yeast and zeocin resistance - (Sep/11/2008 )

I use zeocin as selection marker in Saccharomyces cerevisiae, but the useage concentration is about 50~150 ug/ml,but the yeast strain i use still grow in the concentration 300ug/ml, i don't know why.

can anyone can tell my why?is the yeast i use the zeocin-resistanct strain?

yeast is very resistant to Zeocin/Phleomycin. It is the DNA repair machinery and high rate of homologous recombination.

You could try to two things
1- use a strain with defective DNA repair machinery. knock out one of the rad gene
2- try plating the yeast cells at a lower density. Recover the yeast for in non selective media (~1hr) then incubate on ice for (~1hr). The incubation on ice I am told will lower the background.