title: Two steps in the assembly of complexes at yeast replication origins in vivo.
abstract: The integration of chromosomal DNA replication into the eukaryotic cell cycle might involve temporal regulation of interactions between cellular factors and replication origins. We show here that yeast replication origins exist in two chromatin states during the cell cycle. In the postreplicative state, genomic footprints closely resemble those produced in vitro by the purified ORC and ABF1 proteins, indicating that the binding of these proteins to replication origins is not sufficient to drive the initiation of DNA replication. The prereplicative state is characterized by an additional region of protection overlapping the ORC footprint. This prereplicative complex appears near the end of mitosis and persists through G1. After entry into S phase, origins return to the postreplicative state. Similarities in temporal regulation of the prereplicative state and the Xenopus licensing factor suggest that mechanisms limiting DNA replication to once per cell cycle may be conserved among eukaryotes.
authors.affiliation: Imperial Cancer Research Fund, Clare Hall Laboratories, South Mimms, Hertfordshire, England.
authors.forename: J F
authors.initials: JF
authors.lastname: Diffley
authors.forename: J H
authors.initials: JH
authors.lastname: Cocker
authors.forename: S J
authors.initials: SJ
authors.lastname: Dowell
authors.forename: A
authors.initials: A
authors.lastname: Rowley
mesh_terms: D001483:Base Sequence; D002453:Cell Cycle / Q000235:genetics / Q000502:physiology; D002843:Chromatin / Q000378:metabolism; D004261:DNA Replication / Q000502:physiology*; D004271:DNA, Fungal / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000378:metabolism*; D005656:Fungal Proteins / Q000378:metabolism*; D008954:Models, Biological; D008969:Molecular Sequence Data; D009154:Mutation / Q000502:physiology; D051738:Origin Recognition Complex; D011485:Protein Binding; D012097:Repressor Proteins / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000166:cytology / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins; D013696:Temperature; D014157:Transcription Factors
chemical_list: C061886:ABF1 protein, S cerevisiae; D002843:Chromatin; D004271:DNA, Fungal; D004268:DNA-Binding Proteins; D005656:Fungal Proteins; D051738:Origin Recognition Complex; D012097:Repressor Proteins; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors