Figure 4.

APC/C ^Cdc20 is required to maintain low levels of Dbf2 protein. DBF2-MYC (A1931) and cdc23–1 DBF2-MYC (A2184) cells were arrested in G1 with the use of 5 μg/ml α-factor and released at the restrictive temperature (37°C) in medium lacking pheromone. Samples were taken at the indicated times to determine Dbf2 protein levels and Dbf2 kinase activity. The graph shows the amount of Dbf2 kinase activity per Dbf2 protein. Kar2 (top panel), Dbf2 protein (middle panel) and Dbf2 kinase activity (lower panel).