Cooper P K, Nouspikel T, Clarkson S G, Leadon S A
Life Sciences Division, Building 934, Lawrence Berkeley National Laboratory, University of California, 1 Cyclotron Road, Berkeley, CA 94720, USA.
Science. 1997 Feb 14;275(5302):990-3. doi: 10.1126/science.275.5302.990.
In normal human cells, damage due to ultraviolet light is preferentially removed from active genes by nucleotide excision repair (NER) in a transcription-coupled repair (TCR) process that requires the gene products defective in Cockayne syndrome (CS). Oxidative damage, including thymine glycols, is shown to be removed by TCR in cells from normal individuals and from xeroderma pigmentosum (XP)-A, XP-F, and XP-G patients who have NER defects but not from XP-G patients who have severe CS. Thus, TCR of oxidative damage requires an XPG function distinct from its NER endonuclease activity. These results raise the possibility that defective TCR of oxidative damage contributes to the developmental defects associated with CS.
在正常人类细胞中，紫外线造成的损伤在转录偶联修复（TCR）过程中通过核苷酸切除修复（NER）优先从活性基因中去除，该过程需要科凯恩综合征（CS）中存在缺陷的基因产物。包括胸腺嘧啶乙二醇在内的氧化损伤在正常个体以及患有NER缺陷的着色性干皮病（XP）-A、XP-F和XP-G患者的细胞中可通过TCR去除，但在患有严重CS的XP-G患者细胞中则不能。因此，氧化损伤的TCR需要一种不同于其NER内切核酸酶活性的XPG功能。这些结果增加了氧化损伤的TCR缺陷导致与CS相关的发育缺陷的可能性。
