A novel seminal plasma glycoprotein of a teleost, the Nile tilapia (Oreochromis niloticus), contains a partial von Willebrand factor type D domain and a zona pellucida-like domain.
Our previous study shows that seminal plasma of a teleost, the Nile tilapia, contains a glycoprotein Mr = 120,000 named as SPP (Seminal plasma glycoprotein)120 which forms a homopolymer that has sperm immobilizing activity. In order to elucidate the mechanisms of the formation of the homopolymer and the immobilization of sperm, molecular cloning of SPP120 was conducted. The cDNA for SPP120 contains a complete open reading frame encoding 797 amino acid residues with 14 potential N-glycosylation sites. The predicted amino acid sequence of SPP120 contains a partial von Willebrand factor type D domain and a zona pellucida domain, that are involved in protein-protein adhesion that form filamentous structures in various kinds of cells. This result suggests that SPP120 forms a homopolymer via these domains in seminal plasma and probably interacts with spermatozoa. Northern blotting reveals that the gene is also expressed in ovary, even in ovulated eggs. The results of in situ hybridization indicate that in testis the gene is expressed in Sertoli cells and epithelial cells of sperm ducts, and the localization corresponds to that of the protein analyzed by immunohistochemistry. In the ovary, the gene is expressed at the perinucleolus stage of oocytes; however, the protein is not detected in any cells other than oocytes.
Mochida
Kazuhiko
K
Hokkaido National Fisheries Research Institute, Katsurakoi 116, Kushiro, Hokkaido 085-0802, Japan. kmochida@fra.affrc.go.jp
Matsubara
Takahiro
T
Andoh
Tadashi
T
Ura
Kazuhiro
K
Adachi
Shinji
S
Yamauchi
Kohei
K
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D023681:Cichlids / Q000235:genetics* / Q000378:metabolism; D003001:Cloning, Molecular; D018076:DNA, Complementary; D004527:Egg Proteins / Q000235:genetics*; D005260:Female; D015870:Gene Expression; D006023:Glycoproteins / Q000235:genetics*; D006801:Humans; D008297:Male; D008562:Membrane Glycoproteins / Q000235:genetics*; D008969:Molecular Sequence Data; D010053:Ovary / Q000378:metabolism; D017434:Protein Structure, Tertiary; D011956:Receptors, Cell Surface; D012661:Semen / Q000378:metabolism*; D029589:Seminal Plasma Proteins / Q000235:genetics*; D017422:Sequence Analysis, DNA; D020539:Sequence Analysis, Protein; D017386:Sequence Homology, Amino Acid; D013737:Testis / Q000378:metabolism; D000072216:Zona Pellucida Glycoproteins; D014841:von Willebrand Factor / Q000235:genetics*
D018076:DNA, Complementary; D004527:Egg Proteins; D006023:Glycoproteins; D008562:Membrane Glycoproteins; D011956:Receptors, Cell Surface; D029589:Seminal Plasma Proteins; D000072216:Zona Pellucida Glycoproteins; D014841:von Willebrand Factor