Restriction enzyme accessibility assay.
A, representative polyacrylamide native gels of restriction enzyme accessibility near the DNA ends for intact (I), which contains a single uracil, or a single nucleotide gap (g) at the corresponding uracil location. Lanes M represent a radiolabeled 25-bp DNA ladder. HaeIII cleaves at +51. B, representative 16% polyacrylamide native gels of restriction enzyme accessibility near the dyad with HhaI, which cleaves at +2. C and D, plot of the mean ± 1 S.D. of three independent experiments.