title: Initiation and termination of DNA replication during S phase in relation to cyclins D1, E and A, p21WAF1, Cdt1 and the p12 subunit of DNA polymerase δ revealed in individual cells by cytometry.
abstract: During our recent studies on mechanism of the regulation of human DNA polymerase δ in preparation for DNA replication or repair, multiparameter imaging cytometry as exemplified by laser scanning cytometry (LSC) has been used to assess changes in expression of the following nuclear proteins associated with initiation of DNA replication: cyclin A, PCNA, Ki-67, p21(WAF1), DNA replication factor Cdt1 and the smallest subunit of DNA polymerase δ, p12. In the present review, rather than focusing on Pol δ, we emphasize the application of LSC in these studies and outline possibilities offered by the concurrent differential analysis of DNA replication in conjunction with expression of the nuclear proteins. A more extensive analysis of the data on a correlation between rates of EdU incorporation, likely reporting DNA replication, and expression of these proteins, is presently provided. New data, specifically on the expression of cyclin D1 and cyclin E with respect to EdU incorporation as well as on a relationship between expression of cyclin A vs. p21(WAF1) and Ki-67 vs. Cdt1, are also reported. Of particular interest is the observation that this approach makes it possible to assess the temporal sequence of degradation of cyclin D1, p21(WAF1), Cdt1 and p12, each with respect to initiation of DNA replication and with respect to each other. Also the sequence or reappearance of these proteins in G2 after termination of DNA replication is assessed. The reviewed data provide a more comprehensive presentation of potential markers, whose presence or absence marks the DNA replicating cells. Discussed is also usefulness of these markers as indicators of proliferative activity in cancer tissues that may bear information on tumor progression and have a prognostic value.
authors.affiliation: Brander Cancer Research Institute, Department of Pathology, New York Medical College, Valhalla, NY.
authors.forename: Zbigniew
authors.initials: Z
authors.lastname: Darzynkiewicz
authors.affiliation: Brander Cancer Research Institute, Department of Pathology, New York Medical College, Valhalla, NY.
authors.forename: Hong
authors.initials: H
authors.lastname: Zhao
authors.affiliation: Department of Biochemistry and Molecular Biology, New York Medical College, Valhalla, NY.
authors.forename: Sufang
authors.initials: S
authors.lastname: Zhang
authors.affiliation: Department of Biochemistry and Molecular Biology, New York Medical College, Valhalla, NY.
authors.forename: Marietta Y W T
authors.initials: MY
authors.lastname: Lee
authors.affiliation: Department of Biochemistry and Molecular Biology, New York Medical College, Valhalla, NY.
authors.forename: Ernest Y C
authors.initials: EY
authors.lastname: Lee
authors.affiliation: Department of Biochemistry and Molecular Biology, New York Medical College, Valhalla, NY.
authors.forename: Zhongtao
authors.initials: Z
authors.lastname: Zhang
mesh_terms: D000818:Animals; D018797:Cell Cycle Proteins / Q000378:metabolism; D019925:Cyclin A / Q000378:metabolism; D019938:Cyclin D1 / Q000378:metabolism; D019927:Cyclin E / Q000378:metabolism; D050759:Cyclin-Dependent Kinase Inhibitor p21 / Q000378:metabolism; D004258:DNA Polymerase III / Q000378:metabolism; D004261:DNA Replication / Q000502:physiology*; D006801:Humans; D047569:Laser Scanning Cytometry / Q000379:methods*; D016196:S Phase / Q000502:physiology*
chemical_list: C493956:CDKN1A protein, human; C467199:CDT1 protein, human; D018797:Cell Cycle Proteins; D019925:Cyclin A; D019927:Cyclin E; D050759:Cyclin-Dependent Kinase Inhibitor p21; D019938:Cyclin D1; C521101:POLD4 protein, human; D004258:DNA Polymerase III
keywords: DNA replication; EdU labeling; S-phase; cell cycle; cell proliferation; laser scanning cytometry; polymerase δ