Multiple Vitellogenins (Vgs) in Mosquitofish (Gambusia affinis): Identification and Characterization of Three Functional Vg Genes and Their Circulating and Yolk Protein Products

• Published in: Biology of reproduction 2005-04, Vol.72 (4), p.1045-1060
• Main Authors: SAWAGUCHI, Sayumi, KOYA, Yasunori, YOSHIZAKI, Norio, OHKUBO, Nobuyuki, ANDOH, Tadashi, HIRAMATSU, Naoshi, SULLIVAN, Craig V, HARA, Akihiko, MATSUBARA, Takahiro
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Animals; Binding Sites - genetics; Biological and medical sciences; Cloning, Molecular; Cyprinodontiformes - genetics; Danio rerio; Egg Proteins - chemistry; Egg Proteins - genetics; Egg Proteins - isolation & purification; Female; Fish Proteins - chemistry; Fish Proteins - genetics; Fish Proteins - isolation & purification; Fundamental and applied biological sciences. Psychology; Gambusia affinis; Gene Expression Regulation, Developmental; Isomerism; Mammalian male genital system; Molecular Sequence Data; Morphology. Physiology; Oocytes - physiology; Oogenesis - physiology; Vertebrates: reproduction; Vitellogenins - chemistry; Vitellogenins - genetics; Vitellogenins - isolation & purification
• ISSN: 0006-3363; 1529-7268
• DOI: 10.1095/biolreprod.104.037895

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-17β (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 β′-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. Abstract Three functional Vg genes and their products have been characterized in the mosquito fish, a teleost.