Prolongation of duration of G2 arrest delays and finally blocks entry into M phase in contrast to stable and reversible G1 arrest: Study of a G1/G2 temperature-sensitive mutant of rat 3Y1 fibroblasts
✍ Scribed by Hirokazu Zaitsu; Genki Kimura
- Publisher
- John Wiley and Sons
- Year
- 1985
- Tongue
- English
- Weight
- 529 KB
- Volume
- 124
- Category
- Article
- ISSN
- 0021-9541
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✦ Synopsis
Proliferation of 3YltsF121 cells was arrested in GI and G2 phases after a shift up to 3 9 P C (restrictive temperature). Both arrests were reversible: after a shift down to 33.8OC (permissive temperature), these cells effectively entered the next phases. However, the entry into M phase of the G2-arrested cells was delayed depending on the time in arrest. The GZarrested cells finally became incapable of entering M phase with a prolonged incubation at 39.8OC. Under the same condition, GI-arrested cells did not lose their ability to proliferate, and their delay of entry into S phase was slight. Therefore, cells in G2 phase are, in a sense, more unstable than the cells in GI phase. These results also suggest that the time required for entry into M phase may depend on the preparedness for the initiation of M phase and, that it may be prolonged under the condition where the preparedness for entry into M phase is diminished.