Using a reconstituted DNA replication assay from yeast, we demonstrate that two kinase complexes are essential for the promotion of replication in vitro. An active Clb/Cdc28 kinase complex, or its vertebrate equivalent, is required in trans to stimulate initiation in G(1)-phase nuclei, whereas the Dbf4/Cdc7 kinase complex must be provided by the template nuclei themselves. The regulatory subunit of Cdc7p, Dbf4p, accumulates during late G(1) phase, becomes chromatin associated prior to Clb/Cdc28 activation, and assumes a punctate pattern of localization that is similar to, and dependent on, the origin recognition complex (ORC). The association of Dbf4p with a detergent-insoluble chromatin fraction in G(1)-phase nuclei requires ORC but not Cdc6p or Clb/Cdc28 kinase activity, and correlates with competence for initiation. We propose a model in which Dbf4p targets Cdc7p to the prereplication complex prior to the G(1)/S transition, by a pathway parallel to, but independent of, the Cdc6p-dependent recruitment of MCMs.
A role for the Cdc7 kinase regulatory subunit Dbf4p in the formation of initiation-competent origins of replication
Pasero, P.; Duncker, B. P.; Schwob, E.; Gasser, S. M.
Genes & Development
1999-08-15 / vol 13 / pages 2159-2176
IGMM team(s) involved in this publication
DNA Replication, Genome Instability & Cell Identity
DNA replication; in-vitro; s-phase; protein-kinase; cell-cycle; budding yeast; cdc28; cdc7; chromosomal replication; dbf4; DNA-replication; mcm proteins; recognition complex; s-phase-promoting factor; saccharomyces-cerevisiae cdc7