101
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Weiser BP, Rodriguez G, Cole PA, Stivers JT. N-terminal domain of human uracil DNA glycosylase (hUNG2) promotes targeting to uracil sites adjacent to ssDNA-dsDNA junctions. Nucleic Acids Res 2019; 46:7169-7178. [PMID: 29917162 PMCID: PMC6101581 DOI: 10.1093/nar/gky525] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Accepted: 05/24/2018] [Indexed: 01/29/2023] Open
Abstract
The N-terminal domain (NTD) of nuclear human uracil DNA glycosylase (hUNG2) assists in targeting hUNG2 to replication forks through specific interactions with replication protein A (RPA). Here, we explored hUNG2 activity in the presence and absence of RPA using substrates with ssDNA–dsDNA junctions that mimic structural features of the replication fork and transcriptional R-loops. We find that when RPA is tightly bound to the ssDNA overhang of junction DNA substrates, base excision by hUNG2 is strongly biased toward uracils located 21 bp or less from the ssDNA–dsDNA junction. In the absence of RPA, hUNG2 still showed an 8-fold excision bias for uracil located <10 bp from the junction, but only when the overhang had a 5′ end. Biased targeting required the NTD and was not observed with the hUNG2 catalytic domain alone. Consistent with this requirement, the isolated NTD was found to bind weakly to ssDNA. These findings indicate that the NTD of hUNG2 targets the enzyme to ssDNA–dsDNA junctions using RPA-dependent and RPA-independent mechanisms. This structure-based specificity may promote efficient removal of uracils that arise from dUTP incorporation during DNA replication, or additionally, uracils that arise from DNA cytidine deamination at transcriptional R-loops during immunoglobulin class-switch recombination.
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Affiliation(s)
- Brian P Weiser
- Department of Molecular Biology, Rowan University School of Osteopathic Medicine, Stratford, NJ 08084, USA
| | - Gaddiel Rodriguez
- Department of Pharmacology & Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Philip A Cole
- Division of Genetics, Department of Medicine and Department of Biological Chemistry & Molecular Pharmacology, Harvard Medical School and Brigham and Women's Hospital, Boston, MA 02115, USA
| | - James T Stivers
- Department of Pharmacology & Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
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102
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Wang QM, Yang YT, Wang YR, Gao B, Xi XG, Hou XM. Human replication protein A induces dynamic changes in single-stranded DNA and RNA structures. J Biol Chem 2019; 294:13915-13927. [PMID: 31350334 DOI: 10.1074/jbc.ra119.009737] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Revised: 07/25/2019] [Indexed: 01/05/2023] Open
Abstract
Replication protein A (RPA) is the major eukaryotic ssDNA-binding protein and has essential roles in genome maintenance. RPA binds to ssDNA through multiple modes, and recent studies have suggested that the RPA-ssDNA interaction is dynamic. However, how RPA alternates between different binding modes and modifies ssDNA structures in this dynamic interaction remains unknown. Here, we used single-molecule FRET to systematically investigate the interaction between human RPA and ssDNA. We show that RPA can adopt different types of binding complexes with ssDNAs of different lengths, leading to the straightening or bending of the ssDNAs, depending on both the length and structure of the ssDNA substrate and the RPA concentration. Importantly, we noted that some of the complexes are highly dynamic, whereas others appear relatively static. On the basis of the above observations, we propose a model explaining how RPA dynamically engages with ssDNA. Of note, fluorescence anisotropy indicated that RPA can also associate with RNA but with a lower binding affinity than with ssDNA. At the single-molecule level, we observed that RPA is undergoing rapid and repetitive associations with and dissociation from the RNA. This study may provide new insights into the rich dynamics of RPA binding to ssDNA and RNA.
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Affiliation(s)
- Qing-Man Wang
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Sciences, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Yan-Tao Yang
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Sciences, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Yi-Ran Wang
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Sciences, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Bo Gao
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Sciences, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Xu-Guang Xi
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Sciences, Northwest A&F University, Yangling, Shaanxi 712100, China.,Laboratoire de Biologie et Pharmacologie Appliquée, Ecole Normale Supérieure de Cachan, CNRS, 61 Avenue du Président Wilson, 94235 Cachan, France
| | - Xi-Miao Hou
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Sciences, Northwest A&F University, Yangling, Shaanxi 712100, China
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103
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Lee M, Shin S, Uhm H, Hong H, Kirk J, Hyun K, Kulikowicz T, Kim J, Ahn B, Bohr VA, Hohng S. Multiple RPAs make WRN syndrome protein a superhelicase. Nucleic Acids Res 2019; 46:4689-4698. [PMID: 29668972 PMCID: PMC5961295 DOI: 10.1093/nar/gky272] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2017] [Accepted: 04/11/2018] [Indexed: 02/01/2023] Open
Abstract
RPA is known to stimulate the helicase activity of Werner syndrome protein (WRN), but the exact stimulation mechanism is not understood. We use single-molecule FRET and magnetic tweezers to investigate the helicase activity of WRN and its stimulation by RPA. We show that WRN alone is a weak helicase which repetitively unwind just a few tens of base pairs, but that binding of multiple RPAs to the enzyme converts WRN into a superhelicase that unidirectionally unwinds double-stranded DNA more than 1 kb. Our study provides a good case in which the activity and biological functions of the enzyme may be fundamentally altered by the binding of cofactors.
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Affiliation(s)
- Mina Lee
- Center for Nano-Bio Measurement, Korea Research Institute of Standards and Science, Daejeon, Republic of Korea
| | - Soochul Shin
- Department of Physics and Astronomy, Institute of Applied Physics, National Center of Creative Research Initiatives, Seoul National University, Seoul, Republic of Korea
| | - Heesoo Uhm
- Department of Physics and Astronomy, Institute of Applied Physics, National Center of Creative Research Initiatives, Seoul National University, Seoul, Republic of Korea
| | - Heesun Hong
- Department of Physics and Astronomy, Institute of Applied Physics, National Center of Creative Research Initiatives, Seoul National University, Seoul, Republic of Korea
| | - Jaewon Kirk
- Department of Physics and Astronomy, Institute of Applied Physics, National Center of Creative Research Initiatives, Seoul National University, Seoul, Republic of Korea
| | - Kwangbeom Hyun
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon 34141, Republic of Korea
| | - Tomasz Kulikowicz
- Laboratory of Molecular Gerontology, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA
| | - Jaehoon Kim
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon 34141, Republic of Korea
| | - Byungchan Ahn
- Department of Life Sciences, University of Ulsan, Ulsan, Republic of Korea
| | - Vilhelm A Bohr
- Laboratory of Molecular Gerontology, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA
| | - Sungchul Hohng
- Department of Physics and Astronomy, Institute of Applied Physics, National Center of Creative Research Initiatives, Seoul National University, Seoul, Republic of Korea
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104
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Kang J, Yeom G, Jang H, Oh J, Park CJ, Kim MG. Development of Replication Protein A-Conjugated Gold Nanoparticles for Highly Sensitive Detection of Disease Biomarkers. Anal Chem 2019; 91:10001-10007. [PMID: 31269392 DOI: 10.1021/acs.analchem.9b01827] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Paper-based lateral flow immunoassays (LFIAs) using conventional sandwich-type immunoassays are one of the most commonly used point-of-care (PoC) tests. However, the application of gold nanoparticles (AuNPs) in LFIAs does not meet sensitivity requirements for the detection of infectious diseases or biomarkers present at low concentrations in body fluids because of the limited number of AuNPs that can bind to the target. To overcome this problem, we first developed a single-stranded DNA binding protein (RPA70A, DNA binding domain A of human Replication Protein A 70 kDa) conjugated to AuNPs for a sandwich assay using a capture antibody immobilized in the LFIA and an aptamer as a detection probe, thus, enabling signal intensity enhancement by attaching several AuNPs per aptamer. We applied this method to detect the influenza nucleoprotein (NP) and cardiac troponin I (cTnI). We visually detected spiked targets at a low femtomolar range, with limits of detection for NP in human nasal fluid and for cTnI in serum of 0.26 and 0.23 pg·mL-1, respectively. This technique showed significantly higher sensitivity than conventional methods that are widely used in LFIAs involving antibody-conjugated AuNPs. These results suggest that the proposed method can be universally applied to the detection of substances requiring high sensitivity and can be used in the field of PoC testing for early disease diagnosis.
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Affiliation(s)
- Juyoung Kang
- Department of Chemistry, School of Physics and Chemistry , Gwangju Institute of Science and Technology (GIST) , 123 Cheomdangwagi-ro , Buk-gu, Gwangju , 61005 , Republic of Korea
| | - Gyuho Yeom
- Department of Chemistry, School of Physics and Chemistry , Gwangju Institute of Science and Technology (GIST) , 123 Cheomdangwagi-ro , Buk-gu, Gwangju , 61005 , Republic of Korea
| | - Hyungjun Jang
- Department of Chemistry, School of Physics and Chemistry , Gwangju Institute of Science and Technology (GIST) , 123 Cheomdangwagi-ro , Buk-gu, Gwangju , 61005 , Republic of Korea
| | - Jusung Oh
- Department of Chemistry, School of Physics and Chemistry , Gwangju Institute of Science and Technology (GIST) , 123 Cheomdangwagi-ro , Buk-gu, Gwangju , 61005 , Republic of Korea
| | - Chin-Ju Park
- Department of Chemistry, School of Physics and Chemistry , Gwangju Institute of Science and Technology (GIST) , 123 Cheomdangwagi-ro , Buk-gu, Gwangju , 61005 , Republic of Korea
| | - Min-Gon Kim
- Department of Chemistry, School of Physics and Chemistry , Gwangju Institute of Science and Technology (GIST) , 123 Cheomdangwagi-ro , Buk-gu, Gwangju , 61005 , Republic of Korea
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105
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Haas KT, Lee M, Esposito A, Venkitaraman AR. Single-molecule localization microscopy reveals molecular transactions during RAD51 filament assembly at cellular DNA damage sites. Nucleic Acids Res 2019; 46:2398-2416. [PMID: 29309696 PMCID: PMC5861458 DOI: 10.1093/nar/gkx1303] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2017] [Accepted: 12/19/2017] [Indexed: 11/14/2022] Open
Abstract
RAD51 recombinase assembles on single-stranded (ss)DNA substrates exposed by DNA end-resection to initiate homologous recombination (HR), a process fundamental to genome integrity. RAD51 assembly has been characterized using purified proteins, but its ultrastructural topography in the cell nucleus is unexplored. Here, we combine cell genetics with single-molecule localization microscopy and a palette of bespoke analytical tools, to visualize molecular transactions during RAD51 assembly in the cellular milieu at resolutions approaching 30-40 nm. In several human cell types, RAD51 focalizes in clusters that progressively extend into long filaments, which abut-but do not overlap-with globular bundles of replication protein A (RPA). Extended filaments alter topographically over time, suggestive of succeeding steps in HR. In cells depleted of the tumor suppressor protein BRCA2, or overexpressing its RAD51-binding BRC repeats, RAD51 fails to assemble at damage sites, although RPA accumulates unhindered. By contrast, in cells lacking a BRCA2 carboxyl (C)-terminal region targeted by cancer-causing mutations, damage-induced RAD51 assemblies initiate but do not extend into filaments. We suggest a model wherein RAD51 assembly proceeds concurrently with end-resection at adjacent sites, via an initiation step dependent on the BRC repeats, followed by filament extension through the C-terminal region of BRCA2.
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Affiliation(s)
- Kalina T Haas
- The Medical Research Council Cancer Unit, University of Cambridge, Hills Road, Cambridge CB2 0XZ, UK
| | - MiYoung Lee
- The Medical Research Council Cancer Unit, University of Cambridge, Hills Road, Cambridge CB2 0XZ, UK
| | - Alessandro Esposito
- The Medical Research Council Cancer Unit, University of Cambridge, Hills Road, Cambridge CB2 0XZ, UK
| | - Ashok R Venkitaraman
- The Medical Research Council Cancer Unit, University of Cambridge, Hills Road, Cambridge CB2 0XZ, UK
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106
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Protein Environment and DNA Orientation Affect Protein-Induced Cy3 Fluorescence Enhancement. Biophys J 2019; 117:66-73. [PMID: 31235181 DOI: 10.1016/j.bpj.2019.05.026] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Revised: 05/23/2019] [Accepted: 05/29/2019] [Indexed: 11/20/2022] Open
Abstract
The cyanine dye Cy3 is a popular fluorophore used to probe the binding of proteins to nucleic acids as well as their conformational transitions. Nucleic acids labeled only with Cy3 can often be used to monitor interactions with unlabeled proteins because of an enhancement of Cy3 fluorescence intensity that results when the protein contacts Cy3, a property sometimes referred to as protein-induced fluorescence enhancement (PIFE). Although Cy3 fluorescence is enhanced upon contacting most proteins, we show here in studies of human replication protein A and Escherichia coli single-stranded DNA binding protein that the magnitude of the Cy3 enhancement is dependent on both the protein as well as the orientation of the protein with respect to the Cy3 label on the DNA. This difference in PIFE is due entirely to differences in the final protein-DNA complex. We also show that the origin of PIFE is the longer fluorescence lifetime induced by the local protein environment. These results indicate that PIFE is not a through space distance-dependent phenomenon but requires a direct interaction of Cy3 with the protein, and the magnitude of the effect is influenced by the region of the protein contacting Cy3. Hence, use of the Cy3 PIFE effect for quantitative studies may require careful calibration.
