Budding yeast Mph1 promotes sister chromatid interactions by a mechanism involving strand invasion.
Stalling of replication forks at lesions is a serious threat to genomic integrity and cell viability. Cells have developed a variety of pathways that allow continuation of synthesis, including translesion synthesis, postreplication repair and homologous recombination. We have devised a sensitive genetic system for detection of sister chromatid interactions in Saccharomyces cerevisiae. A 266bp sequence duplication in the KanMX4 module was generated and reversions were scored via G418 resistant colonies. Both 4-NQO induced and spontaneous reversions are strictly dependent on RAD52. Damage-induced reversions are also largely dependent on RAD51. Thus, most damage-induced events require a strand invasion step. Induced reversions were not affected in rev3 mutants and partially reduced in rad30 mutants indicating an involvement of Pol η. In cells lacking Mph1, a member of the FANCM family of DNA helicases, that has been implicated in a pathway for fork reactivation involving homologous recombination, damage-induced events are significantly reduced. Together with the spontaneous mutator phenotype of mph1 mutants this data strongly suggest that Mph1 has an additional function in recombination besides its previously described ability to disrupt D-loops. We propose that Mph1 promotes D-loop formation.
Abteilung für Molekulare Genetik, Institut für Mikrobiologie und Genetik, Georg-August-Universität Göttingen, Griesebachstraße 8, Göttingen, Germany. cede@gwdg.de
Christopher
C
Ede
Christian J
CJ
Rudolph
Sabrina
S
Lehmann
K Anke
KA
Schürer
Wilfried
W
Kramer
D015112:4-Nitroquinoline-1-oxide / Q000009:adverse effects; D003049:Coccidiostats; D053487:DEAD-box RNA Helicases / Q000187:drug effects / Q000235:genetics*; D004249:DNA Damage; D004259:DNA-Directed DNA Polymerase / Q000235:genetics; D004351:Drug Resistance; D005839:Gentamicins; D009154:Mutation; D051135:Rad51 Recombinase / Q000235:genetics; D051721:Rad52 DNA Repair and Recombination Protein / Q000235:genetics; D012441:Saccharomyces cerevisiae / Q000187:drug effects / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins / Q000187:drug effects / Q000235:genetics*; D012854:Sister Chromatid Exchange; D000099270:Y-Family DNA Polymerases
D015112:4-Nitroquinoline-1-oxide; D003049:Coccidiostats; D053487:DEAD-box RNA Helicases; D004259:DNA-Directed DNA Polymerase; D005839:Gentamicins; D051135:Rad51 Recombinase; D051721:Rad52 DNA Repair and Recombination Protein; D029701:Saccharomyces cerevisiae Proteins; C497197:RAD52 protein, S cerevisiae; C010680:antibiotic G 418; C495151:RAD51 protein, S cerevisiae; C092602:REV3 protein, S cerevisiae; C112338:Rad30 protein; D000099270:Y-Family DNA Polymerases; C491240:MPH1 protein, S cerevisiae