The type of DNA glycosylase determines the base excision repair pathway in mammalian cells
The type of DNA glycosylase determines the base excision repair pathway in mammalian cells
复制标题
DOI：
10.1074/jbc.274.21.15230
复制
发表时间：
1999-05-21
影响因子：
4.8
通讯作者：
Dogliotti, E
中科院分区：
文献类型：
--
作者：
Fortini, P;Parlanti, E;Dogliotti, E
修饰核苷酸的碱基切除修复(BER)是由损伤特异的DNA糖基酶启动的。由此产生的无嘌呤/脱嘧啶位点的修复包括单核苷酸(短斑块BER)或几个核苷酸(长斑块BER)的替换。控制BER途径选择的机制尚不清楚。我们测试了这样的假设，即DNA上存在的碱基损伤类型，通过确定负责其切除的特定DNA糖基酶，驱动产生的基本位置的修复，中间到BER分支。在哺乳动物细胞中，次黄嘌呤(HX)和1，N-6-乙基腺嘌呤(Epsilon A)都是ANPG蛋白的单功能3-甲基腺嘌呤DNA糖基酶的底物，而7，8-二氢-8-氧鸟嘌呤(8-oxoG)则被双功能DNA糖基酶/β-裂解酶8-oxoG-DNA糖基酶(OGG1)去除。构建了含有单一HX、EA或8-oxoG的环状质粒分子。对HeLa细胞提取物的体外修复分析表明，ex和epsilon A都是通过短补片BER和长补片BER修复的，而8-oxoG主要是通过短补片途径修复的。DNA聚合酶β缺陷小鼠细胞对这种损伤的修复效率低于野生型，证实了8-oxoG优先通过短补片BER修复。这些数据符合一个模型，在这个模型中，识别病变的DNA糖基酶的内在属性选择了将恢复完整DNA模板的BER分支。
The base excision repair (BER) of modified nucleotides is initiated by damage-specific DNA glycosylases. The repair of the resulting apurinic/apyrimidinic site involves the replacement of either a single nucleotide (short patch BER) or of several nucleotides (long patch BER). The mechanism that controls the selection of either BER pathway is unknown. We tested the hypothesis that the type of base damage present on DNA, by determining the specific DNA glycosylase in charge of its excision, drives the repair of the resulting abasic site intermediate to either BER branch. In mammalian cells hypoxanthine (HX) and 1,N-6-ethenoadenine (epsilon A) are both substrates for the monofunctional 3-methyladenine DNA glycosylase, the ANPG protein, whereas 7,8-dihydro-8-oxoguanine (8-oxoG) is removed by the bifunctional DNA glycosylase/beta-lyase 8-oxoG-DNA glycosylase (OGG1). Circular plasmid molecules containing a single HX, EA, Or 8-oxoG were constructed. In vitro repair assays with HeLa cell extracts revealed that EX and epsilon A are repaired via both short and long patch BER, whereas 8-oxoG is repaired mainly via the short patch pathway The preferential repair of 8-oxoG by short patch BER was confirmed by the low efficiency of repair of this lesion by DNA polymerase beta-deficient mouse cells as compared with their wild-type counterpart. These data fit into a model where the intrinsic properties of the DNA glycosylase that recognizes the lesion selects the branch of BER that will restore the intact DNA template.