basic Science (IBS), Daegu, 42988, Korea
- Faculty of Science Education, Jeju National University, Jeju, 63243, Korea
| | - Jae Il Lyu
- Center for Plant Aging Research, Institute for Basic Science (IBS), Daegu, 42988, Korea
| | - Yi Zhang
- Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, Beijing Forestry University, Beijing, 100083, China
| | - Hongwei Guo
- Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, Beijing Forestry University, Beijing, 100083, China
- Department of Biology, Institute of Plant and Food Science, Southern University of Science and Technology (SUSTech), Shenzhen, Guangdong, 518055, China
| | - Hong Gil Nam
- Center for Plant Aging Research, Institute for Basic Science (IBS), Daegu, 42988, Korea
- Department of New Biology, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, 42988, Korea
| | - Hye Ryun Woo
- Department of New Biology, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, 42988, Korea
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42
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Abstract
H3K9 demethylases can remove the repressive H3K9 methylation marks on histones to alter chromatin structure, gene transcription and epigenetic state of cells. By counteracting the function of H3K9 methyltransferases, H3K9 demethylases have been shown to play an important role in numerous biological processes, including diseases such as cancer. Recent evidence points to a key role for some H3K9 demethylases in the repair of DNA double-strand breaks (DSBs) via homologous recombination (HR) and/or non-homologous end joining (NHEJ) pathways. Mechanistically, H3K9 demethylases can upregulate the expression of DNA repair factors. They can also be recruited to the DNA damage sites and regulate the recruitment or function of DNA repair factors. Here, we will discuss the role and mechanisms of H3K9 demethylases in the regulation of DSB repair.
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Affiliation(s)
- Hee-Young Jeon
- Department of Biochemistry and Molecular Biology, University of Maryland, Baltimore, MD, USA.,Marlene and Stewart Greenebaum Comprehensive Cancer Center, Baltimore, MD, USA
| | - Arif Hussain
- Marlene and Stewart Greenebaum Comprehensive Cancer Center, Baltimore, MD, USA.,Baltimore VA Medical Center, Baltimore, MD, USA
| | - Jianfei Qi
- Department of Biochemistry and Molecular Biology, University of Maryland, Baltimore, MD, USA.,Marlene and Stewart Greenebaum Comprehensive Cancer Center, Baltimore, MD, USA
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43
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Pérez-Calero C, Bayona-Feliu A, Xue X, Barroso SI, Muñoz S, González-Basallote VM, Sung P, Aguilera A. UAP56/DDX39B is a major cotranscriptional RNA-DNA helicase that unwinds harmful R loops genome-wide. Genes Dev 2020; 34:898-912. [PMID: 32439635 PMCID: PMC7328515 DOI: 10.1101/gad.336024.119] [Citation(s) in RCA: 68] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Accepted: 04/20/2020] [Indexed: 01/10/2023]
Abstract
In this study, Pérez-Calero et al. set out to investigate the role of UAP56/DDX39B in R-loop removal. Using in vitro and in vivo approaches, the authors demonstrate that UAP56 functions as a DNA–RNA helicase required to eliminate harmful cotranscriptional RNA structures that otherwise would block transcription and replication. Nonscheduled R loops represent a major source of DNA damage and replication stress. Cells have different ways to prevent R-loop accumulation. One mechanism relies on the conserved THO complex in association with cotranscriptional RNA processing factors including the RNA-dependent ATPase UAP56/DDX39B and histone modifiers such as the SIN3 deacetylase in humans. We investigated the function of UAP56/DDX39B in R-loop removal. We show that UAP56 depletion causes R-loop accumulation, R-loop-mediated genome instability, and replication fork stalling. We demonstrate an RNA–DNA helicase activity in UAP56 and show that its overexpression suppresses R loops and genome instability induced by depleting five different unrelated factors. UAP56/DDX39B localizes to active chromatin and prevents the accumulation of RNA–DNA hybrids over the entire genome. We propose that, in addition to its RNA processing role, UAP56/DDX39B is a key helicase required to eliminate harmful cotranscriptional RNA structures that otherwise would block transcription and replication.