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107
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Wang Y, Brady KS, Caiello BP, Ackerson SM, Stewart JA. Human CST suppresses origin licensing and promotes AND-1/Ctf4 chromatin association. Life Sci Alliance 2019; 2:2/2/e201800270. [PMID: 30979824 PMCID: PMC6464128 DOI: 10.26508/lsa.201800270] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2018] [Revised: 04/02/2019] [Accepted: 04/03/2019] [Indexed: 12/17/2022] Open
Abstract
Human CTC1-STN1-TEN1 (CST) is an RPA-like single-stranded DNA-binding protein that interacts with DNA polymerase α-primase (pol α) and functions in telomere replication. Previous studies suggest that CST also promotes replication restart after fork stalling. However, the precise role of CST in genome-wide replication remains unclear. In this study, we sought to understand whether CST alters origin licensing and activation. Replication origins are licensed by loading of the minichromosome maintenance 2-7 (MCM) complex in G1 followed by replisome assembly and origin firing in S-phase. We find that CST directly interacts with the MCM complex and disrupts binding of CDT1 to MCM, leading to decreased origin licensing. We also show that CST enhances replisome assembly by promoting AND-1/pol α chromatin association. Moreover, these interactions are not dependent on exogenous replication stress, suggesting that CST acts as a specialized replication factor during normal replication. Overall, our findings implicate CST as a novel regulator of origin licensing and replisome assembly/fork progression through interactions with MCM, AND-1, and pol α.
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Affiliation(s)
- Yilin Wang
- Department of Biological Sciences, University of South Carolina, Columbia, SC, USA
| | - Kathryn S Brady
- Department of Biological Sciences, University of South Carolina, Columbia, SC, USA
| | - Benjamin P Caiello
- Department of Biological Sciences, University of South Carolina, Columbia, SC, USA
| | - Stephanie M Ackerson
- Department of Biological Sciences, University of South Carolina, Columbia, SC, USA
| | - Jason A Stewart
- Department of Biological Sciences, University of South Carolina, Columbia, SC, USA .,Center for Colon Cancer Research, University of South Carolina, Columbia, SC, USA
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108
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Erickson KD, Garcea RL. Viral replication centers and the DNA damage response in JC virus-infected cells. Virology 2019; 528:198-206. [PMID: 30811999 DOI: 10.1016/j.virol.2018.12.014] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Revised: 12/19/2018] [Accepted: 12/19/2018] [Indexed: 01/09/2023]
Abstract
JCV is a human polyomavirus (PyV) that establishes a persistent infection in its host. Current immunomodulatory therapies, such as Natalizumab for multiple sclerosis, can result in JCV reactivation, leading to the debilitating brain disease progressive multifocal leukoencephalopathy (PML). JCV is among the viruses that recruit and modulate the host DNA damage response (DDR) to replicate its genome. We have identified host proteins recruited to the nuclear sites of JC viral DNA (vDNA) replication using three cell types susceptible to infection in vitro. Using confocal microscopy, we found that JCV recruited a similar repertoire of host DDR proteins to these replication sites previously observed for other PyVs. Electron tomography of JCV "virus factories" showed structural features like those described for murine PyV. These results confirm and extend previous observations for PyVs to JCV emphasizing a similar replication strategy among members of this virus family.
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Affiliation(s)
- Kimberly D Erickson
- The BioFrontiers Institute, University of Colorado, Boulder, CO 80309, United States
| | - Robert L Garcea
- The Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, CO 80309, United States; The BioFrontiers Institute, University of Colorado, Boulder, CO 80309, United States.
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109
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Li S, Dong Z, Yang S, Feng J, Li Q. Chaperoning RPA during DNA metabolism. Curr Genet 2019; 65:857-864. [PMID: 30796471 DOI: 10.1007/s00294-019-00945-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Revised: 02/14/2019] [Accepted: 02/15/2019] [Indexed: 12/17/2022]
Abstract
Single-stranded DNA (ssDNA) is widely generated during DNA metabolisms including DNA replication, repair and recombination and is susceptible to digestion by nucleases and secondary structure formation. It is vital for DNA metabolism and genome stability that ssDNA is protected and stabilized, which are performed by the major ssDNA-binding protein, and replication protein A (RPA) in these processes. In addition, RPA-coated ssDNA also serves as a protein-protein-binding platform for coordinating multiple events during DNA metabolisms. However, little is known about whether and how the formation of RPA-ssDNA platform is regulated. Here we highlight our recent study of a novel RPA-binding protein, Regulator of Ty1 transposition 105 (Rtt105) in Saccharomyces cerevisiae, which regulates the RPA-ssDNA platform assembly at replication forks. We propose that Rtt105 functions as an "RPA chaperone" during DNA replication, likely also promoting the assembly of RPA-ssDNA platform in other processes in which RPA plays a critical role.
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Affiliation(s)
- Shuqi Li
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences and Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, 100871, China.,Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, 100871, China.,Laboratory of Host-Pathogen Biology, The Rockefeller University, 1230 York Avenue, New York, NY, 10065, USA
| | - Ziqi Dong
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences and Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, 100871, China
| | - Shuangshuang Yang
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences and Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, 100871, China
| | - Jianxun Feng
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences and Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, 100871, China
| | - Qing Li
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences and Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, 100871, China. .,Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, 100871, China.
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110
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Pokhrel N, Caldwell CC, Corless EI, Tillison EA, Tibbs J, Jocic N, Tabei SMA, Wold MS, Spies M, Antony E. Dynamics and selective remodeling of the DNA-binding domains of RPA. Nat Struct Mol Biol 2019; 26:129-136. [PMID: 30723327 PMCID: PMC6368398 DOI: 10.1038/s41594-018-0181-y] [Citation(s) in RCA: 76] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Accepted: 12/19/2018] [Indexed: 12/16/2022]
Abstract
Replication protein A (RPA) coordinates important DNA metabolic events by stabilizing single-stranded DNA (ssDNA) intermediates, activating the DNA-damage response and handing off ssDNA to the appropriate downstream players. Six DNA-binding domains (DBDs) in RPA promote high-affinity binding to ssDNA yet also allow RPA displacement by lower affinity proteins. We generated fluorescent versions of Saccharomyces cerevisiae RPA and visualized the conformational dynamics of individual DBDs in the context of the full-length protein. We show that both DBD-A and DBD-D rapidly bind to and dissociate from ssDNA while RPA remains bound to ssDNA. The recombination mediator protein Rad52 selectively modulates the dynamics of DBD-D. These findings reveal how RPA-interacting proteins with lower ssDNA binding affinities can access the occluded ssDNA and remodel individual DBDs to replace RPA.
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Affiliation(s)
- Nilisha Pokhrel
- Department of Biological Sciences, Marquette University, Milwaukee, WI, USA
| | - Colleen C Caldwell
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Elliot I Corless
- Department of Biological Sciences, Marquette University, Milwaukee, WI, USA
| | - Emma A Tillison
- Department of Biological Sciences, Marquette University, Milwaukee, WI, USA
| | - Joseph Tibbs
- Department of Physics, University of Northern Iowa, Cedar Falls, IA, USA
| | - Nina Jocic
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, IA, USA.,Department of Physics, University of Northern Iowa, Cedar Falls, IA, USA
| | - S M Ali Tabei
- Department of Physics, University of Northern Iowa, Cedar Falls, IA, USA
| | - Marc S Wold
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Maria Spies
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, IA, USA.
| | - Edwin Antony
- Department of Biological Sciences, Marquette University, Milwaukee, WI, USA.
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111
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Yates LA, Aramayo RJ, Pokhrel N, Caldwell CC, Kaplan JA, Perera RL, Spies M, Antony E, Zhang X. A structural and dynamic model for the assembly of Replication Protein A on single-stranded DNA. Nat Commun 2018; 9:5447. [PMID: 30575763 PMCID: PMC6303327 DOI: 10.1038/s41467-018-07883-7] [Citation(s) in RCA: 92] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Accepted: 12/03/2018] [Indexed: 12/04/2022] Open
Abstract
Replication Protein A (RPA), the major eukaryotic single stranded DNA-binding protein, binds to exposed ssDNA to protect it from nucleases, participates in a myriad of nucleic acid transactions and coordinates the recruitment of other important players. RPA is a heterotrimer and coats long stretches of single-stranded DNA (ssDNA). The precise molecular architecture of the RPA subunits and its DNA binding domains (DBDs) during assembly is poorly understood. Using cryo electron microscopy we obtained a 3D reconstruction of the RPA trimerisation core bound with ssDNA (∼55 kDa) at ∼4.7 Å resolution and a dimeric RPA assembly on ssDNA. FRET-based solution studies reveal dynamic rearrangements of DBDs during coordinated RPA binding and this activity is regulated by phosphorylation at S178 in RPA70. We present a structural model on how dynamic DBDs promote the cooperative assembly of multiple RPAs on long ssDNA.
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Affiliation(s)
- Luke A Yates
- Section of Structural Biology, Department of Medicine, Imperial College London, Sir Alexander Fleming Building, South Kensington, London, SW7 2AZ, UK
| | - Ricardo J Aramayo
- Section of Structural Biology, Department of Medicine, Imperial College London, Sir Alexander Fleming Building, South Kensington, London, SW7 2AZ, UK
| | - Nilisha Pokhrel
- Department of Biological Sciences, Marquette University, Milwaukee, WI, 53201, USA
| | - Colleen C Caldwell
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, IA, 52241, USA
| | - Joshua A Kaplan
- Section of Structural Biology, Department of Medicine, Imperial College London, Sir Alexander Fleming Building, South Kensington, London, SW7 2AZ, UK
| | - Rajika L Perera
- Section of Structural Biology, Department of Medicine, Imperial College London, Sir Alexander Fleming Building, South Kensington, London, SW7 2AZ, UK
- Poseidon LLC, 2265 East Foothill Boulevard, Pasadena, CA, 91107, USA
| | - Maria Spies
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, IA, 52241, USA
| | - Edwin Antony
- Department of Biological Sciences, Marquette University, Milwaukee, WI, 53201, USA
| | - Xiaodong Zhang
- Section of Structural Biology, Department of Medicine, Imperial College London, Sir Alexander Fleming Building, South Kensington, London, SW7 2AZ, UK.
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112
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Schaub JM, Zhang H, Soniat MM, Finkelstein IJ. Assessing Protein Dynamics on Low-Complexity Single-Stranded DNA Curtains. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:14882-14890. [PMID: 30044093 PMCID: PMC6679933 DOI: 10.1021/acs.langmuir.8b01812] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Single-stranded DNA (ssDNA) is a critical intermediate in all DNA transactions. Because ssDNA is more flexible than double-stranded (ds) DNA, interactions with ssDNA-binding proteins (SSBs) may significantly compact or elongate the ssDNA molecule. Here, we develop and characterize low-complexity ssDNA curtains, a high-throughput single-molecule assay to simultaneously monitor protein binding and correlated ssDNA length changes on supported lipid bilayers. Low-complexity ssDNA is generated via rolling circle replication of short synthetic oligonucleotides, permitting control over the sequence composition and secondary structure-forming propensity. One end of the ssDNA is functionalized with a biotin, while the second is fluorescently labeled to track the overall DNA length. Arrays of ssDNA molecules are organized at microfabricated barriers for high-throughput single-molecule imaging. Using this assay, we demonstrate that E. coli SSB drastically and reversibly compacts ssDNA templates upon changes in NaCl concentration. We also examine the interactions between a phosphomimetic RPA and ssDNA. Our results indicate that RPA-ssDNA interactions are not significantly altered by these modifications. We anticipate that low-complexity ssDNA curtains will be broadly useful for single-molecule studies of ssDNA-binding proteins involved in DNA replication, transcription, and repair.
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Affiliation(s)
- Jeffrey M. Schaub
- Department of Molecular Biosciences and Institute for Cellular and Molecular Biology
| | - Hongshan Zhang
- Department of Molecular Biosciences and Institute for Cellular and Molecular Biology
| | - Michael M. Soniat
- Department of Molecular Biosciences and Institute for Cellular and Molecular Biology
| | - Ilya J. Finkelstein
- Department of Molecular Biosciences and Institute for Cellular and Molecular Biology
- Center for Systems and Synthetic Biology, The University of Texas at Austin, Austin, Texas 78712, United States
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113
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Byrne BM, Oakley GG. Replication protein A, the laxative that keeps DNA regular: The importance of RPA phosphorylation in maintaining genome stability. Semin Cell Dev Biol 2018; 86:112-120. [PMID: 29665433 DOI: 10.1016/j.semcdb.2018.04.005] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Revised: 03/30/2018] [Accepted: 04/06/2018] [Indexed: 11/25/2022]
Abstract
The eukaryotic ssDNA-binding protein, Replication protein A (RPA), was first discovered almost three decades ago. Since then, much progress has been made to elucidate the critical roles for RPA in DNA metabolic pathways that help promote genomic stability. The canonical RPA heterotrimer (RPA1-3) is an essential coordinator of DNA metabolism that interacts with ssDNA and numerous protein partners to coordinate its roles in DNA replication, repair, recombination and telomere maintenance. An alternative form of RPA, termed aRPA, is formed by a complex of RPA4 with RPA1 and RPA3. aRPA is expressed differentially in cells compared to canonical RPA and has been shown to inhibit canonical RPA function while allowing for regular maintenance of cell viability. Interestingly, while aRPA is defective in DNA replication and cell cycle progression, it was shown to play a supporting role in nucleotide excision repair and recombination. The binding domains of canonical RPA interact with a growing number of partners involved in numerous genome maintenance processes. The protein interactions of the RPA-ssDNA complex are not only governed by competition between the binding proteins but also by post-translation modifications such as phosphorylation. Phosphorylation of RPA2 is an important post-translational modification of the RPA complex, and is essential for directing context-specific functions of the RPA complex in the DNA damage response. Due to the importance of RPA in cellular metabolism, it was identified as an appealing target for chemotherapeutic drug development that could be used in future cancer treatment regimens.
