title: CDC45 is required in conjunction with CDC7/DBF4 to trigger the initiation of DNA replication.
abstract: The initiation of DNA replication in Saccharomyces cerevisiae requires the protein product of the CDC45 gene. We report that although Cdc45p is present at essentially constant levels throughout the cell cycle, it completes its initiation function in late G1, after START and prior to DNA synthesis. Shortly after mitosis, cells prepare for initiation by assembling prereplicative complexes at their replication origins. These complexes are then triggered at the onset of S phase to commence DNA replication. Cells defective for CDC45 are incapable of activating the complexes to initiate DNA replication. In addition, Cdc45p and Cdc7p/Dbf4p, a kinase implicated in the G1/S phase transition, are dependent on one another for function. These data indicate that CDC45 functions in late G1 phase in concert with CDC7/DBF4 to trigger initiation at replication origins after the assembly of the prereplicative complexes.
authors.affiliation: Department of Microbiology and Immunology, University of California, San Francisco, CA 94143-0414, USA.
authors.forename: J C
authors.initials: JC
authors.lastname: Owens
authors.forename: C S
authors.initials: CS
authors.lastname: Detweiler
authors.forename: J J
authors.initials: JJ
authors.lastname: Li
mesh_terms: D002352:Carrier Proteins / Q000235:genetics*; D002453:Cell Cycle; D018797:Cell Cycle Proteins / Q000235:genetics*; D004261:DNA Replication; D004271:DNA, Fungal / Q000235:genetics*; D004268:DNA-Binding Proteins; D005656:Fungal Proteins / Q000235:genetics*; D015966:Gene Expression Regulation, Fungal; D009687:Nuclear Proteins / Q000235:genetics*; D011494:Protein Kinases / Q000235:genetics*; D017346:Protein Serine-Threonine Kinases; D012441:Saccharomyces cerevisiae / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins
chemical_list: C102209:CDC45 protein, S cerevisiae; D002352:Carrier Proteins; D018797:Cell Cycle Proteins; D004271:DNA, Fungal; D004268:DNA-Binding Proteins; C088096:Dbf4 protein, S cerevisiae; D005656:Fungal Proteins; D009687:Nuclear Proteins; D029701:Saccharomyces cerevisiae Proteins; D011494:Protein Kinases; C489404:CDC7 protein, S cerevisiae; D017346:Protein Serine-Threonine Kinases