CDNA Cloning,Phylogenetic Analysis Of Two Gonadotropin Receptors Of Schizothorax Prenanti

Gonadotropins, belong to glycoprotein hormone, are the regulators of vertebrate gonad to promote sexual hormones and secretion. The physiological functions of gonadotropins are achieved through specific receptors distributed in the gonads. So far, there are no reports about Schizothorax prenanti GtHRs. Therefore, the investigation of the functions of FSHR and LHR will benefit to understand the reproduction of vertebrate and improve the reproductive performance of fish. To understand the reproductive physiology and rules of Schizothorax prenanti, we cloned and characterized the partial cDNA of FSHR and LHR from prenant’s Schizothoracin pituitary gland. The result as follows:(1) The partial cDNA of FSHR and LHR was 791bp and 360bp and encoding peptides of 263 and 120 amino acids, respectively. BLAST analysis indicated that FSHR nucleotide sequence/amino acid sequence of Schizothorax prenanti has the highest similarity to zebrafish (84.5%/85.1%), LHR has the highest similarity to Ctenopharyngodon idellus (87.1%/68.6%)(2) Phylogenetic analysis indicated that FSHR of Schizothorax prenanti is clustered with zebrafish and Pelteobagrus fulvidraco. The genetic distance between Schizothorax prenanti and zebrafish is the shortest. LHR is clustered with Ctenopharyngodon idellus and zebrafish, and the genetic distance between Schizothorax prenanti and Ctenopharyngodon idellus is the shortest.(3) The tissue expression profile analysis indicated that both FSHR and LHR were abundantly expressed in the Schizothorax prenanti gonads which were in breeding seasons, but is quite the contrary in non-breeding seasons. FSHR and LHR also had been detected in blood, muscle; the FSHβ were predominantly expressed in brian, blood and intestine. The expression of LHβ were not detectable in all tissues.(4) The developmental expression analysis indicated that both gonadotropin receptors showed a high expression in gonad during breeding season. However, almost no expression during anestrous season; In breeding season, the expression of FSHβ in gonad is significantly lower than anestrous season. In breeding season, the expression of LHβ in sexually mature fish is significantly higher than the anestrous season and immature.