Distinct translation regulation by two alternative 5′UTRs of a stress-responsive protein – dPrx I

Translation efficiency is often regulated in part by 5′-untranslated region (5′UTR). Sequence analysis of an evolutionarily conserved stress-responsive protein, Drosophila Peroxiredoxin I (dPrx I), found the transcript to have two alternative 5′UTRs that lead to an identical coding sequence: namely Ia and Ib. Although both isoforms coexisted in Drosophila cells, the Ia isoform appeared to be dominant. Furthermore, reporter assay found that Ia enhanced translation in steady-state cells while Ib increased translation in cells under oxidative stress. Together, our data suggest that the two alternative 5′UTRs of dPrx I may be involved in a translational regulatory mechanism that responds to cellular oxidative stress.