Lack of GNB3 exon 9 polymorphism in primary hypertensive and normotensive dogs.

The 5500T allele variant of the C5500T single nucleotide polymorphism in the human G protein beta3 subunit (GNB3) has been reported to be associated with primary hypertension. In this study, the GNB3 gene of primary hypertensive and normotensive dogs was examined for an analogous nucleotide polymorphism associated with hypertension. The genomic GNB3 dna, with 10 exons and nine introns coding for 340 amino acids, is described. PCR product sequencing of the GNB3 exon 9 from 25 dogs (including five hypertensive animals) failed to detect any nucleotide polymorphism. In contrast to human beings, there was no polymorphism at either the analogous nucleotide or in the respective exon. Only the human hypertension-associated thymine was detected, regardless of whether the dogs were hypertensive or normotensive. Furthermore, examinations of 565 dogs of 85 distinct breeds for the presence of the human 5500C nucleotide at the analogous nucleotide side failed to detect a cytosine that is present with high allele frequency in normotensive man. Owing to the lack of allele variance, it is concluded that canine primary hypertension is not associated with a polymorphism at either the respective human hypertension-associated nucleotide site or in the entire exon.