Error-free and error-prone lesion bypass by human DNA polymerase kappa in vitro.
Error-free and error-prone lesion bypass by human DNA polymerase kappa in vitro.
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DOI：
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发表时间：
2000
影响因子：
14.9
通讯作者：
Y. Zhang;F. Yuan;X. Wu;M. Wang;O. Rechkoblit;J. Taylor;N. Geacintov;Z. Wang
中科院分区：
文献类型：
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作者：
Y. Zhang;F. Yuan;X. Wu;M. Wang;O. Rechkoblit;J. Taylor;N. Geacintov;Z. Wang
无错误病变旁路和易错病变旁路是复制过程中对DNA损伤的重要细胞反应，这两者都需要DNA聚合酶（Pol）。为了鉴定病变旁路DNA聚合酶，我们纯化了由DINB 1基因编码的人Polkappa，并检测了其对受损DNA模板的反应。在这里，我们表明，人类Polkappa是一种新的病变旁路聚合酶在体外。纯化的人Polkappa有效地绕过了模板8-氧代鸟嘌呤，主要结合A和较少的C相对的病变。人类Polkappa最常掺入A，与模板脱碱基位点相对。有效的进一步延伸需要T作为下一个模板碱基，并且主要由一个核苷酸缺失机制介导。人类Polkappa能够绕过DNA中的乙酰氨基芴修饰的G，掺入C或T，而相对于病变的A效率较低。此外，人Polkappa有效地绕过模板（-）-反式-抗-苯并[a]芘-N：（2）-dG损伤，在一个错误的方式，通过纳入一个C相反的庞大的加合物。相比之下，人类Polkappa无法绕过模板TT二聚体或TT（6-4）光产物，这是两种主要的UV损伤。这些结果表明，Polkappa在人类无错误和易出错病变旁路中起着重要作用。
Error-free lesion bypass and error-prone lesion bypass are important cellular responses to DNA damage during replication, both of which require a DNA polymerase (Pol). To identify lesion bypass DNA polymerases, we have purified human Polkappa encoded by the DINB1 gene and examined its response to damaged DNA templates. Here, we show that human Polkappa is a novel lesion bypass polymerase in vitro. Purified human Polkappa efficiently bypassed a template 8-oxoguanine, incorporating mainly A and less frequently C opposite the lesion. Human Polkappa most frequently incorporated A opposite a template abasic site. Efficient further extension required T as the next template base, and was mediated mainly by a one-nucleotide deletion mechanism. Human Polkappa was able to bypass an acetylaminofluorene-modified G in DNA, incorporating either C or T, and less efficiently A opposite the lesion. Furthermore, human Polkappa effectively bypassed a template (-)-trans-anti-benzo[a]pyrene-N:(2)-dG lesion in an error-free manner by incorporating a C opposite the bulky adduct. In contrast, human Polkappa was unable to bypass a template TT dimer or a TT (6-4) photoproduct, two of the major UV lesions. These results suggest that Polkappa plays an important role in both error-free and error-prone lesion bypass in humans.