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Affiliation(s)
- Carmen Pérez-Calero
- Centro Andaluz de Biología Molecular y Medicina Regenerativa (CABIMER) Universidad de Sevilla-CSIC-Universidad Pablo de Olavide, Sevilla 41092, Spain
| | - Aleix Bayona-Feliu
- Centro Andaluz de Biología Molecular y Medicina Regenerativa (CABIMER) Universidad de Sevilla-CSIC-Universidad Pablo de Olavide, Sevilla 41092, Spain
| | - Xiaoyu Xue
- Molecular Biophysics and Biochemistry, School of Medicine, University of Yale, New Haven, Connecticut 06510, USA.,Department of Chemistry and Biochemistry, Texas State University, San Marcos, Texas 78666, USA
| | - Sonia I Barroso
- Centro Andaluz de Biología Molecular y Medicina Regenerativa (CABIMER) Universidad de Sevilla-CSIC-Universidad Pablo de Olavide, Sevilla 41092, Spain
| | - Sergio Muñoz
- Centro Andaluz de Biología Molecular y Medicina Regenerativa (CABIMER) Universidad de Sevilla-CSIC-Universidad Pablo de Olavide, Sevilla 41092, Spain
| | - Víctor M González-Basallote
- Centro Andaluz de Biología Molecular y Medicina Regenerativa (CABIMER) Universidad de Sevilla-CSIC-Universidad Pablo de Olavide, Sevilla 41092, Spain
| | - Patrick Sung
- Molecular Biophysics and Biochemistry, School of Medicine, University of Yale, New Haven, Connecticut 06510, USA.,Department of Biochemistry and Structural Biology, University of Texas Health Science Center at San Antonio, San Antonio, Texas 78229, USA
| | - Andrés Aguilera
- Centro Andaluz de Biología Molecular y Medicina Regenerativa (CABIMER) Universidad de Sevilla-CSIC-Universidad Pablo de Olavide, Sevilla 41092, Spain
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Zhao H, Huang X, Halicka HD, Darzynkiewicz Z. Detection of Histone H2AX Phosphorylation on Ser-139 as an Indicator of DNA Damage. ACTA ACUST UNITED AC 2020; 89:e55. [PMID: 31237414 DOI: 10.1002/cpcy.55] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
This unit describes immunocytochemical detection of histone H2AX phosphorylated on Ser-139 (γH2AX) to reveal DNA damage, particularly when the damage involves the presence of DNA double-strand breaks (DSBs). These breaks often result from DNA damage induced by ionizing radiation or by treatment with anticancer drugs such as DNA topoisomerase inhibitors. Furthermore, DSBs are generated in the course of DNA fragmentation during apoptosis. The unit presents strategies to distinguish radiation- or drug-induced DNA breaks from those intrinsically formed in untreated cells or associated with apoptosis. The protocol describes immunocytochemical detection of γH2AX combined with measurement of DNA content to identify cells that have DNA damage and concurrently to assess their cell-cycle phase. The detection is based on indirect immunofluorescence using FITC- or Alexa Fluor 488-labeled antibody, with DNA counterstained with propidium iodide and cellular RNA removed with RNase A. © 2019 by John Wiley & Sons, Inc.
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Affiliation(s)
- Hong Zhao
- Brander Cancer Research Institute, Department of Pathology, New York Medical College, Valhalla, New York
| | - Xuan Huang
- Brander Cancer Research Institute, Department of Pathology, New York Medical College, Valhalla, New York
| | - H Dorota Halicka
- Brander Cancer Research Institute, Department of Pathology, New York Medical College, Valhalla, New York
| | - Zbigniew Darzynkiewicz
- Brander Cancer Research Institute, Department of Pathology, New York Medical College, Valhalla, New York
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45
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Munnur D, Somers J, Skalka G, Weston R, Jukes-Jones R, Bhogadia M, Dominguez C, Cain K, Ahel I, Malewicz M. NR4A Nuclear Receptors Target Poly-ADP-Ribosylated DNA-PKcs Protein to Promote DNA Repair. Cell Rep 2020; 26:2028-2036.e6. [PMID: 30784586 PMCID: PMC6381605 DOI: 10.1016/j.celrep.2019.01.083] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2018] [Revised: 11/30/2018] [Accepted: 01/23/2019] [Indexed: 12/12/2022] Open
Abstract
Although poly-ADP-ribosylation (PARylation) of DNA repair factors had been well documented, its role in the repair of DNA double-strand breaks (DSBs) is poorly understood. NR4A nuclear orphan receptors were previously linked to DSB repair; however, their function in the process remains elusive. Classically, NR4As function as transcription factors using a specialized tandem zinc-finger DNA-binding domain (DBD) for target gene induction. Here, we show that NR4A DBD is bi-functional and can bind poly-ADP-ribose (PAR) through a pocket localized in the second zinc finger. Separation-of-function mutants demonstrate that NR4A PAR binding, while dispensable for transcriptional activity, facilitates repair of radiation-induced DNA double-strand breaks in G1. Moreover, we define DNA-PKcs protein as a prominent target of ionizing radiation-induced PARylation. Mechanistically, NR4As function by directly targeting poly-ADP-ribosylated DNA-PKcs to facilitate its autophosphorylation-promoting DNA-PK kinase assembly at DNA lesions. Selective targeting of the PAR-binding pocket of NR4A presents an opportunity for cancer therapy.
