A study of microRNAs in silico and in vivo

Abstract

MicroRNAs (miRNAs) are a class of small noncoding RNA molecules that account for 1% of the genome; they are transcribed by RNA polymerase II in the nucleus, processed into a single-stranded mature miRNA of 19–25 nucleotides by the enzyme Dicer in the cytoplasm, and then destabilize or inhibit the translation of their target mRNAs in the genomes of plants and animals. About 1000 miRNAs have been identified by experimental and bioinformatic analysis since the first miRNA, lin-4, was identified in Caenorhabditis elegans in 1993. Recent evidence suggests that the production of miRNAs is signal-specific and celltype specific, and that miRNAs modulate the posttranscriptional regulation of their targets in diverse biological regulatory systems, including cell growth, differentiation and cell death. In addition, miRNAs are involved in the molecular mechanisms of diseases such as cancers and diabetes. The miRNAs involved in diseases have been a significant focus of attention in work on miRNA–mRNA molecular networks and in clinical reagents for imaging, diagnosis and the treatment of disease. Many studies have identified and described the biology of miRNAs at the molecular and cellular levels. However, we are just beginning to understand the expression of miRNAs and how they regulate their targets in the development of disease.