High-level expression of the bacterial opd gene in Drosophila melanogaster: improved inducible insecticide resistance.

The bacterial parathion hydrolase gene (opd) was expressed in transformed D. melanogaster under the control of an hsp70 promoter. Transformed lines carrying chimaeric genes designed for either cytoplasmic or secretory expression exhibited high- or low-level heat-shock-inducible transient resistance to paraoxon respectively. Greatest levels of resistance occurred approximately 12-16 h after heat shock and well after periods of maximal transcription. Insecticide resistance conferred by the cytoplasmic form of opd is expressed as a semidominant trait.