Figure 1.

A hypertonic environment rescues the mitotic exit defect of MEN mutants. (A) Strains carrying temperature-sensitive alleles of genes encoding components of the MEN were spotted on solid media supplemented with sorbitol or NaCl. Strains used (from top) are A1411, A1740, A1674, A851, A5321, and A859. Note that the cdc5-1 strain was sensitive to 0.5 M NaCl. (B) A hypertonic environment does not accelerate exit from mitosis: wild-type cells were arrested with 15 μg/ml nocodazole followed by release from the block in the presence or absence of 1.5 M sorbitol. The percentage of cells with metaphase and anaphase spindles was determined at the indicated times. Note that all cells were arrested by the nocodazole treatment. However, upon washout of the drug (0 time point), repolymerization of metaphase spindles is sluggish leading to only 30–50% of cells having reformed metaphase spindles at the beginning of the time course.