Tissue-specific targeting of Hsp26 has no effect on heat resistance of neural function in larval Drosophila

Cell Stress Chaperones. Spring 2008;13(1):85-95. doi: 10.1007/s12192-008-0016-6. Epub 2008 Feb 15.

Abstract

Hsp26 belongs to the small heat-shock protein family and is normally expressed in all cells during heat stress. We aimed to determine if overexpression of this protein protects behavior and neural function in Drosophila melanogaster during heat stress, as has previously been shown for Hsp70. We used the UAS-GAL4 expression system to drive expression of Hsp26 in the whole animal (ubiquitously), in the motoneurons, and in the muscles of wandering third-instar larvae. There were slight increases in time to crawling failure and normalized excitatory junction potential (EJP) area for some of the transgenic lines, but these were not consistent. In addition, Hsp26 had no effect on the temperature at failure of EJPs, normalized EJP peak amplitude, and normalized EJP half-width. Overexpression larvae had a similar number of motoneuronal boutons and length of nerve terminals as controls, indicating that the occasional protective effects on locomotion were not due to changes at the synapse. We conclude that overexpression had a small thermoprotective effect on locomotion and no effect on neural function. As it has been shown that Hsp26 requires action of other Hsps to reactivate the denatured proteins to which it binds, we propose that at least in larvae, the function of Hsp26 was masked in the relative absence of other Hsps.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Action Potentials
  • Animals
  • Animals, Genetically Modified
  • Drosophila Proteins / antagonists & inhibitors
  • Drosophila Proteins / genetics
  • Drosophila Proteins / physiology*
  • Drosophila melanogaster / genetics
  • Drosophila melanogaster / growth & development
  • Drosophila melanogaster / physiology*
  • Gene Expression Regulation, Developmental
  • Genotype
  • Heat-Shock Proteins / antagonists & inhibitors
  • Heat-Shock Proteins / genetics
  • Heat-Shock Proteins / physiology*
  • Hot Temperature / adverse effects
  • Larva
  • Locomotion
  • Motor Neurons / metabolism*
  • Muscles / metabolism*
  • Neuromuscular Junction / physiopathology*
  • Organ Specificity
  • Recombinant Fusion Proteins / biosynthesis
  • Recombinant Fusion Proteins / physiology
  • Stress, Physiological / genetics
  • Stress, Physiological / physiology*
  • Synapses / physiology
  • Synapses / ultrastructure

Substances

  • Drosophila Proteins
  • Heat-Shock Proteins
  • Hsp26 protein, Drosophila
  • Recombinant Fusion Proteins