DNA damage excision repair in microplate wells with chemiluminescence detection: development and perspectives

The development of in vitro repair assays with human cell-free extracts led to new insights on the mechanism of excision of DNA damage which consists of incision/excision and repair synthesis/ligation. We have adapted the repair synthesis reaction with cells extracts incubated with damaged plasmid DNA performed in liquid phase to solid phase by DNA adsorption into microplate wells. Since cells extracts are repair competent in base excision and nucleotide excision repair, all types of substrate DNA lesions were detected with chemiluminescence measurement after incorporation of biotin-deoxynucleotide during the repair synthesis step. Derivatives of our initial 3D-assay (DNA damage detection) have been set up to: i) screen antioxidative compounds and NER inhibitors; ii) capture genomic DNA (3D(Cell)-assay) that allows detection of alkylated base and consequently determines the kinetics of the cellular repair; and iii) immunodetect the repair proteins in an ELISA reaction (3D(Rec)-assay). The 3D derived assays are presented and discussed.