I don’t get really excited about science very often, and I rarely go to seminars outside of departmental requirements, and I certainly never get excited about scientific seminars…but today I went to one that blew my tiny little brain apart! Now mind you, I am JUST a research assistant, so much of the meat and potatoes of this talk went a bit over my head, but I am enough of a scientist to know when I have just heard some cool stuff from a really smart guy, and today, that smart guy was John Mattick.

I have been vaguely aware that there have been some big changes in the dogma of ‘junk DNA’ in the decades that ensued between the time I bashed my first promoter and the completion of the human genome project, but I haven’t really kept with the current theories or research. (And if you are hoping for a well-referenced and linked-up blog entry here, well, sorry.) For example, I have heard that the genome may be transcribed in both directions (such that when read forwards it encodes a transcription factor, but backwards says that John Lennon is Satan), and that much of what is thought to have no function, may actually be transcribed into ‘non-coding RNA’ that does…oh, something or other.

But today, John convinced me that not only is RNA the primary regulator of gene expression and cell differentiation, it is most likely THE mechanism by which environmental factors feed back to a cell to alter the function of expressed proteins and alter the genetic code. Basically, RNA provides a very plausible and rapid mechanism for evolution – and not in a “oops, I made a mutation, let’s see if there is a selective advantage” kind of way, but in a “hmmm, this change in receptor function is really working for me, let’s incorporate it into the gene – oh heck, let’s put it in the germ line and remember this change for future generations” kind of way.

Radical!

Without going into the all nitty-gritty bits (it would take a week – and it was only a one hour seminar), he showed some compelling evidence that many of the regulatory functions of a cell are mediated by RNA. I have often wondered just how a signaling cascade of all the same players can result in such different functions in different cells – John suggested that RNA molecules may serve as chaperones, guiding protein-DNA or even protein-protein interactions.

Some of his other crazy notions:

1. 3’UTRs may be expressed independently of their cis-coding sequences, sometimes even in completely different cell types that do NOT express the CDS at all…AND knocking down expression of the 3’UTR bit can alter function of said gene product. (I don’t know why, but this idea actually makes me moist.)
2. RNA polymerases can ‘create’ small bits of RNA by backtracking and clipping out 18 nucleotides when they bump into a +1 nucleosome and that these little bits help mark the places where transcription has occurred, and may influence epi-genetic modifications.
3. DNA:DNA:RNA triplexes are allllllll over the genome. Just what are they doing??
4. RNA editing of mRNA (or any RNA for that matter) by non-coding RNAs can occur in response to environmental stimuli (for example, in glutamate receptors)
5. RNA directed re-coding of DNA via epigenetic mechanisms may be the basis for plasticity and memory.
6. Non-coding RNA may even function as an extracellular signaling mechanism.
7. Dawkins and Gould pussed out and didn’t go far enough…intelligence is not a by-product of selection – it is inevitable.

…and that was when my brain exploded.

Phew, I need a beer!