Vitelline envelope

All animal eggs are surrounded by egg envelopes which must be traversed by sperm on their journey to the egg surface. These egg envelopes are known by various terms in different organisms, being called the vitelline layer in sea urchins, the vitelline envelope in amphibians, and the zona pellucida in mammals. The fertilizing sperm must penetrate the egg envelope in order to fuse with the plasma membrane and transfer its haploid set of chromosomes into the cell cytoplasm. 

Fujita, T., M. Shimizu, N. Hiramatsu, H. Fukada and A. Hara. Purification of serum precursor proteins to vitelline envelope (choriogenins) in masu salmon, Oncorhynchus masou. Comp. Biochem. Physiol. 32B 599-610, 2002. 

Hyllner, S.J. andC. Haux. Immunochemical detection of the major vitelline envelope proteins in the plasma and oocytes of the maturing female rainbow trout, Oncorhynchus mykiss. J. Endocrinol. 135 303 -309,1992. 

Hyllner, S.J., B. Norberg and C. Haux. Isolation, partial characterization, induction, and the occurrence in plasma of the major vitelline envelope proteins in the Atlantic halibut (Hippoglossus hippoglossus) during sexual maturation. Can. J. Fish. Aquat. Sci. 51 1700-1707, 1994. 

Hyllner, S.J., H.F.-P. Barber, D.G.J. Larsson and C. Haux. Amino acid composition and endocrine control of vitelline envelope proteins in European sea bass (Dicentrarchus labrax) and gilthead sea bream (Sparus aurata). Mol. Reprod. Dev. 41 339-347, 1995. 

LaFleur, G.J., Jr., B.M. Byrne, C. Haux, R.M. Greenberg and R.A. Wallace. Liver-derived cDNAs vitellogenin and vitelline envelope protein precursors (choriogenins). In Proceedings of the Fifth International Symposium on the Reproductive Physiology of Fish, edited by F.W. Goetz and P. Thomas, Austin, University of Texas, pp. 336-338, 1995. 

Larsson, D.G.J., SJ. Hyllner and C. Haux. Induction of vitelline envelope proteins by estradiol-17/3 in 10 teleost species. Gen. Comp. Endocrinol. 96 445-450, 1994. 

Shimizu, M., T. Fujitaand A. Hara. Purification of the precursors to vitelline envelope proteins from serum of Sakhalin taimen, Hucho perryi. J. Exp. Zool. 282 385-395, 1998. 

Figure 1. An unfertilized egg of the red abalone Haliotis rufescens. The dark egg is 1 75 l m in diameter. The vitelline envelope is 0.6 pm in thickness and 245 pm in diameter (from Lewis et al., 1982).

Figure2. Dark field microscopy of isolated/-/, rufescens vitelline envelopes (from Lewis etal., 1982).

Figure 17. The vitelline envelope receptor for lysin (VERL) is a giant glycoprotein. (Left panel), electrophoresis of VERL on 2.5% acrylamide gels (silver staining) shows it resolves as two sharp bands between titin (2,800K) and nebulin (770K), Lane 1, rabbit muscle extract myosin (205) lanes 2-6, different loads of pink abalone VERL resolved into two components. (Right panel), electron micrography of VERL molecules negatively stained with uranyl acetate. The VERL fibers are 13 nm in diameter (from Swanson and Vacquier, 1997).

Swanson, W.J. and Vacquier, V.D. (1997). The abalone egg vitelline envelope receptor for sperm lysin is a giant, multivalent molecule. Proc. Natl. Acad. Sci. USA. 94 6724-6730. 

Kdn-rich glycoprotein isolated from vitelline envelope and/or female ovarian fluid of rainbow trout... 

Mucin-type glycoproteins found in the vitelline envelope and ovarian fluid of salmonid fish... 

More recently, Kdn-containing di- and triantennary N-glycan chains were identified in Kdn-gp isolated from rainbow trout vitelline envelope [54] (see Fig. 5). Based on composition and the yield of the carbohydrate chains, about 1000 O-glycans and 60 N-glycans are linked to a 3000 kDa Kdn-gp. 

Fig. 5. Structures of (a) Kdn-containing O- and N-linked glycan chains (b) NeuSGc-containing 0-glycan chains of Kdn-gp and Sia-gp isolated from the vitelline envelope of salmonid fish species.

Immunohistochemical methods revealed that Kdn-gp is localized in the second layer of the outer surface of the vitelline envelope [56]. 

Kdn-gp appeared to be synthesized during relatively later stages of oogenesis, since it was undetectable in the oocyte 3 months prior to ovulation. Although the cell types that synthesize Kdn-gp have not been identified, it is most likely synthesized under hormonal control in some extraoocj e cells (i.e. follicle cells), secreted and partly incorporated into the second outermost layer of the vitelline envelope just before ovulation. Kdn-gp may thus be a molecule homologous to the oviduct glycoproteins of mammals that are reported to be secreted and partly incorporated into the egg surface [58-60]. 

During fertilization, sperm must first bind in a species-specific manner to the eggs thick extracellular coat, the zona peUucida or vitelline envelope and then undergo a form of... 

The vitelline envelops are removed with Dumont 5 watchmakers forceps. For cutting embryos, we use eyebrow hairs embedded in wax in the tips of pulled, disposable Pasteur pipets. Hairloops, which are used to position and hold embryonic tissues, are also embedded in pipets. Pipets are pulled to a diameter... 

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