Figure 1.

Cellular responses to replication/ genotoxic stress involving Cdc7 kinase. During G1, p53 downregulates Cdc7 level through two pathways to prevent entry into S phase. p53 also inhibits Cdk through p21 and this facilitates Cdc7 destruction (not shown in figure). During S, Cdc7 plays roles as both replication stress checkpoint activator and target. Cdc7 also recruits lesion bypass machinery at the stalled fork.