We have studied the mutagenic specificity of abasic sites using the yeast oligonucleotides transformation assay. We introduced oligonucleotide containing a natural abasic site and a tetrahydrofuran abasic site into Rev1 mutants, rev1AA, which contains mutations of Asp467 and Glu468 residues of Rev1p to Ala in order to inactivate dCMP transferase activity, and rev1 delta, which lacks its whole coding sequence. The transformation efficiencies of rev1AA with abasic-containing oligonucleotides were lower than those of B7528, a strain proficient in REV1 gene, but much higher than rev1 delta mutant. Sequence analysis opposite the lesions showed that the mutation spectra were different among these three strains.
