Zona pellucida

Zona pellucida
Human ovum. The zona pellucida is seen as a thick clear girdle surrounded by the cells of the corona radiata.
Gray's	subject #3 38
MeSH	Zona+Pellucida

The zona pellucida (plural zonae pellucidae, also egg coat) is a glycoprotein membrane surrounding the plasma membrane of an oocyte. It is a vital constitutive part of the oocyte, external but of essential importance to it. The zona pellucida first appears in multilaminar primary oocytes.

This structure binds spermatozoa, and is required to initiate the acrosome reaction. In the mouse (the best characterised mammalian system) the zona glycoprotein, ZP3, is responsible for sperm binding, adhering to proteins on the sperm plasma membrane (GalT). ZP3 is then involved in the induction of the acrosome reaction, whereby a spermatozoon releases the contents of the acrosomal vesicle. The exact characterisation of what occurs in other species has become more complicated as further zona proteins have been identified.

In humans, five days after the fertilization, the blastocyst performs zona hatching; the zona pellucida degenerates and decomposes to be replaced by the underlying layer of trophoblastic cells.

The zona pellucida is essential for oocyte death and fertilization.

In some older texts, it has also been called zona striata and stratum lucidum (not to be confused with the stratum lucidum of the skin).

Immunocontraception

Glycoproteins in ZP1, 2, 3 and 4 are targets for immunocontraception in the human.

In non-mammalian animals, the zona pellucida (called vitelline layer) plays an important role in preventing cross-breeding of different species, especially in species that fertilize outside of the body (e.g. fish).

The zona pellucida is commonly used to control wildlife population problems by immunocontraception. When the zona pellucida of one animal species is injected into the bloodstream of another, it results in sterility of the second species due to immune response. This effect can be temporary or permanent, depending on the method used. In New Jersey, Porcine zona pellucida is used to keep deer populations low, and this process is commonly referred to as "spay-vac".

Zona pellucida glycoproteins

There are four major zona pellucida glycoproteins, termed ZP1-4. ZP1, ZP3 and ZP4 bind to capacitated spermatozoa and induce the acrosome reaction.Successful fertilization depends on the ability of sperm to penetrate extracellular matrix surrounding eggs. In the mouse:

• ZP3 allows species-specific sperm binding
• ZP2 mediates subsequent sperm binding
• ZP1 cross-links ZP2 and ZP3.

Data with native human protein is not currently available.

Additional images

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  First stages of segmentation of a mammalian ovum.

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  Section of vesicular ovarian follicle of cat. x50.

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  The initial stages of human embryogenesis

See also

• Maternal influence on sex determination

Further reading

• Bork, Peer; Sander, Chris (1992). "A large domain common to sperm receptors (Zp2 and Zp3) and TGF-β type III receptor". FEBS Letters 300 (3): 237–40. doi:10.1016/0014-5793(92)80853-9. PMID 1313375. 
• Oehninger, Sergio (2003). "Biochemical and functional characterization of the human zona pellucida". Reproductive BioMedicine Online 7 (6): 641–8. doi:10.1016/S1472-6483(10)62086-X. PMID 14748962. 
• Boja, E. S.; Hoodbhoy, T; Fales, HM; Dean, J (2003). "Structural Characterization of Native Mouse Zona Pellucida Proteins Using Mass Spectrometry". Journal of Biological Chemistry 278 (36): 34189–202. doi:10.1074/jbc.M304026200. PMID 12799386. 
• Bagnell C (2005). "Animal Reproduction". Rutgers University Department of Animal Sciences.
• Jovine, Luca; Darie, Costel C.; Litscher, Eveline S.; Wassarman, Paul M. (2005). "Zona Pellucida Domain Proteins". Annual Review of Biochemistry 74: 83–114. doi:10.1146/annurev.biochem.74.082803.133039. PMID 15952882. 
• Monné, Magnus; Han, Ling; Jovine, Luca (2006). "Tracking Down the ZP Domain: From the Mammalian Zona Pellucida to the Molluscan Vitelline Envelope". Seminars in Reproductive Medicine 24 (4): 204–16. doi:10.1055/s-2006-948550. PMID 16944418. 
• Wassarman, P. M. (2008). "Zona Pellucida Glycoproteins". Journal of Biological Chemistry 283 (36): 24285–9. doi:10.1074/jbc.R800027200. PMC 2528931. PMID 18539589. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2528931. 
• Wassarman, Paul M.; Litscher, Eveline S. (2008). "Mammalian fertilization:the eggs multifunctional zona pellucida". The International Journal of Developmental Biology 52 (5–6): 665–76. doi:10.1387/ijdb.072524pw. PMID 18649280. 
• Monné, Magnus; Han, Ling; Schwend, Thomas; Burendahl, Sofia; Jovine, Luca (2008). "Crystal structure of the ZP-N domain of ZP3 reveals the core fold of animal egg coats". Nature 456 (7222): 653–7. doi:10.1038/nature07599. PMID 19052627. 
• Han, Ling; Monné, Magnus; Okumura, Hiroki; Schwend, Thomas; Cherry, Amy L.; Flot, David; Matsuda, Tsukasa; Jovine, Luca (2010). "Insights into Egg Coat Assembly and Egg-Sperm Interaction from the X-Ray Structure of Full-Length ZP3". Cell 143 (3): 404–15. doi:10.1016/j.cell.2010.09.041. PMID 20970175. 

External links

• Histology at BU 18404loa - "Female Reproductive System: ovary, cumulus oophorus "
• Histology at BU 14805loa - "Female Reproductive System: ovary, multilaminar primary follicle"
• Organology at UC Davis Reproductive/mammal/ovary2/ovary7 - "Mammal, canine ovary (LM, High)"
• Image at um.edu.mt
• Image at um.edu.mt