Long non coding RNAs: a proofreading of the central dogma of molecular biology
Recent advances in deep sequencing technologies have unequivocally demonstrated that the genomes of mammals, as well as other organisms, produce thousands of long transcripts that have no significant protein-coding capacity and thus are referred to as long non-coding RNAs (lncRNAs). They are strikingly similar to messenger RNAs (mRNAs): they are RNA polymerase II transcripts that are capped, spliced and polyadenylated, nevertheless do not function as templates for protein synthesis. Many functions have been assigned to lncRNAs, affecting many biological processes, including regulation of gene expression, dosage compensation, genomic imprinting, nuclear organization and compartmentalization.
We have recently identified two lncRNAs, linc-31 and linc-MD1, and defined their expression profile and function during muscle differentiation. These lncRNAs are able to regulate the expression of specific mRNAs at post-transcriptional level by competing for microRNA binding via their microRNA recognition motifs. We demonstrated that these lncRNAs are involved in the timing of muscle differentiation acting as “sponges” for specific microRNAs controlling the expression of key factors involved in the myogenic program. Therefore, we suggest that lncRNAs,imposing an additional level of post-transcriptional control, may play a relevant role in the complex network of regulatory interactions governing muscle differentiation.