Enzymes of Neurospora crassa which attack UV-irradiated DNA.

Two excision-deficient mutants of Neurospora crassa contain normal levels of two enzymes, a single-strand-specific exonuclease and a single-strand specific endonuclease, which attack UV-irradiated DNA. Mutants of N. crassa have been obtained in which the activity of the latter enzyme as well as an activity with native DNA are simultaneously affected. These activities are also apparently low in excision-proficient uvs3 strain of N. crassa which has many of the characteristics of the recA mutants of E. coli.