Molecular and phenotypic characterization of MsrA MsrB mutants of Drosophila melanogaster

Aging is a multifactoral biological process of progressive and deleterious changes partially attributed to a build up of oxidatively damaged biomolecules resulting from attacks by free radicals. Methionine sulfoxide reductases (Msrs) are enzymes that repair oxidized methionine (Met) residues found in proteins. Oxidized Met produces two enantiomers, Met-S-(o) and Met-R-(o), reduced by MsrA and MsrB respectively. Unlike other model organisms, our MsrA null fly mutant did not display increased sensitivity to oxidative stress or shortened lifespan, suggesting that in Drosophila, having either a functional copy of either Msr is sufficient. Here, two Msr mutant types were phenotypically assayed against isogenic controls. Results suggest that only the loss of both MsrA and MsrB produces increased sensitivity to oxidative stress and shortened lifespan, while locomotor defects became more severe with the full Msr knockout fly.