Molecular Genetic Dissection of Mammalian Excision Repair

To elucidate the mechanism of excision repair in mammalian cells we have focussed on the cloning of human genes involved in this process. The strategy followed consists of transfection of human genomic DNA to excision deficient CHO mutants from different complementation groups (e.g.), followed by selection of repair proficient transformants and ‘rescue’ of the transferred human sequences responsible for correction of the repair defect. Applying this strategy to mutants 43–3B (c.g.l), 27–1 (e.g.3) and UV-61 (e.g.6) we have cloned the complementing human genes ERCC-1, -3 and -6., respectively.