title: Mcl1p is a polymerase alpha replication accessory factor important for S-phase DNA damage survival.
abstract: Mcl1p is an essential fission yeast chromatin-binding protein that belongs to a family of highly conserved eukaryotic proteins important for sister chromatid cohesion. The essential function is believed to result from its role as a Pol1p (polymerase alpha) accessory protein, a conclusion based primarily on analogy to Ctf4p's interaction with Pol1p. In this study, we show that Mcl1p also binds to Pol1p with high affinity for the N terminus of Pol1p during S phase and DNA damage. Characterization of an inducible allele of mcl1+, (nmt41)mcl1-MH, shows that altered expression levels of Mcl1p lead to sensitivity to DNA-damaging agents and synthetic lethality with the replication checkpoint mutations rad3Delta, rqh1Delta, and hsk1-1312. Further, we find that the overexpression of the S-phase checkpoint kinase, Cds1, or the loss of Hsk1 kinase activity can disrupt Mcl1p's interaction with chromatin and Pol1p during replication arrest with hydroxyurea. We take these data to mean that Mcl1p is a dynamic component of the polymerase alpha complex during replication and is important for the replication stress response in fission yeast.
authors.affiliation: Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, Colorado, USA. Dewight.williams@vanderbilt.edu
authors.forename: Dewight R
authors.initials: DR
authors.lastname: Williams
authors.forename: J R
authors.initials: JR
authors.lastname: McIntosh
mesh_terms: D000483:Alleles; D018797:Cell Cycle Proteins / Q000378:metabolism; D002843:Chromatin / Q000737:chemistry / Q000378:metabolism; D002868:Chromosomal Proteins, Non-Histone / Q000502:physiology*; D004247:DNA / Q000737:chemistry; D004249:DNA Damage; D004256:DNA Polymerase I / Q000378:metabolism*; D015180:Electrophoresis, Gel, Two-Dimensional; D005838:Genotype; D005982:Glutathione Transferase / Q000378:metabolism; D049452:Green Fluorescent Proteins / Q000737:chemistry; D008954:Models, Biological; D009154:Mutation; D010641:Phenotype; D011485:Protein Binding; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D017434:Protein Structure, Tertiary; D016196:S Phase; D012568:Schizosaccharomyces / Q000378:metabolism*; D029702:Schizosaccharomyces pombe Proteins / Q000378:metabolism / Q000502:physiology*; D013395:Sucrose / Q000494:pharmacology; D013696:Temperature
chemical_list: D018797:Cell Cycle Proteins; D002843:Chromatin; D002868:Chromosomal Proteins, Non-Histone; C470561:Mcl1 protein, S pombe; D029702:Schizosaccharomyces pombe Proteins; D049452:Green Fluorescent Proteins; D013395:Sucrose; D004247:DNA; D005982:Glutathione Transferase; C094761:HSK1 protein, S pombe; D017346:Protein Serine-Threonine Kinases; D004256:DNA Polymerase I