Replication of 2-hydroxyadenine-containing DNA and recognition by human MutSα
Replication of 2-hydroxyadenine-containing DNA and recognition by human MutSα
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DOI：
10.1016/j.dnarep.2006.11.002
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发表时间：
2007-03-01
期刊：
影响因子：
3.8
通讯作者：
Bignami, Margherita
中科院分区：
文献类型：
--
作者：
Barone, Flavia;McCulloch, Scott D.;Bignami, Margherita
2-羟基腺嘌呤（2-OH-A）是DNA氧化的产物，是突变的潜在来源。我们研究了来自A、B和Y家族的代表性DNA聚合酶如何在引物延伸实验中处理2-OH-A。模板2-OH-A降低了DNA聚合酶α（Pol α）和Klenow片段（Kf（exo-））的掺入率。两个Y家族DNA聚合酶，人类聚合酶eta（Pol eta）和古细菌Dpo 4聚合酶受到不同的影响。通过Pol eta的旁路是非常低效的，而Dpo 4有效地复制2-OH-A。复制的模板2-OH-A的两种酶是致突变的，并引起碱基取代。dpo 4还引入了单碱基缺失。热力学分析表明，2-OH-A与T、C和G形成稳定的碱基对，并在较小程度上与A形成稳定碱基对。含有2-OH-A碱基对的寡核苷酸，包括优选的2-OH-A：T，被人MutS α错配修复（MMR）识别。MutS alpha还识别位于重复序列中的2-OH-A，其模拟移码中间体。(c)2006 Elsevier B. V.保留所有权利。
2-Hydroxyadenine (2-OH-A), a product of DNA oxidation, is a potential source of mutations. We investigated how representative DNA polymerases from the A, B and Y families dealt with 2-OH-A in primer extension experiments. A template 2-OH-A reduced the rate of incorporation by DNA polymerase alpha (Pol alpha) and Klenow fragment (Kf(exo-)). Two Y family DNA polymerases, human polymerase eta (Pol eta) and the archeal Dpo4 polymerase were affected differently. Bypass by Pol eta was very inefficient whereas Dpo4 efficiently replicated 2-OH-A. Replication of a template 2-OH-A by both enzymes was mutagenic and caused base substitutions. Dpo4 additionally introduced single base deletions. Thermodynamic analysis showed that 2-OH-A forms stable base pairs with T, C and G, and to a lesser extent with A. Oligonucleotides containing 2-OH-A base pairs, including the preferred 2-OH-A:T, were recognized by the human MutS alpha mismatch repair (MMR). MutS alpha also recognized 2-OH-A located in a repeat sequence that mimics a frameshift intermediate. (c) 2006 Elsevier B.V. All rights reserved.