Tissue-specific expression of alternative oxidase in Drosophila melanogaster

Abstract

Dysfunctions in the respiratory chain complexes may cause increase of reactive oxygen species that damage the genetic and structural material of the cell. The alternative oxidase (AOX) allows electron flow from the ubiquinone directly to molecular oxygen, bypassing complexes III and IV and causing beneficial effects in organisms with malfunctions in such enzymes. When expressed in Drosophila melanogaster, AOX reduced considerably the deleterious phenotypes of flies with neuronal or mitochondrial dysfunctions. Because AOX does not pump protons to the mitochondrial intermembrane space, it may affect ATP synthesis. In the presence of carbohydrates in the diet, however, this might be compensated by the preference for a glycolytic metabolism. It is then imperative to validate the AOX benefits in absence of carbohydrates. In previous works of our laboratory, transgenic D. melanogaster expressing AOX and cultivated in carbohydrate-restricted diet showed dramatic decrease in adult eclosion rate. To better understand the roles of AOX, the goal of this work is to express AOX specifically in muscular and neuronal tissues in absence of carbohydrates in the diet. Crosses between the lines UAS-AOXF6, carrying the UAS promotor fused to the AOX transgene, and MhcGal4 and ElavGal4, which drive the expression of the enzyme specifically to muscular and neuronal tissues respectively, will be performed. UAS-GFP and w111 will be used as controls. The progeny of each cross will be subjected both to carbohydrate-rich and -restricted diets, and the eclosion rate will be computed from the number of pupae and the number of adults eclosed. (AU)