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Affiliation(s)
- Brendan M Byrne
- University of Nebraska Medical Center Department of Oral Biology, Lincoln NE, USA.
| | - Gregory G Oakley
- University of Nebraska Medical Center Department of Oral Biology, Lincoln NE, USA; Eppley Cancer Center, Omaha NE, USA.
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114
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Liu P, Rojo de la Vega M, Sammani S, Mascarenhas JB, Kerins M, Dodson M, Sun X, Wang T, Ooi A, Garcia JGN, Zhang DD. RPA1 binding to NRF2 switches ARE-dependent transcriptional activation to ARE-NRE-dependent repression. Proc Natl Acad Sci U S A 2018; 115:E10352-E10361. [PMID: 30309964 PMCID: PMC6217430 DOI: 10.1073/pnas.1812125115] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
NRF2 regulates cellular redox homeostasis, metabolic balance, and proteostasis by forming a dimer with small musculoaponeurotic fibrosarcoma proteins (sMAFs) and binding to antioxidant response elements (AREs) to activate target gene transcription. In contrast, NRF2-ARE-dependent transcriptional repression is unreported. Here, we describe NRF2-mediated gene repression via a specific seven-nucleotide sequence flanking the ARE, which we term the NRF2-replication protein A1 (RPA1) element (NRE). Mechanistically, RPA1 competes with sMAF for NRF2 binding, followed by interaction of NRF2-RPA1 with the ARE-NRE and eduction of promoter activity. Genome-wide in silico and RNA-seq analyses revealed this NRF2-RPA1-ARE-NRE complex mediates negative regulation of many genes with diverse functions, indicating that this mechanism is a fundamental cellular process. Notably, repression of MYLK, which encodes the nonmuscle myosin light chain kinase, by the NRF2-RPA1-ARE-NRE complex disrupts vascular integrity in preclinical inflammatory lung injury models, illustrating the translational significance of NRF2-mediated transcriptional repression. Our findings reveal a gene-suppressive function of NRF2 and a subset of negatively regulated NRF2 target genes, underscoring the broad impact of NRF2 in physiological and pathological settings.
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Affiliation(s)
- Pengfei Liu
- Department of Pharmacology and Toxicology, College of Pharmacy, University of Arizona, Tucson, AZ 85721
| | | | - Saad Sammani
- Department of Medicine, University of Arizona Health Sciences, University of Arizona, Tucson, AZ 85721
| | - Joseph B Mascarenhas
- Department of Medicine, University of Arizona Health Sciences, University of Arizona, Tucson, AZ 85721
| | - Michael Kerins
- Department of Pharmacology and Toxicology, College of Pharmacy, University of Arizona, Tucson, AZ 85721
| | - Matthew Dodson
- Department of Pharmacology and Toxicology, College of Pharmacy, University of Arizona, Tucson, AZ 85721
| | - Xiaoguang Sun
- Department of Medicine, University of Arizona Health Sciences, University of Arizona, Tucson, AZ 85721
| | - Ting Wang
- Department of Medicine, University of Arizona Health Sciences, University of Arizona, Tucson, AZ 85721
| | - Aikseng Ooi
- Department of Pharmacology and Toxicology, College of Pharmacy, University of Arizona, Tucson, AZ 85721
| | - Joe G N Garcia
- Department of Medicine, University of Arizona Health Sciences, University of Arizona, Tucson, AZ 85721;
| | - Donna D Zhang
- Department of Pharmacology and Toxicology, College of Pharmacy, University of Arizona, Tucson, AZ 85721;
- The University of Arizona Cancer Center, University of Arizona, Tucson, AZ 85721
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115
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Yates M, Maréchal A. Ubiquitylation at the Fork: Making and Breaking Chains to Complete DNA Replication. Int J Mol Sci 2018; 19:E2909. [PMID: 30257459 PMCID: PMC6213728 DOI: 10.3390/ijms19102909] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Revised: 09/20/2018] [Accepted: 09/24/2018] [Indexed: 12/11/2022] Open
Abstract
The complete and accurate replication of the genome is a crucial aspect of cell proliferation that is often perturbed during oncogenesis. Replication stress arising from a variety of obstacles to replication fork progression and processivity is an important contributor to genome destabilization. Accordingly, cells mount a complex response to this stress that allows the stabilization and restart of stalled replication forks and enables the full duplication of the genetic material. This response articulates itself on three important platforms, Replication Protein A/RPA-coated single-stranded DNA, the DNA polymerase processivity clamp PCNA and the FANCD2/I Fanconi Anemia complex. On these platforms, the recruitment, activation and release of a variety of genome maintenance factors is regulated by post-translational modifications including mono- and poly-ubiquitylation. Here, we review recent insights into the control of replication fork stability and restart by the ubiquitin system during replication stress with a particular focus on human cells. We highlight the roles of E3 ubiquitin ligases, ubiquitin readers and deubiquitylases that provide the required flexibility at stalled forks to select the optimal restart pathways and rescue genome stability during stressful conditions.
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Affiliation(s)
- Maïlyn Yates
- Department of Biology, Université de Sherbrooke, Sherbrooke, QC J1K 2R1, Canada.
| | - Alexandre Maréchal
- Department of Biology, Université de Sherbrooke, Sherbrooke, QC J1K 2R1, Canada.
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116
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Single-stranded telomere-binding protein employs a dual rheostat for binding affinity and specificity that drives function. Proc Natl Acad Sci U S A 2018; 115:10315-10320. [PMID: 30249661 PMCID: PMC6187146 DOI: 10.1073/pnas.1722147115] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Proteins that bind nucleic acids are frequently categorized as being either specific or nonspecific, with interfaces to match that activity. In this study, we have found that a telomere-binding protein exhibits a degree of specificity for ssDNA that is finely tuned for its function, which includes specificity for G-rich sequences with some tolerance for substitution. Mutations of the protein that dramatically impact its affinity for single-stranded telomeric DNA are lethal, as expected; however, mutations that alter specificity also impact biological function. Unexpectedly, we found mutations that make the protein more specific are also deleterious, suggesting that specificity and nonspecificity in nucleic acid recognition may be achieved through more nuanced mechanisms than currently recognized. ssDNA, which is involved in numerous aspects of chromosome biology, is managed by a suite of proteins with tailored activities. The majority of these proteins bind ssDNA indiscriminately, exhibiting little apparent sequence preference. However, there are several notable exceptions, including the Saccharomyces cerevisiae Cdc13 protein, which is vital for yeast telomere maintenance. Cdc13 is one of the tightest known binders of ssDNA and is specific for G-rich telomeric sequences. To investigate how these two different biochemical features, affinity and specificity, contribute to function, we created an unbiased panel of alanine mutations across the Cdc13 DNA-binding interface, including several aromatic amino acids that play critical roles in binding activity. A subset of mutant proteins exhibited significant loss in affinity in vitro that, as expected, conferred a profound loss of viability in vivo. Unexpectedly, a second category of mutant proteins displayed an increase in specificity, manifested as an inability to accommodate changes in ssDNA sequence. Yeast strains with specificity-enhanced mutations displayed a gradient of viability in vivo that paralleled the loss in sequence tolerance in vitro, arguing that binding specificity can be fine-tuned to ensure optimal function. We propose that DNA binding by Cdc13 employs a highly cooperative interface whereby sequence diversity is accommodated through plastic binding modes. This suggests that sequence specificity is not a binary choice but rather is a continuum. Even in proteins that are thought to be specific nucleic acid binders, sequence tolerance through the utilization of multiple binding modes may be a broader phenomenon than previously appreciated.
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117
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Liao H, Ji F, Helleday T, Ying S. Mechanisms for stalled replication fork stabilization: new targets for synthetic lethality strategies in cancer treatments. EMBO Rep 2018; 19:embr.201846263. [PMID: 30108055 DOI: 10.15252/embr.201846263] [Citation(s) in RCA: 121] [Impact Index Per Article: 20.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Revised: 07/06/2018] [Accepted: 07/20/2018] [Indexed: 01/24/2023] Open
Abstract
Timely and faithful duplication of the entire genome depends on completion of replication. Replication forks frequently encounter obstacles that may cause genotoxic fork stalling. Nevertheless, failure to complete replication rarely occurs under normal conditions, which is attributed to an intricate network of proteins that serves to stabilize, repair and restart stalled forks. Indeed, many of the components in this network are encoded by tumour suppressor genes, and their loss of function by mutation or deletion generates genomic instability, a hallmark of cancer. Paradoxically, the same fork-protective network also confers resistance of cancer cells to chemotherapeutic drugs that induce high-level replication stress. Here, we review the mechanisms and major pathways rescuing stalled replication forks, with a focus on fork stabilization preventing fork collapse. A coherent understanding of how cells protect their replication forks will not only provide insight into how cells maintain genome stability, but also unravel potential therapeutic targets for cancers refractory to conventional chemotherapies.
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Affiliation(s)
- Hongwei Liao
- Department of Pharmacology & Key Laboratory of Respiratory Disease of Zhejiang Province, Department of Respiratory and Critical Care Medicine, Second Affiliated Hospital, Institute of Respiratory Diseases, Zhejiang University School of Medicine, Hangzhou, China
| | - Fang Ji
- Department of Pharmacology & Key Laboratory of Respiratory Disease of Zhejiang Province, Department of Respiratory and Critical Care Medicine, Second Affiliated Hospital, Institute of Respiratory Diseases, Zhejiang University School of Medicine, Hangzhou, China
| | - Thomas Helleday
- Science for Life Laboratory, Division of Translational Medicine and Chemical Biology, Department of Medical Biochemistry and Biophysics, Karolinska Institute, Stockholm, Sweden .,Sheffield Cancer Centre, Department of Oncology and Metabolism, University of Sheffield, Sheffield, UK
| | - Songmin Ying
- Department of Pharmacology & Key Laboratory of Respiratory Disease of Zhejiang Province, Department of Respiratory and Critical Care Medicine, Second Affiliated Hospital, Institute of Respiratory Diseases, Zhejiang University School of Medicine, Hangzhou, China
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118
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Li S, Xu Z, Xu J, Zuo L, Yu C, Zheng P, Gan H, Wang X, Li L, Sharma S, Chabes A, Li D, Wang S, Zheng S, Li J, Chen X, Sun Y, Xu D, Han J, Chan K, Qi Z, Feng J, Li Q. Rtt105 functions as a chaperone for replication protein A to preserve genome stability. EMBO J 2018; 37:embj.201899154. [PMID: 30065069 DOI: 10.15252/embj.201899154] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2018] [Revised: 06/28/2018] [Accepted: 07/06/2018] [Indexed: 02/05/2023] Open
Abstract
Generation of single-stranded DNA (ssDNA) is required for the template strand formation during DNA replication. Replication Protein A (RPA) is an ssDNA-binding protein essential for protecting ssDNA at replication forks in eukaryotic cells. While significant progress has been made in characterizing the role of the RPA-ssDNA complex, how RPA is loaded at replication forks remains poorly explored. Here, we show that the Saccharomyces cerevisiae protein regulator of Ty1 transposition 105 (Rtt105) binds RPA and helps load it at replication forks. Cells lacking Rtt105 exhibit a dramatic reduction in RPA loading at replication forks, compromised DNA synthesis under replication stress, and increased genome instability. Mechanistically, we show that Rtt105 mediates the RPA-importin interaction and also promotes RPA binding to ssDNA directly in vitro, but is not present in the final RPA-ssDNA complex. Single-molecule studies reveal that Rtt105 affects the binding mode of RPA to ssDNA These results support a model in which Rtt105 functions as an RPA chaperone that escorts RPA to the nucleus and facilitates its loading onto ssDNA at replication forks.
