title: Molecular identification of StAR and 3βHSD1 and characterization in response to GnIH stimulation in protogynous hermaphroditic grouper (Epinephelus coioides).
abstract: Gonadal steroids are critical factors in reproduction and sex reverse process. StAR (steroidogenic acute regulatory protein), transferring the cholesterol from the outer mitochondrial membrane to the inner membrane, is the rate-limiting factor of steroidogenesis. 3βHSD (3β-hydroxysteroid dehydrogenase/Δ5-Δ4 isomerase), converting Δ5-steroids into Δ4-steroids, is an important oxidoreductase in steroidogenesis. In the present study, StAR and 3βHSD1 were cloned and characterized from protogynous orange-spotted grouper. StAR cDNA contains an 861bp open reading frame (ORF), encoding a predicted protein of 286 amino acids, and the ORF of 3βHSD1 was 1125bp, encoding a predicted protein of 374 amino acids. The transcript of StAR was mainly expressed in gonad, while 3βHSD1 mRNA was predominantly detected in brain and gonad. In the previous study, we found the expression of GnIH mRNA level in male, as well as in 17 alpha-methyltestosterone (MT)-induced male fish was significantly higher than in female fish, this indicating that GnIH/GnIHR signaling might be involved in the regulation of sex reversal and male maintenance. In order to figure out the function of GnIH in steroidogenesis, the expression of StAR and 3βHSD1 regulated by GnIH was examined. In vitro study showed that treatment of cultured ovary fragments with gGnIH peptides significantly stimulated the expression of StAR and 3βHSD1. In addition, the mRNA levels of StAR and 3βHSD1 were significantly increased after intraperitoneal injection (i.p.) with gGnIH peptides. Moreover, during MT-induced sex change from female to male, the levels of StAR mRNA significantly increased by 5.2, 24.8 and 353.5 folds, and that of 3βHSD1 mRNA by 3.5, 32.5 and 55.4 folds at the 2nd, 4th and 6th week after MT implantation, respectively. Collectively, our results indicate that GnIH may be involved in the regulation of sex reversal or male maintenance by stimulating the expression of StAR and 3βHSD1 in protogynous grouper.
authors.affiliation: State Key Laboratory of Biocontrol, Guangdong Province Key Laboratory for Improved Variety Reproduction of Aquatic Economic Animals, 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, Guangdong Province Key Laboratory for Improved Variety Reproduction of Aquatic Economic Animals, 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, Guangdong Province Key Laboratory for Improved Variety Reproduction of Aquatic Economic Animals, Institute of Aquatic Economic Animals, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, China.
authors.forename: Haipei
authors.initials: H
authors.lastname: Tang
authors.affiliation: State Key Laboratory of Biocontrol, Guangdong Province Key Laboratory for Improved Variety Reproduction of Aquatic Economic Animals, 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, Guangdong Province Key Laboratory for Improved Variety Reproduction of Aquatic Economic Animals, 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, Guangdong Province Key Laboratory for Improved Variety Reproduction of Aquatic Economic Animals, Institute of Aquatic Economic Animals, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, China.
authors.forename: Gaofei
authors.initials: G
authors.lastname: Li
authors.affiliation: Key Laboratory of Aquatic Animal Breeding and Culturing for South China Sea, Ministry of Agriculture, PR China.
authors.forename: Xiaoli
authors.initials: X
authors.lastname: Yang
authors.affiliation: Marine Fisheries Development Center of Guangdong Province, Huizhou 516081, China.
authors.forename: Haifa
authors.initials: H
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Biocontrol, Guangdong Province Key Laboratory for Improved Variety Reproduction of Aquatic Economic Animals, Institute of Aquatic Economic Animals, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, China; South China Sea Bio-Resource Exploitation and Utilization Collaborative Innovation Center, China. Electronic address: lsslxc@mail.sysu.edu.cn.
authors.forename: Xiaochun
authors.initials: X
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Biocontrol, Guangdong Province Key Laboratory for Improved Variety Reproduction of Aquatic Economic Animals, Institute of Aquatic Economic Animals, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, China; South China Sea Bio-Resource Exploitation and Utilization Collaborative Innovation Center, China.
authors.forename: Haoran
authors.initials: H
authors.lastname: Lin
mesh_terms: D015096:3-Hydroxysteroid Dehydrogenases / Q000235:genetics*; D000818:Animals; D001492:Bass / Q000235:genetics* / Q000254:growth & development*; D003001:Cloning, Molecular; D005260:Female; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects*; D007028:Hypothalamic Hormones / Q000494:pharmacology*; D008297:Male; D010750:Phosphoproteins / Q000235:genetics*; D019849:Sex Determination Processes / Q000187:drug effects*; D000098682:Steroidogenic Acute Regulatory Protein
chemical_list: D007028:Hypothalamic Hormones; D010750:Phosphoproteins; D000098682:Steroidogenic Acute Regulatory Protein; D015096:3-Hydroxysteroid Dehydrogenases
keywords: 3βHSD1; Epinephelus coioides; GnIH; GnIHR; Sex reversal; StAR