1
|
Crickard JB, Greene EC. Helicase Mechanisms During Homologous Recombination in Saccharomyces cerevisiae. Annu Rev Biophys 2019; 48:255-273. [PMID: 30857400 DOI: 10.1146/annurev-biophys-052118-115418] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Helicases are enzymes that move, manage, and manipulate nucleic acids. They can be subdivided into six super families and are required for all aspects of nucleic acid metabolism. In general, all helicases function by converting the chemical energy stored in the bond between the gamma and beta phosphates of adenosine triphosphate into mechanical work, which results in the unidirectional movement of the helicase protein along one strand of a nucleic acid. The results of this translocation activity can range from separation of strands within duplex nucleic acids to the physical remodeling or removal of nucleoprotein complexes. In this review, we focus on describing key helicases from the model organism Saccharomyces cerevisiae that contribute to the regulation of homologous recombination, which is an essential DNA repair pathway for fixing damaged chromosomes.
Collapse
Affiliation(s)
- J Brooks Crickard
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA; ,
| | - Eric C Greene
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA; ,
| |
Collapse
|
2
|
Nguyen JHG, Viterbo D, Anand RP, Verra L, Sloan L, Richard GF, Freudenreich CH. Differential requirement of Srs2 helicase and Rad51 displacement activities in replication of hairpin-forming CAG/CTG repeats. Nucleic Acids Res 2017; 45:4519-4531. [PMID: 28175398 PMCID: PMC5416882 DOI: 10.1093/nar/gkx088] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2016] [Accepted: 01/31/2017] [Indexed: 12/25/2022] Open
Abstract
Trinucleotide repeats are a source of genome instability, causing replication fork stalling, chromosome fragility, and impaired repair. Specialized helicases play an important role in unwinding DNA structures to maintain genome stability. The Srs2 helicase unwinds DNA hairpins, facilitates replication, and prevents repeat instability and fragility. However, since Srs2 is a multifunctional protein with helicase activity and the ability to displace Rad51 recombinase, it was unclear which functions were required for its various protective roles. Here, using SRS2 separation-of-function alleles, we show that in the absence of Srs2 recruitment to PCNA or in helicase-deficient mutants, breakage at a CAG/CTG repeat increases. We conclude that Srs2 interaction with PCNA allows the helicase activity to unwind fork-blocking CAG/CTG hairpin structures to prevent breaks. Independently of PCNA binding, Srs2 also displaces Rad51 from nascent strands to prevent recombination-dependent repeat expansions and contractions. By 2D gel electrophoresis, we detect two different kinds of structured intermediates or joint molecules (JMs). Some JMs are Rad51-independent and exhibit properties of reversed forks, including being processed by the Exo1 nuclease. In addition, in a helicase-deficient mutant, Rad51-dependent JMs are detected, probably corresponding to recombination between sisters. These results clarify the many roles of Srs2 in facilitating replication through fork-blocking hairpin lesions.
Collapse
Affiliation(s)
| | - David Viterbo
- Institut Pasteur, Department Genomes & Genetics, CNRS, UMR3525, Université Pierre et Marie Curie, UFR927, 25 rue du Dr Roux, F-75015 Paris, France
| | - Ranjith P Anand
- Department of Biology, Tufts University, Medford, MA 02155, USA
| | - Lauren Verra
- Department of Biology, Tufts University, Medford, MA 02155, USA
| | - Laura Sloan
- Department of Biology, Tufts University, Medford, MA 02155, USA
| | - Guy-Franck Richard
- Institut Pasteur, Department Genomes & Genetics, CNRS, UMR3525, Université Pierre et Marie Curie, UFR927, 25 rue du Dr Roux, F-75015 Paris, France
| | | |
Collapse
|
3
|
Dosage Mutator Genes in Saccharomyces cerevisiae: A Novel Mutator Mode-of-Action of the Mph1 DNA Helicase. Genetics 2016; 204:975-986. [PMID: 27585847 PMCID: PMC5105872 DOI: 10.1534/genetics.116.192211] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2016] [Accepted: 08/25/2016] [Indexed: 01/25/2023] Open
Abstract
Mutations that cause genome instability are considered important predisposing events that contribute to initiation and progression of cancer. Genome instability arises either due to defects in genes that cause an increased mutation rate (mutator phenotype), or defects in genes that cause chromosome instability (CIN). To extend the catalog of genome instability genes, we systematically explored the effects of gene overexpression on mutation rate, using a forward-mutation screen in budding yeast. We screened ∼5100 plasmids, each overexpressing a unique single gene, and characterized the five strongest mutators, MPH1 (mutator phenotype 1), RRM3, UBP12, PIF1, and DNA2 We show that, for MPH1, the yeast homolog of Fanconi Anemia complementation group M (FANCM), the overexpression mutator phenotype is distinct from that of mph1Δ. Moreover, while four of our top hits encode DNA helicases, the overexpression of 48 other DNA helicases did not cause a mutator phenotype, suggesting this is not a general property of helicases. For Mph1 overexpression, helicase activity was not required for the mutator phenotype; in contrast Mph1 DEAH-box function was required for hypermutation. Mutagenesis by MPH1 overexpression was independent of translesion synthesis (TLS), but was suppressed by overexpression of RAD27, a conserved flap endonuclease. We propose that binding of DNA flap structures by excess Mph1 may block Rad27 action, creating a mutator phenotype that phenocopies rad27Δ. We believe this represents a novel mutator mode-of-action and opens up new prospects to understand how upregulation of DNA repair proteins may contribute to mutagenesis.
