Multiple pathways cooperate to facilitate DNA replication fork progression through alkylated DNA.
Eukaryotic genomes are especially vulnerable to DNA damage during the S phase of the cell cycle, when chromosomes must be duplicated. The stability of DNA replication forks is critical to achieve faithful chromosome replication and is severely compromised when forks encounter DNA lesions. To maintain genome integrity, replication forks need to be protected by the S-phase checkpoint and DNA insults must be repaired. Different pathways help to repair or tolerate the lesions in the DNA, but their contribution to the progression of replication forks through damaged DNA is not well known. Here we show in budding yeast that, when the DNA template is damaged with the alkylating agent methyl methanesulfonate (MMS), base excision repair, homologous recombination and DNA damage tolerance pathways, together with a functional S-phase checkpoint, are essential for the efficient progression of DNA replication forks and the maintenance of cell survival. In the absence of base excision repair, replication forks stall reversibly in cells exposed to MMS. This repair reaction is necessary to eliminate the lesions that impede fork progression and has to be coordinated with recombination and damage tolerance activities to avoid fork collapse and allow forks to resume and complete chromosome replication.
Vázquez
María Victoria
MV
Centro de Biología Molecular Severo Ochoa (CSIC/UAM), Cantoblanco, Madrid, Spain.
Rojas
Vanesa
V
Tercero
José Antonio
JA
D000478:Alkylation / Q000187:drug effects; D004249:DNA Damage; D004260:DNA Repair / Q000187:drug effects; D004261:DNA Replication / Q000187:drug effects; D004271:DNA, Fungal / Q000378:metabolism*; D008741:Methyl Methanesulfonate / Q000494:pharmacology; D011995:Recombination, Genetic / Q000187:drug effects; D016196:S Phase / Q000187:drug effects; D012441:Saccharomyces cerevisiae / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects
D004271:DNA, Fungal; D029701:Saccharomyces cerevisiae Proteins; D008741:Methyl Methanesulfonate