Figure 3.

GEA1 GEA2 conditional double mutants accumulate membranes at the nonpermissive temperature. gea1-4 Δgea2 cells were grown to early log phase in YPD at 23°C (permissive temperature). The culture was split in half. One-half remained at 23°C, and the other half was transferred to 37°C (restrictive temperature) for 1 h. The cells were prepared for electron microscopy and ultrathin sections were stained. (A and B) Cells grown at 23°C. (C and D) Cells that were shifted to 37°C for 1 h. Note the membrane accumulation, especially ER membranes at 37°C and Golgi structures even at 23°C. Some examples are highlighted with arrows. Pictures were taken at the same magnification. Bar, 0.9 μm.