Association of human 8-oxoguanine DNA glycosylase 1 beta isoform with NDUFB10 and its potential role in mitochondrial DNA repair

• Main Authors: Yen-Ling Lee, 李彥陵
• Other Authors: Wenya Huang
• Format: Others
• Language: en_US
• Published: 2009
• Online Access: http://ndltd.ncl.edu.tw/handle/31306611064364281137

碩士 === 國立成功大學 === 醫學檢驗生物技術學系碩博士班 === 97 === The human 8-oxoguanine-DNA glycosylase 1 (hOGG1) is an essential base excision repair (BER) for oxidative DNA damage. hOGG1 yields two alternatively spliced isoforms, designated alpha- and beta-hOGG1. The alpha-hOGG1 is localized in nucleus and mitochondria (mt); whereas the beta-hOGG1 is mainly localized in mitochondria. In nucleus, the function and regulation of alpha-hOGG1 is well known. However, the potential functions of alpha- or beta-hOGG1 in mitochondrial DNA repair were not extensively investigated yet. In order to understand the possible roles of alpha- and beta-hOGG1 in mtDNA repair, we previously used yeast two-hybrid screening assays to screen for the proteins that are associated with them. We found that beta- but not alpha-hOGG1 directly interacts with NADH dehydrogenase (ubiquinone) 1 beta subcomplex 10 (NDUFB10). NDUFB10 is a subunit of the NADH:ubiquinone oxidoreductase complex I, which is located on mitochondrial inner membrane. We also confirmed the in vivo interaction between beta-hOGG1 with NDUFB10 by co-immunoprecipitation and immunofluorescence assays. By co-IP studies, it was found that association of ���{hOGG1 with NDUFB10 was enhanced after treatment of hydrogen peroxide, suggesting that beta-hOGG1 repairs mtDNA damages through its interaction with NDUFB10 upon oxidative stress. Furthermore, alpha-hOGG1 also interacts with beta-hOGG1 and might form a repair complex with beta-hOGG1 and NDUFB10 for mtDNA repair. Although, we tried to look for the interaction region of beta-hOGG1 that directly binds with NDUFB10. However, the co-IP result validated either helix-hairpin-helix motif or predictive transmembrane region (C terminus) is not the binding domain. The results of these studies will help us to understand the role of beta-hOGG1 on mitochondrial DNA repair or other relevant functions.