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Incorporation into the pre‐replication complex activates the Mcm2‐7 replicative DNA helicase for phosphorylation by the S‐phase kinase, Cdc7‐Dbf4
Author(s) -
Bell Stephen P,
Francis Laura I,
Randell John C. W.,
Takara Thomas J
Publication year - 2009
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.23.1_supplement.201.1
Subject(s) - helicase , pre replication complex , biology , dna replication , minichromosome maintenance , microbiology and biotechnology , origin recognition complex , kinase , origin of replication , eukaryotic dna replication , genetics , computational biology , dna , gene , rna
The essential S‐phase kinase, Cdc7‐Dbf4, acts at eukaryotic origins of replication to trigger a cascade of protein associations that activate the Mcm2‐7 replicative helicase. Also known as Dbf4‐dependent kinase (DDK), this kinase is limiting in cells and acts at individual origins of replication at the time of initiation. Here we address the mechanisms that control the specificity of DDK action. We show that DDK preferentially targets a conformationally distinct sub‐population of Mcm2‐7 complexes that are tightly linked to the origin DNA during pre‐replicative complex (pre‐RC) formation. This targeting requires DDK to tightly associate with Mcm2‐7 complexes in a Dbf4‐dependent manner. Importantly, we find that DDK association with and phosphorylation of origin‐linked Mcm2‐7 complexes require prior phosphorylation of the pre‐RC. Our findings provide insights into the mechanisms that ensure that DDK action is spatially and temporally restricted to the subset of origin‐bound Mcm2‐7 complexes that will drive replication fork movement during S phase and suggest new mechanisms that could regulate origin activity. This research was supported by funding from the National Institute of General Medical Sciences, the Howard Hughes Medical Institute, and the Leukemia and Lymphoma Society.