title: Molecular identification of GnIH/GnIHR signal and its reproductive function in protogynous hermaphroditic orange-spotted grouper (Epinephelus coioides).
abstract: Gonadotropin-inhibitory hormone (GnIH) and its receptor (GnIHR) play an important role in reproduction regulation in birds, mammals and some teleost species. In protogynous hermaphroditic orange-spotted grouper (Epinephelus coioides), the GnIH/GnIHR signaling pathway and its reproductive function have not been addressed yet. In this study, GnIH and GnIHR in orange-spotted grouper were characterized. gGnIH possessed three putative peptides (gGnIH-I, -II, -III), while gGnIHR showed the characteristics of G protein-coupled receptor and was clustered with GPR147. Functional assays demonstrated that three synthetic gGnIH peptides significantly decreased the forskolin-induced CRE promoter activity, but only gGnIH-I could significantly decrease SRE promoter activity in COS-7 cells transfected with gGnIHR. During the process of ovarian differentiation and development, gGnIH mRNA level in hypothalamus was low at the gonadal primordium stage with gonia, then increased significantly at the early differentiated gonad with primary growth oocytes, while decreased significantly at the developing gonads with cortical-alveolus and vitellogenic stage oocytes. During MT-induced sex reversal, gGnIH mRNA level in hypothalamus increased significantly when the fish completely reversed from female to male. However, gGnIHR mRNA level in pituitary decreased significantly in intersex and completely reversed male fish. Intraperitoneal injection (i.p.) of three gGnIH peptides significantly decreased GnRH1 mRNA levels in hypothalamus, and gGnIH-II significantly inhibited synthesis of LHβ in pituitary. In summary, we firstly identified the GnIH/GnIHR signal in protogynous orange-spotted grouper, which might be involved in the regulation of the reproductive function of sex differentiation, gonadal development and sex reversal via regulating the synthesis of both GnRH and GtH.
authors.affiliation: State Key Laboratory of Biocontrol, The Guangdong Province Key Laboratory for Aquatic Economic Animals, and Institute of Aquatic Economic Animals, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, China.
authors.forename: Qingqing
authors.initials: Q
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Biocontrol, The Guangdong Province Key Laboratory for Aquatic Economic Animals, and Institute of Aquatic Economic Animals, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, China.
authors.forename: Xin
authors.initials: X
authors.lastname: Qi
authors.affiliation: State Key Laboratory of Biocontrol, The Guangdong Province Key Laboratory for Aquatic Economic Animals, and Institute of Aquatic Economic Animals, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, China.
authors.forename: Yin
authors.initials: Y
authors.lastname: Guo
authors.affiliation: State Key Laboratory of Biocontrol, The Guangdong Province Key Laboratory for Aquatic Economic Animals, and Institute of Aquatic Economic Animals, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, China.
authors.forename: Shuisheng
authors.initials: S
authors.lastname: Li
authors.affiliation: State Key Laboratory of Biocontrol, The Guangdong Province Key Laboratory for Aquatic Economic Animals, and Institute of Aquatic Economic Animals, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, China.
authors.forename: Yong
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Biocontrol, The Guangdong Province Key Laboratory for Aquatic Economic Animals, and Institute of Aquatic Economic Animals, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, China. Electronic address: lsslxc@mail.sysu.edu.cn.
authors.forename: Xiaochun
authors.initials: X
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Biocontrol, The Guangdong Province Key Laboratory for Aquatic Economic Animals, and Institute of Aquatic Economic Animals, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, China. Electronic address: lsslhr@mail.sysu.edu.cn.
authors.forename: Haoran
authors.initials: H
authors.lastname: Lin
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D019556:COS Cells; D002454:Cell Differentiation / Q000187:drug effects; D002522:Chlorocebus aethiops; D003001:Cloning, Molecular; D005576:Colforsin / Q000494:pharmacology; D029941:Fish Proteins / Q000235:genetics / Q000378:metabolism*; D007987:Gonadotropin-Releasing Hormone / Q000235:genetics / Q000378:metabolism; D006062:Gonadotropins / Q000378:metabolism*; D006066:Gonads / Q000166:cytology / Q000378:metabolism*; D057850:Hermaphroditic Organisms; D007028:Hypothalamic Hormones / Q000235:genetics / Q000378:metabolism*; D037101:Luteinizing Hormone, beta Subunit / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D009865:Oocytes / Q000166:cytology / Q000378:metabolism; D010473:Perciformes / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D011967:Receptors, Gonadotropin / Q000235:genetics / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017386:Sequence Homology, Amino Acid; D019849:Sex Determination Processes / Q000187:drug effects; D012733:Sex Differentiation / Q000187:drug effects / Q000235:genetics*; D015398:Signal Transduction / Q000187:drug effects; D014665:Vasodilator Agents / Q000494:pharmacology
chemical_list: D029941:Fish Proteins; D006062:Gonadotropins; D007028:Hypothalamic Hormones; D037101:Luteinizing Hormone, beta Subunit; D012333:RNA, Messenger; D011967:Receptors, Gonadotropin; D014665:Vasodilator Agents; D005576:Colforsin; D007987:Gonadotropin-Releasing Hormone
keywords: Epinephelus coioides; GnIH/GnIHR; GnRH; GtH