Click here to close Hello! We notice that you are using Internet Explorer, which is not supported by Xenbase and may cause the site to display incorrectly. We suggest using a current version of Chrome, FireFox, or Safari.
XB-ART-10917
EMBO J 2000 Jun 01;1911:2728-38. doi: 10.1093/emboj/19.11.2728.
Show Gene links Show Anatomy links

Selective instability of Orc1 protein accounts for the absence of functional origin recognition complexes during the M-G(1) transition in mammals.

Natale DA , Li CJ , Sun WH , DePamphilis ML .


???displayArticle.abstract???
To investigate the events leading to initiation of DNA replication in mammalian chromosomes, the time when hamster origin recognition complexes (ORCs) became functional was related to the time when Orc1, Orc2 and Mcm3 proteins became stably bound to hamster chromatin. Functional ORCs, defined as those able to initiate DNA replication, were absent during mitosis and early G(1) phase, and reappeared as cells progressed through G(1) phase. Immunoblotting analysis revealed that hamster Orc1 and Orc2 proteins were present in nuclei at equivalent concentrations throughout the cell cycle, but only Orc2 was stably bound to chromatin. Orc1 and Mcm3 were easily eluted from chromatin during mitosis and early G(1) phase, but became stably bound during mid-G(1) phase, concomitant with the appearance of a functional pre-replication complex at a hamster replication origin. Since hamster Orc proteins are closely related to their human and mouse homologs, the unexpected behavior of hamster Orc1 provides a novel mechanism in mammals for delaying assembly of pre-replication complexes until mitosis is complete and a nuclear structure has formed.

???displayArticle.pubmedLink??? 10835370
???displayArticle.pmcLink??? PMC212765
???displayArticle.link??? EMBO J


Species referenced: Xenopus laevis
Genes referenced: mcm3 orc1 orc2

References [+] :
Abdurashidova, Cell cycle modulation of protein-DNA interactions at a human replication origin. 1998, Pubmed, Xenbase