Cdc7 Background Information Cell cycle progression is controlled at a point late in G1 designated Start. Passage through Start requires the activity of the cyclin-dependent protein kinase Cdc28 (1,2). Transition from G1 to S phase requires the association of Cdc28 with members of the G1 cyclin family, including Cln1, Cln2 and Cln3 (also designated Daf1 or Wh11) (3). Srb10 and Kin28 are members of the Cdc28 family of cyclin dependent kinases and are required for cell proliferation (4). The G2 to M phase transition requires the M phase cyclins, Clb1 (also designated Scb1) and Clb2, as well as the G2 cyclins, Clb3 and Clb4 (5,6). The S phase cyclins, Clb5 and Clb6, coordinate DNA replication with cytokinesis (6). The Dbf4/Cdc7 protein kinase complex allows the activation of replication origins during S phase.
