A sequencing strategy for identifying variation throughout the prion gene of BSE-affected cattle.
BACKGROUND
Classical and atypical bovine spongiform encephalopathies (BSEs) are cattle prion diseases. Distinct bovine prion gene (PRNP) alleles have been associated with classical and atypical BSE susceptibility. However, the full extent of PRNP allele association with BSE susceptibility is not known. A systematic sequence-based genotyping method that detects variation throughout PRNP would be useful for: 1) detecting rare PRNP alleles that may be present in BSE-affected animals and 2) testing PRNP alleles for an association with either classical or atypical BSE susceptibility.


RESULTS
We improved a Sanger-based sequencing strategy for detecting bovine PRNP variation through all exons, introns, and part of the promoter (25.2 kb). Our current method can detect 389 known and other potentially unknown PRNP polymorphisms that may be present in BSE-affected cattle. We determined PRNP genotypes for the first U.S. BSE case and her sire. Previously unknown PRNP polymorphisms were not detected in either animal and all PRNP genotypes support the sire-daughter relationship.


CONCLUSIONS
The methodologies described here characterize variation throughout PRNP. Consequently, rare PRNP alleles that may be present in BSE-affected cattle can be detected.
Clawson
Michael L
ML
United States Department of Agriculture (USDA), Agricultural Research Service (ARS), US Meat Animal Research Center (USMARC), Clay Center, NE 68933, USA. mike.clawson@ars.usda.gov
Heaton
Michael P
MP
Keele
John W
JW
Smith
Timothy Pl
TP
Harhay
Gregory P
GP
Richt
Juergen A
JA
Laegreid
William W
WW