title: In vitro biosynthesis of three sulfated glycoproteins of murine zonae pellucidae by oocytes grown in follicle culture.
abstract: The zona pellucida is an extracellular glycocalyx that surrounds the growing oocyte and mediates specific biological functions essential to early mammalian development. We have isolated by a novel technique intact zonae pellucidae from a murine follicle culture system which mimics in vivo granulosa cell-oocyte interactions. Using radioactive precursors we have demonstrated that all three zona proteins, ZP-1, ZP-2, and ZP-3, are sulfated glycoproteins. Incubation of the follicle culture with tunicamycin (0.5 microgram/ml), an antibiotic that blocks N-glycosylation, inhibits new protein deposition in the zona. Under these same conditions overall protein synthesis is decreased only 30%. Biosynthetic studies indicate that after 6 days in culture the zona proteins are produced at 0.4 pg/oocyte/h, which represents 2-3% of the total oocyte protein synthesis. This synthesis stops at or before ovulation and the extremely long half-life (greater than 100 h) of the zona may be essential to preserve its known biological functions, all of which occur after ovulation.
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D004527:Egg Proteins; D005260:Female; D006023:Glycoproteins / Q000096:biosynthesis*; D008562:Membrane Glycoproteins; D051379:Mice; D008811:Mice, Inbred DBA; D008970:Molecular Weight; D006080:Ovarian Follicle / Q000378:metabolism; D010063:Ovum / Q000378:metabolism*; D011956:Receptors, Cell Surface; D014415:Tunicamycin / Q000494:pharmacology; D015044:Zona Pellucida / Q000187:drug effects / Q000378:metabolism*; D000072216:Zona Pellucida Glycoproteins
chemical_list: D004527:Egg Proteins; D006023:Glycoproteins; D008562:Membrane Glycoproteins; D011956:Receptors, Cell Surface; D000072216:Zona Pellucida Glycoproteins; C000606519:Zp1 protein, mouse; C000606520:Zp2 protein, mouse; C000606521:Zp3 protein, mouse; D014415:Tunicamycin