Origin recognition complex, subunit 1
Symbols ORC1; HSORC1; ORC1L; PARC1
External IDs OMIM601902 MGI1328337 HomoloGene31221 GeneCards: ORC1 Gene
RNA expression pattern
PBB GE ORC1L 205085 at tn.png
More reference expression data
Species Human Mouse
Entrez 4998 18392
Ensembl ENSG00000085840 ENSMUSG00000028587
UniProt Q13415 Q3TPY7
RefSeq (mRNA) NM_001190818.1 NM_011015.2
RefSeq (protein) NP_001177747.1 NP_035145.2
Location (UCSC) Chr 1:
52.84 – 52.87 Mb
Chr 4:
108.25 – 108.29 Mb
PubMed search [1] [2]

Origin recognition complex subunit 1 is a protein that in humans is encoded by the ORC1 gene.[1][2]



The origin recognition complex (ORC) is a highly conserved six subunits protein complex essential for the initiation of the DNA replication in eukaryotic cells. Studies in yeast demonstrated that ORC binds specifically to origins of replication and serves as a platform for the assembly of additional initiation factors such as Cdc6 and Mcm proteins. The protein encoded by this gene is the largest subunit of the ORC 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. This protein is found to be selectively phosphorylated during mitosis. It is also reported to interact with MYST histone acetyltransferase 2 (MYST2/HBO1), a protein involved in control of transcription silencing.[2]


ORC1L has been shown to interact with ORC2L,[3][4][5][6] ORC4L,[3] ORC5L,[3] MCM4,[3] MYST2,[7] CDC6,[3][8] Cyclin-dependent kinase 2,[6] MCM6,[3] SKP2,[6] MCM7,[3] MCM2,[3] CDC45-related protein[3] and Cell division cycle 7-related protein kinase.[3]


  1. ^ Eki T, Okumura K, Amin A, Ishiai M, Abe M, Nogami M, Taguchi H, Hurwitz J, Murakami Y, Hanaoka F (Feb 1997). "Mapping of the human homologue (ORC1L) of the yeast origin recognition complex subunit 1 gene to chromosome band 1p32". Genomics 36 (3): 559–61. doi:10.1006/geno.1996.0511. PMID 8884289. 
  2. ^ a b "Entrez Gene: ORC1L origin recognition complex, subunit 1-like (yeast)". http://www.ncbi.nlm.nih.gov/sites/entrez?Db=gene&Cmd=ShowDetailView&TermToSearch=4998. 
  3. ^ a b c d e f g h i j Kneissl, Margot; Pütter Vera, Szalay Aladar A, Grummt Friedrich (Mar. 2003). "Interaction and assembly of murine pre-replicative complex proteins in yeast and mouse cells". J. Mol. Biol. (England) 327 (1): 111–28. doi:10.1016/S0022-2836(03)00079-2. ISSN 0022-2836. PMID 12614612. 
  4. ^ Fujita, Masatoshi; Ishimi Yukio, Nakamura Hiromu, Kiyono Tohru, Tsurumi Tatsuya (Mar. 2002). "Nuclear organization of DNA replication initiation proteins in mammalian cells". J. Biol. Chem. (United States) 277 (12): 10354–61. doi:10.1074/jbc.M111398200. ISSN 0021-9258. PMID 11779870. 
  5. ^ Vashee, S; Simancek P, Challberg M D, Kelly T J (Jul. 2001). "Assembly of the human origin recognition complex". J. Biol. Chem. (United States) 276 (28): 26666–73. doi:10.1074/jbc.M102493200. ISSN 0021-9258. PMID 11323433. 
  6. ^ a b c Méndez, Juan; Zou-Yang X Helena, Kim So-Young, Hidaka Masumi, Tansey William P, Stillman Bruce (Mar. 2002). "Human origin recognition complex large subunit is degraded by ubiquitin-mediated proteolysis after initiation of DNA replication". Mol. Cell (United States) 9 (3): 481–91. doi:10.1016/S1097-2765(02)00467-7. ISSN 1097-2765. PMID 11931757. 
  7. ^ Iizuka, M; Stillman B (Aug. 1999). "Histone acetyltransferase HBO1 interacts with the ORC1 subunit of the human initiator protein". J. Biol. Chem. (UNITED STATES) 274 (33): 23027–34. doi:10.1074/jbc.274.33.23027. ISSN 0021-9258. PMID 10438470. 
  8. ^ Saha, P; Chen J, Thome K C, Lawlis S J, Hou Z H, Hendricks M, Parvin J D, Dutta A (May. 1998). "Human CDC6/Cdc18 associates with Orc1 and cyclin-cdk and is selectively eliminated from the nucleus at the onset of S phase". Mol. Cell. Biol. (UNITED STATES) 18 (5): 2758–67. ISSN 0270-7306. PMC 110655. PMID 9566895. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=110655. 

Further reading


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