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Mrc1 marks early-firing origins and coordinates timing and efficiency of initiation in fission yeast

ABSTRACT: How early- and late-firing origins are selected on eukaryotic chromosomes is largely unknown. Here we show that Mrc1, a conserved factor required for stabilization of stalled replication forks, selectively binds to the early-firing origins in a manner independent of Cdc45 and Hsk1 kinase in fission yeast. In mrc1∆ (and in swi1∆ to some extent), efficiency of firing is stimulated and its timing is advanced selectively at those origins that are normally bound by Mrc1. In contrast, the late or inefficient origins which are not bound by Mrc1 are not activated in mrc1∆. The enhanced firing and precocious Cdc45 loading at Mrc1-bound early-firing origins are not observed in a checkpoint mutant of mrc1, suggesting that non-checkpoint function is involved in maintaining the normal program of early-firing origins. We propose that pre-firing binding of Mrc1 is an important marker of early-firing origins which are precociously activated by the absence this protein. Mrc1 binding profiles at G1/S boundary or early S-phase in wild type vs hsk1-89 mutant.

ORGANISM(S): Schizosaccharomyces pombe

PROVIDER: GSE28182 | GEO | 2011/03/26

SECONDARY ACCESSION(S): PRJNA139537

REPOSITORIES: GEO

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Checkpoint-independent Regulation of Origin Firing by Mrc1 through Interaction with Hsk1 kinase

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Schizosaccharomyces pombe

Project description:Mrc1 marks early-firing origins and coordinates timing and efficiency of initiation in fission yeast

| PRJNA139537 | ENA

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