Translesion synthesis is a DNA damage tolerance mechanism that relies on a series of specialized DNA polymerases able to bypass a lesion on a DNA template strand during replication or post-repair synthesis. Specialized translesion synthesis DNA polymerases pursue replication by inserting a base opposite to this lesion, correctly or incorrectly depending on the lesion nature, involved DNA polymerase(s), sequence context, and still unknown factors. To measure the correct or mutagenic outcome of 8-oxo-7,8-dihydro-2′-deoxyguanosine bypass by translesion synthesis, a primer-extension assay was performed in vitro on a template DNA bearing this lesion in the presence of nuclear proteins extracted from human intestinal epithelial cells (FHs 74 Int cell line); the reaction products were analyzed by both denaturing capillary electrophoresis (to measure the yield of translesion elongation) and pyrosequencing (to determine the identity of the nucleotide inserted in front of the lesion). The influence of 14 natural polyphenols on the correct or mutagenic outcome of translesion synthesis through 8-oxo-7,8-dihydro-2′-deoxyguanosine was then evaluated in 2 experimental conditions by adding the polyphenol either (i) to the reaction mix during the primer extension assay; or (ii) to the culture medium, 24 h before cell harvest and nuclear proteins extraction. Most of the tested polyphenols significantly influenced the outcome of translesion synthesis, either through an error-free (apigenin, baicalein, sakuranetin, and myricetin) or a mutagenic pathway (epicatechin, chalcone, genistein, magnolol, and honokiol).

中文翻译：

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化学预防性天然化合物对 8-oxo-7,8-dihydro-2'-deoxyguanosine Translesion 合成准确度的影响

跨损伤合成是一种 DNA 损伤耐受机制，它依赖于一系列专门的 DNA 聚合酶，能够在复制或修复后合成过程中绕过 DNA 模板链上的损伤。专门的跨病灶合成 D​​NA 聚合酶通过插入与该病灶相反的碱基来进行复制，根据病灶性质、涉及 DNA 聚合酶、序列背景和仍然未知的因素，正确或不正确地插入碱基。为了通过跨病灶合成测量 8-oxo-7,8-dihydro-2'-deoxyguanosine 旁路的正确或诱变结果，在提取的核蛋白存在的情况下，在体外对带有该病灶的模板 DNA 进行引物延伸测定来自人肠上皮细胞（FHs 74 Int 细胞系）；通过变性毛细管电泳（以测量跨病灶延伸的产量）和焦磷酸测序（以确定插入病灶前的核苷酸的身份）分析反应产物。14 种天然多酚对通过 8-oxo-7,8-dihydro-2'-deoxyguanosine 的跨损伤合成的正确或诱变结果的影响然后在 2 个实验条件下通过在反应混合物中添加多酚 (i) 来评估引物延伸测定；或 (ii) 在细胞收获和核蛋白提取前 24 小时加入培养基。大多数测试的多酚通过无错误（芹菜素、黄芩素、樱花素和杨梅素）或诱变途径（表儿茶素、查尔酮、染料木黄酮、厚朴酚和和厚朴酚）显着影响跨损伤合成的结果。