Long Noncoding RNA: Genome Organization and Mechanism of Action.

For the last four decades, we have known that noncoding RNAs maintain critical housekeeping functions such as transcription, RNA processing, and translation. However, in the late 1990s and early 2000s, the advent of high-throughput sequencing technologies and computational tools to analyze these large sequencing datasets facilitated the discovery of thousands of small and long noncoding RNAs (lncRNAs) and their functional role in diverse biological functions. For example, lncRNAs have been shown to regulate dosage compensation, genomic imprinting, pluripotency, cell differentiation and development, immune response, etc. Here we review how lncRNAs bring about such copious functions by employing diverse mechanisms such as translational inhibition, mRNA degradation, RNA decoys, facilitating recruitment of chromatin modifiers, regulation of protein activity, regulating the availability of miRNAs by sponging mechanism, etc. In addition, we provide a detailed account of different mechanisms as well as general principles by which lncRNAs organize functionally different nuclear sub-compartments and their impact on nuclear architecture.