RNA gets curtain call

In what might be the understatement of the year, the scientific director of NHGRI has said of the machinery of the human genome “oh my gosh, this is really complicated”.

Quite! I finally had some time to read the ENCODE report published this month in Nature, along with the updated definition of a gene proposed by Gerstein et al. The project, which has been running for 3 ½ years, has analysed and reported in detail on 1% of the human genome (around 30 Mb), particularly its functional aspects.

The two findings getting the most coverage are (1) the splicing and sharing of the same bases for different functional products and (2) the prevalence and increased importance of non-protein coding genes, particularly RNA.

As a consequence, Gerstein et al suggest that we update the definition of a gene: “the gene is a union of genomic sequences encoding a coherent set of potentially overlapping functional products”.

The traditional “dogma” is that DNA is transcribed to RNA, which is in turn translated into proteins. Although we’ve known of transcribed RNA that aren’t translated into proteins, for example tRNA and rRNA, ENCODE suggests that we’ve significantly underestimated the amount of RNA that is transcribed, much of it of unknown function. The report says that almost all of the 1% of human genome studied results in functional products, whether protein or non-protein (i.e. RNA).

Whether this extra RNA is simply an artifact or really does have important function could be contentious and some are bound to question the importance of the findings.

However, the general feeling is that what we have here is an important paradigm shift. Publishers must be rubbing their hands at the prospect of new editions of molecular biology textbooks!

More:

• Nature ENCODE focus
• ENCODE project
• It was bound to happen