Apurinic endonuclease from Drosophila melanogaster: reduced enzymatic activity in excision-deficient mutants of the mei-9 and mus(2)201 Loci.

An endonuclease activity, which is specific for partially depurinated PM2 DNA, has been assayed in extracts prepared from cultured cells and larval brain ganglia of Drosophila melanogaster. Activity detected in repair-proficient cells is stimulated by Mg++ and is inhibited by EDTA. Extracts prepared from established cell cultures of the excision-deficient strain mei-9a and from larval brain ganglia derived from y mei-9a, mei-9L1, sn3 mei-9D2 and sn3 mei-9D4 are partially deficient in this activity. At least one allele of a second excision-deficient strain, cn mus (2)201D1, also shows reduced AP-endonuclease activity in ganglia extracts.