title: The role of single-stranded DNA and polymerase alpha in establishing the ATR, Hus1 DNA replication checkpoint.
abstract: Using a nucleus-free DNA replication system we have investigated the roles of Xenopus ATR (XATR) and Hus1 (Xhus1) as the DNA replication checkpoint sensors. Like XATR, Xhus1 is required for the checkpoint-dependent phosphorylation of Xchk1 and associates with chromatin in an initiation-dependent manner. While removal of replication protein A inhibits chromatin association of both XATR and Xhus1, removal of polymerase alpha only disrupts chromatin association of Xhus1. In addition, chromatin association of XATR and Xhus1 are independent of each other. Finally, like XATR, Xhus1 associates with chromatin in unperturbed S phase and dissociates from chromatin following completion of DNA replication.
authors.affiliation: Division of Biology, University of California-San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0349, USA.
authors.forename: Zhongsheng
authors.initials: Z
authors.lastname: You
authors.forename: Lindsay
authors.initials: L
authors.lastname: Kong
authors.forename: John
authors.initials: J
authors.lastname: Newport
mesh_terms: D000818:Animals; D064007:Ataxia Telangiectasia Mutated Proteins; D015153:Blotting, Western; D002110:Caffeine / Q000494:pharmacology; D018797:Cell Cycle Proteins / Q000235:genetics*; D002843:Chromatin / Q000378:metabolism; D003001:Cloning, Molecular; D004256:DNA Polymerase I / Q000502:physiology*; D018076:DNA, Complementary / Q000378:metabolism; D004277:DNA, Single-Stranded; D020224:Expressed Sequence Tags; D005982:Glutathione Transferase / Q000378:metabolism; D008954:Models, Biological; D008969:Molecular Sequence Data; D010726:Phosphodiesterase Inhibitors / Q000494:pharmacology; D010766:Phosphorylation; D011485:Protein Binding; D014176:Protein Biosynthesis; D017346:Protein Serine-Threonine Kinases; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D029702:Schizosaccharomyces pombe Proteins; D014981:Xenopus; D029867:Xenopus Proteins
chemical_list: D018797:Cell Cycle Proteins; D002843:Chromatin; D018076:DNA, Complementary; D004277:DNA, Single-Stranded; D010726:Phosphodiesterase Inhibitors; D011993:Recombinant Fusion Proteins; D029702:Schizosaccharomyces pombe Proteins; D029867:Xenopus Proteins; C106332:hus1 protein, S pombe; D002110:Caffeine; D005982:Glutathione Transferase; C576898:Atr protein, Xenopus; D064007:Ataxia Telangiectasia Mutated Proteins; D017346:Protein Serine-Threonine Kinases; D004256:DNA Polymerase I