Showing papers on "Heat shock protein published in 1979"

Specific protection from phenocopy induction by heat shock

Abstract: Mild heat treatments applied to whole animals or cell cultures of Drosophila prior to lethal heat shocks result in increased survival and protection against phenocopy induction The optimal condition for the preliminary mild heat treatment is that which induces the synthesis of heat-shock proteins but does not turn off the protein synthesis that is in progress Recovery of protein synthesis but not RNA synthesis following a drastic heat shock is much enhanced by the pretreatments The results suggest that the protection for survival and against phenocopy induction is due to storage of messenger RNA

Heat shock induced proteins in plant cells

Abstract: Tobacco (Nicotiana tabacum) and soybean (Glycine max) tissue culture cells were exposed to a heat shock and protein synthesis studied by SDS-polyacrylamide gel electrophoresis after labeling with radioactive amino acids. A new pattern of protein synthesis is observed in heat-shocked cells compared to that in control cells. About 12 protein bands, some newly appearing, others synthesized in greatly increased quantities in heat-shock cells, are seen. Several of the heat-shock proteins (HSPs) in both tobacco and soybean are similar in size. One of the HSPs in soybean (76K) shares peptide homology with its presumptive 25°C counterpart, indicating that the synthesis of at least some HSPs may not be due to activation of new genes. The optimum temperature for maximal induction of most HSPs is 39–40°C. Total protein synthesis decreases as heat-shock temperature is increased and is barely detectable at 45°C. The heat-shock response is maintained for a relatively short time in tobacco cells. After 3 hr at 39°C, a decrease is seen in the synthesis of the HSPs, and after 4 hr practically no HSPs are synthesized. After exposure to 39°C for 1 hr, followed by a return of tobacco cells to 26°C, recovery to the control pattern of synthesis requires greater than 6 hours. These results indicate that cells of flowering plants exhibit a heat-shock response similar to that observed in animal cells.

Patterns of protein synthesis following heat shock in pupae of Drosophila melanogaster

Abstract: Pupae of Drosophila melanogaster were heat-shocked under conditions required to induce phenocopies in more than 90% of the flies that subsequently emerge. The effects of these treatments on protein synthesis in two tissues (thoracic epithelium and brain) were followed for several hours after the heat treatments. Results from pulse-labeling and protein separations on sodium dodecylsulfate (SDS) acrylamide gels showed a virtually complete cessation of protein synthesis immediately after the shock, followed by a noncoordinate resumption of the starting pattern. Similar experiments following double heat shocks demonstrated a more rapid resumption of synthesis of heat shock proteins after two successive heat treatments than after a single one.

Mutation generating a fragment of the major heat shock-inducible polypeptide in Drosophila melanogaster

Abstract: Drosophila melanogaster tissues carrying a third chromosome with the deletion Df(3R)KarD2 make a 40,000-dalton (Dal) heat shock protein not made by wild type. The unusual polypeptide was inducible in every tissue examined. Tryptic peptide fingerprints showed it to include part of the 70,000-Dal major heat shock protein. Mapping experiments placed the mutation responsible for the 40,000-Dal protein at or close to the karD2 deletion. One break point of the deletion is in subdivision 87A, close to or at a heat shock locus that codes for the 70,000-Dal protein. The results are consistent with the possibility that this break point is within a gene for the 70,000-Dal protein, leaving only the initial portion of its coding sequence. This would specify the direction of transcription of the mutant gene as proximal to distal on the normal chromosome. The 87A heat shock locus should contain at least two genes for the 70,000-Dal protein, because embryos homozygous for the karD2 deletion and lacking the heat shock locus at 87C, which also codes for the 70,000-Dal protein, nevertheless produced both the 40,000-Dal and the 70,000-Dal proteins upon temperature elevation. Using the presence of the 40,000-Dal protein to monitor chromosome segregation, we found that embryos homozygous for deletions of the heat shock puff site at 93D exhibited a normal electrophoretic pattern of heat shock proteins.

The analysis of a temperature-sensitive (ts) mutation influencing the expression of heat shock-inducible genes in Drosophila melanogaster.

Abstract: The effect of a ts-mutation belonging to the cell-lethal type on protein and RNA synthesis under heat shock conditions has been investigated. The mutation studied, l(l)ts-403, localized in the X-chromosome has significant effect on the kinetics of protein synthesis in salivary gland subjected to heat treatment under in vivo and in vitro conditions. The animals homozygous for l(l)ts-403 are characterized by a rapid drop of label incorporation into heat shock proteins. It is shown that the mutation affects not only the kinetics of heat-shock proteins synthesis but their electrophoretic pattern as well. The experiments performed enable us to conclude that the presumptive regulatory gene realized its action at the level of transcription of heat shock loci.

Organization ofthemultiple genesforthe70,000-dalton heat-shock protein inDrosophila melanogaster

Abstract: Theorganizationandnumberof70,000-daltonheat-shockproteingenesofDrosophilamelanogasterhasbeeninvestigated inawild-typeOregonRflystockandinaKCcellline. Six copies werefound in theKCcells, andslightly morewerefoundintheOregonRpopulationexamined.In bothcases, thebasicgeneelementconsistingofthemRNAcodingregionplus ashort 5' "noncoding"sequenceelementwasconserved.Twogene variants distinguished by specific restriction siteswerefoundin bothgenomicDNAs.Restriction mapsofthesixgenesin KCcells showedthatthesetwogenevariants are ar-rangeddifferently.RestrictionanalysisofOregonRembryonicDNArevealedpolymorphismintheorganizationofthe genes, whichis notobservedinKCcells.Thedatasuggestthatthear-rangementaswellasthenumberofgenesforthe70,000-daltonheat-shockprotein in D.melanogasteris subjecttovariationsatboththe87Aand87Ccytogenetic loci.Thechangein thepatternofgeneexpressionafterheatshockinDrosophila melanogaster(Dm)providesasystemparticu- larly suited for theinvestigation of thefunctional