Inhibition by cytochalasin B of DNA synthesis in a thermosensitive anchorage-independent growth mutant
✍ Scribed by Kiichi Miyashita
- Publisher
- John Wiley and Sons
- Year
- 1987
- Tongue
- English
- Weight
- 993 KB
- Volume
- 131
- Category
- Article
- ISSN
- 0021-9541
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✦ Synopsis
After a shift from a nonpermissive to a permissive temperature, synchronized DNA synthesis and cell division were observed in a cold-sensitive anchorageindependent growth mutant (cs-17-25) of Chinese hamster lung cells in Methocel culture. Only 15 rnin exposure to the permissive temperature was sufficient for induction of DNA synthesis in the cells. A low dose of actinomycin D (0.02 pglml) or cytochalasin B (5 pglml) 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.
Methods
Cell cultures Cells of cs-17-25, a cold-sensitive anchorage-independent mutant isolated from Chinese hamster lung cells (CHL) for growth in soft agar, were grown on lOOmm plastic dishes (Falcon Plastics Co., CA) in a humidified COZ incubator. The culture medium used was Ham's F12 medium (Grand Island Biological Company, NY)