Origin Recognition Complex

ORC or Origin Recognition Complex is a multisubunit complex existing in the replication procedure of DNA. It marks the replication origin by binding to and marking ori sequences in all eukaryotes in an ATP-dependent manner. During the G1 phase of the cell cycle, ORC recruits cdc6 and cdt1 proteins. Once formed, the ORC is activated by two kinases, CDK and DDK, which trigger the transition into DNA replication.