The bank vole’s unique PrP protein

Prion diseases are rare progressive neurodegenerative disorders. Prion diseases tend to progress rapidly and to be fatal; characteristics include brain damage, long incubation periods, and lack of inflammatory response. Prion diseases are distinct because they aren’t triggered by bacteria or viruses, rather they are triggered by infectious proteins. The diseases are caused by prions, abnormally shaped proteins. When PrP- a normal brain protein- twists into an unnatural shape, it remakes other PrP proteins into the same unnatural shape. These prions then clump together into dangerous plaques.

Interested in the “exclusivity” of prion diseases, I decided to find out what type of animals can contract prion diseases of other animals. I came upon an article published in April 2014 in ScienceNews. This article focuses on bank vole PrP’s and the bank vole’s high susceptibility to prion diseases. https://www.sciencenews.org/article/bank-voles-provide-clue-prion-disease-susceptibility

Considering the fact that prion diseases hardly ever transfer from species to species, bank voles, a small rodent similar to mice, are an interesting species to study. Bank voles are unique in that they are especially susceptible to prion diseases. While usually a prion from one species is unable to corrupt PrP proteins of another species, the PrP proteins of bank voles are susceptible to every single prion disease when the prions are directly injected into the brain. Interestingly though, a wild bank vole has never been found to have a prion disease that was developed outside of the lab.

Joel Watts, University of Toronto neuroscientist, and his colleagues studied the PrP proteins of bank voles in order to find out if the vole’s high level of susceptibility was due to the vole’s physiology or to the vole’s PrP protein itself. Watts placed bank vole PrP proteins into mice and then injected infectious prions- ones that mice are usually not susceptible to- into the brains of the mice. While mouse PrP proteins and bank vole PrP proteins are different, they only differ by eight amino acids. The result was that the mice that quickly developed the neurological diseases were the same mice that had large amounts of vole PrP proteins. Thus, it can be assumed from the study that the vole PrP is a “universal acceptor”. This knowledge can be very useful for studying new diseases. Scientists can test if the diseases are prion diseases by placing infected brain matter into the brains of mice carrying vole PrP proteins and then seeing if the mice become infected with the disease. If the mice become infected, the disease is most likely a prion disease.