Single nucleotide polymorphisms at 15 codons of the prion protein gene from a scrapie-affected herd of Suffolk sheep in Brazil

Pesquisa Veterinária Brasileira

Caroline Pinto De Andrade²  Laura Lopes De Almeida²  Luiza Amaral De Castro²  Juliano Souza Leal¹  Sergio Ceroni Da Silva²  David Driemeier¹ 

[1] ,Universidade Federal do Rio Grande do Sul Faculdade de Veterinária Laboratório de Biologia Molecular AplicadaPorto Alegre RS

关键词: Spongiform encephalopathy;    Prion protein;    Suffolk;    genetics and DNA sequencing;    Encefalopatia espongiforme;    proteína priônica;    Suffolk;    genética e sequenciamento de DNA;   

DOI  :  10.1590/S0100-736X2011001000010

来源: SciELO

【 摘 要 】

Scrapie is a transmissible spongiform encephalopathy of sheeps and goats, associated with the deposition of a isoform of the prion protein (PrPsc). This isoform presents an altered conformation that leads to aggregation in the host's central nervous and lymphoreticular systems. Predisposition to the prion agent infection can be influenced by specific genotypes related to mutations in amino acids of the PrPsc gene. The most characterized mutations occur at codons 136, 154 and 171, with genotypes VRQ being the most susceptible and ARR the most resistant. In this study we have analyzed polymorphisms in 15 different codons of the PrPsc gene in sheeps from a Suffolk herd from Brazil affected by an outbreak of classical scrapie. Amplicons from the PrPsc gene, encompassing the most relevant altered codons in the protein, were sequenced in order to determine each animal's genotype. We have found polymorphisms at 3 of the 15 analyzed codons (136, 143 and 171). The most variable codon was 171, where all described alleles were identified. A rare polymorphism was found at the 143 codon in 4% of the samples analyzed, which has been described as increasing scrapie resistance in otherwise susceptible animals. No other polymorphisms were detected in the remaining 12 analyzed codons, all of them corresponding to the wild-type prion protein. Regarding the risk degree of developing scrapie, most of the animals (96%) had genotypes corresponding to risk groups 1 to 3 (very low to moderate), with only 4% in the higher risks group. Our data is discussed in relation to preventive measures involving genotyping and positive selection to control the disease.

【 授权许可】

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