Translational thermotolerance in Saccharomyces cerevisiae.
While protein synthesis is rapidly inactivated in Saccharomyces cerevisiae, cells shifted from log growth at 30 degrees C to 43 degrees C, a 1-h 37 degrees C treatment given to cells just prior to the shift to 43 degrees C partially blocks this inactivation. By contrast, such a pre-heat shock treatment has no protective effect on translational inactivation at 45 degrees C or higher. Cells allowed to approach stationary phase not only develop an enhanced thermotolerance relative to log cells but also exhibit a pronounced resistance to inactivation of protein synthesis at 43 degrees C as well as at 45 degrees C. We have found that this 'translational thermotolerance' can also be induced in S. cerevisiae by briefly treating log phase cells at 30 degrees C with cycloheximide. Using such a procedure to induce stabilization of protein synthesis at 43 degrees C, we have been able to show that heat shock-induced proteins are not responsible for the establishment of this protective effect. This work shows that enhanced thermotolerance can be induced in log cells even after a shift to 43 degrees C, as long as a prior translational thermotolerance has been established. Furthermore, we show that the capacity of plateau cells to maintain translation at 43 degrees C contributes significantly to their state of enhanced thermotolerance.
Hallberg
E M
EM
Department of Biology, Syracuse University, NY 13244, USA.
Hallberg
R L
RL
D015153:Blotting, Western; D002470:Cell Survival / Q000502:physiology; D004591:Electrophoresis, Polyacrylamide Gel; D005656:Fungal Proteins / Q000096:biosynthesis* / Q000302:isolation & purification; D018869:Heat-Shock Response / Q000502:physiology*; D006358:Hot Temperature; D014176:Protein Biosynthesis / Q000502:physiology*; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000502:physiology*
D005656:Fungal Proteins