8-Oxoguanine DNA glycosylase (Ogg1) causes a transcriptional inactivation of damaged DNA in the absence of functional Cockayne syndrome B (Csb) protein
8-Oxoguanine DNA glycosylase (Ogg1) causes a transcriptional inactivation of damaged DNA in the absence of functional Cockayne syndrome B (Csb) protein
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DOI：
10.1016/j.dnarep.2008.11.006
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发表时间：
2009-03-01
期刊：
影响因子：
3.8
通讯作者：
Epe, Bernd
中科院分区：
文献类型：
--
作者：
Khobta, Andriy;Kitsera, Nataliya;Epe, Bernd
我们分析了氧化鸟嘌呤损伤对小鼠胚胎成纤维细胞中缺乏Cockayne综合征B蛋白（Csb）和/或8-氧鸟嘌呤DNA糖基化酶（Ogg1）的转染报告基因表达的影响。我们使用了一种高度敏感的基于流式细胞术的方法和定量实时PCR来测量载体DNA中由光敏化产生的氧化鸟嘌呤残基的存在引起的基因表达变化。在野生型细胞中，少量（一个或三个）氧化鸟嘌呤在转染后的短时间内不会影响基因表达，而在稍后的时间点观察到转基因表达的逐渐减少。虽然Ogg1对氧化鸟嘌呤碱基的修复有重要作用，但它的缺失对基因表达没有强烈影响。相反，缺乏功能性Csb蛋白会导致受损的报告基因明显失活。最引人注目的是，额外的Ogg1缺陷显著减弱了这种效果。结果表明，Ogg1处理氧化鸟嘌呤修饰可以介导宿主细胞失活而不是受损基因的再激活，并且在缺乏Csb的情况下这种作用强烈增强。(C) 2008 Elsevier B.V.版权所有
We have analysed the effect of oxidative guanine lesions on the expression of a transfected reporter gene in mouse embryonic fibroblasts deficient in Cockayne syndrome B protein (Csb) and/or the 8-oxoguanine DNA glycosylase (Ogg1). We used a highly sensitive flow cytometry-based approach and quantitative real-time PCR to measure the changes in gene expression caused by the presence of oxidised guanine residues generated by photosensitisation in the vector DNA. In wild-type cells, small numbers (one or three) of oxidised guanines did not affect gene expression at short times after transfections, whereas progressive reduction of the transgene expression was observed at later time points. Although Ogg1 has a major contribution to the repair of oxidised guanine bases, its absence did not have a strong effect on the gene expression. In contrast, the lack of functional Csb protein caused a pronounced inactivation of the damaged reporter gene. Most strikingly, an additional Ogg1 deficiency significantly attenuated this effect. The results indicate that the processing of oxidative guanine modifications by Ogg1 can mediate host cell inactivation rather than reactivation of the damaged genes and that this effect is strongly enhanced in the absence of Csb. (C) 2008 Elsevier B.V. All rights reserved.