Translational regulation of ferritin synthesis by iron.

摘要: This review starts with a description of certain features mammalian ferritins and their DNA RNA structures relevant to translational control ferritin synthesis. Although the amino acid sequences two subunits (H L) diverge in about 50% coding region, five alpha-helices exon sizes genes are compatible proposition that they diverged from single ancestral gene. Of particular note is long 5'-untranslated regions (5'UTRs) which include 28-nucleotide sequence almost completely identical H- L-subunits range species. motif near cap region 5'-UTR, forms specific stem-loop structure, provides for regulation translation L-ferritin mRNAs. When intracellular levels chelatable iron not excess, large reserve L-mRNAs present cell sap, restrained by protein an Mr 90-100,000 binds structure. excess floods cytosol, this protein/RNA complex appears dissociate 40S ribosome subunit now able initiate synthesis so dormant mRNAs become active transferred polyribosomes. The mechanism whereby binding regulated response currently under investigation. regulatory occurs sap several interchangeable appear differ redox state sulphydryls within protein. Under some circumstances, abundance these be altered status. It unclear how influences mRNA. Some investigators consider form heme protein, offer vitro evidence. We have examined role versus inorganic oxygenase rat fibroblasts hepatoma cells. By manipulating flow between pools we concluded can act as regulator manner independent formation. conclusion does exclude specialized types.