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Affiliation(s)
| | | | | | - Ria Weston
- Centre for Biomedicine, Manchester Metropolitan University, Manchester M15 6BH, UK
| | | | - Mohammed Bhogadia
- Department of Molecular and Cell Biology, University of Leicester, Leicester LE1 7RH, UK
| | - Cyril Dominguez
- Department of Molecular and Cell Biology, University of Leicester, Leicester LE1 7RH, UK
| | | | - Ivan Ahel
- Sir William Dunn School of Pathology, South Parks Road, University of Oxford, Oxford OX1 3RE, UK
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Ray U, Raul SK, Gopinatha VK, Ghosh D, Rangappa KS, Mantelingu K, Raghavan SC. Identification and characterization of novel SCR7-based small-molecule inhibitor of DNA end-joining, SCR130 and its relevance in cancer therapeutics. Mol Carcinog 2020; 59:618-628. [PMID: 32189406 DOI: 10.1002/mc.23186] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [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: 12/19/2019] [Revised: 02/26/2020] [Accepted: 02/27/2020] [Indexed: 12/20/2022]
Abstract
Targeting DNA repair with small-molecule inhibitors is an attractive strategy for cancer therapy. Majority of DNA double-strand breaks in mammalian cells are repaired through nonhomologous end-joining (NHEJ). It has been shown that small-molecule inhibitors of NHEJ can block efficient repair inside cancer cells, leading to cell death. Previously, we have reported that SCR7, an inhibitor of NHEJ can induce tumor regression in mice. Later studies have shown that different forms of SCR7 can inhibit DNA end-joining in Ligase IV-dependent manner. Recently, we have derivatized SCR7 by introducing spiro ring into core structure. Here, we report the identification of a novel inhibitor of NHEJ, named SCR130 with 20-fold higher efficacy in inducing cytotoxicity in cancer cell lines. SCR130 inhibited DNA end-joining catalyzed by rat tissue extract. Specificity analysis revealed that while SCR130 was specific to Ligase IV, it showed minimal or no effect on Ligase III and Ligase I mediated joining. Importantly, SCR130 exhibited the least cytotoxicity in Ligase IV-null cell line as compared with wild type, confirming Ligase IV-specificity. Furthermore, we demonstrate that SCR130 can potentiate the effect of radiation in cancer cells when used in combination with γ-radiation. Various cellular assays in conjunction with Western blot analysis revealed that treatment with SCR130 led to loss of mitochondrial membrane potential leading to cell death by activating both intrinsic and extrinsic pathways of apoptosis. Thus, we describe a novel inhibitor of NHEJ with higher efficacy and may have the potential to be developed as cancer therapeutic.
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Affiliation(s)
- Ujjayinee Ray
- Department of Biochemistry, Indian Institute of Science, Bangalore, India
| | - Sanjay Kumar Raul
- Department of Biochemistry, Indian Institute of Science, Bangalore, India
| | - Vindya K Gopinatha
- Department of Studies in Chemistry, ManasaganFindo-frgotri, University of Mysore, Mysuru, India
| | - Dipayan Ghosh
- Department of Biochemistry, Indian Institute of Science, Bangalore, India
| | | | - Kempegowda Mantelingu
- Department of Studies in Chemistry, ManasaganFindo-frgotri, University of Mysore, Mysuru, India
| | - Sathees C Raghavan
- Department of Biochemistry, Indian Institute of Science, Bangalore, India
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47
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Wu Q. Structural mechanism of DNA-end synapsis in the non-homologous end joining pathway for repairing double-strand breaks: bridge over troubled ends. Biochem Soc Trans 2019; 47:1609-19. [PMID: 31829407 DOI: 10.1042/BST20180518] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Revised: 11/25/2019] [Accepted: 11/27/2019] [Indexed: 12/18/2022]
Abstract
Non-homologous end joining (NHEJ) is a major repair pathway for DNA double-strand breaks (DSBs), which is the most toxic DNA damage in cells. Unrepaired DSBs can cause genome instability, tumorigenesis or cell death. DNA end synapsis is the first and probably the most important step of the NHEJ pathway, aiming to bring two broken DNA ends close together and provide structural stability for end processing and ligation. This process is mediated through a group of NHEJ proteins forming higher-order complexes, to recognise and bridge two DNA ends. Spatial and temporal understanding of the structural mechanism of DNA-end synapsis has been largely advanced through recent structural and single-molecule studies of NHEJ proteins. This review focuses on core NHEJ proteins that mediate DNA end synapsis through their unique structures and interaction properties, as well as how they play roles as anchor and linker proteins during the process of 'bridge over troubled ends'.
