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Green tea polyphenols may protect cells from UV damage through antioxidant activities and by stimulating the removal of damaged or cross-linked DNA. Recently, DNA repair pathways have been predicted as possible targets of epigallocatechin gallate (EGCG)-initiated signaling. However, whether and how green tea polyphenols can promote nucleotide excision repair and homologous recombination in diverse organisms requires further investigation. In this report, we used the budding yeast, Saccharomyces cerevisiae , as a model to investigate the effects of green tea extract on DNA repair pathways. We first showed that green tea extract increased the survival rate and decreased the frequency of mutations in yeast exposed to UVB-irradiation. Furthermore, green tea extract increased the expression of homologous recombination genes, RFA1 , RAD51 and RAD52 , and nucleotide excision repair genes, RAD4 and RAD14 . Importantly, we further used a specific strand invasion assay to show that green tea extract promotes homologous recombination at double-strand breaks. Thus, green tea extract acts to preserve genome stability by activating DNA repair pathways in yeast. Because homologous recombination repair is highly conserved in yeast and humans, this study demonstrates yeast may be a useful platform for future research to investigate the underlying mechanisms of the bioactive compounds in DNA repair.

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