A ferroportin transcript that lacks an iron-responsive element enables duodenal and erythroid precursor cells to evade translational repression.

ABSTRACT: Ferroportin (FPN1), the sole characterized mammalian iron exporter, has an iron-responsive element (IRE) in its 5' untranslated region, which ensures that its translation is repressed by iron regulatory proteins (IRPs) in iron-deficient conditions to maintain cellular iron content. However, here we demonstrate that duodenal epithelial and erythroid precursor cells utilize an alternative upstream promoter to express a FPN1 transcript, FPN1B, which lacks the IRE and is not repressed in iron-deficient conditions. The FPN1B transcript encodes ferroportin with an identical open reading frame and contributes significantly to ferroportin protein expression in erythroid precursors and likely also in the duodenum of iron-starved animals. The identification of FPN1B reveals how FPN1 expression can b

SUBMITTER: Zhang DL 

PROVIDER: S-EPMC2685206 | biostudies-literature | 2009 May

REPOSITORIES: biostudies-literature