The storage of iron in eukaryotic cells is regulated by the protein ferritin. When intracellular iron concentrations are depleted, specific iron regulatory proteins (IRPs) bind to iron response elements (IREs) in the 5′-UTR5'\text{-UTR}5′-UTR (untranslated region) of the ferritin mRNA transcript. This binding sterically hinders the assembly of the translation initiation complex, preventing the ribosome from translating the transcript into polypeptide chains.
At which level of control is gene expression being regulated in this scenario?
transcriptional
post-transcriptional
translational
post-translational
