DNA-REPAIR ACTIVITY IN PROTEIN EXTRACTS FROM RAT-TISSUES

Among DNA repair pathways, nucleotide excision repair (NER) is able to recognize and process a wide variety of DNA lesions, The NER mechanis m can be summarized in two stages: incision/excision of the lesion and DNA repair synthesis. Here, we have assessed the repair synthesis act ivity of protein extracts from different rat tissues by an in vitro bi ochemical assay that reproduces the entire NER reaction, The protein e xtraction procedure was adapted to rat tissues and the biochemical par ameters of the assay (high salt concentration, addition of EGTA) in or der to minimize non-specific nuclease activity which allows the measur ement of repair activity, Using this repair assay me detected a small increase in the extent of repair synthesis in liver compared to brain and lung tissue protein extracts, Similar results were obtained using a derivative assay that allows the measurement of the incision activit y of tissue protein extracts with lower incision activity in lung tiss ue extract, (C) 1997 Federation of European Biochemical Societies.