Cloning of the Elk TSH .BETA.-Subunit cDNA and Seasonal Expression of the Pituitary Glycoprotein Hormone Genes

Abstract

Abstract. We report the elk (Cervus elaphus) thyroid stimulating hormone (TSH) β-subunit cDNA cloning, nucleotide and deduced amino acid sequences. The TSH β-subunit cDNA was obtained by RT-PCR of polyadenylated pituitary RNA. The deduced elk TSH β-subunit peptide chain shares between 93 to 99% sequence similarities with the reported TSH β-subunit of a sub-set of related species. The TSH β-subunit gene is expressed in the elk pituitary gland as a mature transcript of approximately 600 bases, which corresponds to the size of the mRNA expressed in the sheep pituitary gland. Seasonal expression of the pituitary gonadotropin genes was investigated by Northern blot analyses. Samples of elk pituitary glands collected during the breeding season showed elevated steady state levels of common α-subunit and FSH and LH β-subunit gene expression, consistent with the seasonal reproductive cycling of this species. Samples collected before the breeding season demonstrated decreased expression of the gonadotropin genes. TSH, which is not directly tied to reproduction, had similar levels of expression, regardless of the animal's reproductive status. North American elk are temperate cervids and strict seasonal breeders, which start the mating season in autumn, in response to decreasing photoperiod [3]. Hence, most of their lifesustaining activities, such as feeding, locomotion, s l e e p a n d r e p r o d u c t i o n a r e p h o t o p e r i o d dependent. Activity of their reproductive organs, including testis, ovaries and accessory sex glands, exhibit substantial annual changes along with the circulatory levels of sex and pituitary hormones [4,5]. In the absence of pregnancy, deer hinds are polyestrous and are capable of exhibiting between four to nine continuous 17-19 day oestrous cycles over a 3-6 month period between autumn and spring [6][7][8]. Thus, the pituitary gland responding to photoperiod stimulus would change expression of the pituitary gonadotropin genes according to the reproductive season. We are interested in studying expression of the pituitary glycoprotein

Characterization of the Luteinizing Hormone Beta (LH-β) Subunit Gene in the Goat

“…The nucleotides and deduced amino acids sequences of the LHβ subunit molecule available for 7 mammalian species, namely, Buffalo Pig [D00579] and Human [X00264] were used for the analysis. Isolation and analysis of these genes in different species may help in understanding and production of recombinant hormones (Clark et al, 2005). Analysis of the nucleotide and deduced amino acid sequences of LHβ may further provides insight into the evolution of this family of hormones (Wallis, 2001).…”