Changes in protein phosphorylation during the maturation of mammalian oocytes in vitro.
Cumulus-enclosed sheep oocytes were cultured in gonadotrophin-containing medium for up to 9 hr and were then incubated for 3 hr in the presence of [32P]phosphate. The incorporation of 32P into TCA-insoluble material was measured, and oocyte proteins were separated by one- and two-dimensional gel electrophoresis. Incorporation of [32P]phosphate into protein increased after 3 hr culture and again after 9 hr, the time of germinal vesicle breakdown (GVBD). Qualitative and quantitative changes in the phosphorylation of proteins occurred over the 12-hr period studied. One of the most prominent changes was the appearance of a band of Mr 33,000, which was absent at 0-3 hr but appeared with increasing intensity with longer periods of culture. Two-dimensional electrophoresis revealed that the bulk of material in this band was a neutral polypeptide. No significant incorporation of [32P]phosphate was found in ribosomal extracts of oocytes.
D000818:Animals; D001345:Autoradiography; D002478:Cells, Cultured; D004591:Electrophoresis, Polyacrylamide Gel; D005260:Female; D008540:Meiosis; D009865:Oocytes / Q000378:metabolism*; D010710:Phosphates / Q000378:metabolism*; D010750:Phosphoproteins / Q000032:analysis / Q000096:biosynthesis*; D010766:Phosphorylation; D012269:Ribosomal Proteins / Q000032:analysis; D012756:Sheep
D010710:Phosphates; D010750:Phosphoproteins; D012269:Ribosomal Proteins