Identifying Novel Polymorphisms in the Canine Tryptophan Hydroxylase 2 Gene

Abstract

ABSTRACT. Tryptophan hydroxylase (TPH) serves as the rate-limiting enzyme in the biosynthesis of serotonin, and two forms of TPH genes, TPH1 and TPH2, have been reported with specific nucleotide sequences and expression patterns. We determined the sequences of these two genes and identified polymorphisms within their coding regions. We identified five novel single nucleotide polymorphisms in the TPH2 gene, one of which resulted in a non-synonymous mutation and the remaining four in synonymous mutations. Comparison of the genotype frequencies of the polymorphisms among five popular breeds with different behavioral traits revealed statistically significant interbreed differences for three polymorphisms. These results suggest that these polymorphisms would be useful genetic markers when performing behavior studies in dogs. KEY WORDS: breed difference, canine, polymorphism, TPH.

The study of changes in gene regulation of serotonin signaling pathway and circulating serotonin concentration in dogs with pulmonary hypertension due to degenerative mitral valve disease

“…The central pool of serotonin is a neurotransmitter in the central nervous system (CNS) synthesized by tryptophan hydroxylase-2 (TPH-2), the rate-limiting enzyme, in the raphe nuclei located on the midline of the brainstem (Declerck and Boone, 2016). Serotonin plays a crucial role in the cognition and development of the nervous system as well as the abnormalities of the serotonergic system including temperament and behavior disorders (Moiseiwitsch et al, 2001;Fukumoto et al, 2005;Kaneko et al, 2008;De-Miguel et al, 2015). The peripheral pool of serotonin is a biogenic amine synthesized by TPH-1, which is mainly produced in the enterochromaffin cells in the intestine (Berger et al, 2009).…”