Fig. 1. Analysis of the steady-state levels of Cdc16p and Byr4p through the cell cycle. Cells of the genotypes indicated below were synchronised by cdc25-22 arrest-release. Cells were collected at the indicated times (minutes after release), fixed and stained with DAPI and Calcofluor. The percentage of cells in anaphase or septation was determined. Western analysis was performed on lysates of the different strains with the indicated antibodies. (A) cdc25-22 leu1::cdc16-HA(ura4⁺) cdc16⁺. (B) cdc25-22 byr4⁺. The three arrows to the right of the western blot in B indicate the different forms of Byr4p seen in mitosis (upper and lower) and the interphase form of the Byr4p (middle). The western blot on the right is part of the 60 minute protein sample treated with alkaline phosphatase (+P) or alkaline phosphatase in the presence of phosphatase inhibitors (M).