lncRNAs: significance and function mechanisms

In mammals, the majority of products of gene expression are non-coding ribonucleotide sequences. They include short and long RNA molecules with sizes ranging of tens to hundreds of nucleotides. Among them, the molecules with more than 200 nucleotides are called long non-coding RNAs or lncRNAs. While LncRNAs functions depend on their unique molecular structures, they play important roles in regulating gene expression at epigenetic, transcriptional and post-transcriptional levels. Interacting with other biological molecules such as DNA, RNA and protein, LncRNAs have been found to play important roles in normal cell physiological activities. Activation of transcription factors, guidance of ribonucleoprotein complexes, aggregation of partner proteins, regulation of alternative processing, cooperation in chromatin remodeling, facilitation of genomic imprinting, maintaining of multipotential state and control of nucleus/cytoplasm traffic are some of crucial approaches Implemented by LncRNAs. Modern technologies have been developed to identify lncRNA molecules, and many relevant databases have been designated to facilitate research and academic exchange of data concerning them. In this review article, signification, identification, classification, biological evolution, genomic position, configuration, expression, localization and remarkable functions of LncRNAs have been discussed.