CuZn-SOD promoter-driven expression in the Drosophila central nervous system.

The aim of this study was to ascertain the status of CuZn superoxide dismutase (CuZn-SOD) expression in the central nervous system of Drosophila melanogaster. Immunoblot analysis of dissected tissue extracts revealed low levels of the CuZn-SOD protein in adult brains relative to other adult and larval tissues. To explore further this observation, three different reporter constructs containing different elements of the CuZn-SOD promoter domain were used for the generation of transgenic flies. A high level of reporter gene expression occurred during the second wave of neurogenesis (third instar and early pupal stages) in scattered, proliferating neuroblasts (NBs) and in proliferation centers of the optic lobe. In mature, postmitotic neurons, this expression was lower relative to other tissues. In adult flies, at all ages examined, there was little if any detectable reporter gene expression in cells of the central nervous system. These results suggest that one of the key components of the antioxidant defenses, CuZn-SOD, is quite low in postmitotic neural tissue, rendering it particularly susceptible to oxidative damage during aging.