Heat shock at 42°caused a rapid inhibition of protein synthesis in Reuber H35 hepatoma cells. Inhibition was maximal within 5 min after the temperature was increased. After heat shock at 42°for 30 min, protein synthesis was restored in 4 to 5 hr. Heat shock did not inhibit amino acid transport or cause a decrease of cellular amino acid pools, excluding a direct effect of these parameters on t...

Human heat shock transcription factor 1 (HSF1) is responsible for stress-induced transcription of heat shock protein genes. The activity of the HSF1 transcriptional activation domains is modulated by a separate regulatory domain, which confers repression at control temperature and heat inducibility. We show here that two specific proline-directed serine motifs are important for function of the ...

OLDSCHMIDT ( 1935) first demonstrated responses to temperature shock G when he showed that heat treatment of normal flies resulted in individuals whose phenotypes resembled those observed in known mutants including crossveinless (cv) . Such individuals were termed phenocopies. MILKMAN ( 1962,1964, 1966) and MOHLER (1965a) have demonstrated that some of the selected crossveinless-like (cvl) line...

Two-cell bovine embryos become arrested in development when exposed to a physiologically relevant heat shock. One of the major ultrastructural modifications caused by heat shock is translocation of organelles toward the center of the blastomere. The objective of the present study was to determine if heat- shock-induced movement of organelles is a result of cytoskeletal rearrangement. Two-cell b...

The heat shock loci of Drosophila melanogaster chromosome subdivisions 87A and 87C have been studied by using cloned DNA. Both sites contain a number of copies of a 2,4-kilobase (kb) region homologous to mRNA for the 70,000-dalton heat shock protein. In situ hybridization to chromosomal RNA shows that transcripts of this sequence accumulate at both sites after temperature elevation. At 87C ther...

Expression of several heat shock operons, mainly coding for small heat shock proteins, is under the control of ROSE (repression of heat shock gene expression) in various rhizobial species. This negatively cis-acting element confers temperature control by preventing expression at physiological temperatures. We provide evidence that ROSE-mediated regulation occurs at the post-transcriptional leve...

In Drosophila larvae, acquired synaptic thermotolerance after heat shock has previously been shown to correlate with the induction of heat shock proteins (Hsps) including HSP70. We tested the hypothesis that synaptic thermotolerance would be significantly diminished in a temperature-sensitive strain (Drosophila heat shock factor mutant hsf4), which has been reported not to be able to produce in...

The response to heat shock at 47 degrees C was examined in the cyanobacterium (blue-green alga) Synechococcus sp. strain PCC 6301. On heat shock, the growth of the cells decreased and they preferentially synthesized a limited number of polypeptides. The rate of synthesis of these proteins increased markedly in the early period of temperature shift up and gradually decreased afterwards. Among th...

The effect of supraoptimal temperature on macronuclear DNA synthesis in Tetrahymena was studied by radioautography during prolonged heat and heat-shock synchronization treatments. Prolonged heat treatments (34 degrees C) delayed the initiation of S, but did not appreciably delay DNA synthesis in progress. Return to optimal temperature (28 degrees C) 50 or 100 min later resulted in initiation of...

Trypanosome procyclic forms multiply in the midgut of Tsetse flies, and are routinely cultured at 27°C. Heat shocks of 37°C and above result in general inhibition of translation, and severe heat shock (41°C) results in sequestration of mRNA in granules. The mRNAs that are bound by the zinc-finger protein ZC3H11, including those encoding refolding chaperones, escape heat-induced translation inhi...