The Xenopus Cdc6 protein is essential for the initiation of a single round of DNA replication in cell-free extracts.
We have cloned a Xenopus Cdc6 homolog (Xcdc6) and characterized its role in DNA replication with Xenopus egg extracts. Immunodepletion of Xcdc6 abolishes chromosomal replication but not elongation on single-stranded DNA templates. Xcdc6 binds to chromatin at the beginning of interphase but disappears from chromatin upon initiation of replication. Immunodepletion studies indicate that binding of Xcdc6 to chromatin requires Xorc2, a component of the origin recognition complex. Moreover, Xmcm3 cannot bind to chromatin lacking Xcdc6, suggesting that Xorc2, Xcdc6, and Xmcm3 associate with the DNA sequentially. In postreplicative nuclei, Xcdc6 is associated with the nuclear envelope. These studies indicate that Xcdc6, is essential for initiation of replication in vertebrates and that interaction with the nuclear envelope may regulate its function.
Coleman
T R
TR
Division of Biology, Howard Hughes Medical Institute, California Institute of Technology, Pasadena 91125, USA.
Carpenter
P B
PB
Dunphy
W G
WG
D000595:Amino Acid Sequence; D000818:Animals; D002453:Cell Cycle; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism / Q000494:pharmacology / Q000502:physiology*; D002457:Cell Extracts; D002843:Chromatin; D003001:Cloning, Molecular; D004261:DNA Replication / Q000187:drug effects / Q000502:physiology*; D018076:DNA, Complementary / Q000235:genetics; D004268:DNA-Binding Proteins / Q000032:analysis / Q000378:metabolism; D007399:Interphase; D008969:Molecular Sequence Data; D009865:Oocytes; D051738:Origin Recognition Complex; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D051716:Replication Protein A; D029701:Saccharomyces cerevisiae Proteins; D014981:Xenopus
C066503:CDC6 protein, S cerevisiae; D018797:Cell Cycle Proteins; D002457:Cell Extracts; D002843:Chromatin; D018076:DNA, Complementary; D004268:DNA-Binding Proteins; D051738:Origin Recognition Complex; D011993:Recombinant Fusion Proteins; D051716:Replication Protein A; D029701:Saccharomyces cerevisiae Proteins