A DNA glycosylase for oxidized thymine residues in Drosophila melanogaster.

A DNA glycosylase activity which excises fragmented thymine residues has been identified in cell extracts from Drosophila melanogaster embryos. The enzyme has an apparent Mr = 40,000, acts preferentially on double-stranded polydeoxyribonucleotide substrate and requires no co-factors. The DNA glycosylase presumably acts in excision-repair of pyrimidines damaged by hydroxyl radicals and other oxidizing species. This is the first identification of a DNA glycosylase in Drosophila cells.