Site-specific ORC binding, pre-replication complex assembly and DNA synthesis at Schizosaccharomyces pombe replication origins

AUTOR(ES)

Kong, Daochun

FONTE

Oxford University Press

RESUMO

Previous studies have shown that the Schizo saccharomyces pombe Orc4 subunit is solely responsible for in vitro binding of origin recognition complex (ORC) to specific AT-rich sites within S.pombe replication origins. Using ARS3001, a S.pombe replication origin consisting of four genetically required sites, we show that, in situ as well as in vitro, Orc4 binds strongly to the Δ3 site, weakly to the Δ6 site and not at all to the remaining sequences. In situ, the footprint over Δ3 is extended during G1 phase, but only when Cdc18 is present and Mcm proteins are bound to chromatin. Moreover, this footprint extends into the adjacent Δ2 site, where leading strand DNA synthesis begins. Therefore, we conclude that ARS3001 consists of a single primary ORC binding site that assembles a pre-replication complex and initiates DNA synthesis, plus an additional novel origin element (Δ9) that neither binds ORC nor functions as a centromere, but does bind an as yet unidentified protein throughout the cell cycle. Schizosaccharomyces pombe may be an appropriate paradigm for the complex origins found in the metazoa.

Documentos Relacionados

• Site-Specific DNA Binding of the Schizosaccharomyces pombe Origin Recognition Complex Is Determined by the Orc4 Subunit
• Xenopus origin recognition complex (ORC) initiates DNA replication preferentially at sequences targeted by Schizosaccharomyces pombe ORC
• The plant cell cycle: Pre-Replication complex formation and controls
• Complex mechanism of site-specific DNA replication termination in fission yeast
• Site-specific carcinogen binding to DNA.