Collapse
|
4
|
Biochemical Activities and Genetic Functions of the Drosophila melanogaster Fancm Helicase in DNA Repair. Genetics 2016; 204:531-541. [PMID: 27466228 DOI: 10.1534/genetics.116.192534] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2016] [Accepted: 07/18/2016] [Indexed: 11/18/2022] Open
Abstract
Repair of DNA damage is essential to the preservation of genomic stability. During repair of double-strand breaks, several helicases function to promote accurate repair and prevent the formation of crossovers through homologous recombination. Among these helicases is the Fanconi anemia group M (FANCM) protein. FANCM is important in the response to various types of DNA damage and has been suggested to prevent mitotic crossovers during double-strand break repair. The helicase activity of FANCM is believed to be important in these functions, but no helicase activity has been detected in vitro We report here a genetic and biochemical study of Drosophila melanogaster Fancm. We show that purified Fancm is a 3' to 5' ATP-dependent helicase that can disassemble recombination intermediates, but only through limited lengths of duplex DNA. Using transgenic flies expressing full-length or truncated Fancm, each with either a wild-type or mutated helicase domain, we found that there are helicase-independent and C-terminal-independent functions in responding to DNA damage and in preventing mitotic crossovers.
Collapse
|
5
|
Abstract
Members of the conserved FANCM family of DNA motor proteins play key roles in genome maintenance processes. In this review, Xue et al. provide an integrated view of the functions and regulation of these enzymes in humans and model organisms and how they advance our understanding of genome maintenance processes. Members of the conserved FANCM family of DNA motor proteins play key roles in genome maintenance processes. FANCM supports genome duplication and repair under different circumstances and also functions in the ATR-mediated DNA damage checkpoint. Some of these roles are shared among lower eukaryotic family members. Human FANCM has been linked to Fanconi anemia, a syndrome characterized by cancer predisposition, developmental disorder, and bone marrow failure. Recent studies on human FANCM and its orthologs from other organisms have provided insights into their biological functions, regulation, and collaboration with other genome maintenance factors. This review summarizes the progress made, with the goal of providing an integrated view of the functions and regulation of these enzymes in humans and model organisms and how they advance our understanding of genome maintenance processes.
Collapse
Affiliation(s)
- Xiaoyu Xue
- Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, Connecticut 06520, USA
| | - Patrick Sung
- Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, Connecticut 06520, USA
| | - Xiaolan Zhao
- Molecular Biology Program, Memorial Sloan Kettering Cancer Center, New York, New York 10065, USA
| |
Collapse
|
6
|
Xue X, Choi K, Bonner JN, Szakal B, Chen YH, Papusha A, Saro D, Niu H, Ira G, Branzei D, Sung P, Zhao X. Selective modulation of the functions of a conserved DNA motor by a histone fold complex. Genes Dev 2015; 29:1000-5. [PMID: 25956905 PMCID: PMC4441048 DOI: 10.1101/gad.259143.115] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2015] [Accepted: 04/14/2015] [Indexed: 01/10/2023]
Abstract
Budding yeast Mph1 helicase and its orthologs drive multiple DNA transactions. Here, Xue et al. show that the conserved histone fold MHF complex promotes Mph1-mediated repair of damaged replication forks but does not influence the outcome of DNA double-strand break repair. Budding yeast Mph1 helicase and its orthologs drive multiple DNA transactions. Elucidating the mechanisms that regulate these motor proteins is central to understanding genome maintenance processes. Here, we show that the conserved histone fold MHF complex promotes Mph1-mediated repair of damaged replication forks but does not influence the outcome of DNA double-strand break repair. Mechanistically, scMHF relieves the inhibition imposed by the structural maintenance of chromosome protein Smc5 on Mph1 activities relevant to replication-associated repair through binding to Mph1 but not DNA. Thus, scMHF is a function-specific enhancer of Mph1 that enables flexible response to different genome repair situations.
Collapse
Affiliation(s)
- Xiaoyu Xue
- Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, Connecticut 06520, USA
| | - Koyi Choi
- Molecular Biology Program, Memorial Sloan Kettering Cancer Center, New York, New York 10065, USA; Programs in Biochemistry, Cell, and Molecular Biology, Weill Graduate School of Medical Sciences of Cornell University, New York, New York 10065, USA
| | - Jacob N Bonner
- Molecular Biology Program, Memorial Sloan Kettering Cancer Center, New York, New York 10065, USA; Programs in Biochemistry, Cell, and Molecular Biology, Weill Graduate School of Medical Sciences of Cornell University, New York, New York 10065, USA
| | - Barnabas Szakal
- IFOM, Fondazione Istituto FIRC di Oncologia Molecolare, Milan 20139, Italy
| | - Yu-Hung Chen
- Molecular Biology Program, Memorial Sloan Kettering Cancer Center, New York, New York 10065, USA; Programs in Biochemistry, Cell, and Molecular Biology, Weill Graduate School of Medical Sciences of Cornell University, New York, New York 10065, USA
| | - Alma Papusha
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Dorina Saro
- Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, Connecticut 06520, USA
| | - Hengyao Niu
- Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, Connecticut 06520, USA
| | - Grzegorz Ira
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Dana Branzei
- IFOM, Fondazione Istituto FIRC di Oncologia Molecolare, Milan 20139, Italy
| | - Patrick Sung
- Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, Connecticut 06520, USA
| | - Xiaolan Zhao
- Molecular Biology Program, Memorial Sloan Kettering Cancer Center, New York, New York 10065, USA; Programs in Biochemistry, Cell, and Molecular Biology, Weill Graduate School of Medical Sciences of Cornell University, New York, New York 10065, USA;
| |
Collapse
|