Figure 5.

The N terminus of Ndc80 is sufficient to induce proteolysis. (A) Schematic of the Ndc80 tail-Ame1 fusion. The tail of Ndc80 (residues 2–112), including both the 27-residue sequence and the Ipl1 phosphorylation sites, is fused to the C terminus of Ame1. The fusion construct is controlled by the NDC80 promoter, which allows synthesis repression in meiotic prophase. (B) Ame1-tail is degraded in meiotic prophase in an Ipl1-dependent manner. The IPL1 AME1 (UB20358), IPL1 AME1-tail (UB20354), and ipl1-mn AME1-tail (UB22397) cells were sporulated as described in Figure 2A. In all of the strains, Ndc80 was tagged with 3V5, the same epitope tag for Ame1, as an internal control. The relative Ndc80 levels were calculated as described in Figure 1C. The relative Ame1 levels were calculated by normalizing Ame1 levels to Hxk2 levels in each lane, and then dividing the normalized values to that of time 0 h.