Mechanisms of DNA Exit during Neutral and Alkaline Comet Assay

摘要

Results of the kinetics of DNA exit in neutral and alkaline variants of single cell gel electrophoresis are compared. It is shown that preincubation of samples in an alkaline buffer makes DNA exit in neutral electrophoresis impossible and, in contrast, effectively facilitates it within such buffers. We conclude that the alkali disrupts interactions between the loop domains of the DNA and the matrix proteins. We discuss the hypothetical nature of these interactions. The results obtained suggest that the mechanisms of DNA exit in the course of neutral and alkaline electrophoresis are substantially different. In the case of neutral electrophoresis, comet tails are formed by relaxed loop domains; during alkaline electrophoresis, they are formed by single-strand DNA fragments that are extracted, by the force of the electric field, from coils not yet bound to matrixes.