FIG. 5.

Tor1 positively regulates mitosis. (A) The Δtor1 mutation is synthetic lethal with cdc25-22. A diploid strain heterozygous for Δtor1 and cdc25-22 was subjected to meiosis and tetrad analysis. Plates were incubated at 25°C. (B) Overexpression of gad8⁺ rescues the synthetic lethality of tor1 cdc25-22. The same diploid strain as above was transformed with pIRT2-tor1⁺, pREP41-gad8⁺ (moderate overexpression), and pREP1-gad8⁺ (strong overexpression). Two double mutant spores containing each of the plasmids were isolated and streaked onto plates at 28°C (no viable spores were obtained with an empty vector). (C) The cdc2-Y15F mutation suppresses the elongated phenotype of cells lacking Tor1. Bars: 20 μm. (D) The Δtor1 mutation reverses the suppression of cdc25-22 by wee1-50. Cells from the indicated genotypes were streaked onto plates either at 28°C or 35°C (left panel), and cells were visualized by light microscopy (right panel). Bars: 20 μm. (E) The wee1-50 mutation partially suppresses the elongated phenotype of cells lacking Tor1. Cells were grown to mid-log phase at 30°C, photographed, and subjected to FACS analysis.