Rgf1p (Rho1p GEF) is required for double-strand break repair in fission yeast.
Rho GTPases are conserved molecules that control cytoskeletal dynamics. These functions are expedited by Rho GEFs that stimulate the release of GDP to enable GTP binding, thereby allowing Rho proteins to initiate intracellular signaling. How Rho GEFs and Rho GTPases protect cells from DNA damage is unknown. Here, we explore the extreme sensitivity of a deletion mutation in the Rho1p exchange factor Rgf1p to the DNA break/inducing antibiotic phleomycin (Phl). The Rgf1p mutant cells are defective in reentry into the cell cycle following the induction of severe DNA damage. This phenotype correlates with the inability of rgf1Δ cells to efficiently repair fragmented chromosomes after Phl treatment. Consistent with this observation Rad11p (ssDNA binding protein, RPA), Rad52p, Rad54p and Rad51p, which facilitate strand invasion in the process of homology-directed repair (HDR), are permanently stacked in Phl-induced foci in rgf1Δ cells. These phenotypes are phenocopied by genetic inhibition of Rho1p. Our data provide evidence that Rgf1p/Rho1p activity positively controls a repair function that confers resistance against the anti-cancer drug Phl.
Instituto de Biología Funcional y Genómica, CSIC. Departamento de Microbiología y Genética, Universidad de Salamanca. C/Zacarías González, s/n. Salamanca, Spain.
Elvira
E
Manjón
Instituto de Biología Funcional y Genómica, CSIC. Departamento de Microbiología y Genética, Universidad de Salamanca. C/Zacarías González, s/n. Salamanca, Spain.
Tomás
T
Edreira
Instituto de Biología Funcional y Genómica, CSIC. Departamento de Microbiología y Genética, Universidad de Salamanca. C/Zacarías González, s/n. Salamanca, Spain.
Sofía
S
Muñoz
Instituto de Biología Funcional y Genómica, CSIC. Departamento de Microbiología y Genética, Universidad de Salamanca. C/Zacarías González, s/n. Salamanca, Spain.
Yolanda
Y
Sánchez
D015825:Chromosomes, Fungal / Q000235:genetics; D053903:DNA Breaks, Double-Stranded / Q000187:drug effects; D004260:DNA Repair / Q000187:drug effects; D059565:G2 Phase Cell Cycle Checkpoints / Q000187:drug effects; D049452:Green Fluorescent Proteins / Q000378:metabolism; D020662:Guanine Nucleotide Exchange Factors / Q000378:metabolism*; D059765:Homologous Recombination / Q000187:drug effects; D050296:Microbial Viability / Q000187:drug effects; D009154:Mutation / Q000235:genetics; D010692:Phleomycins / Q000494:pharmacology; D012568:Schizosaccharomyces / Q000187:drug effects / Q000378:metabolism*; D029702:Schizosaccharomyces pombe Proteins / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects
D020662:Guanine Nucleotide Exchange Factors; D010692:Phleomycins; C511265:Rgf1 protein, S pombe; D029702:Schizosaccharomyces pombe Proteins; D049452:Green Fluorescent Proteins