Houtsmuller A B, Rademakers S, Nigg A L, Hoogstraten D, Hoeijmakers J H, Vermeulen W
Department of Pathology (Josephine Nefkens Institute, Erasmus University, Post Office Box 1738, 3000 DR Rotterdam, Netherlands.
Science. 1999 May 7;284(5416):958-61. doi: 10.1126/science.284.5416.958.
To study the nuclear organization and dynamics of nucleotide excision repair (NER), the endonuclease ERCC1/XPF (for excision repair cross complementation group 1/xeroderma pigmentosum group F) was tagged with green fluorescent protein and its mobility was monitored in living Chinese hamster ovary cells. In the absence of DNA damage, the complex moved freely through the nucleus, with a diffusion coefficient (15 +/- 5 square micrometers per second) consistent with its molecular size. Ultraviolet light-induced DNA damage caused a transient dose-dependent immobilization of ERCC1/XPF, likely due to engagement of the complex in a single repair event. After 4 minutes, the complex regained mobility. These results suggest (i) that NER operates by assembly of individual NER factors at sites of DNA damage rather than by preassembly of holocomplexes and (ii) that ERCC1/XPF participates in repair of DNA damage in a distributive fashion rather than by processive scanning of large genome segments.
为了研究核苷酸切除修复（NER）的核组织和动力学，用绿色荧光蛋白标记核酸内切酶ERCC1/XPF（切除修复交叉互补组1/着色性干皮病F组），并在活的中国仓鼠卵巢细胞中监测其移动性。在没有DNA损伤的情况下，该复合物在细胞核中自由移动，其扩散系数（每秒15±5平方微米）与其分子大小一致。紫外线诱导的DNA损伤导致ERCC1/XPF短暂的剂量依赖性固定，这可能是由于该复合物参与了单个修复事件。4分钟后，该复合物恢复移动性。这些结果表明：（i）NER通过在DNA损伤位点组装单个NER因子起作用，而不是通过全复合物的预组装；（ii）ERCC1/XPF以分布式方式参与DNA损伤修复，而不是通过对大基因组片段进行连续性扫描。
