FIG. 4.
Growth phenotypes of pkh1D398G pkh2Δ mutants. (A) Viability of pkh1D398G pkh2Δ mutants. INA106-3B cells (pkh1D398G pkh2Δ::LEU2) were grown in YPGlu medium at 25°C (open symbols) and shifted to 35°C (closed symbols). At the times indicated, cell number and viability were assayed. Cell number was determined by phase-contrast light microscopy with a hemacytometer. Percent viability was determined by comparing the colony number obtained after incubation for 48 h in YPGlu with that expected from the number of cells observed in the plated sample. (B) Cell lysis of pkh1D398G pkh2Δ::LEU2 mutants. Yeast strains were patched onto YPGlu medium, incubated at 25°C for 1 day, and then shifted to 37°C for 1 day. The patches were assayed in situ for release of alkaline phosphatase as an indication of cell lysis. Yeast strains were 15Dau (wild type), INA106-3B (pkh1D398G pkh2Δ::LEU2), and SYT11-12A (pkc1ts stt1-1).