Point mutation in the polyomavirus enhancer alters local DNA conformation.

A point mutation in the enhancer of polyomavirus host range mutant, PyEC F441, permits productive infection of the murine embryonal carcinoma cell line, F9. This mutation at nucleotide position 5258 introduces a local conformational change in naked viral DNA. The effect of all four possible nucleotide sequences at position 5258 on local DNA conformation was analyzed by gel electrophoresis of fragments produced by ligation of synthetic oligonucleotides having these sequences. The results indicated that both the wild-type and the F441 sequences introduced local structural polymorphism that can lead to DNA bending. The wild-type sequence had a greater effect on DNA curvature than the F441 sequence. The two other sequences at nucleotide 5258 did not appear to introduce detectable amounts of DNA curvature.