Cell division cycle 7-related protein kinase 7 (CDC7) is critical for the activation and firing of replication origins during S-phase. Cdc7 kinase activity is activated and regulated by Dbf4. Substrates of CDC7 include the MCM (mini-chromosome maintenance) proteins, DNA polymerase alpha, Cdc45, Orc4, geminin and SV40 T-antigen. CDC7 has also been implicated to play a role in the DNA damage response. Alternative names for CDC7 include;CDC7L1, hsCDC7, huCDC7, and Hsk1.