Figure 5.

Temperature sensitivity of strains containing the kar3-Δ allele was mostly corrected by addition of benomyl to the medium or deletion of TUB3. Cells of the indicated genotypes were suspended in water and serial dilutions placed on YPD plates with or without 5 μg/ml benomyl, at 30° or 37°C, for 2–3 d. Growth of kar3-Δ cells was observed to be partially inhibited at 37°C. This temperature sensitivity was eliminated by addition of benomyl to the medium or by deletion of TUB3. The benomyl sensitivity caused by the tub3-Δ allele was not rescued by kar3-Δ (not shown). The kar3-Δ, tub3-Δ, and tub3-Δ kar3-Δ double mutants are all from the same tetrad. (Growth of kar3-Δ mutants at 37°C did not cause a noticeable cell cycle arrest phenotype, results not shown.) In contrast, deletion of CIN8, which also causes slight temperature sensitivity, could not be rescued by benomyl.