Influence of selenoprotein methionine‐R‐sulfoxide reductase B1 on the lifespan of fruit flies

Abstract

Selenoproteins are a group of proteins (25 in mammals) that have a rare amino acid, selenocysteine. Selenoproteins serve critical functions in redox regulation. The Drosophila melanogaster has only 3 selenoproteins. D. melanogaster in which selenoprotein synthesis is disrupted has normal lifespan and is resistant to oxidative stress. Here, the GAL4‐UAS system was used to drive the expression of a recombinant selenoprotein, mouse methionine sulfoxide reductase 1 (mMsrB1), in the whole body and the nervous system of flies. mMsrB1 catalyzes the reduction of oxidized methionine residues in proteins and its function is implicated in the regulation of aging. The expression of mMsrB1 was confirmed by 75Se metabolic labeling and enzyme activity assays. mMsrB1‐expressing flies had a significant decrease in lifespan (up to 50%), but showed an increased resistance to oxidative stress. These data suggest that expression of a recombinant selenoprotein is toxic to fruit flies. This finding is consistent with the fact that the use of selenoproteins was reduced in insects via selenoprotein gene loss or their conversion to Cys‐containing homologs. This work was supported by the NIH grant AG021518 (to VNG).