MRC1-dependent scaling of the budding yeast DNA replication timing program.
We describe the DNA replication timing programs of 14 yeast mutants with an extended S phase identified by a novel genome-wide screen. These mutants are associated with the DNA replication machinery, cell-cycle control, and dNTP synthesis and affect different parts of S phase. In 13 of the mutants, origin activation time scales with the duration of S phase. A limited number of origins become inactive in these strains, with inactive origins characterized by small replicons and distributed throughout S phase. In sharp contrast, cells deleted of MRC1, a gene implicated in replication fork stabilization and in the replication checkpoint pathway, maintained wild-type firing times despite over twofold lengthening of S phase. Numerous dormant origins were activated in this mutant. Our data suggest that most perturbations that lengthen S phase affect the entire program of replication timing, rather than a specific subset of origins, maintaining the relative order of origin firing time and delaying firing with relative proportions. Mrc1 emerges as a regulator of this robustness of the replication program.
Koren
Amnon
A
Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 76100, Israel.
Soifer
Ilya
I
Barkai
Naama
N
D018797:Cell Cycle Proteins / Q000235:genetics / Q000502:physiology*; D002469:Cell Separation; D042522:DNA Replication Timing; D004271:DNA, Fungal / Q000096:biosynthesis*; D004843:Epistasis, Genetic; D005434:Flow Cytometry; D009154:Mutation; D020133:Reverse Transcriptase Polymerase Chain Reaction; D016196:S Phase; D012441:Saccharomyces cerevisiae / Q000166:cytology / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000502:physiology*
D018797:Cell Cycle Proteins; D004271:DNA, Fungal; C441579:MRC1 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins