Cloning of a Rare Chronic Wasting Disease Prion Allele from Mule Deer
The prion protein is thought to be the causative agent for Chronic Wasting Disease in mule deer (Odocoileus hemionus). Prion protein polymorphisms at amino acid 225 cause three different allele product combinations: homozygous 225 serine/serine, heterozygous 225 serine/phenylalanine, and homozygous 225 phenylalanine/phenylalanine. The most common combination of allele products in clinically progressed CWD in O. hemionus is serine/serine at 225. The phenylalanine substitution is underrepresented in diseased animals. The goal of this project was to clone the very rare phenylalanine encoding prion allele for future study. The polymerase chain reaction (PCR) was used to amplify the prion protein structural gene but not the pseudogene that is present in deer. Positional cloning was used to insert this amplified product into a DNA vector. Successful cloning of the phenylalanine allele was confirmed by restriction enzyme analysis and DNA sequencing. In the future, the cloned gene can be used to generate a recombinant virus that will be used to express this rare protein for in vitro study.