Genetic Variation in the Prion Protein Gene (PRNP) of Two Tunisian Goat Populations

Abstract

Scrapie is a fatal prion disease. It belongs to transmissible spongiform encephalopathies (TSEs), and occurs in sheep and goats. Similarly, to ovine species, the prion protein gene (PRNP) plays a major role in conferring resistance or susceptibility to TSE in goats. This study assesses the variability of PRNP in native and crossed-breed goat populations raised in the Southeast of Tunisia and provides information on the distribution of PRNP haplotypes and genotypes in these goat populations. A total of 116 unrelated goats including 82 native and 34 crossed-breed goats were screened for PRNP polymorphisms using Sanger sequencing. Sequence analysis revealed 10 non-synonymous polymorphisms (G37V, M137I, R139S, I142M, H143R, N146D, R154H, R211Q, Q222K, and S240P), giving rise to 12 haplotypes and 23 genotypes. Moreover, four silent mutations were detected at codons 30, 42, 138, and 179; the former was reported for the first time in goat (nucleotide 60 c→t). Interestingly, the PrP variants associated with resistance (D146 and K222) or with a prolonged incubation time of goat to scrapie (M142, R143, H154, Q211) were absent or detected with low frequencies except for H154 variant, which is present with high frequency (1%, 1%, 4%, 0%, 88%, and 6%, respectively, for native goats, and 0%, 1%, 0%, 1%, 78%, and 1%, respectively, for crossed goats). The analysis of PRNP polymorphisms of goats raised in other regions of the country will be useful in getting a global view of PRNP genetic variability and the feasibility of goat breeding programs in Tunisia.

Genetic Polymorphism at 15 Codons of the Prion Protein Gene in 156 Goats from Romania

“…The scrapie-positive goat analysed in our study was a female Banat’s White breed (GenBank ID: ON015441) without polymorphism associated with increased resistance (G37G, W102W, T110T, G127G, I142I, H143H, N146N, R151R, R154R, P168P, S173S, R211R, I218I, Q222Q, and S240S). The genotype ON015441 was consistent with our current understanding of which genotypes are susceptible [ 15 , 16 , 17 , 22 , 26 , 30 , 31 , 32 , 33 , 37 , 57 , 58 ].…”

“…The scientific knowledge concerning genetic resistance to classical scrapie and polymorphisms of the PRNP gene in European goat breeds/populations is sufficient to consider the development of guidance on how to increase goat genetic resistance to classical scrapie by disseminating resistant alleles in goat breeds [ 15 , 19 , 26 , 28 , 35 , 37 , 44 , 48 , 49 ]; our data give particular information for a future Romanian guide of breeding goats resistant to scrapie. Moreover, our research covered two local breeds (a total of 103 GenBank IDs of Carpathian and Banat’s White were obtained) and one of the most common European goat breeds (French Alpine); it also generated data for future metanalyses.…”

“…In the last 10 years, genetic variation of PRNP was reported in goat populations/breeds from Algeria [ 11 ], Canada [ 12 ], Ethiopia [ 13 , 14 ], Greece [ 15 , 16 , 17 ], Italy [ 18 , 19 , 20 ], Korea [ 21 , 22 ], Spain [ 23 , 24 ], Türkiye [ 25 ], Tunis [ 26 ], UK [ 27 ], and USA [ 28 ]. In addition to these reports, there is in-depth research on genetic resistance associated with some PRNP alleles, including those related to the K222 allele.…”

“…In addition, the PRNP polymorphisms at codons 21, 23, 37, 49, 102, 110, 127, 133, 137, 139, 142, 142, 143, 146, 146, 151, 154, 168, 173, 211, 218, 220, and 240 have been evaluated for scrapie genetic resistance in goats [ 15 , 16 , 17 , 22 , 26 , 30 , 31 , 32 , 33 ]. However, the EFSA summary results of goat genetic surveys in the EU emphasizes only codons 142, 146, 154, and 211–222 as codons with alleles of interest in breeding programmes to promote resistance to classical scrapie in goats.…”

Polymorphisms of Codons 110, 146, 211 and 222 at the Goat PRNP Locus and Their Association with Scrapie in Greece

“…In addition, the PrP Sc of atypical scrapie is relatively sensitive to proteinases [ 30 , 31 ]. In the last 15 years, many polymorphisms associated with resistance/susceptibility to scrapie, such as 110T/P, 127G/S, 142M/I, 145G/D, 146N/D/S, 154R/H, 211R/Q, and 222Q/K have been described in different breeds of goats and regions [ 5 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 ]. Based on these data and experimental challenge studies, the European Food Safety Authority (EFSA) has assigned the polymorphisms 222K, 146D, and 146S as acceptable candidates for breeding towards resistance against scrapie [ 13 , 41 ].…”