Relationship of the xeroderma pigmentosum group E DNA repair defect to the chromatin and DNA binding proteins UV-DDB and replication protein A
Relationship of the xeroderma pigmentosum group E DNA repair defect to the chromatin and DNA binding proteins UV-DDB and replication protein A
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DOI：
10.1128/mcb.18.6.3182
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发表时间：
1998-06-01
影响因子：
5.3
通讯作者：
Wood, RD
中科院分区：
文献类型：
--
作者：
Otrin, VR;Kuraoka, I;Wood, RD
遗传性日光敏感性疾病着色性干皮病（XP）的互补组A至G的细胞在受损DNA的核苷酸切除修复中显示出缺陷。代表组A、B、C、D、F和G的蛋白质是核心识别和修复切割机制的亚基。XP组E（XP-E）是最轻微的疾病形式，细胞通常显示约50%的正常修复水平。我们研究了先前与XP-E缺陷有关的两种蛋白质因子，UV损伤DNA结合蛋白（UV-DDB）和复制蛋白A（RPA），（XP 23 PV、XP 25 PV和以前分类为XP变体的品系）在UV-DDB结合活性上有缺陷，但RPA水平在正常范围内。XP-E细胞提取物没有显示出显着的核苷酸切除修复缺陷，在体外，无论是紫外线照射的DNA或一个独特的放置顺铂病变作为底物。纯化的UV-DDB蛋白不能促进DDB-XP-E细胞提取物对裸DNA的修复，但将该蛋白显微注射到DDB-XP-E细胞中可部分纠正该修复缺陷。RPA在正常、XP-E或来自其他XP组的补充提取物中刺激修复，因此RPA的作用对XP-E细胞提取物没有特异性。这些数据加强了XP-E和UV-DDB之间的联系，加上以前的结果，研究结果表明UV-DDB在染色质中的DNA修复中具有作用。
Cells from complementation groups A through G of the heritable sun-sensitive disorder xeroderma pigmentosum (XP) show defects in nucleotide excision repair of damaged DNA, Proteins representing groups A, B, C, D, F, and G are subunits of the core recognition and incision machinery of repair. XP group E (XP-E) is the mildest form of the disorder, and cells generally show about 50% of the normal repair level, We investigated two protein factors previously implicated in the XP-E defect, UV-damaged DNA binding protein (UV-DDB) and replication protein A (RPA), Three newly identified XP-E cell lines (XP23PV, XP25PV, and a line formerly classified as an XP variant) were defective in UV-DDB binding activity but had levels of RPA in the normal range. The XP-E cell extracts did not display a significant nucleotide excision repair defect in vitro, with either UV-irradiated DNA or a uniquely placed cisplatin lesion used as a substrate. Purified UV-DDB protein did not stimulate repair of naked DNA by DDB- XP-E cell extracts, but microinjection of the protein into DDB- XP-E cells could partially correct the repair defect. RPA stimulated repair in normal, XP-E, or complemented extracts from other XP groups, and so the effect of RPA was not specific for XP-E cell extracts. These data strengthen the connection between XP-E and UV-DDB, Coupled with previous results, the findings suggest that UV-DDB has a role in the repair of DNA in chromatin.