Human mutations in SOD2 are thought to play a role in numerous human disease conditions including cancer, mitochondrial disease, cardiopathy, diabetic neuropathy, and neurodegeneration (Rosenblum et al. 1996; Valenti et al. 2004; Mollsten et al. 2007). Within the human SOD2 gene six mutations have been characterized: three mutations have been identified within promoter region that presumably reduce expression (Xu et al. 1999, 2007, 2008), one mutation affects the mitochondrial targeting of the enzyme (Rosenblum et al. 1996), and Inhibitors,research,lifescience,medical two missense mutations affect coding exon 3 (Borgstahl et al. 1996; Hernandez-Saavedra and McCord 2003). SOD2Ala16Val affects the MTS

and is associated with cardiomyopathy (Rosenblum et al. 1996; Valenti et al. 2004) Inhibitors,research,lifescience,medical and diabetic nephropathy (Mollsten et al. 2007). There has been significant work performed in model systems to understand the role of SOD2. In a murine model, mice lacking SOD2 (SOD2tm1Cje) develop dilated cardiomyopathy and neonatal lethality (Li et al. 1995); this same mutation in a different genetic background exhibits inhibition or inactivation of electron transport chain and other mitochondrial

enzymes, and results in the accumulation of oxidative DNA damage (Melov et al. 1999). In Drosophila, previous studies have shown that SOD2 Inhibitors,research,lifescience,medical RNAi and null mutations are associated with reduced longevity and neural dysfunction (Kirby et al. 2002; Duttaroy et al. 2003; Belton et al. 2006; Martin et al. 2009). Here,

we report a novel missense mutation affecting SOD2 in Drosophila that Inhibitors,research,lifescience,medical leads to reduced longevity, sensitivity to hyperoxia, progressive increased mitochondrial ROS accumulation, neurodegeneration, and abnormal brain morphology. Our data demonstrate aberrant axonal targeting that likely underlies the abnormal brain morphology. Importantly, in silico studies support the conclusion that this mutation does Inhibitors,research,lifescience,medical not result in a major structural change to the SOD2 protein, yet Endocrinology antagonist dramatic reductions in steady state protein levels result, suggesting a marked increase in protein turnover of this mutant mitochondrial protein. Materials and Methods enough Fly husbandry, life spans, and stress-sensitivity tests Flies were maintained on standard cornmeal, molasses food. Life spans and stress-sensitivity tests were performed at 25 and 29°C, as previously reported (Palladino et al. 2002, 2003; Celotto et al. 2006b; Fergestad et al. 2006b, 2008; Seigle et al. 2008). The SOD2 mutant reported here was initially studied in the lab of Dr. Barry Ganetzky at the University of Wisconsin Madison where it was known as “hr2” and was identified in our previous screen of conditional mutants (Palladino et al. 2002). The SOD2 deficiency line utilized is Df(2R)Exel7145 and was obtained from the Bloomington Stock Center. Western blot Four fly heads were homogenized in 60 μL ice-cold lysis buffer (50 mmol/L Tris pH 6.8, 10% glycerol, 2% SDS, 0.