Induction of sequence-specific binding of Drosophila heat shock activator protein without protein synthesis

Nature. 1987 Jun 25-Jul 1;327(6124):727-30. doi: 10.1038/327727a0.

Abstract

Drosophila tissue culture cells stimulated by heat shock contain high levels of heat shock activator protein, which binds specifically to the heat-shock control DNA element. In contrast, nonshocked cells have low basal levels of binding activity. Here, we show that within 30 seconds of heat shock of intact cells the sequence-specific binding activity in whole cell extracts increases significantly, reaching a plateau by 5 min after the start of the shock; removal of the heat stimulus returns the activity to basal levels. Known chemical inducers of heat-shock genes elicit a similar pattern of specific binding activity. Moreover, this pattern is observed in the presence of protein synthesis inhibitors, even if the stimulus-withdrawal is repeated sequentially through five cycles. Our results are inconsistent with models which propose proteolysis as the chief means of mediating heat-shock transcriptional control. Rather, they suggest that heat shock activator pre-exists in normal cells in a nonbinding form, which is converted upon cell stimulus to a high affinity, sequence-specific binding form, most probably by a post-translational modification. This conversion may be crucial for the transcriptional activation of heat shock genes.

MeSH terms

  • Animals
  • Base Sequence
  • Cell Line
  • DNA / metabolism*
  • DNA-Binding Proteins*
  • Dinitrophenols / pharmacology
  • Drosophila / genetics
  • Drosophila / metabolism*
  • Drosophila Proteins
  • Heat Shock Transcription Factors
  • Heat-Shock Proteins / biosynthesis
  • Heat-Shock Proteins / genetics*
  • Hot Temperature
  • Kinetics
  • Proteins / metabolism*
  • Sodium Salicylate / pharmacology
  • Transcription Factors
  • Transcription, Genetic

Substances

  • DNA-Binding Proteins
  • Dinitrophenols
  • Drosophila Proteins
  • Heat Shock Transcription Factors
  • Heat-Shock Proteins
  • Hsf protein, Drosophila
  • Proteins
  • Transcription Factors
  • DNA
  • Sodium Salicylate