ABSTRACT
MicroRNAs [miRNAs] are a class of short, endogenously-initiated, non-coding RNAs that post-transcriptionally control gene expression via translational repression or mRNA turnover. MiRNAs have attracted much attention in recent years as they play critical roles in gene expression and are promising tools with many biotech and therapeutic applications. The molecular mechanisms underlying the translational control of mRNAs are not fully understood but emerging evidence point to a key role for microRNAs in this process. In this review, we discuss the potential role of miRNAs as regulators of mRNA traffic and translational control, focusing on molecular mechanisms of miRNA-mediated control of eukaryotic mRNA stability and translational efficiency. Translational control by miRNAs is often associated with silencing and repression of mRNAs via accumulation within cytoplasmic processing bodies [P-bodies], the site of mRNA storage and/or decay. Specific miRNAs can interact with the 3'UTR or 5'UTR of target mRNAs and regulate their stability as well as translational efficiency. A better understanding of these mechanisms is critical in advancing our knowledge of the role of these regulatory RNAs in modulating protein synthesis and controlling metabolic pathways in health and disease. The discovery of miRNAs and their important role in controlling many aspects of cell function and metabolism have led to considerable interest in biotech applications of miRNAs and their application in modulating specific gene expression. We thus highlight the growing biotech and therapeutic applications of miRNAs.