Identification of Ama1p degrons. A: Location of conserved APC/C degrons in Ama1p. The consensus sequences of destruction box and GXEN motifs are in bold face. The mutations described in the text are indicated below the consensus sequences. B: Both Db1 and GxEN degrons mediate Ama1p degradation during meiosis. Wild-type cells (RSY335) harboring plasmids expressing Ama1p-T7 or mutants as indicated were induced to enter meiosis and samples taken for immunoprecipitation and immunoblot analysis at the timepoints indicated. Tub1p levels were used as a loading control. C: Quantitation of the degradation kinetics of wild-type Ama1p-T7 and the Db1-GxEN double mutant obtained in Panel B. The mean ± s.e.m. is shown for each timepoint (n=3 independent experiments). D: The percent of tetra-nucleated cells during a meiotic timecourse in ama1∆ cells (RSY562) expressing either wild-type Ama1p (squares) or the DB1/GxEN double mutant (circles) plasmids. E: Fluorescence microscopy (1000X magnification) and Nomarski optics (Nom.) of DAPI Db1/GxEN expression plasmids. The percent viability of dissected spores (n=40, WT normalized to 100%) is given below.