Error-prone bypass patch by a low-fidelity variant of DNA polymerase zeta in human cells
Error-prone bypass patch by a low-fidelity variant of DNA polymerase zeta in human cells
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DOI：
10.1016/j.dnarep.2021.103052
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发表时间：
2021-02-17
期刊：
影响因子：
3.8
通讯作者：
Nohmi, Takehiko
中科院分区：
文献类型：
--
作者：
Suzuki, Tetsuya;Sassa, Akira;Nohmi, Takehiko
DNA聚合酶zeta（Pol zeta）是一种参与跨损伤DNA合成（translesion DNA synthesis，TLS）的特异性Pol，特别是在绕过DNA损伤后引物DNA的延伸中。之前，我们建立了表达Pol zeta变体形式的人类细胞，其中催化亚基REV 3L中的亮氨酸2618变为甲硫氨酸（L2618 M）（DNA Repair，45，34-43，2016）。这种氨基酸的改变使细胞对苯并[a]芘二醇环氧化物（BPDE）的致突变性更敏感。在这项研究中，我们将BPDE-N-2 -鸟嘌呤嵌入穿梭质粒上supF基因的确定位置，并将其引入REV 3 L2618 M细胞或野生型（WT）细胞，以检查Pol zeta L2618 M在绕过病变后延伸引物DNA的程度。加合物在两种细胞系的加合位点主要诱导G至T和G至C，但在REV 3 L2618 M细胞中比在WT细胞中更频繁地产生额外的序列变化，例如在延伸补丁中的碱基取代、缺失和添加。在REV 3 L2618 M细胞的延伸补丁中的突变最常发生在距离内收位点10 bp内。然后，突变的数量逐渐减少，并且在距病变30和40 bp之间没有观察到突变。我们得出结论，人Pol zeta L2618 M和可能的WT Pol将引物DNA从体内病变处延伸至约30 bp。讨论了Polzeta L2618 M参与TLS插入步骤的可能性。
DNA polymerase zeta (Pol zeta) is a specialized Pol that is involved in translesion DNA synthesis (TLS), in particular, in the extension of primer DNA after bypassing DNA lesions. Previously, we established human cells that express a variant form of Pol zeta with an amino acid change of leucine 2618 to methionine (L2618M) in the catalytic subunit REV3L (DNA Repair, 45, 34-43, 2016). This amino acid change made the cells more sensitive to the mutagenicity of benzo [a] pyrene diol epoxide (BPDE). In this study, we embedded BPDE-N-2 -guanine at a defined position in the supF gene on the shuttle plasmid and introduced it to REV3 L2618M cells or the wild-type (WT) cells to examine how far Pol zeta L2618M extends the primer DNA after bypassing the lesion. The adduct induced primarily G to T and G to C at the adducted site in both cell lines, but generated additional sequence changes such as base substitutions, deletions and additions in the extension patch much more often in REV3 L2618M cells than in the WT cells. Mutations in the extension patch in REV3 L2618M cells occurred most often within 10 bps from the adducted site. Then, the number of mutations gradually decreased and no mutations were observed between 30 and 40 bps from the lesion. We concluded that human Pol zeta L2618M and perhaps WT Pol extend the primer DNA up to approximately 30 bps from the lesion in vivo. The possibility of involvement of Pol zeta L2618M in the insertion step of TLS is discussed.