Alkaline elution of yeast DNA: a simple method of detection of DNA single-strand breaks.

A method of analysis has been developed to study the induction and repair of single-strand breaks in yeast DNA by alkaline elution from filters. By this technique sphaeroplasts obtained from yeast cells were lysed on the filters and single-strand DNA fragments selectively eluted by alkaline elution. Three different approaches are proposed: (i) pH step alkaline elution from the filters; (ii) alkaline elution from the filters using one selected level of pH; (iii) alkaline elution from the filter in which fractions were collected directly on Whatman 17 glass filter paper, thus simplifying the procedure. We found that the first method was the most sensitive, while the next two were much simpler but less sensitive. On the other hand, these two methods enabled us to express semiquantitatively the degree of DNA damage and repair.