Disease relevance of Hsp70Bbb

• Toxicity of cypermethrin: hsp70 as a biomarker of response in transgenic Drosophila [1].
• The homology between the Hsp70 gene of Drosophila and the E. coli dnaK gene illustrates the remarkable conservation of the heat shock genes in evolution [2].
• Caulobacter crescentus has a single dnaK gene that is highly homologous to the hsp70 family of heat shock genes [3].
• We also provide evidence that hsps protect cells from the toxic effects of anoxia, as well as heat, and conclude that nuclear translocation of hsp70 is related to its function in protecting the organism from both forms of environmental stress [4].
• Both methods produced a range of defects that included embryonic muscle disruption, reduced viability and female sterility, which could be rescued by hsp70-nautilus cDNA transgenes [5].

High impact information on Hsp70Bbb

• A 250 bp region upstream of both aur and a divergent transcription unit corresponds to the site of a specific chromatin structure (scs') previously proposed to be a barrier to insulate enhancers of the major hsp70 gene at 87A7 [6].
• Neither cross-linking method detects histones on the hsp70 promoter region [7].
• These puffs appear and regress with kinetics indistinguishable from the puffing of the heat shock locus, 87C, from which the hsp70 gene, used in these studies, was isolated [8].
• A hypersensitive site in hsp70 chromatin requires adjacent not internal DNA sequence [9].
• To gain some understanding of the molecular basis of these hypersensitive sites, we have now examined the pair of sites upstream of the Drosophila hsp70 gene in a series of plasmids that contain deletions in the hypersensitive region and have been transformed into yeast cells [9].

Chemical compound and disease context of Hsp70Bbb

• We have devised a heat shock-inducible indole-3-acetic acid (IAA) synthesis system for plant cells, which is based on the iaa genes of the Agrobacterium tumefaciens T-DNA and the heat shock promoter hsp70 of Drosophila melanogaster [10].

Biological context of Hsp70Bbb

• Furthermore, through the use of RNA interference in vivo, we show that dEloA is required for the proper expression of one of these genes, HSP70, and that its requirement for heat shock gene expression is exerted after the initiation of transcription at heat shock loci [11].
• We report here that the gene product of a rearranged mouse c-myc gene is capable of stimulating expression of chimaeric genes containing a Drosophila hsp70 promoter region and 5'-flanking sequences [12].
• Regulation of heat-shock genes: a DNA sequence upstream of Drosophila hsp70 genes is essential for their induction in monkey cells [13].
• Heat-shock genes coding for heat-shock protein 70 (HSP70) in Drosophila melanogaster were subcloned into an SV40/plasmid recombinant capable of replication in permissive monkey COS cells [13].
• A second Adh fusion gene in which the mRNA synthesized contained the first 95 nucleotides of the Hsp70 non-translated leader sequence gave rise, at high temperature, to mRNA which was translated during the heat shock [14].

Anatomical context of Hsp70Bbb

• Although devoid of mutant protein, this neurodegeneration exhibits neuronal inclusion bodies that are Hsp70 and ubiquitin positive [15].
• The level of expression of the mammalian heat shock protein 70 (HSP70) gene is elevated in several tumour cell lines, implying that a cellular function expressed in these tumour lines can stimulate HSP70 production [12].
• After heat-shock, the efficiency of hsp70 transcription in COS cells containing 2-4 X 10(4) gene copies was found to be 15-30% of that measured in Drosophila, on a per gene basis [13].
• The puffing pattern is very similar to that in salivary glands, but an unexpected difference is found in the relative activity of the 87A7 and 87C1 loci, which contain the hsp70 genes [16].
• It is known from earlier studies that the heat shock (HS) response in Malpighian tubules (MTs) of Drosophila larvae is different from that in other tissues because instead of the Hsp70 and other common heat shock proteins, Hsp64 and certain other new proteins are induced immediately after HS [17].

Associations of Hsp70Bbb with chemical compounds

• The main aims of our study were (1) to evaluate the cytotoxic potential of cypermethrin; and (2) to investigate the suitability of stress-induced heat shock protein Hsp70 as a biomarker for environmental pollutants in transgenic Drosophila melanogaster (Hsp70-lacZ)Bg(9) [1].
• By testing a series of 5' deletion mutants in this inducible transcription assay it was found that a sequence less than 70 bp long, directly upstream of the hsp70 gene, was essential for the heat or arsenite induction of transcription [13].
• Inhibition of heat-induced Hsp70 transcription by either Actinomycin D (Act D) or 5,6-dichloro-1-beta-D-ribofuranosylbenzimidazole (DRB) inhibited topoisomerase I cleavage except at the 5' and to a lesser extent the 3' end of the gene [18].
• This supports a transcriptional dysregulation of endogenous hsp70 gene induction in polyglutamine flies [19].
• The 5' untranslated leader sequence, approximately 200 bp long, is not interrupted by introns and is very rich (48%) in adenine residues, resembling Drosophila heat-inducible hsp70 genes [20].

Analytical, diagnostic and therapeutic context of Hsp70Bbb

• This arrangement has thwarted standard genetic approaches to generate an Hsp70-null fly, making this an ideal test of gene targeting [21].
• The initial two-to-four hsp70 duplication occurred 10--15 MYA, according to fixed in situ hybridization to polytene chromosomes, before the origin and divergence of the melanogaster and five other species subgroups of the melanogaster group [22].
• Transcript abundance, as estimated by Northern blot analysis and reverse transcription-polymerase chain reaction, shows that heat shock treatment (45 degrees C for 3 hours) does not elevate hsp70 messenger ribonucleic acid levels in fat bodies or in neural tissues [23].
• In the present study, we examined the kinetics of the synthesis of Hsp70 and Hsp64 immediately after HS and during recovery from HS by 35S-methionine labeling and Western blotting [17].
• Restriction mapping and blot hybridization indicated the presence of six putative hsp70 genes in these two closely linked regions [20].

References