sentence: ( B ) Tenfold dilutions of equal numbers of ( otherwise isogenic ) wild-type , pol30 , GAL1 ,10 : UBP10 and GAL1 ,10 : UBP10 pol30 cells incubated at 25 ° C on YAPD plates ( GAL OFF ) to repress GAL1 ,10 - driven UBP10 expression or YAPGal plates ( GAL ON ) to induce GAL1-driven UBP10 expression ( with or without MMS , as indicated ) .