Lack of uncoupling of S phase and mitosis after irradiation in p53- human lymphoblast cell lines.
Lack of uncoupling of S phase and mitosis after irradiation in p53- human lymphoblast cell lines.
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DOI：
10.2307/3579569
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发表时间：
1997-08
影响因子：
3.4
通讯作者：
F. Wenz;Y. Yu;H. Nagasawa;A. Imrich;P. Keng;J. Little
中科院分区：
文献类型：
--
作者：
F. Wenz;Y. Yu;H. Nagasawa;A. Imrich;P. Keng;J. Little
研究表明，p53-人类结直肠癌细胞在DNA损伤后处于g2样状态，然后可能在不干预有丝分裂的情况下进行DNA合成（Waldman等人，Nature 381, 713-716, 1996）。为了进一步阐明p53在G2/ m期检查点调控中的作用，我们研究了三种密切相关的人淋巴母细胞样细胞系（TK6、WTK1和TK6E6，一种HPV16 e6转染的TK6细胞系）p53状态不同的细胞。用含或不含2 mM咖啡因的1.5-12 Gy伽马射线照射细胞。在p53-细胞系、WTK1和TK6E6中没有发现辐照后DNA合成和有丝分裂解偶联的证据，提示这种解偶联可能不是普遍现象。照射p53- WTK1细胞系后，四倍体细胞的明显形成是由于先前存在的四倍体群体中发生了g2期阻滞。这些结果支持了辐照后不同细胞类型对G2/ m期检查点的控制可能不同的结论。
It has been shown that p53- human colorectal cancer cells arrest after DNA damage in a G2-like state and may then undergo DNA synthesis without intervening mitosis (Waldman et al., Nature 381, 713-716, 1996). To further clarify the role of p53 in the regulation of the G2/M-phase checkpoint, we have studied cells of three closely related human lymphoblastoid cell lines (TK6, WTK1 and TK6E6, an HPV16 E6-transfected TK6 line) with differing p53 status. The cells were irradiated with 1.5-12 Gy gamma rays with or without 2 mM caffeine. There was no evidence of uncoupling of DNA synthesis and mitosis after irradiation in the p53- cell lines, WTK1 and TK6E6, suggesting that this uncoupling may not be a universal phenomenon. The apparent formation of tetraploid cells after irradiation of cells of the p53- WTK1 line was due to the occurrence of a G2-phase block in a pre-existing tetraploid population. These results support the conclusion that control of the G2/M-phase checkpoint after irradiation may differ among different cell types.