PMID- 28175398
OWN - NLM
STAT- MEDLINE
DCOM- 20170906
LR  - 20201209
IS  - 1362-4962 (Electronic)
IS  - 0305-1048 (Print)
IS  - 0305-1048 (Linking)
VI  - 45
IP  - 8
DP  - 2017 May 5
TI  - Differential requirement of Srs2 helicase and Rad51 displacement activities in 
      replication of hairpin-forming CAG/CTG repeats.
PG  - 4519-4531
LID - 10.1093/nar/gkx088 [doi]
AB  - 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.
CI  - (c) The Author(s) 2017. Published by Oxford University Press on behalf of Nucleic 
      Acids Research.
FAU - Nguyen, Jennifer H G
AU  - Nguyen JHG
AD  - Department of Biology, Tufts University, Medford, MA 02155, USA.
FAU - Viterbo, David
AU  - Viterbo D
AD  - Institut Pasteur, Department Genomes & Genetics, CNRS, UMR3525, Universite Pierre 
      et Marie Curie, UFR927, 25 rue du Dr Roux, F-75015 Paris, France.
FAU - Anand, Ranjith P
AU  - Anand RP
AD  - Department of Biology, Tufts University, Medford, MA 02155, USA.
FAU - Verra, Lauren
AU  - Verra L
AD  - Department of Biology, Tufts University, Medford, MA 02155, USA.
FAU - Sloan, Laura
AU  - Sloan L
AD  - Department of Biology, Tufts University, Medford, MA 02155, USA.
FAU - Richard, Guy-Franck
AU  - Richard GF
AD  - Institut Pasteur, Department Genomes & Genetics, CNRS, UMR3525, Universite Pierre 
      et Marie Curie, UFR927, 25 rue du Dr Roux, F-75015 Paris, France.
FAU - Freudenreich, Catherine H
AU  - Freudenreich CH
AD  - Department of Biology, Tufts University, Medford, MA 02155, USA.
LA  - eng
GR  - P01 GM105473/GM/NIGMS NIH HHS/United States
PT  - Journal Article
PL  - England
TA  - Nucleic Acids Res
JT  - Nucleic acids research
JID - 0411011
RN  - 0 (DNA, Fungal)
RN  - 0 (Proliferating Cell Nuclear Antigen)
RN  - 0 (Saccharomyces cerevisiae Proteins)
RN  - 125481-05-2 (SRS2 protein, S cerevisiae)
RN  - EC 2.7.7.- (RAD51 protein, S cerevisiae)
RN  - EC 2.7.7.- (Rad51 Recombinase)
RN  - EC 3.1.- (Exodeoxyribonucleases)
RN  - EC 3.1.11.1 (exodeoxyribonuclease I)
RN  - EC 3.6.4.- (DNA Helicases)
SB  - IM
MH  - Alleles
MH  - Chromosome Fragility
MH  - DNA Helicases/*genetics/metabolism
MH  - *DNA Replication
MH  - DNA, Fungal/*genetics/metabolism
MH  - Electrophoresis, Gel, Two-Dimensional
MH  - Exodeoxyribonucleases/genetics/metabolism
MH  - *Genome, Fungal
MH  - Genomic Instability
MH  - Inverted Repeat Sequences
MH  - Proliferating Cell Nuclear Antigen/*genetics/metabolism
MH  - Protein Binding
MH  - Rad51 Recombinase/*genetics/metabolism
MH  - Saccharomyces cerevisiae/*genetics/metabolism
MH  - Saccharomyces cerevisiae Proteins/*genetics/metabolism
MH  - Trinucleotide Repeats
PMC - PMC5416882
EDAT- 2017/02/09 06:00
MHDA- 2017/09/07 06:00
PMCR- 2017/02/08
CRDT- 2017/02/09 06:00
PHST- 2016/05/12 00:00 [received]
PHST- 2017/01/31 00:00 [accepted]
PHST- 2017/02/09 06:00 [pubmed]
PHST- 2017/09/07 06:00 [medline]
PHST- 2017/02/09 06:00 [entrez]
PHST- 2017/02/08 00:00 [pmc-release]
AID - 2975289 [pii]
AID - gkx088 [pii]
AID - 10.1093/nar/gkx088 [doi]
PST - ppublish
SO  - Nucleic Acids Res. 2017 May 5;45(8):4519-4531. doi: 10.1093/nar/gkx088.