FIG. 5.

ß-Estradiol-inducible NDT80 bypasses the sum1-ci meiotic block. SUM1 GAL4-ER pGAL-NDT80 (WT) and sum1-ci GAL4-ER pGAL-NDT80 (sum1-ci) cells were transferred to sporulation medium, and 1 μM ß-estradiol (+) or vehicle alone (−) was added at 5 h to induce expression of NDT80. The completion of meiosis (MII) was monitored in three independent cultures at 24 h after cells were transferred to sporulation medium (error bars are too small to be visible). Equivalent numbers of cells were collected on a nitrocellulose filter and assayed for the presence of dityrosine, a component of the outer layer of the spore wall, by fluorescence.