Model DNA for investigation of mechanism of nucleotide excision repair.

The living cell DNA is under permanent attack of a variety of exogenous and endogenous damaging factors. Nucleotide excision repair (NER) is main pathway which removes a wide variety of bulky DNA adducts formed by UV light, electrophilic environmental mutagens, and chemotherapeutic agents. NER process in mammalian cells consistently leads to the very specific excision of damaged DNA fragments 24-32 nucleotides in length. The following DNA repair synthesis and DNA ligation restore intact DNA helix. The main set of the genes inactivated in NER-deficient higher eukaryotic cells was identified; about 30 proteins are involved in the specific multi-subunit complexes responsible for NER process. The specific NER feature is wide substrate specificity and great difference of damages elimination efficiencies. A key limiting step in NER is damage recognition and verification. One of the advanced and upcoming approaches to NER process investigation is based on the application of model DNAs - artificial DNA structures, which are analogs of substrate or intermediates of the repair process. This article reviews our current knowledge concerning the model DNA design, synthesis and application as a tool for the NER process comprehensive study. [ABSTRACT FROM AUTHOR]