Fig. 5. srw1p becomes phosphorylated just before S-phase starts, which coincides with the accumulation of cdc13p. (A) Flow cytometry and (B) septation index and percentage of ‘cut’ cells in G1 block and release experiments. cdc10-129 and cdc10-129 srw1Δ strains were blocked for 4 h at 36°C and released into 25°C and incubated for the times indicated. (C) Western blots of the experiments described above using anti-srw1p, anti-cdc13p, anti-phosphotyrosine cdc2p, anti-rum1p and anti-cdc2p antibodies. For anti-rum1p antibody blotting, the same blots were used after the anti-phosphotyrosine cdc2p antibody.