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Affiliation(s)
- Shuqi Li
- Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
| | - Zhiyun Xu
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing, China
| | - Jiawei Xu
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing, China
| | - Linyu Zuo
- Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China.,Center for Quantitative Biology, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
| | - Chuanhe Yu
- Department of Pediatrics and Department of Genetics and Development, Institute for Cancer Genetics, Columbia University College of Physicians and Surgeons, New York, NY, USA
| | - Pu Zheng
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing, China
| | - Haiyun Gan
- Department of Pediatrics and Department of Genetics and Development, Institute for Cancer Genetics, Columbia University College of Physicians and Surgeons, New York, NY, USA
| | - Xuezheng Wang
- Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
| | - Longtu Li
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing, China
| | - Sushma Sharma
- Medical Biochemistry and Biophysics, Umeå University, Umeå, Sweden
| | - Andrei Chabes
- Medical Biochemistry and Biophysics, Umeå University, Umeå, Sweden
| | - Di Li
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing, China
| | - Sheng Wang
- State Key Laboratory of Membrane Biology, Biodynamic Optical Imaging Center (BIOPIC), School of Life Sciences, Peking University, Beijing, China
| | - Sihao Zheng
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences and the Institute for Advanced Studies, Wuhan University, Wuhan, China
| | - Jinbao Li
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences and the Institute for Advanced Studies, Wuhan University, Wuhan, China
| | - Xuefeng Chen
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences and the Institute for Advanced Studies, Wuhan University, Wuhan, China
| | - Yujie Sun
- State Key Laboratory of Membrane Biology, Biodynamic Optical Imaging Center (BIOPIC), School of Life Sciences, Peking University, Beijing, China
| | - Dongyi Xu
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing, China
| | - Junhong Han
- Division of Abdominal Cancer, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, and National Collaborative Center for Biotherapy, Chengdu, China
| | - Kuiming Chan
- Department of Biomedical Sciences, City University of Hong Kong, Hong Kong, China
| | - Zhi Qi
- Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China.,Center for Quantitative Biology, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
| | - Jianxun Feng
- Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China .,State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing, China
| | - Qing Li
- Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China .,State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing, China
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119
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CTC1-STN1 terminates telomerase while STN1-TEN1 enables C-strand synthesis during telomere replication in colon cancer cells. Nat Commun 2018; 9:2827. [PMID: 30026550 PMCID: PMC6053418 DOI: 10.1038/s41467-018-05154-z] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2017] [Accepted: 06/07/2018] [Indexed: 01/20/2023] Open
Abstract
Telomerase elongates the telomeric G-strand to prevent telomere shortening through conventional DNA replication. However, synthesis of the complementary C-strand by DNA polymerase α is also required to maintain telomere length. Polymerase α cannot perform this role without the ssDNA binding complex CST (CTC1-STN1-TEN1). Here we describe the roles of individual CST subunits in telomerase regulation and G-overhang maturation in human colon cancer cells. We show that CTC1-STN1 limits telomerase action to prevent G-overhang overextension. CTC1-/- cells exhibit telomeric DNA damage and growth arrest due to overhang elongation whereas TEN1-/- cells do not. However, TEN1 is essential for C-strand synthesis and TEN1-/- cells exhibit progressive telomere shortening. DNA binding analysis indicates that CTC1-STN1 retains affinity for ssDNA but TEN1 stabilizes binding. We propose CTC1-STN1 binding is sufficient to terminate telomerase action but altered DNA binding dynamics renders CTC1-STN1 unable to properly engage polymerase α on the overhang for C-strand synthesis.
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120
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Méhul B, Perrin A, Grisendi K, Galindo AN, Dayon L, Ménigot C, Rival Y, Voegel JJ. Mass spectrometry and DigiWest technology emphasize protein acetylation profile from Quisinostat-treated HuT78 CTCL cell line. J Proteomics 2018; 187:126-143. [PMID: 30012418 DOI: 10.1016/j.jprot.2018.07.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Revised: 06/20/2018] [Accepted: 07/12/2018] [Indexed: 02/07/2023]
Abstract
Histone deacetylases (HDACs) are key enzymes involved in epigenetic modulation and were targeted by HDAC inhibitors (HDACis) for cancer treatment. The action of HDACis is not restricted to histones and also prevents deacetylation of other proteins, supporting their wide biological actions. The HuT78 cell line is recognized as a key tool to support and understand cutaneous T-cell lymphoma (CTCL) biology and was used as a predictive model since HDACi such as Vorinostat and Panobinostat have both demonstrated apoptotic activities in HuT78 cells and in primary blood CTCL cells. In this study, Quisinostat (JNJ-26481585) a novel second-generation HDACi with highest potency for HDAC1, was tested on HuT78 cell line. Quantitative mass spectrometry (MS)-based proteomics after acetylated-lysine peptide enrichment and a targeted antibody-based immunoassay (DigiWest) were used as complementary technologies to assess the modifications of the acetylated proteome. As expected, several acetylated lysines of histones were increased by the HDACi. Additional acetylated non-histone proteins were modulated after treatment with Quisinostat including the nucleolin (a major nucleolar protein), the replication protein A 70 kDa DNA-binding subunit, the phosphoglycerate kinase 1, the stress-70 protein, the proto-oncogene Myc and the serine hydroxymethyltransferase. A better knowledge of histone and non-histone acetylated protein profile after Quisinostat treatment can strongly support the understanding of non-clinical and clinical results of this HDACi. These technological tools can also help in designing new HDACis in a pharmaceutical drug discovery program. SIGNIFICANCE A better knowledge of histone and non-histone acetylated protein profile after HDAC inhibitors (HDACis) treatment can strongly support the understanding of non-clinical and clinical investigations in a pharmaceutical drug discovery program. Relative quantification using mass spectrometry -based proteomics after acetylated-lysine peptide enrichment and a targeted antibody-based immunoassay (DigiWest) are proposed as complementary technologies to assess the modifications of the acetylated proteome. Quisinostat (JNJ-26481585) a novel second-generation HDACi with highest potency for HDAC1 was better characterized in vitro in HuT78 cells to support and understand cutaneous T-cell lymphoma (CTCL) therapeutic research program.
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Affiliation(s)
- Bruno Méhul
- Galderma, Nestlé Skin Health R & D, 2400, route des Colles, 06410 Biot, France.
| | - Agnes Perrin
- Galderma, Nestlé Skin Health R & D, 2400, route des Colles, 06410 Biot, France
| | - Karine Grisendi
- Galderma, Nestlé Skin Health R & D, 2400, route des Colles, 06410 Biot, France
| | | | - Loïc Dayon
- Proteomics, Nestlé Institute of Health Sciences, 1015 Lausanne, Switzerland
| | - Corinne Ménigot
- Galderma, Nestlé Skin Health R & D, 2400, route des Colles, 06410 Biot, France
| | - Yves Rival
- Galderma, Nestlé Skin Health R & D, 2400, route des Colles, 06410 Biot, France
| | - Johannes J Voegel
- Galderma, Nestlé Skin Health R & D, 2400, route des Colles, 06410 Biot, France
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121
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Syed A, Tainer JA. The MRE11-RAD50-NBS1 Complex Conducts the Orchestration of Damage Signaling and Outcomes to Stress in DNA Replication and Repair. Annu Rev Biochem 2018; 87:263-294. [PMID: 29709199 PMCID: PMC6076887 DOI: 10.1146/annurev-biochem-062917-012415] [Citation(s) in RCA: 255] [Impact Index Per Article: 42.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Genomic instability in disease and its fidelity in health depend on the DNA damage response (DDR), regulated in part from the complex of meiotic recombination 11 homolog 1 (MRE11), ATP-binding cassette-ATPase (RAD50), and phosphopeptide-binding Nijmegen breakage syndrome protein 1 (NBS1). The MRE11-RAD50-NBS1 (MRN) complex forms a multifunctional DDR machine. Within its network assemblies, MRN is the core conductor for the initial and sustained responses to DNA double-strand breaks, stalled replication forks, dysfunctional telomeres, and viral DNA infection. MRN can interfere with cancer therapy and is an attractive target for precision medicine. Its conformations change the paradigm whereby kinases initiate damage sensing. Delineated results reveal kinase activation, posttranslational targeting, functional scaffolding, conformations storing binding energy and enabling access, interactions with hub proteins such as replication protein A (RPA), and distinct networks at DNA breaks and forks. MRN biochemistry provides prototypic insights into how it initiates, implements, and regulates multifunctional responses to genomic stress.
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Affiliation(s)
- Aleem Syed
- Department of Molecular and Cellular Oncology, The University of Texas M.D. Anderson Cancer Center, Houston, Texas 77030, USA; ,
| | - John A Tainer
- Department of Molecular and Cellular Oncology, The University of Texas M.D. Anderson Cancer Center, Houston, Texas 77030, USA; ,
- Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
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122
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Khan AQ, Travers JB, Kemp MG. Roles of UVA radiation and DNA damage responses in melanoma pathogenesis. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2018; 59:438-460. [PMID: 29466611 PMCID: PMC6031472 DOI: 10.1002/em.22176] [Citation(s) in RCA: 75] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Revised: 01/18/2018] [Accepted: 01/22/2018] [Indexed: 05/10/2023]
Abstract
The growing incidence of melanoma is a serious public health issue that merits a thorough understanding of potential causative risk factors, which includes exposure to ultraviolet radiation (UVR). Though UVR has been classified as a complete carcinogen and has long been recognized for its ability to damage genomic DNA through both direct and indirect means, the precise mechanisms by which the UVA and UVB components of UVR contribute to the pathogenesis of melanoma have not been clearly defined. In this review, we therefore highlight recent studies that have addressed roles for UVA radiation in the generation of DNA damage and in modulating the subsequent cellular responses to DNA damage in melanocytes, which are the cell type that gives rise to melanoma. Recent research suggests that UVA not only contributes to the direct formation of DNA lesions but also impairs the removal of UV photoproducts from genomic DNA through oxidation and damage to DNA repair proteins. Moreover, the melanocyte microenvironment within the epidermis of the skin is also expected to impact melanomagenesis, and we therefore discuss several paracrine signaling pathways that have been shown to impact the DNA damage response in UV-irradiated melanocytes. Lastly, we examine how alterations to the immune microenvironment by UVA-associated DNA damage responses may contribute to melanoma development. Thus, there appear to be multiple avenues by which UVA may elevate the risk of melanoma. Protective strategies against excess exposure to UVA wavelengths of light therefore have the potential to decrease the incidence of melanoma. Environ. Mol. Mutagen. 59:438-460, 2018. © 2018 Wiley Periodicals, Inc.
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Affiliation(s)
- Aiman Q Khan
- Department of Pharmacology and Toxicology, Wright State University Boonshoft School of Medicine, Dayton, Ohio
| | - Jeffrey B Travers
- Department of Pharmacology and Toxicology, Wright State University Boonshoft School of Medicine, Dayton, Ohio
- Dayton Veterans Affairs Medical Center, Dayton, Ohio
| | - Michael G Kemp
- Department of Pharmacology and Toxicology, Wright State University Boonshoft School of Medicine, Dayton, Ohio
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123
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The silencing of replication protein A1 induced cell apoptosis via regulating Caspase 3. Life Sci 2018; 201:141-149. [DOI: 10.1016/j.lfs.2018.03.054] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Revised: 03/23/2018] [Accepted: 03/26/2018] [Indexed: 01/15/2023]
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124
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Guarnieri MT, Levering J, Henard CA, Boore JL, Betenbaugh MJ, Zengler K, Knoshaug EP. Genome Sequence of the Oleaginous Green Alga, Chlorella vulgaris UTEX 395. Front Bioeng Biotechnol 2018; 6:37. [PMID: 29675409 PMCID: PMC5895722 DOI: 10.3389/fbioe.2018.00037] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2017] [Accepted: 03/19/2018] [Indexed: 11/13/2022] Open
Affiliation(s)
- Michael T Guarnieri
- National Bioenergy Center, National Renewable Energy Laboratory, Golden, CO, United States
| | - Jennifer Levering
- Division of Host-Microbe Systems and Therapeutics, Department of Pediatrics, University of California, San Diego, La Jolla, CA, United States
| | - Calvin A Henard
- National Bioenergy Center, National Renewable Energy Laboratory, Golden, CO, United States
| | | | - Michael J Betenbaugh
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, MD, United States
| | - Karsten Zengler
- Division of Host-Microbe Systems and Therapeutics, Department of Pediatrics, University of California, San Diego, La Jolla, CA, United States
| | - Eric P Knoshaug
- National Bioenergy Center, National Renewable Energy Laboratory, Golden, CO, United States
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125
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Antony E, Lohman TM. Dynamics of E. coli single stranded DNA binding (SSB) protein-DNA complexes. Semin Cell Dev Biol 2018; 86:102-111. [PMID: 29588158 DOI: 10.1016/j.semcdb.2018.03.017] [Citation(s) in RCA: 71] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Revised: 03/22/2018] [Accepted: 03/23/2018] [Indexed: 01/25/2023]
Abstract
Single stranded DNA binding proteins (SSB) are essential to the cell as they stabilize transiently open single stranded DNA (ssDNA) intermediates, recruit appropriate DNA metabolism proteins, and coordinate fundamental processes such as replication, repair and recombination. Escherichia coli single stranded DNA binding protein (EcSSB) has long served as the prototype for the study of SSB function. The structure, functions, and DNA binding properties of EcSSB are well established: The protein is a stable homotetramer with each subunit possessing an N-terminal DNA binding core, a C-terminal protein-protein interaction tail, and an intervening intrinsically disordered linker (IDL). EcSSB wraps ssDNA in multiple DNA binding modes and can diffuse along DNA to remove secondary structures and remodel other protein-DNA complexes. This review provides an update on these features based on recent findings, with special emphasis on the functional and mechanistic relevance of the IDL and DNA binding modes.
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Affiliation(s)
- Edwin Antony
- Department of Biological Sciences, Marquette University, Milwaukee, WI 53201, USA.
| | - Timothy M Lohman
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63110, USA.
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126
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Stewart JA, Wang Y, Ackerson SM, Schuck PL. Emerging roles of CST in maintaining genome stability and human disease. Front Biosci (Landmark Ed) 2018; 23:1564-1586. [PMID: 29293451 DOI: 10.2741/4661] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
The human CTC1-STN1-TEN1 (CST) complex is a single-stranded DNA binding protein that shares homology with RPA and interacts with DNA polymerase alpha/primase. CST complexes are conserved from yeasts to humans and function in telomere maintenance. A common role of CST across species is in the regulation of telomere extension by telomerase and C-strand fill-in synthesis. However, recent studies also indicate that CST promotes telomere duplex replication as well the rescue of stalled DNA replication at non-telomeric sites. Furthermore, CST dysfunction and mutation is associated with several genetic diseases and cancers. In this review, we will summarize what is known about CST with a particular focus on the emerging roles of CST in DNA replication and human disease.
