499818392ENSG00000085840ENSMUSG00000028587Q13415Q9Z1N2NM_001190818NM_001190819NM_004153NM_001014425NM_011015NP_001177747NP_001177748NP_004144NP_035145Origin recognition complex subunit 1 is a protein that in humans is encoded by the ORC1 gene.

Studies in yeast demonstrated that ORC binds specifically to origins of replication and serves as a platform for the assembly of the pre-replication complex, which includes additional initiation factors such as Cdc6 and Mcm proteins.

The protein encoded by this gene is the largest subunit of the origin recognition complex.

While other ORC subunits are stable throughout the cell cycle, the levels of this protein vary during the cell cycle, which has been shown to be controlled by ubiquitin-mediated proteolysis after initiation of DNA replication.

It is also reported to interact with MYST histone acetyltransferase 2 (MYST2/HBO1), a protein involved in control of transcription silencing.