title: Error-free DNA damage tolerance and sister chromatid proximity during DNA replication rely on the Polα/Primase/Ctf4 Complex.
abstract: Chromosomal replication is entwined with DNA damage tolerance (DDT) and chromatin structure establishment via elusive mechanisms. Here we examined how specific replication conditions affecting replisome architecture and repriming impact on DDT. We show that Saccharomyces cerevisiae Polα/Primase/Ctf4 mutants, proficient in bulk DNA replication, are defective in recombination-mediated damage-bypass by template switching (TS) and have reduced sister chromatid cohesion. The decrease in error-free DDT is accompanied by increased usage of mutagenic DDT, fork reversal, and higher rates of genome rearrangements mediated by faulty strand annealing. Notably, the DDT defects of Polα/Primase/Ctf4 mutants are not the consequence of increased sister chromatid distance, but are instead caused by altered single-stranded DNA metabolism and abnormal replication fork topology. We propose that error-free TS is driven by timely replicative helicase-coupled re-priming. Defects in this event impact on replication fork architecture and sister chromatid proximity, and represent a frequent source of chromosome lesions upon replication dysfunctions.
authors: IFOM, the FIRC Institute of Molecular Oncology, Via Adamello 16, 20139 Milan, Italy.
authors: Marco
authors: M
authors: Fumasoni
authors: Institute of Molecular Cancer Research, University of Zurich, CH-8057, Zurich, Switzerland.
authors: Katharina
authors: K
authors: Zwicky
authors: IFOM, the FIRC Institute of Molecular Oncology, Via Adamello 16, 20139 Milan, Italy.
authors: Fabio
authors: F
authors: Vanoli
authors: Institute of Molecular Cancer Research, University of Zurich, CH-8057, Zurich, Switzerland.
authors: Massimo
authors: M
authors: Lopes
authors: IFOM, the FIRC Institute of Molecular Oncology, Via Adamello 16, 20139 Milan, Italy. Electronic address: dana.branzei@ifom.eu.
authors: Dana
authors: D
authors: Branzei
mesh_terms: D002842:Chromatids / Q000235:genetics*; D004249:DNA Damage; D004256:DNA Polymerase I / Q000235:genetics / Q000378:metabolism*; D019915:DNA Primase / Q000235:genetics / Q000378:metabolism*; D004260:DNA Repair / Q000235:genetics; D004261:DNA Replication / Q000235:genetics*; D004277:DNA, Single-Stranded / Q000235:genetics / Q000378:metabolism / Q000648:ultrastructure; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D059565:G2 Phase Cell Cycle Checkpoints / Q000235:genetics; D008854:Microscopy, Electron; D008957:Models, Genetic; D046912:Multiprotein Complexes / Q000235:genetics / Q000378:metabolism; D009154:Mutation; D011995:Recombination, Genetic; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction / Q000235:genetics; D013997:Time Factors
chemical_list: C078338:CTF4 protein, S cerevisiae; D004277:DNA, Single-Stranded; D004268:DNA-Binding Proteins; D046912:Multiprotein Complexes; D029701:Saccharomyces cerevisiae Proteins; D019915:DNA Primase; D004256:DNA Polymerase I