Identification and Discovery of Novel microRNAs in the Human Genome

Although more than 98% of the human genome is transcribed, most of these transcripts are not translated into proteins. Rather, they are considered as non-coding RNAs. MicroRNAs (miRNAs) are very short non-coding RNAs approximately 22 nucleotides in length which regulate many key processes of cells such as growth, proliferation, differentiation, cell cycle, apoptosis (programmed cell death) and metabolism. On the other hand, it is known that these small regulatory molecules are involved in many human diseases such as different cancers and cardiovascular disorders. Therefore, discovery and functional characterization of novel miRNAs is a primary achievement. Low abundance and spatiotemporal expression of these mediator molecules make their discovery difficult by conventional methods. Therefore, bioinformatics software has been designed for the prediction of stem-loop structures capable of producing miRNA precursors in the human genome. On the other hand, there are several bioinformatics tools for prediction of miRNA target genes. Prediction of miRNA target genes helps to characterize the function of the miRNA. In this paper, we have reviewed some of the common efficient bioinformatics tools and experimental approaches used for prediction and identification of the miRNA genes and their target genes.