Polymorphism in genes of growth hormone receptor (GHR) and insulin-like growth factor-1 (IGF1) and its association with both the IGF1 expression in liver and its level in blood in Polish Holstein-Friesian cattle.

BACKGROUND: Polymorphisms in the bovine ghr and igf1 genes. Ghr and igf1 genes have been associated with milk and meat production of cattle. However, the molecular and physiological mechanisms underlying such associations are unknown. The objective of this study was to examine the effects of polymorphisms in 5'-regions of the bovine ghr and igf1 genes on the igf1 gene expression in the liver and on the level of IGF1 in blood of Polish Holstein-Friesian cattle. METHODS: Individual and combined effects of single nucleotide polymorphisms (SNPs) in the 5'noncoding regions of the bovine igf1 and ghr genes on the IGF1 level in blood and igf1 gene expression in liver were examined. One SNP in the igf1 gene and four SNPs in the ghr gene were analyzed. IGF1 level in blood was measured by radioimmunoassay (RIA) in 211 heifers and bulls of Polish Holstein-Friesian cattle (of Black-and-White type). The igf1 gene expression was measured in livers of bulls carrying different igf1 and ghr genotypes (from three to nine animals per genotype) using real-time reverse transcription-PCR methods with the gapdh gene as a reference. RESULTS: We showed that C/T transition in the promoter region of the igf1 gene influences the gene expression; relative igf1 expression was higher for animals with the CC genotype than for those with the TT and CT genotypes. TESS analysis showed that C/T transition in the igf1 gene co-localizes with the NF1 transcription factor binding site. Also, the ghr genotype appeared to significantly influence the igf1 gene expression in the liver, and we found the highest expression for the genotypes: RFLP-AluI (AT), RFLP-Fnu4HI(CC), and RFLP-NsiI(GA), and for the combined ghr genotype: AluI(AT)/ Fnu4HI(CC)/NsiI(GA). We discovered a significant association between the igf1 genotype and the IGF1 blood level. The highest IGF1 content in blood serum was found in CC genotype animals (1024 ng/ml) vs 698 ng/m and 859 ng/min in the TT and CT igf1 genotypes, respectively. Moreover, we noticed significant differences between ghr genotypes. The highest blood levels of IGF1 were for the animals carrying the ghr genotypes: RFLP-AluI(AA), RFLP-Fnu4HI(CC), and RFLP-NsiI(AG). Ghr haplotypes also significantly affected the IGF1 blood level. Animals of the combined ghr genotypes AluI(AA)/AccI(CC)/Fnu4HI(CC)/NsiI(AG) and AluI(AA)/AccI(CT)/Fnu4HI (CC)/ NsiI(AG) had a higher IGF1 concentration in blood than other genotype carriers. CONCLUSIONS: The present results indicate that the effects of polymorphism in the igf1 and ghr genes on cattle milk or meat production traits could be at least partially mediated through their effects on the igf1 gene expression in the liver and the IGF1 level in blood.

The complete CDS of the prion protein (PRNP) gene of African lion (Panthera leo).

We provide the complete PRNP CDS sequence for the African lion, which is different from the previously published sequence and more similar to other carnivore sequences. The newly obtained prion protein sequence differs from the domestic cat sequence at three amino acid positions and contains only four octapeptide repeats. We recommend that this sequence be used as the reference sequence for future studies of the PRNP gene for this species.

Single base substitution in growth hormone receptor gene influences the receptor density in bovine liver.

