THE MANGANESE SUPEROXIDE-DISMUTASE GENE OF DROSOPHILA - STRUCTURE, EXPRESSION, AND EVIDENCE FOR REGULATION BY MAP KINASE

The gene encoding manganese superoxide dismutase (MnSOD) from Drosophi la melanogaster has been isolated and its expression has been studied. In contrast to several mammalian MnSOD genes, the Drosophila gene con tains a single intron and is transcribed into a single 0.8-kb transcri pt. Whole-mount in situ hybridization reveals extensive transcript acc umulation in ovarian nurse cells and a heavy maternal contribution to the early embryo, Larval imaginal discs are enriched with MnSOD transc ripts relative to other larval tissues, further suggesting a possible relationship between high MnSOD expression and mitotic activity. The 5 '-upstream region contains several well-known regulatory elements incl uding metal response, antioxidant response, and xenobiotic response el ements (MRE, ARE, and XRE, respectively), sites for activator protein- 1 (AP-1), nuclear factor-kappa B (NF-kappa B), adenosine 3',5'-cyclic monophosphate regulator binding element factor (CREB), as well as clas sic TATA and CAAT boxes. That MnSOD expression in Drosophila is regula ted in part by the transcription factor AP-1 via the MAP kinase signal transduction pathway is suggested by experiments which show that a hy pomorphic mutation of the MAP kinase-encoding rolled gene substantiall y reduces levels of MnSOD transcripts and correlates with reduced resi stance to oxidative stress in rolled mutants.