title: Very late DNA replication in the human cell cycle.
abstract: G2 was defined originally as the temporal gap between the termination of DNA replication and the beginning of mitosis. In human cells, the G2 period was estimated to be 3-4 h. However, the absence of replicative DNA synthesis during this period designated G2 has never been shown conclusively. In this report, we show that, at some autosomal and X linked loci, programmed DNA replication continues within 90 min of mitosis. Furthermore, the major accumulation of cyclin B1, a cell-cycle marker that is usually ascribed to G2, overlaps extensively with very late DNA replication. We conclude that the G2 period is much shorter than previously thought and may, in some cells, be nonexistent.
authors.affiliation: Molecular and Cellular Biology Program of the University of Washington and Fred Hutchinson Cancer Research Center, Seattle, WA 98104, USA. rjwidrow@u.washington.edu
authors.forename: R J
authors.initials: RJ
authors.lastname: Widrow
authors.forename: R S
authors.initials: RS
authors.lastname: Hansen
authors.forename: H
authors.initials: H
authors.lastname: Kawame
authors.forename: S M
authors.initials: SM
authors.lastname: Gartler
authors.forename: C D
authors.initials: CD
authors.lastname: Laird
mesh_terms: D002453:Cell Cycle / Q000502:physiology*; D002460:Cell Line; D019926:Cyclin B / Q000378:metabolism; D056744:Cyclin B1; D004261:DNA Replication / Q000235:genetics*; D005260:Female; D005434:Flow Cytometry; D016195:G2 Phase / Q000502:physiology*; D006801:Humans; D008297:Male; D008938:Mitosis / Q000502:physiology; D016133:Polymerase Chain Reaction; D014960:X Chromosome / Q000235:genetics
chemical_list: C534699:CCNB1 protein, human; D019926:Cyclin B; D056744:Cyclin B1