title: Molecular identification and expression of the Foxl2 gene during gonadal sex differentiation in northern snakehead Channa argus.
abstract: Channa argus is one of the most commercially important fish species in China. Studies show that males of C. argus grow faster than females at the same age. In order to explore the sex differentiation mechanism of C. argus, we isolated the full length of the sex-related gene Foxl2 cDNA and analysed its expression patterns during gonadal sex differentiation. Alignment of known Foxl2 amino acid sequences from vertebrates confirmed the conservation of the Foxl2 open reading frame, especially the forkhead domain and C-terminal region. Quantitative RT-PCR revealed that Foxl2 is predominantly expressed in brain, pituitary, gill and ovary, with its highest level in ovary but low levels in testis and other tissues, reflecting a potential role for Foxl2 in the brain-pituitary-gonad axis in C. argus. Our ontogenetic stage data showed that C. argus Foxl2 expression was significantly upregulated from 1 to 11 days posthatching (dph) and that the initiation of expression preceded the first anatomical ovarian differentiation (27 dph), suggesting that Foxl2 might play a potential role in early gonadal sex differentiation in C. argus. In addition, the Foxl2 protein was primarily located in granulosa cells surrounding the oocytes of mature C. argus, implying that Foxl2 may have a basic function in granulosa cell differentiation and the maintenance of oocytes.
authors.affiliation: Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture, College of Fisheries, Huazhong Agricultural University, Wuhan, 430070, People's Republic of China.|Freshwater Aquaculture Collaborative Innovation Center of Hubei Province, Wuhan, 430070, People's Republic of China.
authors.forename: Dan-Dan
authors.initials: DD
authors.lastname: Wang
authors.affiliation: Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture, College of Fisheries, Huazhong Agricultural University, Wuhan, 430070, People's Republic of China.|Freshwater Aquaculture Collaborative Innovation Center of Hubei Province, Wuhan, 430070, People's Republic of China.
authors.forename: Gui-Rong
authors.initials: GR
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture, College of Fisheries, Huazhong Agricultural University, Wuhan, 430070, People's Republic of China. kjwei@mail.hzau.edu.cn.|Freshwater Aquaculture Collaborative Innovation Center of Hubei Province, Wuhan, 430070, People's Republic of China. kjwei@mail.hzau.edu.cn.
authors.forename: Kai-Jian
authors.initials: KJ
authors.lastname: Wei
authors.affiliation: Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture, College of Fisheries, Huazhong Agricultural University, Wuhan, 430070, People's Republic of China.|Freshwater Aquaculture Collaborative Innovation Center of Hubei Province, Wuhan, 430070, People's Republic of China.
authors.forename: Wei
authors.initials: W
authors.lastname: Ji
authors.affiliation: Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture, College of Fisheries, Huazhong Agricultural University, Wuhan, 430070, People's Republic of China.|Freshwater Aquaculture Collaborative Innovation Center of Hubei Province, Wuhan, 430070, People's Republic of China.|School of Biological Sciences, Victoria University of Wellington, PO Box 600, Wellington, 6140, New Zealand.
authors.forename: Jonathan P A
authors.initials: JP
authors.lastname: Gardner
authors.affiliation: Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture, College of Fisheries, Huazhong Agricultural University, Wuhan, 430070, People's Republic of China.|Freshwater Aquaculture Collaborative Innovation Center of Hubei Province, Wuhan, 430070, People's Republic of China.
authors.forename: Rui-Bin
authors.initials: RB
authors.lastname: Yang
authors.affiliation: Key Laboratory of Tropical and Subtropical Fishery Resource Application and Cultivation, Ministry of Agriculture, Pearl River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou, 510380, People's Republic of China.
authors.forename: Kun-Ci
authors.initials: KC
authors.lastname: Chen
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D003001:Cloning, Molecular; D005260:Female; D029941:Fish Proteins / Q000235:genetics / Q000378:metabolism*; D051858:Forkhead Transcription Factors / Q000235:genetics / Q000378:metabolism*; D018507:Gene Expression Regulation, Developmental; D006066:Gonads / Q000502:physiology*; D006107:Granulosa Cells / Q000502:physiology; D008297:Male; D008969:Molecular Sequence Data; D010053:Ovary / Q000502:physiology; D010473:Perciformes / Q000235:genetics / Q000502:physiology*; D012733:Sex Differentiation / Q000235:genetics*; D013737:Testis / Q000502:physiology
chemical_list: D029941:Fish Proteins; D051858:Forkhead Transcription Factors
keywords: Channa argus; Early gonadal development; Foxl2; Gene expression; Molecular identification