Cloning and characterization of a mammalian 8-oxoguanine DNA glycosylase
Cloning and characterization of a mammalian 8-oxoguanine DNA glycosylase
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DOI：
10.1073/pnas.94.14.7429
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发表时间：
1997-07-08
影响因子：
11.1
通讯作者：
Grollman, AP
中科院分区：
文献类型：
--
作者：
Rosenquist, TA;Zharkov, DO;Grollman, AP
DNA 氧化损伤是由活性氧产生的。通过碱基切除修复，从氧化损伤的 DNA 中去除由此过程形成的诱变碱基 8-氧代鸟嘌呤。据报道，细菌和酵母中存在编码识别 8-氧代鸟嘌呤的 DNA 修复酶的基因。我们已经鉴定并鉴定了编码酿酒酵母 8-氧代鸟嘌呤 DNA 糖基化酶 (ogg1) 基因同源物的小鼠和人类 cDNA。 mutM 和 mutY 的双突变大肠杆菌具有突变表型，并且缺乏 8-氧代鸟嘌呤修复。重组小鼠基因 (mOgg1) 抑制 mutY/mutM 大肠杆菌的突变表型。从表达 mOgg1 的 mutY/mutM 大肠杆菌中制备的提取物含有从 DNA 中切除 8-氧代鸟嘌呤的活性和在病变部位 3' 处切割 DNA 的 β 裂解酶活性。小鼠 ogg1 基因产物对 7,8-二羟基-8-氧代-2'-脱氧鸟苷 (8-oxodG) 与 dC 配对的 DNA 双链体有效作用，对 8-oxodG 与 dT 或 dG 配对的双链体作用较弱，而对 8-oxodG 与 dA 配对的双链体无活性。小鼠和人类 ogg1 基因含有螺旋-发夹-螺旋结构基序，具有最近定义的 DNA 糖基化酶家族的保守残基特征。 Ogg1 mRNA 在多种小鼠组织中表达；在睾丸中检测到最高水平。小鼠 ogg1 基因的分离使得调节其在小鼠体内的表达并探索氧化 DNA 的参与成为可能。衰老和癌症中的损伤和相关修复过程。
Oxidative DNA damage is generated by reactive oxygen species. The mutagenic base, 8-oxoguanine, formed by this process, is removed from oxidatively damaged DNA by base excision repair. Genes coding for DNA repair enzymes that recognize 8-oxoguanine have been reported in bacteria and yeast. We have identified and characterized mouse and human cDNAs encoding homologs of the 8-oxoguanine DNA glycosylase (ogg1) gene of Saccharomyces cerevisiae. Escherichia coli doubly mutant for mutM and mutY have a mutator phenotype and are deficient in 8-oxoguanine repair. The recombinant mouse gene (mOgg1) suppresses the mutator phenotype of mutY/mutM E. coli. Extracts prepared from mutY/mutM E. coli expressing mOgg1 contain an activity that excises 8-oxoguanine from DNA and a beta-lyase activity that nicks DNA 3' to the lesion. The mouse ogg1 gene product acts efficiently on DNA duplexes in which 7,8-dihydroxy-8-oxo-2'-deoxyguanosine (8-oxodG) is paired with dC, acts weakly on duplexes in which 8-oxodG is paired with dT or dG, and is inactive against duplexes in which 8-oxodG is paired with dA. Mouse and human ogg1 genes contain a helix-hairpin-helix structural motif with conserved residues characteristic of a recently defined family of DNA glycosylases. Ogg1 mRNA is expressed in several mouse tissues; highest levels were detected in testes. Isolation of the mouse ogg1 gene makes it possible to modulate its expression in mice and to explore the involvement of oxidative DNA. damage and associated repair processes in aging and cancer.