TRANSMISSION, DIFFERENTIATION, AND PATHOBIOLOGY OF TRANSMISSIBLE SPONGIFORM ENCEPHALOPATHIES
Location: Virus and Prion Research Unit
Title: Allele, genotype, and haplotype data for BSE-resistance polymorphisms from healthy U.S. holstein cattle
Submitted to: Journal of Dairy Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 9, 2007
Publication Date: January 1, 2008
Citation: Brunelle, B.W., Kehrli, Jr., M.E., Stabel, J.R., Moody Spurlock, D., Hansen, L.B., Nicholson, E.M. 2007. Allele, genotype, and haplotype data for bovine spongiform encephalopathy-resistance polymorphisms from healthy US holstein cattle. Journal of Dairy Science. 91:338–342.
Interpretive Summary: In this study, the prevalence of genetic polymorphisms associated with resistance to bovine spongiform encephalopathy (BSE) was assessed in U.S. Holstein cattle from 9 states. The frequencies of these polymorphisms were then compared to data from Holstein cattle in Germany, the United Kingdom, and Japan. Overall, the U.S. Holstein cattle have a higher frequency of these polymorphisms, indicating they are not at a greater risk for BSE than Holstein cattle from other countries. The prevalence of these polymorphisms could be increased in cattle by specific breeding programs.
Bovine spongiform encephalopathy (BSE) is a neurodegenerative disease of cattle caused by abnormally folded prion proteins. Two regulatory region polymorphisms in the bovine prion gene are associated with resistance to classical BSE disease: a 23 bp region in the promoter that contains a binding site for the repressor protein RP58, and a 12 bp region in intron 1 that has a binding site for the transcription factor SP1. The presence of these binding sites enhances BSE resistance in cattle, whereas cattle that lack these regions are more susceptible to disease. The present study examined the allele, genotype, and haplotype frequencies for the 23 bp and 12 bp polymorphisms in Holstein cattle from 9 different U.S. states, and then these frequencies were compared to data previously established for Holstein cattle from the United Kingdom, Germany, and Japan. Additionally, the coding region of the prion gene was sequenced from the U.S. samples. Finally, archival samples from U.S. Holstein sires born between 1953 and 1957 were analyzed. We found that the resistant allele and genotype frequencies for the U.S. Holstein cattle were as high, or higher, relative to that observed in other countries. Furthermore, the current U.S. frequencies were comparable to those determined in the archival samples from the 1950s. Based on the frequencies of these regulatory region polymorphisms, the U.S. Holstein population is not at a greater risk for BSE than Holsteins worldwide.