BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS Pages 894-900 POSITIVE REGULATORY GENE FOR TEMPERATURE-CONTROLLED PROTEINS IN ESCHERICHIA COLI

A group of nine proteins of Escherichia coli KI2 vary in steady state level with growth temperature, and are particularly abundant above 4O°C. The identities of most of these HTP (high temperature production) proteins are unknown; they are primarily recognizable on two-dimensional polyacryl-amide gels by their very high rates of synthesis during the ten-minute period following a shift-up in temperature. This stimulation, as much as 20-fold for some HTP proteins, is abolished by a conditionally lethal nonsense muta-tion in a chromosomal gene located at 75 minutes. Evidence suggests that this regulatory gene, htpR, makes an activator protein that is required for heat induction of HTP proteins