Biopolymers and cell. 2002; 18 (5): 394 - 400

Possible molecular mechanisms of untargeted mutagenesis upon a post-replication SOS-reparation after irradiating two-stranded DNA by ultra-violet light

H. A. Grebneva

Possible molecular mechanisms of an untargeted mutagenesis after post-replication SOS-reparation, resulting in formation of adjacent thymine dinners in both DNA chains are analyzed on the qualitative level It is suggested that a dimer is mutagenic only if one or two bases are in rare tautomeric forms and the control over tautomeric states of the template bases at DNA synthesis is diminished due to the SOS-induction. The potential mutations in this case are assumed to be the adenine residues in rare tautomeric forms located in the vicinity of dinners — exactly, opposite to the thymines forming other dimers with changes in their tautomeric state. They can result in transitions, transversions and frameshift mutations.