title: Goldfish neurokinin B: Cloning, tissue distribution, and potential role in regulating reproduction.
abstract: Neurokinin B (NKB) is a member of the tackykinin (TAC) family known to play a critical role in the neuroendocrine regulation of reproduction in mammals. However, its biological functions in teleosts are less clear. The aim of this study was to determine the role of NKB in fish reproduction using goldfish as a model. Two transcripts, TAC3a and TAC3b, which encode several NKBs, including NKBa-13, NKBa-10, NKBb-13, and NKBb-11, were cloned. Phylogenetic analysis revealed that NKBa-10 and NKBb-11 are closely related to mammalian NKB, while NKB-13s are more conserved in teleosts. Quantitative real-time PCR analyses in various tissues showed that TAC3a and TAC3b mRNAs were mainly expressed in the brain. In situ hybridization further detected TAC3a and TAC3b mRNAs in several regions of the brain known to be involved in the regulation of reproduction and metabolism, as well as in the neurohypophysis of the pituitary. To investigate the potential role of NKBs in reproduction, goldfish were injected intraperitoneally with synthetic NKBa-13, -10, NKBb-13, or -11 peptides and the mRNA levels of hypothalamic gonadotropin-releasing hormone (GnRH) and pituitary gonadotropin subunits were measured. NKBa-13, -10, or NKBb-13, but not -11, significantly increased hypothalamic salmon GnRH and pituitary FSHβ and LHβ mRNA levels in both female and male goldfish. Finally, ovariectomy increased, while estradiol replacement reduced, TAC3a mRNA levels without affecting TAC3b expression in the hypothalamus. These data suggest that NKBa-13, -10, and NKBb-13 play a role in mediating the estrogen negative feedback regulation of gonadotropins.
authors.affiliation: State Key Laboratory of Biocontrol, Institute of Aquatic Economic Animals, and the Guangdong Province Key Laboratory for Aquatic Economic Animals, Sun Yat-Sen University, Guangzhou 510275, China; Department of Biology, York University, Toronto, Ontario M3J 1P3, Canada.
authors.forename: Xin
authors.initials: X
authors.lastname: Qi
authors.affiliation: State Key Laboratory of Biocontrol, Institute of Aquatic Economic Animals, and the Guangdong Province Key Laboratory for Aquatic Economic Animals, Sun Yat-Sen University, Guangzhou 510275, China; Department of Biology, York University, Toronto, Ontario M3J 1P3, Canada.
authors.forename: Wenyi
authors.initials: W
authors.lastname: Zhou
authors.affiliation: State Key Laboratory of Biocontrol, Institute of Aquatic Economic Animals, and the Guangdong Province Key Laboratory for Aquatic Economic Animals, Sun Yat-Sen University, Guangzhou 510275, China.
authors.forename: Shuisheng
authors.initials: S
authors.lastname: Li
authors.affiliation: State Key Laboratory of Biocontrol, Institute of Aquatic Economic Animals, and the Guangdong Province Key Laboratory for Aquatic Economic Animals, Sun Yat-Sen University, Guangzhou 510275, China.
authors.forename: Yun
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Department of Biology, York University, Toronto, Ontario M3J 1P3, Canada.
authors.forename: Gang
authors.initials: G
authors.lastname: Ye
authors.affiliation: State Key Laboratory of Biocontrol, Institute of Aquatic Economic Animals, and the Guangdong Province Key Laboratory for Aquatic Economic Animals, Sun Yat-Sen University, Guangzhou 510275, China.
authors.forename: Xiaochun
authors.initials: X
authors.lastname: Liu
authors.affiliation: Department of Biology, York University, Toronto, Ontario M3J 1P3, Canada. Electronic address: cpeng@yorku.ca.
authors.forename: Chun
authors.initials: C
authors.lastname: Peng
authors.affiliation: State Key Laboratory of Biocontrol, Institute of Aquatic Economic Animals, and the Guangdong Province Key Laboratory for Aquatic Economic Animals, Sun Yat-Sen University, Guangzhou 510275, China. Electronic address: lsszy@mail.sysu.edu.cn.
authors.forename: Yong
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Biocontrol, Institute of Aquatic Economic Animals, and the Guangdong Province Key Laboratory for Aquatic Economic Animals, Sun Yat-Sen University, Guangzhou 510275, China; College of Ocean, Hainan University, Haikou 570228, 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; D003001:Cloning, Molecular; D004958:Estradiol / Q000378:metabolism; D005260:Female; D029941:Fish Proteins / Q000235:genetics / Q000378:metabolism*; D005786:Gene Expression Regulation; D006054:Goldfish / Q000254:growth & development / Q000378:metabolism*; D017403:In Situ Hybridization; D008297:Male; D008969:Molecular Sequence Data; D015287:Neurokinin B / Q000235:genetics / Q000378:metabolism*; D018377:Neurotransmitter Agents / Q000235:genetics / Q000378:metabolism*; D010802:Phylogeny; D010902:Pituitary Gland / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D012098:Reproduction / Q000502:physiology*; D017386:Sequence Homology, Amino Acid; D014018:Tissue Distribution
chemical_list: D029941:Fish Proteins; D018377:Neurotransmitter Agents; D012333:RNA, Messenger; D004958:Estradiol; D015287:Neurokinin B
keywords: GnRH; Gonadotrophin; In situ hybridization; Neurokinin B