SNPs identification in swine leptin 5’ flanking region and transcriptional activity of naturally occurring promoter haplotypes

Abstract

Leptin is an adipocyte-derived hormone acting as a major regulator for food intake and energy homeostatis. Previous studies have focused on association between polymorphisms in the coding region of the leptin pig gene and economically important traits. This work was aimed to study the leptin (LEP) gene at the promoter region to search for polymorphisms that could led to a different gene expression regulation. In a 1213 bp 5’ UTR region we identified 15 new single nucleotide polymorphisms (SNP) and 2 deletion (del) in two pig breeds characterized by different fat content namely Casertana (CT) and Large White (LW). In order to investigate whether the polymorphism affects the transcriptional activity of the leptin promoter we evaluated the in vitro reporter-gene activity driven by two constructs harbouring different haplotype and we found a two fold difference in transcription efficiency (Pin vitro results and backfat thikness (BF) and average daily weight gain (ADG) phenotypes, in the considered breeds and we found a weak association of the different allele with backfat thickness. The polymorphisms identified in the 5’-flanking region of the LEP gene may serve as a basis for future studies even in different breeds and might provide molecular data that can be used in the selection schemes.

Keywords

• Leptin, Promoter, SNPs, Pig