title: Multiple vitellogenins (Vgs) in mosquitofish (Gambusia affinis): identification and characterization of three functional Vg genes and their circulating and yolk protein products.
abstract: The objectives of this study were to characterize multiple forms of vitellogenin (Vg) in mosquitofish (Gambusia affinis) and to discover the fate of each Vg during its processing into product yolk proteins. Two Vg preparations, with apparent masses of 600 kDa (600 Vg) and 400 kDa (400 Vg), were isolated from the plasma of fish treated with estradiol-17beta (E(2)) by various chromatographic procedures. Immunological analyses verified the presence of two different Vg proteins (600 VgA and 600 VgB) in the 600 Vg preparation and of a single protein in the 400 Vg preparation. Three major yolk proteins (Yps) with apparent masses of 560, 400, and 28 kDa were observed in extracts of ovarian follicles from vitellogenic females. Immunological analyses demonstrated that the 400 Vg underwent no change in native mass after being incorporated into oocytes. The 600 Vgs gave rise to a 28 kDa beta'-component and a native 560 kDa Yp, which was heterodimeric in structure, consisting of two types of complexes between phosvitin (Pv) and lipovitellin (Lv) heavy- and light-chains. Full-length cDNAs encoding the 600 VgA, 600 VgB, and 400 Vg were isolated from a liver cDNA library of E(2) treated fish. Similar to the zebrafish vg3 gene, the 400 Vg cDNA lacked a Pv domain and was classified as an incomplete or phosvitinless (C-type) Vg. The deduced primary structures of 600 VgA and 600 VgB were complete, and these were categorized as type A and type B Vgs, respectively, according to our recent classification scheme. This is the first report on the characterization of three functional Vg genes and their circulating and yolk protein products in any vertebrate species.
authors.affiliation: Department of Animal Resource Production, the United Graduate School of Agricultural Science, Gifu University, Japan. saysaw@fra.affrc.go.jp
authors.forename: Sayumi
authors.initials: S
authors.lastname: Sawaguchi
authors.forename: Yasunori
authors.initials: Y
authors.lastname: Koya
authors.forename: Norio
authors.initials: N
authors.lastname: Yoshizaki
authors.forename: Nobuyuki
authors.initials: N
authors.lastname: Ohkubo
authors.forename: Tadashi
authors.initials: T
authors.lastname: Andoh
authors.forename: Naoshi
authors.initials: N
authors.lastname: Hiramatsu
authors.forename: Craig V
authors.initials: CV
authors.lastname: Sullivan
authors.forename: Akihiko
authors.initials: A
authors.lastname: Hara
authors.forename: Takahiro
authors.initials: T
authors.lastname: Matsubara
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites / Q000235:genetics; D003001:Cloning, Molecular; D003532:Cyprinodontiformes / Q000235:genetics*; D004527:Egg Proteins / Q000737:chemistry / Q000235:genetics* / Q000302:isolation & purification; D005260:Female; D029941:Fish Proteins / Q000737:chemistry / Q000235:genetics* / Q000302:isolation & purification; D018507:Gene Expression Regulation, Developmental; D007536:Isomerism; D008969:Molecular Sequence Data; D009865:Oocytes / Q000502:physiology; D009866:Oogenesis / Q000502:physiology; D014819:Vitellogenins / Q000737:chemistry / Q000235:genetics* / Q000302:isolation & purification
chemical_list: D004527:Egg Proteins; D029941:Fish Proteins; D014819:Vitellogenins