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Affiliation(s)
- Jason A Stewart
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA,
| | - Yilin Wang
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA
| | - Stephanie M Ackerson
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA
| | - Percy Logan Schuck
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA
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127
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Kang D, Lee S, Ryu K, Cheong H, Kim E, Park C. Interaction of replication protein A with two acidic peptides from human Bloom syndrome protein. FEBS Lett 2018; 592:547-558. [DOI: 10.1002/1873-3468.12992] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Revised: 01/09/2018] [Accepted: 01/24/2018] [Indexed: 11/09/2022]
Affiliation(s)
- Donguk Kang
- Department of Chemistry Gwangju Institute of Science and Technology Gwangju, Korea
| | - Sungjin Lee
- Department of Chemistry Gwangju Institute of Science and Technology Gwangju, Korea
| | | | | | - Eun‐Hee Kim
- Division of Magnetic Resonance KBSI Chungbuk Korea
| | - Chin‐Ju Park
- Department of Chemistry Gwangju Institute of Science and Technology Gwangju, Korea
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128
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Liu XL, Wu RY, Sun XF, Cheng SF, Zhang RQ, Zhang TY, Zhang XF, Zhao Y, Shen W, Li L. Mycotoxin zearalenone exposure impairs genomic stability of swine follicular granulosa cells in vitro. Int J Biol Sci 2018; 14:294-305. [PMID: 29559847 PMCID: PMC5859475 DOI: 10.7150/ijbs.23898] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2017] [Accepted: 12/30/2017] [Indexed: 01/15/2023] Open
Abstract
Zearalenone (ZEA), a metabolite of Fusarium fungi, is commonly found on moldy grains. Because it can competitively combine to estrogen receptor to disrupt estrogenic signaling, it has been reported to have serious adverse effects on animal reproduction systems. In order to explore the genotoxic effects of ZEA exposure on ovarian somatic cells, porcine granulosa cells were exposed to 10 μM and 30 μM ZEA for 24 or 72 h in vitro. The results showed that ZEA exposure for 24 h remarkably reduced the proliferation of porcine granulosa cells in a dose-dependent manner as determined by MTT analysis and flow cytometry. Furthermore, exposure to ZEA for 72 h induced apoptosis, and RNA sequence analysis also revealed that the expression of apoptosis related genes were altered. RT-qPCR, immunofluorescence and western blot analysis further confirmed the expression of DNA damage and repair related genes (γ-H2AX, BRCA1, RAD51 and PRKDC) were increased in ZEA exposed granulosa cells. When the estrogen antagonist, tamoxifen, was added with ZEA in the culture medium, the DNA damage and repairment by ZEA returned to normal level. Collectively, these results illustrate that ZEA disrupts genome stability and inhibits growth of porcine granulosa cells via the estrogen receptors which may promote granulosa cell apoptosis when the DNA repair system is not enough to rescue this serious damage.
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Affiliation(s)
- Xue-Lian Liu
- College of Animal Science and Technology, Qingdao Agricultural University, Qingdao 266109, China
| | - Rui-Ying Wu
- Center for Reproductive Medicine, Qingdao Women's and Children's Hospital, Qingdao University, Qingdao 266034, China
| | - Xiao-Feng Sun
- College of Life Sciences, Institute of Reproductive Sciences, Qingdao Agricultural University, Qingdao 266109, China
| | - Shun-Feng Cheng
- College of Animal Science and Technology, Qingdao Agricultural University, Qingdao 266109, China.,College of Life Sciences, Institute of Reproductive Sciences, Qingdao Agricultural University, Qingdao 266109, China
| | - Rui-Qian Zhang
- College of Animal Science and Technology, Qingdao Agricultural University, Qingdao 266109, China
| | - Tian-Yu Zhang
- College of Animal Science and Technology, Qingdao Agricultural University, Qingdao 266109, China
| | - Xi-Feng Zhang
- College of Biological and Pharmaceutical Engineering, Wuhan Polytechnic University, Wuhan 430023, China
| | - Yong Zhao
- College of Animal Science and Technology, Qingdao Agricultural University, Qingdao 266109, China.,College of Life Sciences, Institute of Reproductive Sciences, Qingdao Agricultural University, Qingdao 266109, China
| | - Wei Shen
- College of Animal Science and Technology, Qingdao Agricultural University, Qingdao 266109, China.,Center for Reproductive Medicine, Qingdao Women's and Children's Hospital, Qingdao University, Qingdao 266034, China.,College of Life Sciences, Institute of Reproductive Sciences, Qingdao Agricultural University, Qingdao 266109, China
| | - Lan Li
- College of Animal Science and Technology, Qingdao Agricultural University, Qingdao 266109, China.,College of Life Sciences, Institute of Reproductive Sciences, Qingdao Agricultural University, Qingdao 266109, China
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129
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Murayama Y, Samora CP, Kurokawa Y, Iwasaki H, Uhlmann F. Establishment of DNA-DNA Interactions by the Cohesin Ring. Cell 2018; 172:465-477.e15. [PMID: 29358048 PMCID: PMC5786502 DOI: 10.1016/j.cell.2017.12.021] [Citation(s) in RCA: 91] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2017] [Revised: 10/12/2017] [Accepted: 12/16/2017] [Indexed: 01/14/2023]
Abstract
The ring-shaped structural maintenance of chromosome (SMC) complexes are multi-subunit ATPases that topologically encircle DNA. SMC rings make vital contributions to numerous chromosomal functions, including mitotic chromosome condensation, sister chromatid cohesion, DNA repair, and transcriptional regulation. They are thought to do so by establishing interactions between more than one DNA. Here, we demonstrate DNA-DNA tethering by the purified fission yeast cohesin complex. DNA-bound cohesin efficiently and topologically captures a second DNA, but only if that is single-stranded DNA (ssDNA). Like initial double-stranded DNA (dsDNA) embrace, second ssDNA capture is ATP-dependent, and it strictly requires the cohesin loader complex. Second-ssDNA capture is relatively labile but is converted into stable dsDNA-dsDNA cohesion through DNA synthesis. Our study illustrates second-DNA capture by an SMC complex and provides a molecular model for the establishment of sister chromatid cohesion.
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Affiliation(s)
- Yasuto Murayama
- Institute of Innovative Research, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8550, Japan.
| | - Catarina P Samora
- Chromosome Segregation Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Yumiko Kurokawa
- Education Academy of Computational Life Sciences, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8550, Japan
| | - Hiroshi Iwasaki
- Institute of Innovative Research, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8550, Japan
| | - Frank Uhlmann
- Institute of Innovative Research, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8550, Japan; Chromosome Segregation Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
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130
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Khodaverdian VY, Hanscom T, Yu AM, Yu TL, Mak V, Brown AJ, Roberts SA, McVey M. Secondary structure forming sequences drive SD-MMEJ repair of DNA double-strand breaks. Nucleic Acids Res 2018; 45:12848-12861. [PMID: 29121353 PMCID: PMC5728401 DOI: 10.1093/nar/gkx1056] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2017] [Accepted: 10/18/2017] [Indexed: 12/29/2022] Open
Abstract
Alternative end-joining (alt-EJ) repair of DNA double-strand breaks is associated with deletions, chromosome translocations, and genome instability. Alt-EJ frequently uses annealing of microhomologous sequences to tether broken ends. When accessible pre-existing microhomologies do not exist, we have postulated that new microhomologies can be created via limited DNA synthesis at secondary-structure forming sequences. This model, called synthesis-dependent microhomology-mediated end joining (SD-MMEJ), predicts that differences between DNA sequences near double-strand breaks should alter repair outcomes in predictable ways. To test this hypothesis, we injected plasmids with sequence variations flanking an I-SceI endonuclease recognition site into I-SceI expressing Drosophila embryos and used Illumina amplicon sequencing to compare repair junctions. As predicted by the model, we found that small changes in sequences near the I-SceI site had major impacts on the spectrum of repair junctions. Bioinformatic analyses suggest that these repair differences arise from transiently forming loops and hairpins within 30 nucleotides of the break. We also obtained evidence for ‘trans SD-MMEJ,’ involving at least two consecutive rounds of microhomology annealing and synthesis across the break site. These results highlight the importance of sequence context for alt-EJ repair and have important implications for genome editing and genome evolution.
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Affiliation(s)
- Varandt Y Khodaverdian
- Department of Biology, Tufts University, 200 Boston Avenue, Suite 4700, Medford, MA 02155, USA
| | - Terrence Hanscom
- Department of Biology, Tufts University, 200 Boston Avenue, Suite 4700, Medford, MA 02155, USA
| | - Amy Marie Yu
- Department of Biology, Tufts University, 200 Boston Avenue, Suite 4700, Medford, MA 02155, USA
| | - Taylor L Yu
- Department of Biology, Tufts University, 200 Boston Avenue, Suite 4700, Medford, MA 02155, USA
| | - Victoria Mak
- Department of Biology, Tufts University, 200 Boston Avenue, Suite 4700, Medford, MA 02155, USA
| | - Alexander J Brown
- School of Molecular Biosciences, Washington State University, P100 Dairy Road, Pullman, WA 99164, USA
| | - Steven A Roberts
- School of Molecular Biosciences, Washington State University, P100 Dairy Road, Pullman, WA 99164, USA
| | - Mitch McVey
- Department of Biology, Tufts University, 200 Boston Avenue, Suite 4700, Medford, MA 02155, USA
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131
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Biochemical characterization of INTS3 and C9ORF80, two subunits of hNABP1/2 heterotrimeric complex in nucleic acid binding. Biochem J 2018; 475:45-60. [PMID: 29150435 PMCID: PMC5748837 DOI: 10.1042/bcj20170351] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2017] [Revised: 10/01/2017] [Accepted: 11/14/2017] [Indexed: 12/15/2022]
Abstract
Human nucleic acid-binding protein 1 and 2 (hNABP1 and hNABP2, also known as hSSB2 and hSSB1 respectively) form two separate and independent complexes with two identical proteins, integrator complex subunit 3 (INTS3) and C9ORF80. We and other groups have demonstrated that hNABP1 and 2 are single-stranded (ss) DNA- and RNA-binding proteins, and function in DNA repair; however, the function of INTS3 and C9OFR80 remains elusive. In the present study, we purified recombinant proteins INTS3 and C9ORF80 to near homogeneity. Both proteins exist as a monomer in solution; however, C9ORF80 exhibits anomalous behavior on SDS–PAGE and gel filtration because of 48% random coil present in the protein. Using electrophoretic mobility shift assay (EMSA), INTS3 displays higher affinity toward ssRNA than ssDNA, and C9ORF80 binds ssDNA but not ssRNA. Neither of them binds dsDNA, dsRNA, or RNA : DNA hybrid. INTS3 requires minimum of 30 nucleotides, whereas C9OFR80 requires 20 nucleotides for its binding, which increased with the increasing length of ssDNA. Interestingly, our GST pulldown results suggest that the N-terminus of INTS3 is involved in protein–protein interaction, while EMSA implies that the C-terminus is required for nucleic acid binding. Furthermore, we purified the INTS3–hNABP1/2–C9ORF80 heterotrimeric complex. It exhibits weaker binding compared with the individual hNABP1/2; interestingly, the hNABP1 complex prefers ssDNA, whereas hNABP2 complex prefers ssRNA. Using reconstituted heterotrimeric complex from individual proteins, EMSA demonstrates that INTS3, but not C9ORF80, affects the nucleic acid-binding ability of hNABP1 and hNABP2, indicating that INTS3 might regulate hNABP1/2's biological function, while the role of C9ORF80 remains unknown.
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132
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Murayama Y. DNA entry, exit and second DNA capture by cohesin: insights from biochemical experiments. Nucleus 2018; 9:492-502. [PMID: 30205748 PMCID: PMC6244732 DOI: 10.1080/19491034.2018.1516486] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Revised: 07/28/2018] [Accepted: 08/16/2018] [Indexed: 12/23/2022] Open
Abstract
Cohesin is a ring-shaped, multi-subunit ATPase assembly that is fundamental to the spatiotemporal organization of chromosomes. The ring establishes a variety of chromosomal structures including sister chromatid cohesion and chromatin loops. At the core of the ring is a pair of highly conserved SMC (Structural Maintenance of Chromosomes) proteins, which are closed by the flexible kleisin subunit. In common with other essential SMC complexes including condensin and the SMC5-6 complex, cohesin encircles DNA inside its cavity, with the aid of HEAT (Huntingtin, elongation factor 3, protein phosphatase 2A and TOR) repeat auxiliary proteins. Through this topological embrace, cohesin is thought to establish a series of intra- and interchromosomal interactions by tethering more than one DNA molecule. Recent progress in biochemical reconstitution of cohesin provides molecular insights into how this ring complex topologically binds and mediates DNA-DNA interactions. Here, I review these studies and discuss how cohesin mediates such chromosome interactions.
