Cell cycle dependence of transformation expression in mouse cells transformed by a thermosensitive mutant (Ts-121) of polyoma virus

✍ Scribed by Yasuhiro S. Okada; Akira Hakura

• Publisher: John Wiley and Sons
• Year: 1979
• Tongue: English
• Weight: 675 KB
• Volume: 100
• Category: Article
• ISSN: 0021-9541
• DOI: 10.1002/jcp.1041000207

✦ Synopsis

Abstract

Change in division capability as a phenotypic expression of cellular transformation was investigated by using one of the temperature‐sensitive (ts) mutants of the polyoma virus‐transformed cell line, the 121‐6‐5 cells of BALB/3T3. When contact ‐inhibited cells were treated with hyaluronidase at 39°C, a single round of cell division was induced after which cell growth was inhibited by cell density. However, if the cells were incubated at 35°C, after the enzyme treatment, density‐inhibition block disappeared and the cells entered a second division. This indicates that the release of cells from density‐inhibition depends on the low temperature incubation. The ability of cells to complete a second division was examined by shifting the cells from 39°C to 35°C during different phases of the first division cycle after the enzyme‐treatment. A 6‐hour incubation of S phase cells at 35°C resulted in a second cycle of division, while the 24‐hour incubation of G1 cells at 35°C did not induce a second round of division. These results suggest that expression of the transformed phenotype in 121‐6‐5 cells is clearly dependent upon both the temperature and the phase of the division cycle.