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Jang Y, Elsayed Z, Eki R, He S, Du KP, Abbas T, Kai M. Intrinsically disordered protein RBM14 plays a role in generation of RNA:DNA hybrids at double-strand break sites. Proc Natl Acad Sci U S A 2020; 117:5329-38. [PMID: 32094185 DOI: 10.1073/pnas.1913280117] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Accumulating evidence suggests participation of RNA-binding proteins with intrinsically disordered domains (IDPs) in the DNA damage response (DDR). These IDPs form liquid compartments at DNA damage sites in a poly(ADP ribose) (PAR)-dependent manner. However, it is greatly unknown how the IDPs are involved in DDR. We have shown previously that one of the IDPs RBM14 is required for the canonical nonhomologous end joining (cNHEJ). Here we show that RBM14 is recruited to DNA damage sites in a PARP- and RNA polymerase II (RNAPII)-dependent manner. Both KU and RBM14 are required for RNAPII-dependent generation of RNA:DNA hybrids at DNA damage sites. In fact, RBM14 binds to RNA:DNA hybrids. Furthermore, RNA:DNA hybrids and RNAPII are detected at gene-coding as well as at intergenic areas when double-strand breaks (DSBs) are induced. We propose that the cNHEJ pathway utilizes damage-induced transcription and intrinsically disordered protein RBM14 for efficient repair of DSBs.
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49
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Pasquini G, Cora V, Swiersy A, Achberger K, Antkowiak L, Müller B, Wimmer T, Fraschka SAK, Casadei N, Ueffing M, Liebau S, Stieger K, Busskamp V. Using Transcriptomic Analysis to Assess Double-Strand Break Repair Activity: Towards Precise in vivo Genome Editing. Int J Mol Sci 2020; 21:E1380. [PMID: 32085662 PMCID: PMC7073035 DOI: 10.3390/ijms21041380] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [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: 01/23/2020] [Revised: 02/13/2020] [Accepted: 02/15/2020] [Indexed: 12/17/2022] Open
Abstract
Mutations in more than 200 retina-specific genes have been associated with inherited retinal diseases. Genome editing represents a promising emerging field in the treatment of monogenic disorders, as it aims to correct disease-causing mutations within the genome. Genome editing relies on highly specific endonucleases and the capacity of the cells to repair double-strand breaks (DSBs). As DSB pathways are cell-cycle dependent, their activity in postmitotic retinal neurons, with a focus on photoreceptors, needs to be assessed in order to develop therapeutic in vivo genome editing. Three DSB-repair pathways are found in mammalian cells: Non-homologous end joining (NHEJ); microhomology-mediated end joining (MMEJ); and homology-directed repair (HDR). While NHEJ can be used to knock out mutant alleles in dominant disorders, HDR and MMEJ are better suited for precise genome editing, or for replacing entire mutation hotspots in genomic regions. Here, we analyzed transcriptomic in vivo and in vitro data and revealed that HDR is indeed downregulated in postmitotic neurons, whereas MMEJ and NHEJ are active. Using single-cell RNA sequencing analysis, we characterized the dynamics of DSB repair pathways in the transition from dividing cells to postmitotic retinal cells. Time-course bulk RNA-seq data confirmed DSB repair gene expression in both in vivo and in vitro samples. Transcriptomic DSB repair pathway profiles are very similar in adult human, macaque, and mouse retinas, but not in ground squirrel retinas. Moreover, human-induced pluripotent stem-cell-derived neurons and retinal organoids can serve as well suited in vitro testbeds for developing genomic engineering approaches in photoreceptors. Our study provides additional support for designing precise in vivo genome-editing approaches via MMEJ, which is active in mature photoreceptors.
