title: Thermoprotection of synaptic transmission in a Drosophila heat shock factor mutant is accompanied by increased expression of Hsp83 and DnaJ-1.
abstract: 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 inducible Hsps in response to heat shock. Contrary to our hypothesis, considerable thermoprotection was still observed at hsf4 larval synapses after heat shock. To investigate the cause of this thermoprotection, we conducted DNA microarray experiments to identify heat-induced transcript changes in these organisms. Transcripts of the hsp83, dnaJ-1 (hsp40), and glutathione-S-transferase gstE1 genes were significantly upregulated in hsf4 larvae after heat shock. In addition, increases in the levels of Hsp83 and DnaJ-1 proteins but not in the inducible form of Hsp70 were detected by Western blot analysis. The mode of heat shock administration differentially affected the relative transcript and translational changes for these chaperones. These results indicate that the compensatory upregulation of constitutively expressed Hsps, in the absence of the synthesis of the major inducible Hsp, Hsp70, could still provide substantial thermoprotection to both synapses and the whole organism.
authors.affiliation: Department of Biology, University of Toronto, Mississauga, Ontario, Canada.
authors.forename: Scott J
authors.initials: SJ
authors.lastname: Neal
authors.forename: Shanker
authors.initials: S
authors.lastname: Karunanithi
authors.forename: Adrienne
authors.initials: A
authors.lastname: Best
authors.forename: Anthony Ken-Choy
authors.initials: AK
authors.lastname: So
authors.forename: Robert M
authors.initials: RM
authors.lastname: Tanguay
authors.forename: Harold L
authors.initials: HL
authors.lastname: Atwood
authors.forename: J Timothy
authors.initials: JT
authors.lastname: Westwood
mesh_terms: D000064:Acclimatization; D000818:Animals; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism*; D004331:Drosophila melanogaster / Q000235:genetics* / Q000378:metabolism; D020869:Gene Expression Profiling / Q000379:methods; D050956:HSP40 Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism*; D000076249:Heat Shock Transcription Factors; D006360:Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism*; D018869:Heat-Shock Response / Q000235:genetics; D006358:Hot Temperature; D007814:Larva / Q000235:genetics / Q000378:metabolism; D009154:Mutation; D020411:Oligonucleotide Array Sequence Analysis; D012333:RNA, Messenger / Q000378:metabolism; D015203:Reproducibility of Results; D009435:Synaptic Transmission / Q000502:physiology*; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D015854:Up-Regulation
chemical_list: D004268:DNA-Binding Proteins; C494637:DnaJ-1 protein, Drosophila; D029721:Drosophila Proteins; D050956:HSP40 Heat-Shock Proteins; D000076249:Heat Shock Transcription Factors; D006360:Heat-Shock Proteins; C053134:Hsf protein, Drosophila; C089272:Hsp83 protein, Drosophila; D012333:RNA, Messenger; D014157:Transcription Factors