Detection of repair activity during the DNA damage-induced G2 delay in human cancer cells
Detection of repair activity during the DNA damage-induced G2 delay in human cancer cells
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DOI：
10.1038/sj.onc.1204445
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发表时间：
2001-06-14
期刊：
影响因子：
8
通讯作者：
Yen, TJ
中科院分区：
文献类型：
--
作者：
Kao, GD;McKenna, WG;Yen, TJ
所有真核细胞暴露于DNA损伤剂后都表现出细胞周期延迟。有人提出，这种细胞周期检查点可能允许DNA修复，但在辐射诱导的G2延迟期间缺乏这种活动的直接证据。我们在这里报道，在G2中被辐射（2-3 Gy）和依托泊苷捕获的细胞在细胞核的离散灶上结合溴脱氧尿苷（BrdU）。我们检测到在G2细胞中表达最多的核蛋白CENP-F的G2细胞，咖啡因和冈田酸都是已建立的放射增敏剂，可以抑制BrdU在G2细胞中的掺入。与辐射敏感的A2780细胞系相比，耐辐射的HT29和OVCAR细胞在G2延迟期间更频繁地显示BrdU灶形成。G2期间形成的修复病灶可通过有丝分裂延续，并可在G1期的子细胞中观察到。综上所述，这些观察结果与相对低剂量辐射诱导的G2延迟期间DNA修复活性的检测结果一致。
All eukaryotic cells manifest cell cycle delay after exposure to DNA damaging agents. It has been proposed that such cell cycle checkpoints may allow DNA repair but direct evidence of such activity during the radiation-induced G2 delay has been lacking. We report here that cells arrested in G2 by radiation (2-3 Gy) and etoposide incorporate bromodeoxyuridine (BrdU) at discrete foci in the nucleus. We detected G2 cells with CENP-F, a nuclear protein maximally expressed in G2, Caffeine and okadaic acid, both established radiosensitizers, inhibit the incorporation of BrdU in G2 cells. Radioresistant HT29 and OVCAR cells demonstrate BrdU foci formation more frequently during the G2 delay when compared to the more radiosensitive A2780 cell line. The repair foci formed during G2 may be followed through mitosis and observed in daughter cells in G1, Taken together, these observations are consistent with the detection of DNA repair activity during the radiation-induced G2 delay after relatively low doses of radiation.