Nucleotide sequence polymorphisms in the promoter region of bovine growth hormone receptor gene (GHR) have no effect on its expression level in liver*

The gene coding for bovine GHR consists of nine protein-coding exons and untranslated, alternative exons 1A, 1B, and 1C in its 5’-region. Distinct promoters regulate transcription from each of the alternative exons. The P1 promoter which drives growth hormone receptor expression in the liver is associated with exon 1A. Earlier the nucleotide sequence polymorphisms have been identified in the bovine GHR gene promoter region, including several single nucleotide polymorphisms (SNPs) and one TG repeat (microsatellite) of variable length. Using computer-aided analysis in TESS programme it has also been shown that the A/G transition at position -154 (RFLP-NsiI) and the C/T transition at position -1104 (Fnu4HI), both located upstream the exon 1A, co-localized with putative transcription factor-binding sites. In light of this the authors decided to study possible effects of these polymorphisms on GHR gene expression in cattle of different GHR genotypes, using Real-time PCR. Interestingly, no difference was found in GHR mRNA accumulation in liver between young Black-and-White (BW) bulls carrying (+/+), (+/-) or (-/-) genotypes at RFLP-NsiI site, (+/-) or (+/+) genotypes at RFLP-Fnu4HI site, and TG17/17 or TG21/21 alleles at TGn microsatellite, located within the P1 promoter of the bovine GHR gene.