RNA polymerase II bypass of oxidative DNA damage is regulated by transcription elongation factors
RNA polymerase II bypass of oxidative DNA damage is regulated by transcription elongation factors
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DOI：
10.1038/sj.emboj.7601403
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发表时间：
2006-11-29
期刊：
影响因子：
11.4
通讯作者：
Egly, Jean Marc
中科院分区：
文献类型：
--
作者：
Charlet-Berguerand, Nicolas;Feuerhahn, Sascha;Egly, Jean Marc
氧化损伤是细胞内最丰富的DNA损伤。在本研究中，我们研究了氧化损伤8-氧鸟嘌呤、胸腺嘧啶乙二醇和5-羟基尿嘧啶对RNA聚合酶II （RNA pol II）转录的影响。我们发现，在纯化的、重组的转录系统中，这些病变在不同程度上阻碍了RNA pol II的延伸，这取决于病变的类型。当在HeLa细胞核提取物中进行转录时，对延伸的阻断减轻了，这表明存在旁路活性。通过纯化该活性，我们发现TFIIF可以通过胸腺嘧啶乙二醇损伤促进延伸。延伸因子伸长素（Elongin）和CSB （CSB）也能刺激胸腺嘧啶乙二醇病变绕道，而伸长素（Elongin）、CSB和TFIIS均能增强8-氧鸟嘌呤病变绕道。通过提高RNA pol II读取氧化损伤的效率，延伸因子可以促进转录诱变，这一活动可能对人类疾病的产生或进展有影响。
Oxidative lesions represent the most abundant DNA lesions within the cell. In the present study, we investigated the impact of the oxidative lesions 8-oxoguanine, thymine glycol and 5-hydroxyuracil on RNA polymerase II (RNA pol II) transcription using a well-defined in vitro transcription system. We found that in a purified, reconstituted transcription system, these lesions block elongation by RNA pol II to different extents, depending on the type of lesion. Suggesting the presence of a bypass activity, the block to elongation is alleviated when transcription is carried out in HeLa cell nuclear extracts. By purifying this activity, we discovered that TFIIF could promote elongation through a thymine glycol lesion. The elongation factors Elongin and CSB, but not TFIIS, can also stimulate bypass of thymine glycol lesions, whereas Elongin, CSB and TFIIS can all enhance bypass of an 8-oxoguanine lesion. By increasing the efficiency with which RNA pol II reads through oxidative lesions, elongation factors can contribute to transcriptional mutagenesis, an activity that could have implications for the generation or progression of human diseases.