poliota, a remarkably error-prone human DNA polymerase.
poliota, a remarkably error-prone human DNA polymerase.
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DOI：
10.1101/gad.14.13.1642
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发表时间：
2000-07
影响因子：
10.5
通讯作者：
A. Tissier;J. McDonald;E. G. Frank;R. Woodgate
中科院分区：
文献类型：
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作者：
A. Tissier;J. McDonald;E. G. Frank;R. Woodgate
酿酒酵母RAD 30基因编码DNA聚合酶eta。人类有两种Rad 30同系物。一种（RAD 30 A/POLH）先前已被表征并显示在人类中具有着色性干皮病变体表型的缺陷。在这里，我们报告的实验表明，第二个人类同系物（RAD 30 B），也编码一种新的DNA聚合酶，我们指定脊髓灰质炎。脊髓灰质炎是一种分布性酶，在复制未受损的DNA时极易出错。在模板G或C，平均错误频率约为1 × 10（-2）。然而，我们的研究揭示了模板A和T的错误掺入频率的显著不对称性。例如，模板A以最高的准确度复制，G、A或C的错误掺入发生的频率约为1 × 10（-4）至2 × 10（-4）。与此形成鲜明对比的是，大多数错误发生在模板T上，事实上，G的错误掺入比正确的核苷酸A的错误掺入约为3：1，T的错误掺入发生频率约为6.7 x 10（-1）。这些研究结果表明，脊髓灰质炎是迄今为止报道的最容易出错的真核聚合酶之一，并在体外表现出不寻常的错误掺入谱。
The Saccharomyces cerevisiae RAD30 gene encodes DNA polymerase eta. Humans possess two Rad30 homologs. One (RAD30A/POLH) has previously been characterized and shown to be defective in humans with the Xeroderma pigmentosum variant phenotype. Here, we report experiments demonstrating that the second human homolog (RAD30B), also encodes a novel DNA polymerase that we designate poliota. poliota, is a distributive enzyme that is highly error-prone when replicating undamaged DNA. At template G or C, the average error frequency was approximately 1 x 10(-2). Our studies revealed, however, a striking asymmetry in misincorporation frequency at template A and T. For example, template A was replicated with the greatest accuracy, with misincorporation of G, A, or C occurring with a frequency of approximately 1 x 10(-4) to 2 x 10(-4). In dramatic contrast, most errors occurred at template T, where the misincorporation of G was, in fact, favored approximately 3:1 over the correct nucleotide, A, and misincorporation of T occurred at a frequency of approximately 6.7 x 10(-1). These findings demonstrate that poliota is one of the most error-prone eukaryotic polymerases reported to date and exhibits an unusual misincorporation spectrum in vitro.