title: Synergistic role of β-catenin1 and 2 in ovarian differentiation and maintenance of female pathway in Nile tilapia.
abstract: Two β-catenin (β-cat) genes exist in teleosts but little is known about their expression and function in ovarian development. We identified β-cat1 and β-cat2 from the Nile tilapia. β-cat1 and β-cat2 displayed a similar expression pattern in the ovary during development, and were mainly expressed in the oogonia and oocytes. In luciferase assays, β-cat1 activated the TOPFlash reporter dose-dependently, whereas β-cat2 failed to do so. Cotransfection of β-cat1 and β-cat2 synergistically enhanced the expression of the reporter. A specific interaction between β-cat1 and β-cat2 was also observed in a mammalian two-hybrid assay. Furthermore, tilapia recombinant Dkk1, an inhibitor of the β-cat pathway, decreased β-cat1 and β-cat2, while increased sox9, dmrt1, cyp11b2 and foxl2 expression in the in vitro cultured tilapia ovary, which could be abolished by simultaneous treatment with Bio, an agonist of β-cat. Consistently, β-cat1 or β-cat2 knockdown in XX fish by TALENs caused the retardation of ovarian differentiation and masculinization, as reflected by the upregulation of dmrt1, cyp11b2, sox9, and serum 11-KT level. On the contrary, serum E2 level was unchanged even though foxl2 transcription was upregulated. These data suggestes that both β-cat1 and β-cat2 are important members and play synergistic roles in the canonical Wnt signal pathway in fish. Independent of Foxl2-leading estrogen pathway, they might be involved in ovarian differentiation and repression of the male pathway gene expression in tilapia.
authors.affiliation: Key Laboratory of Freshwater Fish Reproduction and Development (Ministry of Education), Key Laboratory of Aquatic Science of Chongqing, School of Life Science, Southwest University, Chongqing 400715, China.
authors.forename: Limin
authors.initials: L
authors.lastname: Wu
authors.affiliation: Key Laboratory of Freshwater Fish Reproduction and Development (Ministry of Education), Key Laboratory of Aquatic Science of Chongqing, School of Life Science, Southwest University, Chongqing 400715, China; School of Biological and Food Engineering, Fuyang Teachers College, Key Laboratory of Embryo Development and Reproductive Regulation, Anhui Province, Fuyang 236000, China.
authors.forename: Fengrui
authors.initials: F
authors.lastname: Wu
authors.affiliation: Key Laboratory of Freshwater Fish Reproduction and Development (Ministry of Education), Key Laboratory of Aquatic Science of Chongqing, School of Life Science, Southwest University, Chongqing 400715, China.
authors.forename: Lang
authors.initials: L
authors.lastname: Xie
authors.affiliation: Key Laboratory of Freshwater Fish Reproduction and Development (Ministry of Education), Key Laboratory of Aquatic Science of Chongqing, School of Life Science, Southwest University, Chongqing 400715, China. Electronic address: wdeshou@swu.edu.cn.
authors.forename: Deshou
authors.initials: D
authors.lastname: Wang
authors.affiliation: Key Laboratory of Freshwater Fish Reproduction and Development (Ministry of Education), Key Laboratory of Aquatic Science of Chongqing, School of Life Science, Southwest University, Chongqing 400715, China. Electronic address: yanlinzhou916@126.com.
authors.forename: Linyan
authors.initials: L
authors.lastname: Zhou
mesh_terms: D000818:Animals; D023681:Cichlids / Q000235:genetics / Q000502:physiology*; D005260:Female; D055786:Gene Knockout Techniques; D008156:Luciferases / Q000378:metabolism; D008297:Male; D009866:Oogenesis / Q000235:genetics*; D010053:Ovary / Q000166:cytology*; D017422:Sequence Analysis, DNA; D012733:Sex Differentiation / Q000235:genetics*; D051820:TCF Transcription Factors / Q000378:metabolism; D014018:Tissue Distribution; D060449:Wnt Signaling Pathway; D051176:beta Catenin / Q000235:genetics / Q000502:physiology*
chemical_list: D051820:TCF Transcription Factors; D051176:beta Catenin; D008156:Luciferases
keywords: Expression; Interaction; Ovarian differentiation; TALENs; β-cat1 and β-cat2