mRNA Untranslated Regions (UTRs)

Flavio Mignone, Università di Milano, Milan, Italy
Graziano Pesole, Università di Bari and Istituto di Biomembrane e Bioenergetica del Consiglio Nazionale delle Ricerche, Bari, Italy

Published online: August 2011

DOI: 10.1002/9780470015902.a0005009.pub2

Eukaryotic messenger ribonucleic acids (mRNAs) possess a tripartite structure that comprises a 5¢ untranslated region, a coding region made up of the amino acid coding triplet codons and a 3¢ untranslated region. During nuclear maturation of primary transcripts, both ends of mRNA are post-transcriptionally modified through the addition of a 7-methyl-guanosine cap structure at the 5¢ end and a polyadenosine tail at the 3¢ end. Untranslated regions are involved in the post-transcriptional regulation of gene expression by modulating mRNA stability, nucleo-cytoplasm transport, subcellular localisation and translation efficiency thus allowing a fine control of the protein product. This regulatory activity is mediated by cis-acting oligonucleotide elements that interact with binding proteins and noncoding RNAs through a combination of primary and secondary structures.

Key Concepts:

  • UTRs are involved in the post-transcriptional regulation of gene expression.
  • UTRs regulate mRNA stability, nucleo-cytoplasm transport, subcellular localisation and translation efficiency.
  • Alternative splicing can result in mRNAs encoding the same protein under the control of different UTRs.

Keywords: post-transcriptional regulation; RNA-binding proteins; translation; mRNA stability; mRNA localisation

Figure 1. Examples of untranslated (UTR) elements with known secondary structure: (a) human basic fibroblast growth factor (GenBank accession number J) IRES element; (b) IRE structure of human transferrin (GenBank accession number M); (c) selenocysteine insertion sequence from human SelZ mRNA (GenBank accession number AF). Nucleotides that are conserved among the same elements from different transcripts are highlighted by filled circles.
Figure 2. Structure of a eukaryotic mRNA that depicts some post-transcriptional regulatory elements. Factors influencing message stability include uAUGs, uORFs, antisense noncoding RNAs (ncRNAs) and elements embedded in both the 5¢ and 3¢ UTRs. Modulation of translation may be mediated by the secondary structure of the 5¢ UTR, uAUGs or uORFs, as well as by protein-mediated poly(A) tail interaction with the 7mG cap. Subcellular localisation of mRNA is often mediated by miRNA elements located in the 3¢ UTR.
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Related Sub-Topics:

Nucleic Acid Structure | Translational Regulation | RNA Structure and Function | Noncoding RNA | Posttranscriptional Modification
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Article Title: mRNA Untranslated Regions (UTRs)
 
How to Cite close
Mignone, Flavio, and Pesole, Graziano(Aug 2011) mRNA Untranslated Regions (UTRs). In: eLS. John Wiley & Sons Ltd, Chichester. http://www.els.net [doi: 10.1002/9780470015902.a0005009.pub2]