title: Characterization of a Novel MMS-Sensitive Allele of Schizosaccharomyces pombe mcm4.
abstract: The minichromosome maintenance (MCM) complex is the conserved helicase motor of the eukaryotic replication fork. Mutations in the Mcm4 subunit are associated with replication stress and double strand breaks in multiple systems. In this work, we characterize a new temperature-sensitive allele of Schizosaccharomyces pombe mcm4+Uniquely among known mcm4 alleles, this mutation causes sensitivity to the alkylation damaging agent methyl methanesulfonate (MMS). Even in the absence of treatment or temperature shift, mcm4-c106 cells show increased repair foci of RPA and Rad52, and require the damage checkpoint for viability, indicating genome stress. The mcm4-c106 mutant is synthetically lethal with mutations disrupting fork protection complex (FPC) proteins Swi1 and Swi3. Surprisingly, we found that the deletion of rif1+suppressed the MMS-sensitive phenotype without affecting temperature sensitivity. Together, these data suggest that mcm4-c106 destabilizes replisome structure.
authors.affiliation: Program in Molecular and Computational Biology, University of Southern California, Los Angeles, California 90089.
authors.forename: Nimna S
authors.initials: NS
authors.lastname: Ranatunga
authors.affiliation: Program in Molecular and Computational Biology, University of Southern California, Los Angeles, California 90089 forsburg@usc.edu.
authors.forename: Susan L
authors.identifier: 0000-0002-4895-8598
authors.initials: SL
authors.lastname: Forsburg
mesh_terms: D000483:Alleles; D018906:Antineoplastic Agents, Alkylating / Q000494:pharmacology*; D020090:Chromosome Segregation; D004249:DNA Damage / Q000187:drug effects; D004260:DNA Repair; D004261:DNA Replication; D008741:Methyl Methanesulfonate / Q000494:pharmacology*; D050296:Microbial Viability / Q000187:drug effects / Q000235:genetics; D064148:Minichromosome Maintenance Complex Component 4 / Q000235:genetics*; D009154:Mutation; D010641:Phenotype; D012568:Schizosaccharomyces / Q000187:drug effects* / Q000235:genetics*; D029702:Schizosaccharomyces pombe Proteins / Q000235:genetics*
chemical_list: D018906:Antineoplastic Agents, Alkylating; D029702:Schizosaccharomyces pombe Proteins; D008741:Methyl Methanesulfonate; D064148:Minichromosome Maintenance Complex Component 4
keywords: DNA replication; MCM complex; MMS; checkpoint; fission yeast; fork protection complex