Repair activity of the polymorphic Cys 326 variant of OGG1 under conditions of oxidative stress

Kaur, Mehak Preet (2016). Repair activity of the polymorphic Cys 326 variant of OGG1 under conditions of oxidative stress. University of Birmingham. M.Sc.

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Abstract

Reactive oxygen species (ROS) have damaging effect on cell metabolism and function via various DNA and protein modifications. Cells have evolved many mechanisms to reduce such ROS-induced damage, for instance the base excision repair (BER) pathway. This research emphases the effect of the common Ser326Cys polymorphism in the OGG 1 gene, which is an important part of BER to remove mutagenic 8-oxo deoxyguanosine from genomic DNA. Previous studies have highlighted the importance of Ser326Cys polymorphism of OGG 1 relating it to many forms of cancer and various degenerative diseases due to variant OGG 1 been reported being repair deficient. In the current study, we report the novel application of bimolecular
fluorescence complementation (BiFC) to study OGG 1 protein complex formation in the native cellular environment and report accumulation of Cys326-0GG 1 protein complexes as assessed by confocal microscopy. We observed fluorescence both in and around the nucleus of cells expressing Cys326-0GG 1 specifically under conditions of cellular oxidative stress, with increased ROS levels and depletion of GSH following treatment with both buthionine sulfoximine (BSO) and hydrogen peroxide. Furthermore, loss of BiFC fluorescence was seen when cells were treated with thiol reducing agents providing evidence of the role a disulfide bond. In summary, we report for the first time formation of Cys326 OGG 1 complexes in the native cellular environment particularly under conditions of oxidative stress. This finding could
explain the reduced repair capability of Cys3260GG 1 under oxidative stress environment.

Type of Work:

Thesis (Masters by Research > M.Sc.)

Award Type:

Masters by Research > M.Sc.

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