UV-induced T-->C transition at a TT photoproduct site is dependent on Saccharomyces cerevisiae polymerase eta in vivo.
UV-induced T-->C transition at a TT photoproduct site is dependent on Saccharomyces cerevisiae polymerase eta in vivo.
复制标题
UV 诱导的 TT 光产物位点处的 T→C 转变取决于体内酿酒酵母聚合酶 eta。
DOI：
10.1093/nar/30.5.1262
复制
发表时间：
2002
影响因子：
14.9
通讯作者：
Siede,Wolfram
中科院分区：
文献类型：
--
作者：
Zhang,Hong;Siede,Wolfram
在酿酒酵母中，紫外光诱导的arg4-17等位基因的还原主要依赖于翻译聚合酶η (Rad30p)，已知它可以以无差错的方式绕过环丁烷型TT二聚体。arg4-17位点的逆转主要是由于TT光产物位点的3′T T127的T→C跃迁。在arad30缺失突变体中，无论核苷酸切除修复状态如何，这一事件至少减少了20倍。这些数据与已知的6-4 TT光产物的性质和聚合酶η的体外特性相关联，表明聚合酶η在6-4 TT光产物的3′T方向插入G的过程中起着重要的作用。另外，聚合酶η在该位点对环丁烷型光产物进行前所未有的易出错处理，必须假定这是关键机制。虽然光活化结果确实暗示了后一种可能性，但减少总体紫外线损伤负荷对非环丁烷型嘧啶二聚体光产物旁路概率的可能调节影响不应被忽视。
UV-induced reversion of thearg4-17ochreallele inSaccharomyces cerevisiaeis largely dependent on translesion polymerase η (Rad30p), known to bypass cyclobutane-type TT dimers in an error-free fashion.arg4-17locus reversion was predominantly due to T→C transition of T127, the 3′ T of a TT photoproduct site. This event was at least 20-fold reduced in arad30deletion mutant, irrespective of the status of nucleotide excision repair. These data correlate with known properties of 6–4 TT photoproducts andin vitrocharacteristics of polymerase η and suggest that polymerase η plays an importantin vivorole in inserting G opposite the 3′ T of 6–4 TT photoproducts at this site. Alternatively, an unprecedented error-prone processing of cyclobutane-type photoproducts at this site by polymerase η must be assumed as the critical mechanism. Whereas photoreactivation results indeed hint at the latter possibility, a possible regulatory influence of reducing the overall UV damage load on the bypass probability of non-cyclobutane-type pyrimidine dimer photoproducts should not be dismissed.