Figure 1.

Plant mitochondria possess UDG and AP endonuclease activity. Double-stranded oligodeoxyribonucleotides Oug (A) and Oap (B), [³²P]-labeled at the 5′-end of the strand carrying the lesion, were incubated in the presence of enriched A. thaliana mitochondrial enzymatic extract (25 µg of protein) for increasing times. To evaluate the extent of lesion-specific incision, the samples were subsequently denatured and analyzed by electrophoresis on polyacrylamide gels in the presence of 7 M urea. The migration of size markers is indicated by arrows.