title: Expression of proliferation-associated antigens (PCNA, p120, p145) during the reentry of G0 cells into the cell cycle.
abstract: Flow cytometric bivariate analysis was used to evaluate the expression of PCNA, p120, and p145 during the G0 reentry of CHO-K1 cells into the cell cycle. CHO-K1 cells were placed in a G0-like state using serum depletion and stimulated to reenter the cell cycle by replating into fresh, serum-containing medium. At discrete intervals after stimulation, replicate samples were stained for either PCNA, p120, or 145; stained for DNA (Coulter DNA-Prep); evaluated on the EPICS Profile I; and analyzed on the EPICS ELITE workstation. PCNA stained less than 10% of the G0 cells; in contrast, however, 30-35% of the G0 cells were positive for p120 and p145. Eight hours after stimulating G0 cells to reenter the cell cycle (during G0/G1), p120 reached 88% positivity, while p145 and PCNA were 63% and 30% positive, respectively. Cells in S phase (12 and 16 h following G0 stimulation) were greater than 90% positive for all three antigens. PCNA had the greatest change throughout the G0 reentry process, both in percentage positive and quantitatively (mean channel fluorescence). This report indicates that all three proliferation-associated antigens studied are differentially expressed during the reentry of G0 cells into the cell cycle. Furthermore, these antigens may be useful in the early detection of G0 recruitment.
authors.affiliation: Coulter Corporation, Miami, Florida 33116.
authors.forename: W E
authors.initials: WE
authors.lastname: Bolton
authors.forename: J W
authors.initials: JW
authors.lastname: Freeman
authors.forename: W R
authors.initials: WR
authors.lastname: Mikulka
authors.forename: C G
authors.initials: CG
authors.lastname: Healy
authors.forename: R J
authors.initials: RJ
authors.lastname: Schmittling
authors.forename: N S
authors.initials: NS
authors.lastname: Kenyon
mesh_terms: D000818:Animals; D001483:Base Sequence; D015415:Biomarkers; D016466:CHO Cells / Q000166:cytology; D002453:Cell Cycle; D002455:Cell Division; D006224:Cricetinae; D005434:Flow Cytometry; D005455:Fluorescent Antibody Technique; D006801:Humans; D007399:Interphase; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000032:analysis*; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma / Q000473:pathology; D018809:Proliferating Cell Nuclear Antigen / Q000032:analysis*; D016196:S Phase; D014407:Tumor Cells, Cultured; D012359:tRNA Methyltransferases
chemical_list: D015415:Biomarkers; D009687:Nuclear Proteins; D018809:Proliferating Cell Nuclear Antigen; C091182:proliferating cell nuclear antigen p145; C065028:NOP2 protein, human; D012359:tRNA Methyltransferases