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) is a glycoprotein membrane surrounding the plasma membrane of an oocyte. It is a vital constitutive part of the latter, external but not extraneous to it. The zona pellucida first appears in multilaminar primary oocytes.

This structure binds spermatozoa, and is required to initiate the acrosome reaction. The zona glycoprotein, ZP3, is responsible for sperm binding, adhering to proteins on the sperm plasma membrane. There is evidence that ZP3 is then involved in the induction of the acrosome reaction, whereby a spermatozoon releases the contents of the acrosomal vesicle.

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^[1] (not to be confused with the stratum lucidum of the skin).

Immunocontraception

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

In non-mammalian animals, the zona pellucida (called vitelline layer) plays an important role in preventing 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".

Four Major Glycoproteins

• ZP3 allows species-specific sperm binding
• ZP2 mediates subsequent sperm binding
• ZP1 cross-links ZP2 and ZP3. It is important for structural integrity of zona pellucida but not essential for fertilization.
• ZP4 Its true function is still quite unknown but evidence shows in a pig, the primary sperm receptor is a heterocomplex of ZP3 and ZP4. ^[2]

Additional images

First stages of segmentation of a mammalian ovum.

Section of vesicular ovarian follicle of cat. x50.

References

• Bork P, Sander C (1992). "A large domain common to sperm receptors (Zp2 and Zp3) and TGF-beta type III receptor". FEBS Lett 300 (3): 237–40. doi:10.1016/0014-5793(92)80853-9. PMID 1313375. 

• Oehninger S (2003). "Biochemical and functional characterization of the human zona pellucida". Reprod Biomed Online 7 (6): 641–8. PMID 14748962. 

• Boja ES, Hoodbhoy T, Fales HM, Dean J (2003). "Structural characterization of native mouse zona pellucida proteins using mass spectrometry". J Biol Chem 278 (36): 34189–202. doi:10.1074/jbc.M304026200. PMID 12799386. 

• Bagnell C (2005). "Animal Reproduction". Rutgers University Department of Animal Sciences.

• Jovine L, Darie CC, Litscher ES, Wassarman PM (2005). "Zona pellucida domain proteins". Annu Rev Biochem 74: 83–114. doi:10.1146/annurev.biochem.74.082803.133039. PMID 15952882. 

• Monné M, Han L, Jovine L. (2006). "Tracking down the ZP domain: From the mammalian zona pellucida to the molluscan vitelline envelope". Semin Reprod Med 24 (4): 204–16. doi:10.1055/s-2006-948550. PMID 16944418. 

• Wassarman PM (2008). "Zona pellucida glycoproteins". J Biol Chem 283 (36): 24285–9. doi:10.1074/jbc.R800027200. PMID 18539589. 

• Wassarman PM, Litscher ES (2008). "Mammalian fertilization: the egg's multifunctional zona pellucida". Int J Dev Biol 52 (5-6): 665–76. doi:10.1387/ijdb.072524pw. PMID 18649280. 

• Monné M, Han L, Schwend T, Burendahl S, Jovine L (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. 

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