The Thai Journal of Veterinary Medicine


Leptin is a versatile important hormone that regulates several metabolic pathways, such as controlling body weight, feed intake, energy expenditure, immune function, and reproduction. This study was conducted to describe the single nucleotide polymorphisms (SNPs) within bovine leptin (LEP) gene, and their possible consequences on leptin structure and function in Holstein cattle. After collecting blood samples from 60 Holstein cattle, extracting their genomic DNA, two PCR-specific primers were designed. Both PCR and SSCP experiments were optimized and performed for each PCR fragment. Each different set of SSCP resolved bands was sequenced and analyzed. Two SSCP patterns representing two genotypes (AA, and AB) were detected with two alleles. Four SNPs were observed in this study, intronic, exonic synonymous, exonic non-synonymous, and nonsense SNP. All the observed SNPs were computationally analyzed using several bioinformatics tools. The most exciting novel SNP was a p.E115Ter nonsense mutation, which caused a premature termination of leptin and truncation of its last thirty-one amino acid residues. The deleted segment contained α-helix E, α-helix D, and Cyst146. Thus, it is strongly suggested that such mutation has a series of deleterious consequences, at least in terms of leptin receptor binding or its subsequent signaling activity. Nonetheless, such highly damaging mutation might not be abolished for the whole milk production trait in the studied cattle population. Although this study did not associate the observed mutations with production traits, it shows the findings of dramatic nonsense mutation, which might be important in future studies, and laid the basis for further association analyses needed to evaluate the potential use of this truncation as genetic hallmarks of the highly economically important Holstein cattle breed.

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