PREMATURE CHROMOSOME CONDENSATION IN A TS DNA-MUTANT OF BHK CELLS
PREMATURE CHROMOSOME CONDENSATION IN A TS DNA-MUTANT OF BHK CELLS
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DOI：
10.1016/0092-8674(78)90017-x
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发表时间：
1978-01-01
期刊：
影响因子：
64.5
通讯作者：
BASILICO, C
中科院分区：
文献类型：
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作者：
NISHIMOTO, T;EILEN, E;BASILICO, C
BHK的一个温度敏感突变体，命名为ts BN-2，当异步培养从33.5度移位时，随着细胞周期中G1期细胞的积累，~3H-胸腺嘧啶核苷的参入率迅速下降。C到39.5度的不允许温度。同步化培养的ts BN-2细胞在G1期上移时不进入DNA合成。在S期开始的培养上移导致DNA合成速率基本正常，持续约2小时，然后DNA合成速率迅速下降，在完成约0.5轮DNA复制后，细胞在S中期停止生长。大多数细胞失去核膜，出现过早的染色体凝聚。观察到含有多个微核的细胞，随后出现细胞破裂和死亡。在允许的条件下，不允许的温度对DNA短片段的伸长和S相完成后有丝分裂的执行都没有明显的影响。TS缺陷可能直接限制DNA合成的启动或改变染色质缩合的调节。
A temperature-sensitive mutant of BHK [baby hamster kidney], designated ts BN-2, shows a rapid drop in 3H-thymidine incorporation along with accumulation of the cells in the G1 phase of the cycle when asynchronous cultures are shifted from 33.5.degree. C to the nonpermissive temperature of 39.5.degree. C. Synchronized cultures of ts BN-2 cells did not enter DNA synthesis when shifted up in G1. Shift-up of cultures at the beginning of the S phase resulted in an approximately normal rate of DNA synthesis for about 2 h. The rate of DNA synthesis then quickly declined, and the cells became arrested in mid-S after completion of approximately 0.5 rounds of DNA replication. The majority of cells lost the nuclear membrane and displayed premature chromosome condensation. Cells containing several micronuclei were observed and cell disruption and death ensued. The nonpermissive temperature apparently had no effect on either the elongation of short fragments of DNA or the execution of mitosis after the completion of the S phase under permissive conditions. The ts defect may directly limit the initiation of DNA synthesis or alter the regulation of chromatin condensation.