title: Epidermal growth factor has a unique effect in combination with fetal bovine serum to bypass the ts-block of G0-specific ts mutant tsJT60.
abstract: tsJT60 cells are G0-specific temperature-sensitive mutants of the cell cycle from Fischer rats i.e., they grow exponentially at both 34 degrees and 39.5 degrees C, but when stimulated with fetal bovine serum (FBS) from the resting state (G0) they enter S phase at 34 degrees C but not at 39.5 degrees C. Epidermal growth factor (EGF) also induced DNA synthesis, although weakly, in G0-arrested tsJT60 cells at 34 degrees C but failed at 39.5 degrees C. When G0-arrested tsJT60 cells were stimulated at 39.5 degrees C with FBS plus EGF, they entered S phase and divided. Somatomedin C, insulin, or transferrin had a weak effect in inducing DNA synthesis in G0-arrested cells when applied at 34 degrees C or with FBS at 39.5 degrees C. Fibroblast growth factor, platelet-derived growth factor, or 12-O-tetradecanoylphorbol 13-acetate had no such stimulatory effect at 39.5 degrees C. Binding of 125I-somatomedin C was not temperature-sensitive. Several other ts mutant cells that were blocked at 39.5 degrees C from entering S phase from the resting state following FBS addition were stimulated by FBS plus EGF at 34 degrees C but not at 39.5 degrees C.
mesh_terms: D000818:Animals; D001769:Blood; D002455:Cell Division; D002460:Cell Line; D003470:Culture Media; D004247:DNA / Q000096:biosynthesis; D004815:Epidermal Growth Factor / Q000494:pharmacology*; D006133:Growth Substances / Q000494:pharmacology; D007334:Insulin-Like Growth Factor I / Q000378:metabolism; D007399:Interphase; D007700:Kinetics; D009154:Mutation; D051381:Rats; D013696:Temperature
chemical_list: D003470:Culture Media; D006133:Growth Substances; D004815:Epidermal Growth Factor; D007334:Insulin-Like Growth Factor I; D004247:DNA