A team led by researchers at The St. Laurent Institute present data that challenges the notion that RNAs produced from the vast expanse of intronic space are just pieces of pre-mRNAs or excised introns en route to degradation. The function of RNA from the non-coding regions of the genome has been a subject of considerable recent debate. Perhaps the most controversy is regarding the function of RNAs found in introns of annotated transcripts, where most of the reads that map outside of exons are usually found.
By performing a highly quantitative RNA-seq analysis of transcriptome changes during an inflammation time course, they show that intronic RNAs have a number of features that would be expected from functional, standalone RNA species. They suggest that the sequences encoded in the introns appear to harbor a yet unexplored reservoir of novel, functional RNAs. As such, they should not be ignored in surveys of functional transcripts or other genomic studies.
- St Laurent G 3rd, Shtokalo D, Tackett M, Yang Z, Eremina T, Wahlestedt C, Inchima SU, Seilheimer B, McCaffrey TA, Kapranov P. (2012) Intronic RNAs constitute the major fraction of the non-coding RNA in mammalian cells. BMC Genomics. 13(1), 504. [article]