Contrary to the previous assumption that large tracts of the eukaryotic genomes are not transcriptionally active, recent evidence from transcriptome sequencing approaches have revealed pervasive transcription in many genomes of higher eukaryotes. Many of these loci encode transcripts that have no obvious protein-coding potential and are designated as non-coding RNA (ncRNA). Noncoding RNAs are classified empirically as small and long non-coding RNAs based on the size of the functional RNAs. Each of these classes is further classified into functional subclasses.
Although microRNAs (miRNA), one of the major subclass of ncRNAs, have been extensively studied for their roles in regulation of gene expression and involvement in a large number of patho-physiological processes, the functions of a large proportion of long noncoding RNAs (lncRNA) still remains elusive.
Researchers at the CSIR Institute of Genomics and Integrative Biology, India hypothesized that some lncRNAs could potentially be processed to small RNA and thus could have a dual regulatory output.
- Jalali S, Jayaraj GG, Scaria V. (2012) Integrative transcriptome analysis suggest processing of a subset of long non-coding RNAs to small RNAs. Biol Direct 7(1), 25. [abstract]