An October ‘miniblog extra’ from John, related to his September post about a potential cure for Huntington’s Disease.

John writes ...

Science sometimes comes up with results which are puzzling and/or difficult to fit into current understanding. Many years ago, early in my career, one of my PhD students was doing research on tobacco mosaic virus, which like the virus which causes COVID, has a genome made of RNA and not DNA. Thus, we expected infected plants to express a virus gene encoding an enzyme which copies RNA into RNA (so that the virus genome is replicated in the infected plant). This expectation was fulfilled but very puzzlingly, there were two such enzymes, not one, with the second one being present in uninfected plants. The latter fact means that it was encoded in the plant’s genome, not the virus’s. We checked and double-checked but the result was still clear: plants had an enzyme which copied RNA into RNA but why they did was a complete mystery. Our paper attracted some attention but then was quietly forgotten. 

In my recent blog post, I wrote about  types of RNA that cells synthesise as part of a process to get rid of unwanted messenger RNA molecules* that are no longer needed. One of these regulatory RNAs, anti-sense RNA was discovered about ten years after we discovered our mysterious enzyme. We now know that our ‘orphan enzyme’ has a major role in the synthesis of anti-sense RNA, although the discoverers of the latter were actually credited with discovering the enzyme. It was several years later, in a conversation between me and one of the leaders of the anti-sense research group, that it was recognised that our discovery was indeed the enzyme that made anti-sense RNA and it was a pity that our paper had not gained as much attention as it should have done. But, hey, that’s science and my research group has been very happy in making significant contributions to our understanding the control of the replication of DNA genomes (including the discovery of another pivotal enzyme).
* See pages 115 – 121 in the book if you need to know more about messenger RNA.
 
John Bryant
Topsham, Devon
October 2025