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Affiliation(s)
- Yasuto Murayama
- Chromosome Biochemistry Laboratory, Center for Frontier Research, National Institute of Genetics, Mishima, Shizuoka, Japan
- Department of Genetics, SOKENDAI (The Graduate University for Advanced Studies), Mishima, Shizuoka, Japan
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133
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Bhattacharjee A, Wang Y, Diao J, Price CM. Dynamic DNA binding, junction recognition and G4 melting activity underlie the telomeric and genome-wide roles of human CST. Nucleic Acids Res 2017; 45:12311-12324. [PMID: 29040642 PMCID: PMC5716219 DOI: 10.1093/nar/gkx878] [Citation(s) in RCA: 63] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2017] [Accepted: 09/22/2017] [Indexed: 11/14/2022] Open
Abstract
Human CST (CTC1-STN1-TEN1) is a ssDNA-binding complex that helps resolve replication problems both at telomeres and genome-wide. CST resembles Replication Protein A (RPA) in that the two complexes harbor comparable arrays of OB-folds and have structurally similar small subunits. However, the overall architecture and functions of CST and RPA are distinct. Currently, the mechanism underlying CST action at diverse replication issues remains unclear. To clarify CST mechanism, we examined the capacity of CST to bind and resolve DNA structures found at sites of CST activity. We show that CST binds preferentially to ss-dsDNA junctions, an activity that can explain the incremental nature of telomeric C-strand synthesis following telomerase action. We also show that CST unfolds G-quadruplex structures, thus providing a mechanism for CST to facilitate replication through telomeres and other GC-rich regions. Finally, smFRET analysis indicates that CST binding to ssDNA is dynamic with CST complexes undergoing concentration-dependent self-displacement. These findings support an RPA-based model where dissociation and re-association of individual OB-folds allow CST to mediate loading and unloading of partner proteins to facilitate various aspects of telomere replication and genome-wide resolution of replication stress.
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Affiliation(s)
| | - Yongyao Wang
- Department of Cancer Biology, University of Cincinnati, Cincinnati, OH 45267, USA.,School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, China
| | - Jiajie Diao
- Department of Cancer Biology, University of Cincinnati, Cincinnati, OH 45267, USA
| | - Carolyn M Price
- Department of Cancer Biology, University of Cincinnati, Cincinnati, OH 45267, USA
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134
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Abstract
Genetic recombination occurs in all organisms and is vital for genome stability. Indeed, in humans, aberrant recombination can lead to diseases such as cancer. Our understanding of homologous recombination is built upon more than a century of scientific inquiry, but achieving a more complete picture using ensemble biochemical and genetic approaches is hampered by population heterogeneity and transient recombination intermediates. Recent advances in single-molecule and super-resolution microscopy methods help to overcome these limitations and have led to new and refined insights into recombination mechanisms, including a detailed understanding of DNA helicase function and synaptonemal complex structure. The ability to view cellular processes at single-molecule resolution promises to transform our understanding of recombination and related processes.
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135
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Mills M, Harami GM, Seol Y, Gyimesi M, Martina M, Kovács ZJ, Kovács M, Neuman KC. RecQ helicase triggers a binding mode change in the SSB-DNA complex to efficiently initiate DNA unwinding. Nucleic Acids Res 2017; 45:11878-11890. [PMID: 29059328 PMCID: PMC5714189 DOI: 10.1093/nar/gkx939] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Revised: 09/29/2017] [Accepted: 10/09/2017] [Indexed: 11/12/2022] Open
Abstract
The single-stranded DNA binding protein (SSB) of Escherichia coli plays essential roles in maintaining genome integrity by sequestering ssDNA and mediating DNA processing pathways through interactions with DNA-processing enzymes. Despite its DNA-sequestering properties, SSB stimulates the DNA processing activities of some of its binding partners. One example is the genome maintenance protein RecQ helicase. Here, we determine the mechanistic details of the RecQ-SSB interaction using single-molecule magnetic tweezers and rapid kinetic experiments. Our results reveal that the SSB-RecQ interaction changes the binding mode of SSB, thereby allowing RecQ to gain access to ssDNA and facilitating DNA unwinding. Conversely, the interaction of RecQ with the SSB C-terminal tail increases the on-rate of RecQ-DNA binding and has a modest stimulatory effect on the unwinding rate of RecQ. We propose that this bidirectional communication promotes efficient DNA processing and explains how SSB stimulates rather than inhibits RecQ activity.
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Affiliation(s)
- Maria Mills
- Laboratory of Single Molecule Biophysics, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Gábor M. Harami
- Department of Biochemistry, ELTE-MTA “Momentum” Motor Enzymology Research Group, Eötvös Loránd University, Pázmány P. s. 1/c, H-1117 Budapest, Hungary
| | - Yeonee Seol
- Laboratory of Single Molecule Biophysics, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Máté Gyimesi
- Department of Biochemistry, ELTE-MTA “Momentum” Motor Enzymology Research Group, Eötvös Loránd University, Pázmány P. s. 1/c, H-1117 Budapest, Hungary
| | - Máté Martina
- Department of Biochemistry, ELTE-MTA “Momentum” Motor Enzymology Research Group, Eötvös Loránd University, Pázmány P. s. 1/c, H-1117 Budapest, Hungary
| | - Zoltán J. Kovács
- Department of Biochemistry, ELTE-MTA “Momentum” Motor Enzymology Research Group, Eötvös Loránd University, Pázmány P. s. 1/c, H-1117 Budapest, Hungary
| | - Mihály Kovács
- Department of Biochemistry, ELTE-MTA “Momentum” Motor Enzymology Research Group, Eötvös Loránd University, Pázmány P. s. 1/c, H-1117 Budapest, Hungary
| | - Keir C. Neuman
- Laboratory of Single Molecule Biophysics, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA
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136
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Pavani RS, Vitarelli MO, Fernandes CAH, Mattioli FF, Morone M, Menezes MC, Fontes MRM, Cano MIN, Elias MC. Replication Protein A-1 Has a Preference for the Telomeric G-rich Sequence in Trypanosoma cruzi. J Eukaryot Microbiol 2017; 65:345-356. [PMID: 29044824 DOI: 10.1111/jeu.12478] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Revised: 09/21/2017] [Accepted: 10/09/2017] [Indexed: 01/20/2023]
Abstract
Replication protein A (RPA), the major eukaryotic single-stranded binding protein, is a heterotrimeric complex formed by RPA-1, RPA-2, and RPA-3. RPA is a fundamental player in replication, repair, recombination, and checkpoint signaling. In addition, increasing evidences have been adding functions to RPA in telomere maintenance, such as interaction with telomerase to facilitate its activity and also involvement in telomere capping in some conditions. Trypanosoma cruzi, the etiological agent of Chagas disease is a protozoa parasite that appears early in the evolution of eukaryotes. Recently, we have showed that T. cruziRPA presents canonical functions being involved with DNA replication and DNA damage response. Here, we found by FISH/IF assays that T. cruziRPA localizes at telomeres even outside replication (S) phase. In vitro analysis showed that one telomeric repeat is sufficient to bind RPA-1. Telomeric DNA induces different secondary structural modifications on RPA-1 in comparison with other types of DNA. In addition, RPA-1 presents a higher affinity for telomeric sequence compared to randomic sequence, suggesting that RPA may play specific roles in T. cruzi telomeric region.
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Affiliation(s)
- Raphael Souza Pavani
- Laboratório Especial de Ciclo Celular, Instituto Butantan, São Paulo, SP, 05503-900, Brazil.,Center of Toxins, Immune Response and Cell Signaling (CeTICS), Instituto Butantan, São Paulo, SP, 05503-900, Brazil
| | - Marcela O Vitarelli
- Laboratório Especial de Ciclo Celular, Instituto Butantan, São Paulo, SP, 05503-900, Brazil.,Center of Toxins, Immune Response and Cell Signaling (CeTICS), Instituto Butantan, São Paulo, SP, 05503-900, Brazil
| | - Carlos A H Fernandes
- Biophysics and Physics Department, Biosciences Institute, São Paulo State University (UNESP), Botucatu, SP, 18618970, Brazil
| | - Fabio F Mattioli
- Biophysics and Physics Department, Biosciences Institute, São Paulo State University (UNESP), Botucatu, SP, 18618970, Brazil
| | - Mariana Morone
- Center of Toxins, Immune Response and Cell Signaling (CeTICS), Instituto Butantan, São Paulo, SP, 05503-900, Brazil.,Laboratório Especial de Toxinologia Aplicada, Instituto Butantan, São Paulo, SP, 05503-900, Brazil
| | - Milene C Menezes
- Center of Toxins, Immune Response and Cell Signaling (CeTICS), Instituto Butantan, São Paulo, SP, 05503-900, Brazil.,Laboratório Especial de Toxinologia Aplicada, Instituto Butantan, São Paulo, SP, 05503-900, Brazil
| | - Marcos R M Fontes
- Biophysics and Physics Department, Biosciences Institute, São Paulo State University (UNESP), Botucatu, SP, 18618970, Brazil
| | - Maria Isabel N Cano
- Genetics Department, Biosciences Institute, São Paulo State University (UNESP), Botucatu, SP, 18618970, Brazil
| | - Maria Carolina Elias
- Laboratório Especial de Ciclo Celular, Instituto Butantan, São Paulo, SP, 05503-900, Brazil.,Center of Toxins, Immune Response and Cell Signaling (CeTICS), Instituto Butantan, São Paulo, SP, 05503-900, Brazil
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137
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Xue H, Bei Y, Zhan Z, Chen X, Xu X, Fu YV. Utilizing Biotinylated Proteins Expressed in Yeast to Visualize DNA-Protein Interactions at the Single-Molecule Level. Front Microbiol 2017; 8:2062. [PMID: 29123507 PMCID: PMC5662892 DOI: 10.3389/fmicb.2017.02062] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2017] [Accepted: 10/09/2017] [Indexed: 11/30/2022] Open
Abstract
Much of our knowledge in conventional biochemistry has derived from bulk assays. However, many stochastic processes and transient intermediates are hidden when averaged over the ensemble. The powerful technique of single-molecule fluorescence microscopy has made great contributions to the understanding of life processes that are inaccessible when using traditional approaches. In single-molecule studies, quantum dots (Qdots) have several unique advantages over other fluorescent probes, such as high brightness, extremely high photostability, and large Stokes shift, thus allowing long-time observation and improved signal-to-noise ratios. So far, however, there is no convenient way to label proteins purified from budding yeast with Qdots. Based on BirA-Avi and biotin-streptavidin systems, we have established a simple method to acquire a Qdot-labeled protein and visualize its interaction with DNA using total internal reflection fluorescence microscopy. For proof-of-concept, we chose replication protein A (RPA) and origin recognition complex (ORC) as the proteins of interest. Proteins were purified from budding yeast with high biotinylation efficiency and rapidly labeled with streptavidin-coated Qdots. Interactions between proteins and DNA were observed successfully at the single-molecule level.
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Affiliation(s)
- Huijun Xue
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
- Savaid Medical School, University of Chinese Academy of Sciences, Beijing, China
| | - Yuanyuan Bei
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
- Savaid Medical School, University of Chinese Academy of Sciences, Beijing, China
| | - Zhengyan Zhan
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Xiuqiang Chen
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
- Savaid Medical School, University of Chinese Academy of Sciences, Beijing, China
| | - Xin Xu
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Yu V. Fu
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
- Savaid Medical School, University of Chinese Academy of Sciences, Beijing, China
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138
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Touma C, Adams MN, Ashton NW, Mizzi M, El-Kamand S, Richard DJ, Cubeddu L, Gamsjaeger R. A data-driven structural model of hSSB1 (NABP2/OBFC2B) self-oligomerization. Nucleic Acids Res 2017; 45:8609-8620. [PMID: 28609781 PMCID: PMC5737504 DOI: 10.1093/nar/gkx526] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2017] [Accepted: 06/05/2017] [Indexed: 12/19/2022] Open
Abstract
The maintenance of genome stability depends on the ability of the cell to repair DNA efficiently. Single-stranded DNA binding proteins (SSBs) play an important role in DNA processing events such as replication, recombination and repair. While the role of human single-stranded DNA binding protein 1 (hSSB1/NABP2/OBFC2B) in the repair of double-stranded breaks has been well established, we have recently shown that it is also essential for the base excision repair (BER) pathway following oxidative DNA damage. However, unlike in DSB repair, the formation of stable hSSB1 oligomers under oxidizing conditions is an important prerequisite for its proper function in BER. In this study, we have used solution-state NMR in combination with biophysical and functional experiments to obtain a structural model of hSSB1 self-oligomerization. We reveal that hSSB1 forms a tetramer that is structurally similar to the SSB from Escherichia coli and is stabilized by two cysteines (C81 and C99) as well as a subset of charged and hydrophobic residues. Our structural and functional data also show that hSSB1 oligomerization does not preclude its function in DSB repair, where it can interact with Ints3, a component of the SOSS1 complex, further establishing the versatility that hSSB1 displays in maintaining genome integrity.
