Fig. 6. A functional checkpoint is modulated by rfa1-t11 and Rad51. (A) Rad53 kinase activation was analysed by an in-gel autophosphorylation assay (Pellicioli et al., 1999) at the indicated time points after HO induction. Strains are JKM179 (wild type, WT) or derivatives thereof. Equal loading was scored on the same blot with anti-tubulin (TAT-1). (B) The wild-type and rfa1-t11 mutant cells were probed for checkpoint induction by monitoring the shift of phospho-Rad53-Myc (*) by SDS-PAGE. (C) The percentage of mononucleated large budded cells (G2/M arrest) was scored after ethanol fixation and DAPI staining at the indicated time points after HO induction. JKM179 strains and derivatives were used and values represent the mean of three experiments with >300 cells per set.