The Geminin coiled-coil domain-containing protein 1 (GEMC1) is a highly conserved protein that is required for chromosomal replication. GEMC1 contains a region similar to the coiled-coil domain of geminin, an essential vertebrate replication protein in which the coiled-coil domain is required for the function. GEMC1 binds to the checkpoint and replication factor TopBP1, allowing the binding of GEMC1 to chromatin during pre-replication complex formation. GEMC1 also directly interacts with replication factors Cdc45 and Cdk2-CyclinE and stimulates the initiation of DNA replication. Depletion of GEMC1 by siRNA in embryonic and somatic vertebrate cells prevents DNA replication due to impairment of Cdc45 loading onto chromatin, suggesting GEMC1 promotes initiation of DNA replication by mediating TopBP1 and Cdk2 dependent recruitment of Cdc45 onto replication origins.Synonyms: Geminin coiled-coil domain-containing protein 1