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Affiliation(s)
- Christine Touma
- School of Science and Health, Western Sydney University, Penrith, NSW 2751, Australia
| | - Mark N Adams
- School of Biomedical Research, Institute of Health and Biomedical Innovation at the Translational Research Institute, Queensland University of Technology, Woolloongabba, QLD 4102, Australia
| | - Nicholas W Ashton
- School of Biomedical Research, Institute of Health and Biomedical Innovation at the Translational Research Institute, Queensland University of Technology, Woolloongabba, QLD 4102, Australia
| | - Michael Mizzi
- School of Science and Health, Western Sydney University, Penrith, NSW 2751, Australia
| | - Serene El-Kamand
- School of Science and Health, Western Sydney University, Penrith, NSW 2751, Australia
| | - Derek J Richard
- School of Biomedical Research, Institute of Health and Biomedical Innovation at the Translational Research Institute, Queensland University of Technology, Woolloongabba, QLD 4102, Australia
| | - Liza Cubeddu
- School of Science and Health, Western Sydney University, Penrith, NSW 2751, Australia.,School of Life and Environmental Sciences, University of Sydney, NSW 2006, Australia
| | - Roland Gamsjaeger
- School of Science and Health, Western Sydney University, Penrith, NSW 2751, Australia.,School of Life and Environmental Sciences, University of Sydney, NSW 2006, Australia
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139
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Ni Z, Yao C, Zhu X, Gong C, Xu Z, Wang L, Li S, Zou C, Zhu S. Ailanthone inhibits non-small cell lung cancer cell growth through repressing DNA replication via downregulating RPA1. Br J Cancer 2017; 117:1621-1630. [PMID: 29024939 PMCID: PMC5729430 DOI: 10.1038/bjc.2017.319] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2017] [Revised: 08/10/2017] [Accepted: 08/18/2017] [Indexed: 12/24/2022] Open
Abstract
Background: The identification of bioactive compounds from Chinese medicine plays a crucial role in the development of novel reagents against non-small lung cancer (NSCLC). Methods: High throughput screening assay and analyses of cell growth, cell cycle, apoptosis, cDNA microarray, BrdU incorporation and gene expression were performed. Results: Ailanthone (Aila) suppressed NSCLC cell growth and colony formation in vitro and inhibited NSCLC tumour growth in subcutaneously xenografted and orthotopic lung tumour models, leading to prolonged survival of tumour-bearing mice. Moreover, Aila induced cell cycle arrest in a dose-independent manner but did not induce apoptosis in all NSCLC cells. Furthermore, 1222 genes were differentially expressed upon Aila administration, which were involved in 21 signal pathways, such as DNA replication. In addition, Aila dose-dependently decreased BrdU incorporation and downregulated the expression of replication protein A1 (RPA1). Conclusions: Aila inhibited the growth of NSCLC cells through the repression of DNA replication via downregulating RPA1, rather than through cell cycle arrest and apoptosis. Our findings suggested that Aila could be used as a promising therapeutic candidate for NSCLC patients.
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Affiliation(s)
- Zhongya Ni
- Laboratory of Integrative Medicine, School of Basic Medical Sciences, Shanghai University of Traditional Chinese Medicine, 1200 Cai Lun Rd, Shanghai 201203, PR China
| | - Chao Yao
- Laboratory of Integrative Medicine, School of Basic Medical Sciences, Shanghai University of Traditional Chinese Medicine, 1200 Cai Lun Rd, Shanghai 201203, PR China
| | - Xiaowen Zhu
- Laboratory of Integrative Medicine, School of Basic Medical Sciences, Shanghai University of Traditional Chinese Medicine, 1200 Cai Lun Rd, Shanghai 201203, PR China
| | - Chenyuan Gong
- Laboratory of Integrative Medicine, School of Basic Medical Sciences, Shanghai University of Traditional Chinese Medicine, 1200 Cai Lun Rd, Shanghai 201203, PR China
| | - Zihang Xu
- Department of Internal Classic of Medicine, School of Basic Medical Sciences, Shanghai University of Traditional Chinese Medicine, 1200 Cai Lun Rd, Shanghai 201203, PR China
| | - Lixin Wang
- Department of Immunology and Pathogenic Biology, School of Basic Medical Sciences, Shanghai University of Traditional Chinese Medicine, 1200 Cai Lun Rd, Shanghai 201203, PR China
| | - Suyun Li
- Department of Pathology, School of Basic Medical Sciences, Shanghai University of Traditional Chinese Medicine, 1200 Cai Lun Rd, Shanghai 201203, PR China
| | - Chunpu Zou
- Department of Internal Classic of Medicine, School of Basic Medical Sciences, Shanghai University of Traditional Chinese Medicine, 1200 Cai Lun Rd, Shanghai 201203, PR China
| | - Shiguo Zhu
- Laboratory of Integrative Medicine, School of Basic Medical Sciences, Shanghai University of Traditional Chinese Medicine, 1200 Cai Lun Rd, Shanghai 201203, PR China.,Department of Immunology and Pathogenic Biology, School of Basic Medical Sciences, Shanghai University of Traditional Chinese Medicine, 1200 Cai Lun Rd, Shanghai 201203, PR China
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140
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RPA Interacts with HIRA and Regulates H3.3 Deposition at Gene Regulatory Elements in Mammalian Cells. Mol Cell 2017; 65:272-284. [PMID: 28107649 DOI: 10.1016/j.molcel.2016.11.030] [Citation(s) in RCA: 66] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Revised: 07/26/2016] [Accepted: 11/17/2016] [Indexed: 11/20/2022]
Abstract
The histone chaperone HIRA is involved in depositing histone variant H3.3 into distinct genic regions, including promoters, enhancers, and gene bodies. However, how HIRA deposits H3.3 to these regions remains elusive. Through a short hairpin RNA (shRNA) screening, we identified single-stranded DNA binding protein replication protein A (RPA) as a regulator of the deposition of newly synthesized H3.3 into chromatin. We show that RPA physically interacts with HIRA to form RPA-HIRA-H3.3 complexes, and it co-localizes with HIRA and H3.3 at gene promoters and enhancers. Depletion of RPA1, the largest subunit of the RPA complex, dramatically reduces both HIRA association with chromatin and the deposition of newly synthesized H3.3 at promoters and enhancers and leads to altered transcription at gene promoters. These results support a model whereby RPA, best known for its role in DNA replication and repair, recruits HIRA to promoters and enhancers and regulates deposition of newly synthesized H3.3 to these regulatory elements for gene regulation.
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141
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Dai Z, Wang S, Zhang W, Yang Y. Elevated Expression of RPA3 Is Involved in Gastric Cancer Tumorigenesis and Associated with Poor Patient Survival. Dig Dis Sci 2017; 62:2369-2375. [PMID: 28766245 DOI: 10.1007/s10620-017-4696-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/23/2017] [Accepted: 07/26/2017] [Indexed: 12/09/2022]
Abstract
BACKGROUND The replication protein A3 (RPA3) is a component of the RPA protein complex, which plays an essential role in multiple processes of DNA metabolism. AIMS However, the involvement of RPA3 in gastric cancer tumorigenesis has not yet been investigated. METHODS We stably knocked down RPA3 expression using short hairpin RNA in AGS cell line, and performed cell growth, colony formation and soft agar assays. Xenograft experiments were performed to examine tumor promoting properties of RPA3 in vivo. The qRT-PCR and immunohistochemistry were performed to evaluate RPA3 expression levels in 37 and 12 pairs of gastric cancer patient samples, respectively. Association between RPA3 expression and survival was evaluated in an independent cohort of 85 gastric cancer patients. RESULTS Downregulation of RPA3 inhibited cell growth, clonogenicity and soft agar growth in AGS cells. Decreased expression of RPA3 significantly reduced tumor growth rate in AGS xenografts. In addition, RPA3 was upregulated in cancerous tissues compared with matched noncancerous adjacent tissues in gastric cancer patients. High expression of RPA3 was associated with poor patient survival. CONCLUSION Upregulation of RPA3 is involved in gastric cancer tumorigenesis and is associated with poorer patient survival. RPA3 represents a new therapeutic target of gastric cancer and serves as a potential prognostic biomarker for patient survival in gastric cancer.
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Affiliation(s)
- Zhongming Dai
- Department of Digestive Disease, PLA General Hospital, Beijing, 100853, People's Republic of China.,Department of Digestive Disease, Xinjiang Military Region General Hospital, Urumuqi, 830000, Xinjiang Province, People's Republic of China
| | - Shufang Wang
- Department of Digestive Disease, PLA General Hospital, Beijing, 100853, People's Republic of China
| | - Weiping Zhang
- Department of Digestive Disease, Suzhou BenQ Hospital, Suzhou, 215000, Jiangsu Province, People's Republic of China
| | - Yunsheng Yang
- Department of Digestive Disease, PLA General Hospital, Beijing, 100853, People's Republic of China.
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142
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Nuclear DNA Replication in Trypanosomatids: There Are No Easy Methods for Solving Difficult Problems. Trends Parasitol 2017; 33:858-874. [PMID: 28844718 PMCID: PMC5662062 DOI: 10.1016/j.pt.2017.08.002] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Revised: 07/31/2017] [Accepted: 08/02/2017] [Indexed: 01/09/2023]
Abstract
In trypanosomatids, etiological agents of devastating diseases, replication is robust and finely controlled to maintain genome stability and function in stressful environments. However, these parasites encode several replication protein components and complexes that show potentially variant composition compared with model eukaryotes. This review focuses on the advances made in recent years regarding the differences and peculiarities of the replication machinery in trypanosomatids, including how such divergence might affect DNA replication dynamics and the replication stress response. Comparing the DNA replication machinery and processes of parasites and their hosts may provide a foundation for the identification of targets that can be used in the development of chemotherapies to assist in the eradication of diseases caused by these pathogens. In trypanosomatids, DNA replication is tightly controlled by protein complexes that diverge from those of model eukaryotes. There is no consensus for the number of replication origins used by trypanosomatids; how their replication dynamics compares with that of model organisms is the subject of debate. The DNA replication rate in trypanosomatids is similar to, but slightly higher than, that of model eukaryotes, which may be related to chromatin structure and function. Recent data suggest that the origin recognition complex in trypanosomatids closely resembles the multisubunit eukaryotic model. The absence of fundamental replication-associated proteins in trypanosomatids suggests that new signaling pathways may be present in these parasites to direct DNA replication and the replicative stress response.
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143
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Szambowska A, Tessmer I, Prus P, Schlott B, Pospiech H, Grosse F. Cdc45-induced loading of human RPA onto single-stranded DNA. Nucleic Acids Res 2017; 45:3217-3230. [PMID: 28100698 PMCID: PMC5389570 DOI: 10.1093/nar/gkw1364] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Accepted: 01/02/2017] [Indexed: 11/14/2022] Open
Abstract
Cell division cycle protein 45 (Cdc45) is an essential component of the eukaryotic replicative DNA helicase. We found that human Cdc45 forms a complex with the single-stranded DNA (ssDNA) binding protein RPA. Moreover, it actively loads RPA onto nascent ssDNA. Pull-down assays and surface plasmon resonance studies revealed that Cdc45-bound RPA complexed with ssDNA in the 8–10 nucleotide binding mode, but dissociated when RPA covered a 30-mer. Real-time analysis of RPA-ssDNA binding demonstrated that Cdc45 catalytically loaded RPA onto ssDNA. This placement reaction required physical contacts of Cdc45 with the RPA70A subdomain. Our results imply that Cdc45 controlled stabilization of the 8-nt RPA binding mode, the subsequent RPA transition into 30-mer mode and facilitated an ordered binding to ssDNA. We propose that a Cdc45-mediated loading guarantees a seamless deposition of RPA on newly emerging ssDNA at the nascent replication fork.
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Affiliation(s)
- Anna Szambowska
- Research Group Biochemistry, Leibniz Institute on Aging-Fritz Lipmann Institute, Beutenbergstrasse 11, D-07745 Jena, Germany
| | - Ingrid Tessmer
- Rudolf Virchow Center for Experimental Biomedicine, University of Würzburg, Josef Schneider Strasse 2, D-97080 Würzburg, Germany
| | - Piotr Prus
- Biocenter Oulu, P.O. Box 5000, 90014 University of Oulu, Finland
| | - Bernhard Schlott
- Research Group Biochemistry, Leibniz Institute on Aging-Fritz Lipmann Institute, Beutenbergstrasse 11, D-07745 Jena, Germany.,Proteomics Core Facility, Leibniz Institute on Aging-Fritz Lipmann Institute, Beutenbergstrasse 11, D-07745 Jena, Germany
| | - Helmut Pospiech
- Research Group Biochemistry, Leibniz Institute on Aging-Fritz Lipmann Institute, Beutenbergstrasse 11, D-07745 Jena, Germany.,Faculty of Biochemistry and Molecular Medicine, P.O. Box 5000, 90014 University of Oulu, Finland
| | - Frank Grosse
- Research Group Biochemistry, Leibniz Institute on Aging-Fritz Lipmann Institute, Beutenbergstrasse 11, D-07745 Jena, Germany.,Center for Molecular Biomedicine, Friedrich-Schiller University, Biochemistry Department, Jena, Germany
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144
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Weiser BP, Stivers JT, Cole PA. Investigation of N-Terminal Phospho-Regulation of Uracil DNA Glycosylase Using Protein Semisynthesis. Biophys J 2017; 113:393-401. [PMID: 28746850 DOI: 10.1016/j.bpj.2017.06.016] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2017] [Revised: 06/09/2017] [Accepted: 06/12/2017] [Indexed: 11/16/2022] Open
Abstract
Uracil DNA Glycosylase (UNG2) is the primary enzyme in humans that prevents the stable incorporation of deoxyuridine monophosphate into DNA in the form of U/A basepairs. During S-phase, UNG2 remains associated with the replication fork through its interactions with two proteins, Proliferating Cell Nuclear Antigen (PCNA) and Replication Protein A (RPA), which are critical for DNA replication and repair. In this work, we used protein semisynthesis and fluorescence anisotropy assays to explore the interactions of UNG2 with PCNA and RPA and to determine the effects of two UNG2 phosphorylation sites (Thr6 and Tyr8) located within its PCNA-interacting motif (PIP-box). In binding assays, we found that phosphorylation of Thr6 or Tyr8 on UNG2 can impede PCNA binding without affecting UNG2 catalytic activity or its RPA interaction. Our data also suggests that unmodified UNG2, PCNA, and RPA can form a ternary protein complex. We propose that the UNG2 N-terminus may serve as a flexible scaffold to tether PCNA and RPA at the replication fork, and that post-translational modifications on the UNG2 N-terminus disrupt formation of the PCNA-UNG2-RPA protein complex.
