Decreased mitochondrial hydrogen peroxide release in transgenic Drosophilamelanogaster expressing intramitochondrial catalase

The objective of this study was to develop strategies for manipulating oxid ative stress transgenically in a multicellular organism. Ectopic catalase w as introduced into the mitochondrial matrix, which is the main intracellula r site of H2O2 formation and where catalase is normally absent. Transgenic Drosophila melanogaster were generated by microinjection of a P element con struct, containing the genomic catalase sequence of Drosophila, with the mi tochondrial leader sequence of ornithine aminotransferase inserted upstream of the coding region, Total catalase activities in whole-body homogenates of 10-day-old flies from four transgenic lines were similar to 30-160% high er than those from the parental and four vector-only control lines. Express ion of catalase in the mitochondrial matrix was confirmed by immunoblotting and catalase activity assays. Mitochondrial release of H2O2 was decreased by similar to 90% in the transgenic lines when compared to levels in vector -only controls. This in vivo system provides a novel model for examining th e functional significance of decreased mitochondrial H2O2 release. (C) 2000 Academic Press.