title: Molecular cloning of cDNA of gonadotropin-releasing hormones in the Chinese sturgeon (Acipenser sinensis) and the effect of 17β-estradiol on gene expression.
abstract: The Chinese sturgeon, Acipenser sinensis, is a rare and large-sized anadromous bony fish and understanding of its reproductive regulation is a precondition for controlled reproduction. In this study, two gonadotropin-releasing hormone (GnRH) precursor cDNAs, AsGnRH1 (mammalian type) and AsGnRH2 (chicken type 2), were sequenced in A. sinensis. The precursor cDNAs of the AsGnRH1 and AsGnRH2 are 381 and 649 base pairs (bp), encoding signal peptide plus precursors of 92 and 86 amino acids, respectively. Multiple sequence alignment suggests that AsGnRH1 and AsGnRH2 decapeptides are highly conserved among vertebrates. Besides, AsGnRH1 had closer evolutionary relationship with tetrapods, while AsGnRH2 was conservatively grouped with teleosts in the phylogenetic analysis. Tissue distribution analysis shows that AsGnRH2 is exclusively transcribed in the brain, whereas AsGnRH1 exhibits more extensive tissue distribution including brain, liver, spleen and gonad. Furthermore, Chinese sturgeons were subcutaneously implanted with 17β-estradiol (E2) and the effect of E2 on brain GnRH mRNA levels was evaluated by real-time PCR. A significant increase in AsGnRH1 and AsGnRH2 mRNA levels is detected in fish receiving E2 implantation compared to controls after one month (P<0.05). These results indicate that E2 exerts positive feedback effects on the transcription of the two GnRHs in immature Chinese sturgeon.
authors.affiliation: Key Laboratory of Freshwater Biodiversity Conservation, Ministry of Agriculture of China, Yangtze River Fisheries Research Institute, Chinese Academy of Fisheries Science, Wuhan 430223, China; Freshwater Fisheries Research Center, Chinese Academy of Fisheries Science, Wuxi 214081, China.
authors.forename: Huamei
authors.initials: H
authors.lastname: Yue
authors.forename: Huan
authors.initials: H
authors.lastname: Ye
authors.forename: Xihua
authors.initials: X
authors.lastname: Chen
authors.forename: Hong
authors.initials: H
authors.lastname: Cao
authors.forename: Chuangju
authors.initials: C
authors.lastname: Li
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D004958:Estradiol; D005399:Fishes / Q000235:genetics*; D015870:Gene Expression; D007987:Gonadotropin-Releasing Hormone / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics*; D006801:Humans; D008969:Molecular Sequence Data; D011498:Protein Precursors / Q000737:chemistry; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D014018:Tissue Distribution
chemical_list: D011498:Protein Precursors; D007987:Gonadotropin-Releasing Hormone; D004958:Estradiol
keywords: 17β-estradiol; BPG; Chinese sturgeon; E2; GAP; GKR; GnRH; GnRH associated peptide; GnRH1; LS; ORF; RACE; Real-time PCR; UTR; aa; amino acid; brain–pituitary–gonad; cGnRH2; cleavage site; gonadotropin-releasing hormone; open reading frame; proteolytic cleavage site; rapid amplification of cDNA ends; terminal untranslated region