Profiling Cu,Zn-superoxide dismutase expression in Drosophila melanogaster--a critical regulatory role for...

Cu,Zn-superoxide dismutase (SOD1) represents along with catalase the first coordinated line of defense against ROS and is found in all aerobic organisms. The dissection of the regulatory controls that drive the expression of SOD1 may provide further insight into the functional significance of this enzyme. The aim of this study was to elucidate temporal and spatial patterns of SOD1 expression, as well as to identify gene domains that govern its expression. Immunostaining analysis was used to delineate marked tissue and stage-specific expression patterns during the course of development and aging. By and large, there were no significant alterations in SOD1 mRNA and protein levels in response to the stress that accompanies aging, nor in response to different environmental insults, such as heat and hyperoxia. Expression of SOD1 seems to be largely determined by intrinsic factors. By histochemical analysis of transgenics carrying various sod1-reporter gene fusions, it was also possible to identify sequence domains, governing SOD1 expression. In particular a 1140 base pair region, composed of the single sod1 intron along with exon 2, was found to be essential for permitting spatial and temporal expression patterns that approximate normal endogenous expression.