Investigating and characterizing phoenixin and tachykinin receptor-3 in the reproductive axis of the chicken, Gallus gallus
This thesis identifies two new players, phoenixin and tackykinin receptor-3, in the reproductive axis of the chicken. Phoenixin is known to upregulate pituitary gonadotropin-releasing hormone receptor (GnRH-R) messenger RNA (mRNA) and tachykinin receptor-3 to generate GnRH pulsatility in mammals. Through database search, we confirm that these neuroproteins are encoded in the chicken genome. The full-length mRNA sequences were identified by 5’ and 3’ rapid-amplification of complementary DNA ends and annotated. Phoenixin mRNA was detected and quantified in various tissues via conventional and semi-quantitative PCR, respectively (in diencephalon, pituitary, ovary, gut and heart). In the diencephalon and pituitary of different strain, phoenixin was differentially expressed with age. Tackykinin receptor-3 mRNA is differentially expressed across tissues (diencephalon>pituitary>ovary) and in an age-dependent manner in the pituitary. The function of phoenixin was explored through treatment of sexually immature primary chicken pituitary cells and, unlike rodents no independent modulation of GnRH-R-III/I was detected.