Characterization of Human Sperm Binding to Homologous Recombinant Zona Pellucida Proteins

2011 ◽  
Vol 18 (9) ◽  
pp. 876-885 ◽  
Author(s):  
Mayel Chirinos ◽  
Cecilia Cariño ◽  
María Elena González-González ◽  
Ernesto Arreola ◽  
Rodrigo Reveles ◽  
...  
2014 ◽  
Vol 205 (6) ◽  
pp. 801-809 ◽  
Author(s):  
Matteo A. Avella ◽  
Boris Baibakov ◽  
Jurrien Dean

The extracellular zona pellucida surrounds ovulated eggs and mediates gamete recognition that is essential for mammalian fertilization. Zonae matrices contain three (mouse) or four (human) glycoproteins (ZP1–4), but which protein binds sperm remains controversial. A defining characteristic of an essential zona ligand is sterility after genetic ablation. We have established transgenic mice expressing human ZP4 that form zonae pellucidae in the absence of mouse or human ZP2. Neither mouse nor human sperm bound to these ovulated eggs, and these female mice were sterile after in vivo insemination or natural mating. The same phenotype was observed with truncated ZP2 that lacks a restricted domain within ZP251–149. Chimeric human/mouse ZP2 isoforms expressed in transgenic mice and recombinant peptide bead assays confirmed that this region accounts for the taxon specificity observed in human–mouse gamete recognition. These observations in transgenic mice document that the ZP251–149 sperm-binding domain is necessary for human and mouse gamete recognition and penetration through the zona pellucida.


Reproduction ◽  
2011 ◽  
Vol 141 (3) ◽  
pp. 313-319 ◽  
Author(s):  
Belinda Yauger ◽  
Nathan A Boggs ◽  
Jurrien Dean

The molecular basis of human fertilization remains enigmatic. Mouse models are often used to study sperm–egg recognition, but the mouse zona pellucida surrounding ovulated eggs contains three proteins (ZP1, ZP2, and ZP3) whereas the human zona contains four (ZP1, ZP2, ZP3, and ZP4). Human sperm are fastidious and recognize human but not mouse eggs. Transgenic mouse lines were established to ascertain whether human ZP4 is the sole determinant of human sperm binding. Human ZP4 expressed in transgenic mice had a molecular mass similar to the range of native protein isoforms and was incorporated into the extracellular zona matrix. Transgenic females were fertile with normal litter sizes. Mouse sperm readily recognized transgenic ovulated eggs, but human sperm did not. We conclude that human ZP4 is not sufficient to support human sperm binding to the zona pellucida in transgenic mice and that other zona proteins may be needed for human gamete recognition.


Development ◽  
1998 ◽  
Vol 125 (13) ◽  
pp. 2415-2424 ◽  
Author(s):  
T.L. Rankin ◽  
Z.B. Tong ◽  
P.E. Castle ◽  
E. Lee ◽  
R. Gore-Langton ◽  
...  

The mammalian zona pellucida surrounding ovulated eggs mediates sperm binding at fertilization, provides a postfertilization block to polyspermy, and facilitates passage of pre-implantation embryos down the oviduct. Although the three zona proteins (ZP1, ZP2, ZP3) are well conserved, mammalian fertilization is relatively specific and human sperm do not bind to the mouse zona pellucida. There are considerable in vitro data that ZP3 acts as a primary sperm adhesion molecule in mice and, by analogy, a similar role has been postulated for human ZP3. Genetically altered mice lacking ZP3 (Zp3(tm/tm)) do not form a zona pellucida and are infertile. To rescue this phenotype, transgenic mice expressing human ZP3 (67% identical to mouse ZP3) were produced and bred with Zp3(tm/tm) null mice. The resultant human ZP3 rescue females had chimeric zonae pellucidae composed of mouse ZP1, mouse ZP2 and human ZP3. Human ZP3 expressed in mouse oocytes had an apparent mass (64 kDa) indistinguishable from native human ZP3 and distinct from mouse ZP3 (83 kDa). Despite the presence of human ZP3, human sperm did not bind to the chimeric zona pellucida, and notwithstanding the absence of mouse ZP3, mouse sperm bound to ovulated eggs in vitro and fertility was restored in vivo. These data have implications regarding the molecular basis of mouse and human sperm binding to their respective zonae pellucidae.


1990 ◽  
Vol 2 (6) ◽  
pp. 641 ◽  
Author(s):  
DY Liu ◽  
A Lopata ◽  
HW Baker

A test for human sperm binding to the oolemma was developed with oocytes that failed to be fertilized in vitro. The zonae pellucidae of the oocytes were removed under a dissecting microscope by brief exposure to dilute HCl (pH 2.5-3.0) in 0.9% NaCl. The zona-free oocytes (ZFOs) were incubated with a mixture of equal numbers of motile sperm from men to be tested and fertile donors. The sperm was differentially labelled with fluorescein or rhodamine and the results expressed as a ratio of the number of test to control sperm bound to several ZFOs in order to control for variability in the ability of the oolemma to bind sperm. The number of sperm bound to the oolemma increased with time and sperm concentration. The sperm-oolemma binding ratio determined for 32 patients undergoing in vitro fertilization (IVF) was significantly correlated with the sperm-zona pellucida (ZP) binding ratio but was not correlated with other sperm tests. The sperm-oolemma binding ratio was also related to the IVF rate, but this was not significant if the sperm-ZP binding ratio was included in the logistic regression model. Only four of the 32 patients had failure of fertilization in vitro. The human sperm-oolemma binding test may be useful for studying the interaction between gametes, but the test is unlikely to be as useful clinically as the sperm-ZP binding test for predicting fertilization in vitro.


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