TY - JOUR
T1 - Biosynthesis of the major zona pellucida glycoprotein secreted by oocytes during mammalian oogenesis
AU - Greve, Jeffrey M.
AU - Salzmann, George S.
AU - Roller, Richard J.
AU - Wassarman, Paul M.
N1 - Funding Information:
We wish to thank Dr. Martin Snider for his advice and a generous gift of Endo H. Dr. Morris Karnovsky for the use of his cryostat and fluorescence microscope and Dr. Malcolm Gefter for advice and encouragement during the initial stages of this work. We are also grateful to the members of our laboratory group for constructive criticism throughout the course of this research. The research was supported by a grant from the National Institute of Child Health and Human Development. J. M. G. is a postdoctoral fellow of the Rockefeller Foundation, and G. S. S. and R. J. R. are predoctoral fellows supported by National Research Service Awards.
PY - 1982/12
Y1 - 1982/12
N2 - An antiserum directed specifically against ZP2, the major glycoprotein of the mouse egg's extracellular coat (zona pellucida), has been used to immunoprecipitate intracellular precursors of ZP2 that were synthesized by growing mouse oocytes cultured in vitro. Pulse-chase experiments revealed that the immediate precursor of mature, 120 kilodalton (kd) ZP2 is a 91 kd species that unlike mature ZP2, is sensitive to digestion by endo-β-N-acetylglucosaminidase H (Endo H) and is converted by the endoglycosidase into an 81 kd species. An 81 kd species is only found intracellularly when growing oocytes are cultured in the presence of tunicamycin. These results suggest that ZP2 is synthesized as an 81 kd polypeptide chain that is first "core"-glycosylated at asparagine residues with high-mannose-type oligosaccharides, giving rise to a 91 kd intermediate (Endo H-sensitive), and then processed to complextype oligosaccharides prior to secretion as mature, 120 kd ZP2 (Endo H-insensitive). Furthermore, electrophoretic analyses of mature ZP2, ZP2 precursor (91 kd) and Endo H-treated ZP2 precursor (81 kd) suggest that there are six N-linked oligosac-charides per molecule and that the extreme heterogeneity of mature ZP2 is a consequence of the oligosaccharides and not the polypeptide chain itself.
AB - An antiserum directed specifically against ZP2, the major glycoprotein of the mouse egg's extracellular coat (zona pellucida), has been used to immunoprecipitate intracellular precursors of ZP2 that were synthesized by growing mouse oocytes cultured in vitro. Pulse-chase experiments revealed that the immediate precursor of mature, 120 kilodalton (kd) ZP2 is a 91 kd species that unlike mature ZP2, is sensitive to digestion by endo-β-N-acetylglucosaminidase H (Endo H) and is converted by the endoglycosidase into an 81 kd species. An 81 kd species is only found intracellularly when growing oocytes are cultured in the presence of tunicamycin. These results suggest that ZP2 is synthesized as an 81 kd polypeptide chain that is first "core"-glycosylated at asparagine residues with high-mannose-type oligosaccharides, giving rise to a 91 kd intermediate (Endo H-sensitive), and then processed to complextype oligosaccharides prior to secretion as mature, 120 kd ZP2 (Endo H-insensitive). Furthermore, electrophoretic analyses of mature ZP2, ZP2 precursor (91 kd) and Endo H-treated ZP2 precursor (81 kd) suggest that there are six N-linked oligosac-charides per molecule and that the extreme heterogeneity of mature ZP2 is a consequence of the oligosaccharides and not the polypeptide chain itself.
UR - http://www.scopus.com/inward/record.url?scp=0020457338&partnerID=8YFLogxK
U2 - 10.1016/0092-8674(82)90329-4
DO - 10.1016/0092-8674(82)90329-4
M3 - Article
C2 - 6819087
AN - SCOPUS:0020457338
SN - 0092-8674
VL - 31
SP - 749
EP - 759
JO - Cell
JF - Cell
IS - 3 PART 2
ER -