Heat shock proteins and biological response to hyperthermia.

Thermotolerance is of significant interest because the resistance of pre-heated cells greatly surpasses the resistance of control cells. The induction of protein synthesis following a temperature shock (12 min, 45 degrees C) which produces thermotolerance is examined using SDS polyacrylamide gel electrophoresis. It was observed that the synthetic rates of certain proteins following heat shock significantly exceeded their synthetic rates in control (non-heat shocked) cells. The most strongly induced bands were observed at 68,000, 89,000 and 110,000 daltons. The induction of these proteins was blocked by inhibitors of transcription (actinomycin D) or translation (cycloheximide). This phenomenon strongly resembles the heat shock induction of gene transcription well studied in Drosophila melanogaster. The strong induction of gene transcription well studied in Drosophila melanogaster. The strong correlation between the kinetics of the induction of these heat shock proteins and the kinetics of thermotolerance induction is discussed.