Characterization of Coxsackie virus B3 (CVB3) RNA dependent RNA polymerase (RdRp) variants in vitro.

That is the official title of my summer research project.

First, if you want the best explanation of my lab....

http://www.vignuzzilab.eu/research.htm

Second, I want to try and explain what I’m doing for research this summer- I’m sorry if I under/over simplify things!

I am researching RNA virus population dynamics. I am working specifically with the Coxsackie virus B3 (CVB3), an RNA virus that is very similar to the poliovirus. Viruses exist in nature not as a single “species” with tightly controlled genomes, but as “quasispecies”. These genetically diverse populations are better equipped to adapt to new environments, and RNA viruses make the most mutations during replication compared to other types of polymerases. You have probably heard of this in terms of many different infectious agents, and how it is hard to make drugs targeting rapidly evolving organisms- the arms race between virus and host. CVB3 is mainly a third world problem, causing “hand, foot, and mouth disease”, but it is another viral model we can study.

For those who want to read more.
CVB3 has a RNA dependent, RNA polymerase (RdRp) that is responsible for it’s replication, almost identical to the poliovirius RdRp. When studying poliovirus, they discovered mutant populations that were resistant to the antiviral drug Ribavirin. These mutants had RdRps that were making fewer mutations during replication, therefore creating a smaller population cloud of virus, or “quasispecies”. This was the result of a mutation at just one amino acid in the active site of the polymerase-position 64. When these “high fidelity” mutants were then exposed to other antiviral drugs, the viruses were unable to mutate and had attenuated virulence. This has implications in terms of vaccine safety and future treatment with antiviral medication.

I am expanding off the observations in the poliovirus model; instead we induced mutations in the RdRp of CBV3 and are seeing if we can find a mutant that is Ribavirin resistant. What we are finding is that despite the extreme similarity, mutations at the same position effect the two viruses differently and with limited viability. Induced mutations in one region, often become reverted with low fidelity polymerases instead of the high fidelity polymerases. Hopefully, by the end of the summer I can characterize the different types of mutations!