The vitelline membrane of the hen's egg: a chemical and electron microscopical study

The avian perivitelline layer (PL), a vestment homologous to the zona pellucida (ZP) of mammalian oocytes, is composed of at least three glycoproteins. Our previous studies have demonstrated that the matrix's components, ZP3 and ZPD, are synthesized in ovarian granulosa cells. Another component, ZP1, is synthesized in the liver and is transported to the ovary by blood circulation. In this study, we report the isolation of cDNA encoding quail ZP2 and its expression in the female bird. By RNase protection assay and in situ hybridization, we demonstrate that ZP2 transcripts are restricted to the oocytes of small white follicles (SWF). The expression level of ZP2 decreased dramatically during follicular development, and the highest expression was observed in the SWF. Western blot and immunohistochemical analyses using the specific antibody against ZP2 indicate that the 80 kDa protein is the authentic ZP2, and the immunoreactive ZP2 protein is also present in the oocytes. Moreover, ultrastructural analysis demonstrated that the immunoreactive ZP2 localizes to the zona radiata, the perivitelline space, and the oocyte cytoplasm in the SWF. By means of western blot analysis and immunofluorescence microscopy, we detected a possible interaction of the recombinant ZP2 with ZP3 and that this interaction might lead to the formation of amorphous structure on the cell surface. These results demonstrate for the first time that the avian ZP gene is expressed in the oocyte, and that the ZP2 protein in the oocyte might play a role for the PL formation in the immature follicles of the ovary.

Section: Introductionmentioning

confidence: 99%

Zona pellucida protein ZP2 is expressed in the oocyte of Japanese quail (Coturnix japonica)

Kinoshita

Rodler²,

Sugiura³

et al. 2010

“…The avian egg is surrounded by multiple layers of different extracellular matrices, including an inner layer of vitelline membrane, continuous membrane, and an outer layer of vitelline membrane (Bellairs et al 1963). At the time of ovulation, the avian oocyte is only surrounded by the inner layer of vitelline membrane, also referred to as the perivitelline layer (PL), which is a rough meshwork of thick filaments mainly composed of glycoproteins (Wyburn et al 1965).…”

Section: Introductionmentioning

confidence: 99%

Molecular characterization of egg envelope glycoprotein ZPD in the ovary of Japanese quail (Coturnix japonica)

Sato

Kinoshita²,

Kansaku³

et al. 2009

The egg envelope surrounding avian oocytes exhibits a three-dimensional network of coarse fibers between the granulosa cells and the oocyte. Our previous studies have demonstrated that one of the matrix's components, ZP3, is synthesized in the ovarian granulosa cells. Another component, ZP1, which is critically involved in triggering the sperm acrosome reaction, is synthesized in the liver. We have previously isolated cDNAs encoding quail ZP3 and ZP1, and we now report the isolation of cDNA encoding quail ZPD. By RNase protection assay and in situ hybridization, we have demonstrated that ZPD transcripts are restricted to the granulosa cells of preovulatory follicles. The expression level of ZPD increased progressively during follicular development, and the highest expression was observed in the largest follicles. Western blot analyses using the specific antibody against ZPD indicate that the 40 kDa protein is the authentic ZPD, and the contents of ZPD protein also increased during follicular development. Moreover, we found that the addition of FSH to the culture media enhances the ZPD secretion in the cultured granulosa cells. Two-dimensional gel electrophoresis revealed the presence of several ZPD isoforms with different pI values ranging from 5.5 to 7. Immunohistochemical analyses indicate that the materials recognized with anti-quail ZPD antibody were accumulated in the egg envelope of large yellow follicles. These results demonstrate the presence of ZPD protein in the egg envelope, and that the amount of ZPD in the egg envelope as well as the mRNA in the cells increases at the latter stages of folliculogenesis.

“…The enzymes released are required to allow the chicken spermatozoa to hydrolyze the inner perivitelline layer (IPVL) surrounding the oocyte, and this results in holes that permit the passage of one or several spermatozoa through the IPVL (Bakst & Howarth 1977, Steele et al 1994, Robertson et al 1997. The megalecithal oocyte of birds is surrounded by an extracellular matrix, the perivitelline layer (PL) composed of the IPVL at the state of ovulation and fertilization, IPVL then being very rapidly surrounded by an outer perivitelline layer (OPVL) in the infundibulum (Bellairs et al 1963, Kido & Doi 1988. The IPVL can be considered to a certain extent as analogous to the mammalian zona pellucida (ZP; Waclawek et al 1998).…”

Section: Introductionmentioning

confidence: 99%

A reappraisal of the factors involved in in vitro initiation of the acrosome reaction in chicken spermatozoa

Lemoine¹,

Grasseau²,

Brillard³

et al. 2008

Chicken spermatozoa may remain in the female oviduct for a prolonged period before induction of the acrosome reaction on contact with the inner perivitelline layer (IPVL). By contrast, the acrosome reaction may be induced very rapidly in vitro in the presence of IPVL and Ca 2C. In the present study, we examined the extent to which the chicken acrosome reaction can be induced in media of various compositions in the presence or absence of IPVL and/or Ca 2C and other factors known to be efficient in mammals. We also compared the efficacy of perivitelline layer (PL) taken at various states of oocyte maturation in initiating the reaction. The acrosome reaction was induced in less than 5 min in the presence of Ca 2C and IPVL. Incubation of spermatozoa in different saline media (Beltsville poultry semen extender (BPSE); Dulbecco's modified eagle medium; NaCl-TES buffer) without IPVL showed a significant induction of acrosome reaction in BPSE supplemented with 5 mM Ca 2C and in the three media after supplementation with Ca 2C and Ca 2C ionophore A23187.By contrast, the acrosome reaction was never induced without Ca 2C. BSA, NaHCO 3 , and progesterone did not stimulate the acrosome reaction. Ca 2C plus PL taken at various physiological states (follicle IPVL, ovulated IPVL, oviposited IPVL, and/or outer perivitelline layer) strongly stimulated the acrosome reaction, the latest states being the most efficient. Although PL induced the acrosome reaction in the presence of extracellular Ca 2C, it was not possible to induce hyperactivation in chicken spermatozoa. Taken together, these results emphasize the central role of Ca 2C in the in vitro initiation of the acrosome reaction in chickens and show specific features of this induction in birds.