OBJECTIVES: Nucleotide sequence polymorphisms in the coding gene regions may influence the biological properties of proteins encoded by a gene. The A/T substitution in exon 8 of the growth hormone receptor (GHR) gene results in changed amino acid sequence 279 (Phe/Tyr) in the transmembrane domain of the receptor protein and therefore could influence its functional parameters. We searched for the relationship between the A/T nucleotide polymorphism in the GHR gene the receptor binding capacity and dissociation constant. METHODS: Nucleotide sequence variations in the exon 8 (coding for the transmembrane domain of the receptor) of the bovine GHR gene and in fragments of adjacent introns were analysed using PCR-SSCP and sequencing techniques. GH receptor binding capacity (Bmax) and dissociation constant (Kd) for GHR were determined by the Scatchard analysis in livers of ten bulls carrying the AA or AT GHR genotypes. RESULTS: Two single nucleotide polymorphisms (SNPs) were identified--the C/T transition in intron 8 at position 863+32 and the A/T transversion in exon 8 at position 836, the latter resulting in Phe/Tyr amino acid substitution in the receptor protein. The results showed significant differences in the GHR binding capacity between these genotypes. Bmax was significantly greater (p< or =0.01) in bulls carrying TT genotype of GHR in comparison to those with the AT genotype. No significant differences in the dissociation constants (Kd) were found. CONCLUSION: Our results demonstrated that single base substitution in the transmembrane domain encoding region of GH receptor gene may influence the physiological properties of the receptor.

Molecular evolution of coding and non-coding sequences of the growth hormone receptor (GHR) gene in the family Bovidae.

The GHR gene exon 1A and exon 4 with fragments of its flanking introns were sequenced in twelve Bovidae species and the obtained sequences were aligned and analysed by the ClustalW method. In coding exon 4 only three interspecies differences were found, one of which had an effect on the amino-acid sequence--leucine 152 proline. The average mutation frequency in non-coding exon 1A was 10.5 per 100 bp, and was 4.6-fold higher than that in coding exon 4 (2.3 per 100 bp). The mutation frequency in intron sequences was similar to that in non-coding exon 1A (8.9 vs 10.5/100 bp). For non-coding exon 1A, the mutation levels were lower within than between the subfamilies Bovinae and Caprinae. Exon 4 was 100% identical within the genera Ovis, Capra, Bison, and Bos and 97.7% identical for Ovis moschatus, Ammotragus lervia and Bovinae species. The identity level of non-coding exon 1A of the GHR gene was 93.8% between species belonging to Bovinae and Caprinae. The average mutation rate was 0.2222/100 bp/MY and 0.0513/100 bp/MY for the Bovidae GHR gene exons 1A and 4, respectively. Thus, the GHR gene is well conserved in the Bovidae family. Also, in this study some novel intraspecies polymorphisms were found for cattle and sheep.

Association of the polymorphism in the 5'-noncoding region of the bovine growth hormone receptor gene with meat production traits in Polish Black-and-White cattle.

Single and combined effects of polymorphisms in the 5'-noncoding region of the bovine growth hormone receptor (GHR) gene on the traits related to meat production were examined in Polish Black-and-White (BW; Friesian) cattle. Four single nucleotide polymorphisms (SNPs) located in the P1 promoter region were analysed. One-hundred and fifty young bulls were included in the study. The traits analysed were daily weight gain, feed intake and conversion, and carcass parameters. Individual SNPs had no effect on growth rates, feed consumption and conversion but showed marked effect on carcass composition traits. The (-/-) genotype at RFLP-AluI appeared favorable for weight of carcass, carcass dressing percentage, and weight of lean in valuable cuts. Animals with the RFLP-NsiI (+/+) genotype seemed better for most of the carcass parameters. In addition, statistically significant associations were found between combined GHR genotypes and feed consumption, carcass weight and dimensions.

Nucleotide sequence and variation of IGF2 gene exon 6 in Bos taurus and Bos indicus cattle.

The major assumption of this study is that polymorphism of a gene could be used to investigate its allele-specific expression as well as its methylation and imprinting status. Therefore, the aim of this study was to analyze the polymorphism of the coding region of the bovine IGF2 gene and to determine the sequence of its gene exon 6 in Bos taurus and Bos indicus cattle. A single nucleotide "C" deletion/insertion polymorphism was found in both cattle subspecies and a G/T transversion (RFLP-MboII) in the Bos indicus IGF2 gene. A 407-bp fragment of bovine IGF2 exon 6 was sequenced and the sequences (including variable nucleotides) were deposited in the GenBank database. A comparative analysis was performed for this fragment from different species; 99.5% identity was found between Bos taurus and Bos indicus cattle.