1a.Objectives (from AD-416)
The objective of this cooperative research project is to investigate the influence of the bovine Prnp gene polymorphisms, E211K, on the susceptibility to BSE. Specifically, the research project will provide 134 embryos that will be used to generate approximately 62 animals, 31 of which will contain the rare allele for the purposes BSE research.
This ongoing SCA with Iowa State University to produce cattle with the E211K Prnp allele for BSE research has resulted in an E211/K211 heterozygous bull. We are now in the unique position to extend our research on this allele to include animals homozygous for K at position 211. Based upon our understanding of this novel polymorphism one would predict homozygotes would have a more rapid onset of clinical signs associated with genetic BSE than heterozygotes.
1b.Approach (from AD-416)
To achieve the research goals it is imperative to increase the number of animals available to study this Prnp polymorphism. One female calf of the 2006 BSE case was identified and carries the E211K allele. The specific objectives are to be accomplished through the production of multiple offspring from this E211K heifer through superovulation and embryo transfer.
Approximately 50% of the offspring will be heterozygous for the E211K polymorphism while the others will serve as genetically matched non-E211K controls. Collection of semen from an E211K heterozygous bull will allow creation of E211K homozygotes.
To protect this unique resource immediate collection of embryos is necessary. The initial goal is to harvest 134 embryos that should result in approximately 62 pregnancies (half of which will carry the E211K polymorphism) for immediate use in the studies to amplify the E211K material, test for genetic susceptibility to TSE, and develop a breeding group to produce calves for transmissibility studies.
The objective of this cooperative research is to protect the unique resource afforded us in the form of the only known cow possessing the 211K PRNP allele and to produce offspring containing this allele for research purposes. To date, 10 pregnancies have resulted from the harvested embryos. From these, 8 live calves have been delivered, 5 of which contain the 211K PRNP allele. As a derivative of this work we have been able to define the upstream regulatory elements associated with the 211K PRNP allele. Communication with the collaborator has been through a combination of email and face-to-face communication.