From BMC Blogs by Andrew Cosgrove –
The central dogma postulates that genes are first copied into messenger RNAs, which are then decoded into proteins with the help of transfer RNAs and ribosomal RNAs. It has long been known that there is more to the world of RNA than just these three classes, but the development of high-throughput RNA sequencing has revealed just how active RNAs can be. Much of the genome is transcribed, without these transcripts being translated into proteins. As these non-coding RNAs have been characterized, it is clear that many of them have regulatory roles. It has also been revealed how chemical modifications to all classes of RNAs affect their behavior, such as what they interact with and when, and how long they hang around for before being degraded.
Long noncoding RNAs are particularly enigmatic, possibly because the term is a bit of a catch-all term for several different classes of RNA with a variety of functions. Maite Huarte and colleagues have provided a useful Review of the different mechanisms of lncRNA function. The special issue also includes a research paper from the same authors, in which they characterized the role of one particular lncRNA, PINT. They show PINT acts as tumor suppressor by interacting with the Polycomb Repressor Complex 2, hence regulating the expression of genes involved in tumor invasiveness.
Another class of lncRNA arises from antisense transcription, and Wyler et al. have shown that herpes simplex virus causes widespread antisense transcription in cells. This aids infection by preventing apoptosis in the infected cells, allowing the virus to replicate and spread.