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Affiliation(s)
- Brian P Weiser
- Department of Pharmacology and Molecular Sciences, Johns Hopkins School of Medicine, Baltimore, Maryland
| | - James T Stivers
- Department of Pharmacology and Molecular Sciences, Johns Hopkins School of Medicine, Baltimore, Maryland
| | - Philip A Cole
- Department of Pharmacology and Molecular Sciences, Johns Hopkins School of Medicine, Baltimore, Maryland.
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145
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Hom RA, Wuttke DS. Human CST Prefers G-Rich but Not Necessarily Telomeric Sequences. Biochemistry 2017; 56:4210-4218. [PMID: 28726394 DOI: 10.1021/acs.biochem.7b00584] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The human CST (CTC1-STN1-TEN1) heterotrimeric complex plays roles in both telomere maintenance and DNA replication through its ability to interact with single-stranded DNA (ssDNA) of a variety of sequences. The precise sequence specificity required to execute these functions is unknown. Telomere-binding proteins have been shown to specifically recognize key telomeric sequence motifs within ssDNA while accommodating nonspecifically recognized sequences through conformationally plastic interfaces. To better understand the role CST plays in these processes, we have produced a highly purified heterotrimer and elucidated the sequence requirements for CST recognition of ssDNA in vitro. CST discriminates against random sequence and binds a minimal ssDNA comprised of three repeats of telomeric sequence. Replacement of individual nucleotides with their complement reveals that guanines are specifically recognized in a largely additive fashion and that specificity is distributed uniformly throughout the ligand. Unexpectedly, adenosines are also well tolerated at these sites, but cytosines are disfavored. Furthermore, sequences unrelated to the telomere repeat, yet still G-rich, bind CST well. Thus, CST is not inherently telomere-specific, but rather is a G-rich sequence binder. This biochemical activity is reminiscent of the yeast t-RPA and Tetrahymena thermophila CST complexes and is consistent with roles at G-rich sites throughout the genome.
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Affiliation(s)
- Robert A Hom
- Department of Chemistry and Biochemistry, UCB 596, University of Colorado , Boulder, Colorado 80309, United States
| | - Deborah S Wuttke
- Department of Chemistry and Biochemistry, UCB 596, University of Colorado , Boulder, Colorado 80309, United States
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146
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Zhao M, Geng R, Guo X, Yuan R, Zhou X, Zhong Y, Huo Y, Zhou M, Shen Q, Li Y, Zhu W, Wang J. PCAF/GCN5-Mediated Acetylation of RPA1 Promotes Nucleotide Excision Repair. Cell Rep 2017; 20:1997-2009. [DOI: 10.1016/j.celrep.2017.08.015] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Revised: 06/21/2017] [Accepted: 07/14/2017] [Indexed: 12/14/2022] Open
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147
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Diao LT, Chen CC, Dennehey B, Pal S, Wang P, Shen ZJ, Deem A, Tyler JK. Delineation of the role of chromatin assembly and the Rtt101Mms1 E3 ubiquitin ligase in DNA damage checkpoint recovery in budding yeast. PLoS One 2017; 12:e0180556. [PMID: 28749957 PMCID: PMC5531559 DOI: 10.1371/journal.pone.0180556] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2017] [Accepted: 06/16/2017] [Indexed: 01/03/2023] Open
Abstract
The DNA damage checkpoint is activated in response to DNA double-strand breaks (DSBs). We had previously shown that chromatin assembly mediated by the histone chaperone Asf1 triggers inactivation of the DNA damage checkpoint in yeast after DSB repair, also called checkpoint recovery. Here we show that chromatin assembly factor 1 (CAF-1) also contributes to chromatin reassembly after DSB repair, explaining its role in checkpoint recovery. Towards understanding how chromatin assembly promotes checkpoint recovery, we find persistent presence of the damage sensors Ddc1 and Ddc2 after DSB repair in asf1 mutants. The genes encoding the E3 ubiquitin ligase complex Rtt101Mms1 are epistatic to ASF1 for survival following induction of a DSB, and Rtt101Mms1 are required for checkpoint recovery after DSB repair but not for chromatin assembly. By contrast, the Mms22 substrate adaptor that is degraded by Rtt101Mms1 is required for DSB repair per se. Deletion of MMS22 blocks loading of Rad51 at the DSB, while deletion of ASF1 or RTT101 leads to persistent Rad51 loading. We propose that checkpoint recovery is promoted by Rtt101Mms1-mediated ubiquitylation of Mms22 in order to halt Mms22-dependent loading of Rad51 onto double-stranded DNA after DSB repair, in concert with the chromatin assembly-mediated displacement of Rad51 and checkpoint sensors from the site of repair.
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Affiliation(s)
- Li-Ting Diao
- Department of Pathology and Laboratory Medicine, Weill Cornell Medicine, New York, New York, United States of America
| | - Chin-Chuan Chen
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas, MD Anderson Cancer Center, Houston, Texas, United States of America
| | - Briana Dennehey
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas, MD Anderson Cancer Center, Houston, Texas, United States of America
| | - Sangita Pal
- Department of Pathology and Laboratory Medicine, Weill Cornell Medicine, New York, New York, United States of America
| | - Pingping Wang
- Department of Pathology and Laboratory Medicine, Weill Cornell Medicine, New York, New York, United States of America
| | - Zie-Jie Shen
- Department of Pathology and Laboratory Medicine, Weill Cornell Medicine, New York, New York, United States of America
| | - Angela Deem
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas, MD Anderson Cancer Center, Houston, Texas, United States of America
| | - Jessica K. Tyler
- Department of Pathology and Laboratory Medicine, Weill Cornell Medicine, New York, New York, United States of America
- * E-mail:
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148
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Liu X, Dang Y, Matsu-Ura T, He Y, He Q, Hong CI, Liu Y. DNA Replication Is Required for Circadian Clock Function by Regulating Rhythmic Nucleosome Composition. Mol Cell 2017. [PMID: 28648778 DOI: 10.1016/j.molcel.2017.05.029] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Although the coupling between circadian and cell cycles allows circadian clocks to gate cell division and DNA replication in many organisms, circadian clocks were thought to function independently of cell cycle. Here, we show that DNA replication is required for circadian clock function in Neurospora. Genetic and pharmacological inhibition of DNA replication abolished both overt and molecular rhythmicities by repressing frequency (frq) gene transcription. DNA replication is essential for the rhythmic changes of nucleosome composition at the frq promoter. The FACT complex, known to be involved in histone disassembly/reassembly, is required for clock function and is recruited to the frq promoter in a replication-dependent manner to promote replacement of histone H2A.Z by H2A. Finally, deletion of H2A.Z uncoupled the dependence of the circadian clock on DNA replication. Together, these results establish circadian clock and cell cycle as interdependent coupled oscillators and identify DNA replication as a critical process in the circadian mechanism.
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Affiliation(s)
- Xiao Liu
- Department of Physiology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9040, USA
| | - Yunkun Dang
- Department of Physiology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9040, USA
| | - Toru Matsu-Ura
- Department of Molecular and Cellular Physiology, University of Cincinnati, Cincinnati, OH 45267, USA
| | - Yubo He
- Department of Physiology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9040, USA; Department of Biochemistry and Cell Biology, McMurtry College, Rice University, Houston, TX 77005, USA
| | - Qun He
- State Key Laboratory of Agrobiotechnology and MOA Key Laboratory of Soil Microbiology, College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Christian I Hong
- Department of Molecular and Cellular Physiology, University of Cincinnati, Cincinnati, OH 45267, USA
| | - Yi Liu
- Department of Physiology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9040, USA.
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149
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Interactive Roles of DNA Helicases and Translocases with the Single-Stranded DNA Binding Protein RPA in Nucleic Acid Metabolism. Int J Mol Sci 2017; 18:ijms18061233. [PMID: 28594346 PMCID: PMC5486056 DOI: 10.3390/ijms18061233] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2017] [Revised: 05/30/2017] [Accepted: 06/01/2017] [Indexed: 01/05/2023] Open
Abstract
Helicases and translocases use the energy of nucleoside triphosphate binding and hydrolysis to unwind/resolve structured nucleic acids or move along a single-stranded or double-stranded polynucleotide chain, respectively. These molecular motors facilitate a variety of transactions including replication, DNA repair, recombination, and transcription. A key partner of eukaryotic DNA helicases/translocases is the single-stranded DNA binding protein Replication Protein A (RPA). Biochemical, genetic, and cell biological assays have demonstrated that RPA interacts with these human molecular motors physically and functionally, and their association is enriched in cells undergoing replication stress. The roles of DNA helicases/translocases are orchestrated with RPA in pathways of nucleic acid metabolism. RPA stimulates helicase-catalyzed DNA unwinding, enlists translocases to sites of action, and modulates their activities in DNA repair, fork remodeling, checkpoint activation, and telomere maintenance. The dynamic interplay between DNA helicases/translocases and RPA is just beginning to be understood at the molecular and cellular levels, and there is still much to be learned, which may inform potential therapeutic strategies.
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150
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Qu C, Zhao Y, Feng G, Chen C, Tao Y, Zhou S, Liu S, Chang H, Zeng M, Xia Y. RPA3 is a potential marker of prognosis and radioresistance for nasopharyngeal carcinoma. J Cell Mol Med 2017; 21:2872-2883. [PMID: 28557284 PMCID: PMC5661258 DOI: 10.1111/jcmm.13200] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2016] [Accepted: 03/22/2017] [Indexed: 12/15/2022] Open
Abstract
Radioresistance-induced residual and recurrent tumours are the main cause of treatment failure in nasopharyngeal carcinoma (NPC). Thus, the mechanisms of NPC radioresistance and predictive markers of NPC prognosis and radioresistance need to be investigated and identified. In this study, we identified RPA3 as a candidate radioresistance marker using RNA-seq of NPC samples. In vitro studies further confirmed that RPA3 affected the radiosensitivity of NPC cells. Specifically, the overexpression of RPA3 enhanced radioresistance and the capacity for DNA repair of NPC cells, whereas inhibiting RPA3 expression sensitized NPC cells to irradiation and decreased the DNA repair capacity. Furthermore, the overexpression of RPA3 enhanced RAD51 foci formation in NPC cells after irradiation. Immunohistochemical assays in 104 NPC specimens and 21 normal epithelium specimens indicated that RPA3 was significantly up-regulated in NPC tissues, and a log-rank test suggested that in patients with NPC, high RPA3 expression was associated with shorter overall survival (OS) and a higher recurrence rate compared with low expression (5-year OS rates: 67.2% versus 86.2%; 5-year recurrence rates: 14.8% versus 2.3%). Moreover, TCGA data also indicated that high RPA3 expression correlated with poor OS and a high recurrence rate in patients with head and neck squamous cell carcinoma (HNSC) after radiotherapy. Taken together, the results of our study demonstrated that RPA3 regulated the radiosensitivity and DNA repair capacity of NPC cells. Thus, RPA3 may serve as a new predictive biomarker for NPC prognosis and radioresistance to help guide the diagnosis and individualized treatment of patients with NPC.
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Affiliation(s)
- Chen Qu
- Department of Radiation Oncology, Sun Yat-sen University Cancer Centre, Guangzhou, China.,State Key Laboratory of Oncology in South China, Guangzhou, China.,Collaborative Innovation Centre for Cancer Medicine, Guangzhou, China
| | - Yiying Zhao
- State Key Laboratory of Oncology in South China, Guangzhou, China.,Collaborative Innovation Centre for Cancer Medicine, Guangzhou, China.,Department of Experimental Research, Sun Yat-sen University Cancer Centre, Guangzhou, China
| | - Guokai Feng
- State Key Laboratory of Oncology in South China, Guangzhou, China.,Collaborative Innovation Centre for Cancer Medicine, Guangzhou, China.,Department of Experimental Research, Sun Yat-sen University Cancer Centre, Guangzhou, China
| | - Chen Chen
- Department of Radiation Oncology, Sun Yat-sen University Cancer Centre, Guangzhou, China.,State Key Laboratory of Oncology in South China, Guangzhou, China.,Collaborative Innovation Centre for Cancer Medicine, Guangzhou, China
| | - Yalan Tao
- Department of Radiation Oncology, Sun Yat-sen University Cancer Centre, Guangzhou, China.,State Key Laboratory of Oncology in South China, Guangzhou, China.,Collaborative Innovation Centre for Cancer Medicine, Guangzhou, China
| | - Shu Zhou
- Department of Radiation Oncology, Sun Yat-sen University Cancer Centre, Guangzhou, China.,State Key Laboratory of Oncology in South China, Guangzhou, China.,Collaborative Innovation Centre for Cancer Medicine, Guangzhou, China
| | - Songran Liu
- Department of Radiation Oncology, Sun Yat-sen University Cancer Centre, Guangzhou, China.,State Key Laboratory of Oncology in South China, Guangzhou, China.,Collaborative Innovation Centre for Cancer Medicine, Guangzhou, China
| | - Hui Chang
- Department of Radiation Oncology, Sun Yat-sen University Cancer Centre, Guangzhou, China.,State Key Laboratory of Oncology in South China, Guangzhou, China.,Collaborative Innovation Centre for Cancer Medicine, Guangzhou, China
| | - Musheng Zeng
- State Key Laboratory of Oncology in South China, Guangzhou, China.,Collaborative Innovation Centre for Cancer Medicine, Guangzhou, China.,Department of Experimental Research, Sun Yat-sen University Cancer Centre, Guangzhou, China
| | - Yunfei Xia
- Department of Radiation Oncology, Sun Yat-sen University Cancer Centre, Guangzhou, China.,State Key Laboratory of Oncology in South China, Guangzhou, China.,Collaborative Innovation Centre for Cancer Medicine, Guangzhou, China
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