Comparing KISS1 and GPR54 genes between the two breeds of goats with low and high prolificacy

Abstract

There is increasing evidence that kisspeptin, the peptide product of KISS1 gene and its receptor (GPR54), regulate reproductive processes through actions on other organs than hypothalamus. Therefore, the study for the first time, was conducted to investigate the nucleotide sequences and mRNA expression levels of KISS1 and GPR54 genes in pituitary, endometrium, ovary and oviduct of prolific Jintang black goat (JTG) and non-prolific Tibetan goat (TBG) during pro-estrus. By RT-PCR strategy, we obtained that the KISS1 cDNA sequence was 408-bp long, encoding a putative peptide of 135 amino acids. The GPR54 cDNA sequence was 244-bp long, encoding a putative peptide of 81 amino acids. There were two base changes in KISS1, and one base change in GPR54, but these base changes did not result in amino acid substitution between these two breeds. Real-time PCR analyses revealed that both KISS1 and GPR54 genes were expressed in all four tissues examined. KISS1 was most highly expressed in pituitary (p<0.05) and its expression was greater in JTG than TBG (p<0.05). In conclusion, a high KISS1 expression level in pituitary of prolific goat breed might be associated with its great litter size.