Figure 1.

 The steady-state level and in vitro kinase activity of Cdc7p do not change significantly as cells proceed from interphase through mitosis, septum formation, and cytokinesis. Cells were synchronized by arrest–release of cdc25-22 cdc7–HA as described in Materials and Methods. Protein samples were prepared at intervals. The number of cells that were in mitosis or forming a division septum at each time point was determined. (A) The percentage of cells in anaphase (shaded bar), and forming a division septum (solid bar) at each time point; (B) Western blot of total protein extracts, probed with mAb 12CA5; (C) the same samples as in B, probed with TAT-1 as loading control; (D) kinase activity of Cdc7p, assayed using myelin basic protein as substrate; (E) Western blot of Cdc7–HAp in the immunoprecipitates used in D, using mAb 12CA5.