The induction and repair of (6-4) photoproducts in Neurospora crassa

The (6-4) photoproduct lesion found in DNA after UV irradiation is repaired by germinating Neurospora crassa conidia. Wild-type Neurospora removes 80% of the (6-4) photoproduct in approximately 20 min and maximal repair is accomplished by 30 min with approximately 89% of the original lesions removed. Mutagen-sensitive Neurospora mutants belonging to the established excision repair epistasis group, UVS-2, are not defective in the removal of cyclobutane pyrimidine dimers. Furthermore, we find these mutants capable of removing (6-4) photoproducts from their DNA at a rate similar to wild type. Comparable kinetics are also observed in key members of the other two epistasis groups.