Monday, March 26, 2007

Bacteria Use RNAi-Like Mechanism to Ward off Viruses

I vaguely remember Rob blabbing in the bay about the RNAi system being an ancient and conserved mechanism by which cells defend themselves from viral infection. Maybe I will start paying more attention to this blabbing now, because I just read an article in Science that suggests that this idea may amount to more than the mere rantings of a degenerate graduate student. While the RNAi machinery of eukaryotic cells has been thoroughly described and well-documented to play a role in anti-viral defence, this recent paper provides the first evidence to my knowledge for an RNAi system in prokaryotes, and its role in anti-viral defence. Interestingly, the system appears to involve integration of phage sequence into the bacterial genome into regions known as "clustered regularly interspaced short palindromic repeats", which can then serve as a template for the production of short interfereing RNAs targeting phage mRNAs. Thus the system appears to be a primitive form of cell-autonomous immunological memory which protects against repeated viral infection.

Once again, a bayblabber is the first to predict a major breakthrough in biology. Now, if you can outline a full mathematical model describing the dynamics of the interaction between viral quasispecies and the host cell RNAi machinery, then I'll be impressed.


Anonymous said...

That's interesting. When you think of biology in perspective, there are so many mechanisms to battle viruses in prokaryots. For instance, restriction endonucleases, cell wall, now this RNAi like mechanism, yet the viruses can survive and grow withing them. Just goes to show the fine balance between different organisms.

generic cialis said...

If you wanted to use bacteria to produce the product of a human gene why might you want to isolate the mRNA rather than the DNA of that gene?a. mRNA is easier to isolate than is DNA