Targeting mRNA to regulate iron and oxygen metabolism.
A family of non-coding sequences in the mRNA (iso-IREs [iron-responsive elements]) regulate synthesis of key proteins in animal iron and oxidative metabolism such as ferritin and mitochondrial aconitase. Differential recognition between iso-IREs and iso-IRPs (iron regulatory proteins) regulates the translation or degradation of the IRE-containing mRNAs. IREs are hairpin loop structures with an internal loop/bulge or bulge that influence the binding of the iso-IRPs. The iso-IRPs have sequence homology to the aconitases and at least one IRP can be converted to an aconitase. Signals that target the iso-IRE/iso-IRP interactions in mRNA include environmental iron, O2, nitric oxide, H2O2, ascorbate, growth factors, and protein kinase C-dependent IRP phosphorylation. Iso-IRE structural specificity suggests a means of pharmacologically targeting mRNA function with chemicals such as Fe-bleomycin and other transition metal complexes that could be extended to other mRNAs with specific structures. With the iso-IRE/iso-IRP system, nature has evolved coordinated combinatorial control of iron and oxygen metabolism that may exemplify control of mRNAs in other metabolic pathways, viral reproduction, and oncogenesis.
Theil
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Children's Hospital Oakland Research Institute, CA 94609, USA. etheil@mail.cho.org
D000818:Animals; D005786:Gene Expression Regulation; D006801:Humans; D007501:Iron / Q000378:metabolism*; D035925:Iron-Regulatory Proteins; D007506:Iron-Sulfur Proteins / Q000378:metabolism; D008954:Models, Biological; D010100:Oxygen / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism*; D016601:RNA-Binding Proteins / Q000378:metabolism
D035925:Iron-Regulatory Proteins; D007506:Iron-Sulfur Proteins; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; D007501:Iron; D010100:Oxygen