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Xenopus origin recognition complex (ORC) initiates DNA replication preferentially at sequences targeted by Schizosaccharomyces pombe ORC
Author(s) -
Kong Daochun,
Coleman Thomas R.,
DePamphilis Melvin L.
Publication year - 2003
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1093/emboj/cdg319
Subject(s) - biology , schizosaccharomyces pombe , schizosaccharomyces , xenopus , genetics , dna replication , origin recognition complex , dna , microbiology and biotechnology , computational biology , eukaryotic dna replication , gene , saccharomyces cerevisiae
Budding yeast ( Saccharomyces cerevisiae ) origin recognition complex (ORC) requires ATP to bind specific DNA sequences, whereas fission yeast ( Schizosaccharomyces pombe ) ORC binds to specific, asymmetric A:T‐rich sites within replication origins, independently of ATP, and frog ( Xenopus laevis ) ORC seems to bind DNA non‐specifically. Here we show that despite these differences, ORCs are functionally conserved. Firstly, SpOrc1, SpOrc4 and SpOrc5, like those from other eukaryotes, bound ATP and exhibited ATPase activity, suggesting that ATP is required for pre‐replication complex (pre‐RC) assembly rather than origin specificity. Secondly, SpOrc4, which is solely responsible for binding SpORC to DNA, inhibited up to 70% of XlORC‐dependent DNA replication in Xenopus egg extract by preventing XlORC from binding to chromatin and assembling pre‐RCs. Chromatin‐bound SpOrc4 was located at AT‐rich sequences. XlORC in egg extract bound preferentially to asymmetric A:T‐sequences in either bare DNA or in sperm chromatin, and it recruited XlCdc6 and XlMcm proteins to these sequences. These results reveal that XlORC initiates DNA replication preferentially at the same or similar sites to those targeted in S.pombe .