[Mechanisms of DNA exit during neutral and alkaline comet assay]

The results are presented on comparison of the kinetics of DNA exit during neutral and alkaline variants of single cell gel electrophoresis. It has been shown that pre-incubation of samples in alkaline buffer makes impossible DNA exit during the neutral electrophoresis, in contrast to the alkaline conditions where DNA exit is very efficient. The conclusion has been made that the alkaline conditions induce a disruption of DNA matrix interactions. The hypothetical nature of these interactions is discussed. The results obtained suggest that the mechanisms of DNA exit in the course of neutral and alkaline electrophoresis are essentially different. In the case of the neutral electrophoresis the comet tails are formed by the relaxed loop domains while during the alkaline electrophoresis they are formed by single stranded DNA fragments, which are pulled out by one and from the coil that is not bound to the matrix.