The Role of 3'UTR of RNA Viruses on mRNA Stability and Translation Enhancement.

The central dogma of molecular biology explains the flow of genetic information from DNA to functional products such as proteins. In most cases, a linear relationship with a high correlation coefficient exists between the concentration of mRNA, the middle man, and the functional product. Untranslated regions (UTRs) of RNA form a considerable base pairing that contributes to the secondary and tertiary structures of mRNA. The interaction between the mRNA secondary structures (cis-elements), RNA-binding proteins (RBP) and miRs (trans-element) are critical determinants of mRNAs' fate and stability. Among different viral families, the positive sense (+) RNA viruses use the simplest possible strategy of replication and expression, as the same molecule functions both as a genome and mRNA. Additionally, nucleotide composition and codon usage of +RNA viruses are the closest to human codon adaptation index (CAI). Since the origin of replication of viral intermediate RNA molecules is at the 3'-end of the genome, the 3'UTR plays a role in viral RNA replication. Moreover, the messenger role of RNA likely places functional demands on the 3'UTR to serve a role typical of cellular mRNA. This article reviews the effect of 3'UTR of RNA viruses with positive sense and genomes on mRNA stability and translation improvement. A range of animal (e.g., Dengue, Sindbis, Corona and Polio) and plant (Barley yellow dwarf, Brome mosaic, Turnip crinkle, Tobacco mosaic, Cowpea mosaic and Alfalfa mosaic) viruses are examined to highlight the role of 3'UTR in viral survival and as a potential target for pharmaceutical applications.