Natural antisense transcripts: sound or silence?
Antisense RNA was a rather uncommon term in a physiology environment until short interfering RNAs emerged as the tool of choice to knock down the expression of specific genes. As a consequence, the concept of RNA having regulatory potential became widely accepted. Yet, there is more to come. Computational studies suggest that between 15 and 25% of mammalian genes overlap, giving rise to pairs of sense and antisense RNAs. The resulting transcripts potentially interfere with each other's processing, thus representing examples of RNA-mediated gene regulation by endogenous, naturally occurring antisense transcripts. Concerns that the large-scale antisense transcription may represent transcriptional noise rather than a gene regulatory mechanism are strongly opposed by recent reports. A relatively small, well-defined group of antisense or noncoding transcripts is linked to monoallelic gene expression as observed in genomic imprinting, X chromosome inactivation, and clonal expression of B and T leukocytes. For the remaining, much larger group of bidirectionally transcribed genes, however, the physiological consequences of antisense transcription as well as the cellular mechanism(s) involved remain largely speculative.
Werner
Andreas
A
Institute for Cell and Molecular Biosciences, University of Newcastle upon Tyne, Newcastle, United Kingdom. andreas.werner@ncl.ac.uk
Berdal
Ariane
A
D000483:Alleles; D005057:Eukaryotic Cells / Q000378:metabolism*; D005786:Gene Expression Regulation / Q000235:genetics; D016678:Genome / Q000235:genetics; D006801:Humans; D016372:RNA, Antisense / Q000235:genetics* / Q000378:metabolism*; D014158:Transcription, Genetic / Q000235:genetics
D016372:RNA, Antisense