Non-coding RNA Era is Dawning

Michael Abecassis

doi:10.15226/2376-4570/1/1/00102

Abstract

Vast majority of transcripts in eukaryotic organisms are noncoding RNAs (ncRNAs). Except for traditional non-coding transcripts ribosomal RNA (rRNA) and transfer RNA (tRNA), both of which play essential roles in protein translation, most of ncRNAs haven’t been functionally characterized and appreciated. Accumulating evidence, however, suggests that ncRNAs take part in many biological processes, and abnormal expression and/or dysfunction of them may result in a variety of diseases in human, such as cancers, neurodegenerative diseases, cardiovascular diseases and genetic diseases. The current understanding and future potential of ncRNAs in regulation of chromatin dynamics and gene expression, and implication to diseases are briefly outlined here.

Highlights

Regulatory ncRNAs can be grossly classified into small (˂200nt) ncRNAs encompassing small interfering RNAs, microRNAs, and Piwi-interacting RNAs, and long ( ˃200nt) non-coding RNAs [2,3,4]
RRNAs and transfer RNA (tRNA) are integral for translation to take place in the cells
X-inactive-specific transcript (Xist) is positively regulated by a group of long ( ˃200nt) non-coding RNAs (lncRNAs) arising from a region called X inactivation center (Xic), and negatively regulated by an antisense RNA, Tsix [12,13]

Summary

Introduction

Up to 90% of eukaryotic genomes are transcribed. Only ~ 2% of these transcripts encode proteins, while remaining 98% are ncRNAs [1,2]. ncRNAs can be categorized into infrastructural ncRNAs and regulatory ncRNAs. It has been determined that siRNAs and miRNAs regulate gene expression on post-transcriptional level through RNA cleaving and translational inhibition respectively, whereas piRNAs silence transposable elements (TEs) or imprinted loci of the genome through DNA methylation and/or histone modifications transcriptionally, and mRNA degradation or translation inhibition post-transcriptionally [7,8,9,10]. Recent evidence that ncRNAs contribute to the maintenance of chromosomal structure, regulation of gene expression, and development of diseases will be highlighted.

Results

Conclusion