AlkB homologue 2-mediated repair of ethenoadenine lesions in mammalian DNA
AlkB homologue 2-mediated repair of ethenoadenine lesions in mammalian DNA
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DOI：
10.1158/0008-5472.can-08-0796
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发表时间：
2008-06-01
期刊：
影响因子：
11.2
通讯作者：
Klungland, Arne
中科院分区：
文献类型：
--
作者：
Ringvoll, Jeanette;Moen, Marivi N.;Klungland, Arne
诱变DNA加合物1，n -6-乙烯腺嘌呤（epsilon A）的内源性形成源于脂质过氧化。在癌症易发组织中，A的升高水平表明这种加合物在某些癌症的发展中起作用。碱基切除修复途径一直被认为是epsilon A病变的主要修复系统，直到最近，研究表明大肠杆菌AlkB双加氧酶可以直接逆转这种损伤。我们在此报告了重组人AlkB同源物2 （hABH2）的动力学分析，它能够修复DNA中的epsilon A损伤。此外，野生型和mABH2（-/-）小鼠核提取物的阳离子交换层析表明，mABH2是体内EA修复的主要双加氧酶。实验进一步证实了这一点，表明hABH2而不是hABH3能够弥补大肠杆菌alkB突变体对乙二烯加合物的修复缺陷。我们得出结论，ABH2在epsilon A损伤的直接逆转中是活跃的，并且ABH2与烷基- n -腺嘌呤- dna糖基酶（修复epsilon A最有效的酶）一起构成了对epsilon A损伤的细胞防御。
Endogenous formation of the mutagenic DNA adduct 1,N-6-ethenoadenine (epsilon A) originates from lipid peroxidation. Elevated levels of epsilon A in cancer-prone tissues suggest a role for this adduct in the development of some cancers. The base excision repair pathway has been considered the principal repair system for epsilon A lesions until recently, when it was shown that the Escherichia coli AlkB dioxygenase could directly reverse the damage. We report here kinetic analysis of the recombinant human AlkB homologue 2 (hABH2), which is able to repair epsilon A lesions in DNA. Furthermore, cation exchange chromatography of nuclear extracts from wild-type and mABH2(-/-) mice indicates that mABH2 is the principal dioxygenase for EA repair in vivo. This is further substantiated by experiments showing that hABH2, but not hABH3, is able to complement the E. coli alkB mutant with respect to its defective repair of etheno adducts. We conclude that ABH2 is active in the direct reversal of epsilon A lesions, and that ABH2, together with the alkyl-N-adenine-DNA glycosylase, which is the most effective enzyme for the repair of epsilon A, comprise the cellular defense against epsilon A lesions.