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Affiliation(s)
- Giovanni Pasquini
- Center for Regenerative Therapies (CRTD), Technical University Dresden, 01307 Dresden, Germany
| | - Virginia Cora
- Institute of Neuroanatomy & Developmental Biology (INDB), Eberhard Karls University Tübingen, 72074 Tübingen, Germany
| | - Anka Swiersy
- Center for Regenerative Therapies (CRTD), Technical University Dresden, 01307 Dresden, Germany
| | - Kevin Achberger
- Institute of Neuroanatomy & Developmental Biology (INDB), Eberhard Karls University Tübingen, 72074 Tübingen, Germany
| | - Lena Antkowiak
- Institute of Neuroanatomy & Developmental Biology (INDB), Eberhard Karls University Tübingen, 72074 Tübingen, Germany
| | - Brigitte Müller
- Department of Ophthalmology, Justus-Liebig-University, 35392 Giessen, Germany
| | - Tobias Wimmer
- Department of Ophthalmology, Justus-Liebig-University, 35392 Giessen, Germany
| | - Sabine Anne-Kristin Fraschka
- Institute of Medical Genetics and Applied Genomics, University of Tübingen, 72076 Tübingen, Germany
- DFG NGS Competence Center Tübingen, 72076 Tübingen, Germany
| | - Nicolas Casadei
- Institute of Medical Genetics and Applied Genomics, University of Tübingen, 72076 Tübingen, Germany
- DFG NGS Competence Center Tübingen, 72076 Tübingen, Germany
| | - Marius Ueffing
- Department of Ophthalmology, Institute for Ophthalmic Research, University of Tübingen, 72076 Tübingen, Germany
| | - Stefan Liebau
- Institute of Neuroanatomy & Developmental Biology (INDB), Eberhard Karls University Tübingen, 72074 Tübingen, Germany
| | - Knut Stieger
- Department of Ophthalmology, Justus-Liebig-University, 35392 Giessen, Germany
| | - Volker Busskamp
- Center for Regenerative Therapies (CRTD), Technical University Dresden, 01307 Dresden, Germany
- Universitäts-Augenklinik Bonn, University of Bonn, Dept. of Ophthalmology, 53127 Bonn, Germany
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50
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Sankaranarayanan SR, Ianiri G, Coelho MA, Reza MH, Thimmappa BC, Ganguly P, Vadnala RN, Sun S, Siddharthan R, Tellgren-Roth C, Dawson TL, Heitman J, Sanyal K. Loss of centromere function drives karyotype evolution in closely related Malassezia species. eLife 2020; 9:e53944. [PMID: 31958060 PMCID: PMC7025860 DOI: 10.7554/elife.53944] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [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: 11/26/2019] [Accepted: 01/20/2020] [Indexed: 12/14/2022] Open
Abstract
Genomic rearrangements associated with speciation often result in variation in chromosome number among closely related species. Malassezia species show variable karyotypes ranging between six and nine chromosomes. Here, we experimentally identified all eight centromeres in M. sympodialis as 3-5-kb long kinetochore-bound regions that span an AT-rich core and are depleted of the canonical histone H3. Centromeres of similar sequence features were identified as CENP-A-rich regions in Malassezia furfur, which has seven chromosomes, and histone H3 depleted regions in Malassezia slooffiae and Malassezia globosa with nine chromosomes each. Analysis of synteny conservation across centromeres with newly generated chromosome-level genome assemblies suggests two distinct mechanisms of chromosome number reduction from an inferred nine-chromosome ancestral state: (a) chromosome breakage followed by loss of centromere DNA and (b) centromere inactivation accompanied by changes in DNA sequence following chromosome-chromosome fusion. We propose that AT-rich centromeres drive karyotype diversity in the Malassezia species complex through breakage and inactivation.
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Affiliation(s)
- Sundar Ram Sankaranarayanan
- Molecular Mycology Laboratory, Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific ResearchBengaluruIndia
| | - Giuseppe Ianiri
- Department of Molecular Genetics and Microbiology, Duke University Medical CenterDurhamUnited States
| | - Marco A Coelho
- Department of Molecular Genetics and Microbiology, Duke University Medical CenterDurhamUnited States
| | - Md Hashim Reza
- Molecular Mycology Laboratory, Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific ResearchBengaluruIndia
| | - Bhagya C Thimmappa
- Molecular Mycology Laboratory, Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific ResearchBengaluruIndia
| | - Promit Ganguly
- Molecular Mycology Laboratory, Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific ResearchBengaluruIndia
| | | | - Sheng Sun
- Department of Molecular Genetics and Microbiology, Duke University Medical CenterDurhamUnited States
| | | | - Christian Tellgren-Roth
- National Genomics Infrastructure, Science for Life Laboratory, Department of Immunology, Genetics and Pathology, Uppsala UniversityUppsalaSweden
| | - Thomas L Dawson
- Skin Research Institute Singapore, Agency for Science, Technology and Research (A*STAR)SingaporeSingapore
- Department of Drug Discovery, Medical University of South Carolina, School of PharmacyCharlestonUnited States
| | - Joseph Heitman
- Department of Molecular Genetics and Microbiology, Duke University Medical CenterDurhamUnited States
| | - Kaustuv Sanyal
- Molecular Mycology Laboratory, Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific ResearchBengaluruIndia
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