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Journal of Biomedicine and Biotechnology
Volume 2006 (2006), Article ID 69616, 20 pages
Review Article

MicroRNAs in Gene Regulation: When the Smallest Governs It All

1Centre de Recherche en Rhumatologie et Immunologie, Centre de Recherche du CHUL, 2705 Boulevard Laurier, Ste-Foy, Quebec, Canada G1V 4G2
2Faculté de Médecine, Université Laval, Quebec, Canada G1K 7P4

Received 30 January 2006; Accepted 17 April 2006

Copyright © 2006 Dominique L. Ouellet et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Encoded by the genome of most eukaryotes examined so far, microRNAs (miRNAs) are small ~21-nucleotide (nt) noncoding RNAs (ncRNAs) derived from a biosynthetic cascade involving sequential processing steps executed by the ribonucleases (RNases) III Drosha and Dicer. Following their recent identification, miRNAs have rapidly taken the center stage as key regulators of gene expression. In this review, we will summarize our current knowledge of the miRNA biosynthetic pathway and its protein components, as well as the processes it regulates via miRNAs, which are known to exert a variety of biological functions in eukaryotes. Although the relative importance of miRNAs remains to be fully appreciated, deregulated protein expression resulting from either dysfunctional miRNA biogenesis or abnormal miRNA-based gene regulation may represent a key etiologic factor in several, as yet unidentified, diseases. Hence is our need to better understand the complexity of the basic mechanisms underlying miRNA biogenesis and function.