title: Cellular distribution of Mr 25,000 protein, a protein partially overlapping phosvitin and lipovitellin 2 in vitellogenin B1, and yolk proteins in Xenopus laevis oocytes and embryos.
abstract: A phosphorylated protein with molecular mass of 25,000 (pp25) can be derived from Xenopus laevis vitellogenin B1. In order to clarify the distribution of pp25, the changes in the concentration and localization of this protein in oocytes and embryos were examined by immunoblotting and immunohistochemistry using anti-pp25 antibodies, and compared with those of yolk proteins. In oocytes, pp25 was shown to localize characteristically at the surface just below the plasma membrane by immunohistochemical analysis. Interestingly, during embryogenesis, immunocytochemical staining revealed a transition of the pp25 distribution from beneath the outer surface of each germ layers to endoderm during tailbudding. In contrast, yolk proteins were localized in endoderm constantly throughout the developmental stages. However, the level of pp25 in the cytoplasm gradually decreased following the growth of embryos at the tailbud stage and disappeared at the tadpole stage, as shown by immunoblot analysis. These results suggest that pp25 could play different roles from those of yolk proteins such as lipovitellin and phosvitin in X. laevis oocytes and developing embryos.
authors.affiliation: Division of Pathological Biochemistry, Department of Biomedical Sciences, School of Life Sciences, Faculty of Medicine, Tottori University, Yonago 683-8503, Japan.
authors.forename: Hiroyasu
authors.initials: H
authors.lastname: Nakamura
authors.forename: Satoshi
authors.initials: S
authors.lastname: Yoshitome
authors.forename: Isamu
authors.initials: I
authors.lastname: Sugimoto
authors.forename: Yoshikazu
authors.initials: Y
authors.lastname: Sado
authors.forename: Akira
authors.initials: A
authors.lastname: Kawahara
authors.forename: Shuichi
authors.initials: S
authors.lastname: Ueno
authors.forename: Takayuki
authors.initials: T
authors.lastname: Miyahara
authors.forename: Yasunobu
authors.initials: Y
authors.lastname: Yoshida
authors.forename: Naoe
authors.initials: N
authors.lastname: Aoki-Yagi
authors.forename: Eikichi
authors.initials: E
authors.lastname: Hashimoto
mesh_terms: D000818:Animals; D015153:Blotting, Western; D002462:Cell Membrane / Q000378:metabolism; D003593:Cytoplasm / Q000378:metabolism; D004475:Ectoderm / Q000378:metabolism; D015387:Egg Proteins, Dietary / Q000378:metabolism*; D004707:Endoderm / Q000378:metabolism; D005260:Female; D007150:Immunohistochemistry; D007814:Larva / Q000378:metabolism; D008648:Mesoderm / Q000378:metabolism; D008970:Molecular Weight; D009865:Oocytes / Q000378:metabolism*; D010766:Phosphorylation; D010774:Phosvitin / Q000737:chemistry / Q000378:metabolism*; D012455:Salamandridae / Q000196:embryology / Q000378:metabolism; D013997:Time Factors; D014819:Vitellogenins / Q000737:chemistry / Q000378:metabolism*; D029867:Xenopus Proteins / Q000737:chemistry / Q000378:metabolism*; D014982:Xenopus laevis / Q000196:embryology / Q000378:metabolism*