title: Inhibition by cytochalasin B of DNA synthesis in a thermosensitive anchorage-independent growth mutant.
abstract: After a shift from a nonpermissive to a permissive temperature, synchronized DNA synthesis and cell division were observed in a cold-sensitive anchorage-independent growth mutant (cs-17-25) of Chinese hamster lung cells in Methocel culture. Only 15 min exposure to the permissive temperature was sufficient for induction of DNA synthesis in the cells. A low dose of actinomycin D (0.02 micrograms/ml) or cytochalasin B (5 micrograms/ml) was able to inhibit the DNA synthesis when added at an early period after the temperature shift. The inhibitory effects of actinomycin D and cytochalasin B on RNA and protein synthesis were very similar at both temperatures. The degree of multinucleation caused by cytochalasin B was altered quickly depending on the incubation temperature. These results suggest that stimulation of this mutant involves an obligatory actin-mediated step closely correlated to transcription of early mRNAs.
mesh_terms: D000199:Actins / Q000502:physiology; D000818:Animals; D002455:Cell Division / Q000187:drug effects; D002478:Cells, Cultured; D003078:Colchicine / Q000494:pharmacology; D006224:Cricetinae; D003412:Cricetulus; D003571:Cytochalasin B / Q000494:pharmacology*; D004247:DNA / Q000037:antagonists & inhibitors / Q000096:biosynthesis* / Q000187:drug effects; D003609:Dactinomycin / Q000494:pharmacology; D008168:Lung / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism; D009154:Mutation; D012313:RNA / Q000187:drug effects / Q000378:metabolism; D013696:Temperature
chemical_list: D000199:Actins; D003609:Dactinomycin; D003571:Cytochalasin B; D012313:RNA; D004247:DNA; D003078:Colchicine