scholarly journals Could multiple low-affinity bonds mediate primary sperm-zona pellucida binding?

Reproduction ◽  
2002 ◽  
pp. 29-32 ◽  
Author(s):  
PE Castle
Keyword(s):  
Cell Surface ◽  
Zona Pellucida ◽  
Current Model ◽  
Sperm Protein ◽  
High Affinity ◽  
Sperm Binding ◽  
Specific Manner ◽  
Motile Spermatozoon ◽  
A Cell

The current model for primary sperm binding to the zona pellucida is that a cell-surface sperm protein binds with high affinity in an order-specific manner to one of the zona pellucida proteins, ZP3. However, the molecular details of primary sperm-zona pellucida binding remain elusive. A possible revised model is that multiple low-affinity bonds between spermatozoa and the zona pellucida may be sufficient for primary binding. The avidity of several low-affinity bonds can exceed that of a single high-affinity bond, which is sufficient to tether a motile spermatozoon. A mechanism involving multiple low-affinity bonds could account for some of the difficulties in elucidating primary sperm-zona pellucida interactions.

scholarly journals Sperm binding and fertilization envelope formation in a cell surface complex isolated from sea urchin eggs.

1979 ◽  
Vol 81 (1) ◽  
pp. 92-103 ◽  
Author(s):  
G L Decker ◽  
W J Lennarz
Keyword(s):  
Sea Water ◽  
Secretory Vesicles ◽  
Surface Complex ◽  
Surface Complexes ◽  
Exterior Surface ◽  
Thin Sections ◽  
Sperm Binding ◽  
Specific Manner ◽  
A Cell ◽  
Species Specific

An isolated surface complex consisting of the vitelline layer, plasma membrane, and attached secretory vesicles has been examined for its ability to bind sperm and to form the fertilization envelope. Isolated surface complexes (or intact eggs) fixed in glutaraldehyde and then washed in artificial sea water are capable of binding sperm in a species-specific manner. Sperm which bind to the isolated surface complex exhibit the acrosomal process only when they are associated with the exterior surface (vitelline layer) of the complex. Upon resuspension of the unfixed surface complex in artificial sea water, a limiting envelope is formed which, based on examination of thin sections and negatively stained surface preparations, is structurally similar to the fertilization envelope formed by the fertilized egg. These results suggest that the isolated egg surface complex retains the sperm receptor, as well as integrated functions for the secretion of components involved in assembly of the fertilization envelope.

scholarly journals GPI-anchored Proteins and Free GPI Glycolipids of Procyclic Form Trypanosoma brucei Are Nonessential for Growth, Are Required for Colonization of the Tsetse Fly, and Are Not the Only Components of the Surface Coat

2006 ◽  
Vol 17 (12) ◽  
pp. 5265-5274 ◽  
Author(s):  
Maria Lucia Sampaio Güther ◽  
Sylvia Lee ◽  
Laurence Tetley ◽  
Alvaro Acosta-Serrano ◽  
Michael A.J. Ferguson
Keyword(s):  
Cell Surface ◽  
Trypanosoma Brucei ◽  
Current Model ◽  
Apparent Molecular Weight ◽  
Tsetse Fly ◽  
Surface Coat ◽  
Procyclic Form ◽  
Cell Surface Biotinylation ◽  
A Cell

The procyclic form of Trypanosoma brucei exists in the midgut of the tsetse fly. The current model of its surface glycocalyx is an array of rod-like procyclin glycoproteins with glycosylphosphatidylinositol (GPI) anchors carrying sialylated poly-N-acetyllactosamine side chains interspersed with smaller sialylated poly-N-acetyllactosamine–containing free GPI glycolipids. Mutants for TbGPI12, deficient in the second step of GPI biosynthesis, were devoid of cell surface procyclins and poly-N-acetyllactosamine–containing free GPI glycolipids. This major disruption to their surface architecture severely impaired their ability to colonize tsetse fly midguts but, surprisingly, had no effect on their morphology and growth characteristics in vitro. Transmission electron microscopy showed that the mutants retained a cell surface glycocalyx. This structure, and the viability of the mutants in vitro, prompted us to look for non-GPI–anchored parasite molecules and/or the adsorption of serum components. Neither were apparent from cell surface biotinylation experiments but [3H]glucosamine biosynthetic labeling revealed a group of previously unidentified high apparent molecular weight glycoconjugates that might contribute to the surface coat. While characterizing GlcNAc-PI that accumulates in the TbGPI12 mutant, we observed inositolphosphoceramides for the first time in this organism.

scholarly journals TheFET3Gene Product Required for High Affinity Iron Transport in Yeast Is a Cell Surface Ferroxidase

1995 ◽  
Vol 270 (3) ◽  
pp. 1098-1101 ◽  
Author(s):  
Deepika M. De Silva ◽  
Candice C. Askwith ◽  
David Eide ◽  
Jerry Kaplan
Keyword(s):  
Cell Surface ◽  
Iron Transport ◽  
High Affinity ◽  
A Cell

scholarly journals Sperm IZUMO1 Is Required for Binding Preceding Fusion With Oolemma in Mice and Rats

2022 ◽  
Vol 9 ◽  
Author(s):  
Takafumi Matsumura ◽  
Taichi Noda ◽  
Yuhkoh Satouh ◽  
Akane Morohoshi ◽  
Shunsuke Yuri ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Zona Pellucida ◽  
Knockout Mice ◽  
Knockout Mouse ◽  
Acrosome Reaction ◽  
Male Rats ◽  
Sperm Protein ◽  
Complex Processes ◽  
Sperm Binding ◽  
Mammalian Spermatozoa

Fertilization occurs as the culmination of multi-step complex processes. First, mammalian spermatozoa undergo the acrosome reaction to become fusion-competent. Then, the acrosome-reacted spermatozoa penetrate the zona pellucida and adhere to and finally fuse with the egg plasma membrane. IZUMO1 is the first sperm protein proven to be essential for sperm-egg fusion in mammals, as Izumo1 knockout mouse spermatozoa adhere to but fail to fuse with the oolemma. However, the IZUMO1 function in other species remains largely unknown. Here, we generated Izumo1 knockout rats by CRISPR/Cas9 and found the male rats were infertile. Unlike in mice, Izumo1 knockout rat spermatozoa failed to bind to the oolemma. Further investigation revealed that the acrosome-intact sperm binding conceals a decreased number of the acrosome-reacted sperm bound to the oolemma in Izumo1 knockout mice. Of note, we could not see any apparent defects in the binding of the acrosome-reacted sperm to the oolemma in the mice lacking recently found fusion-indispensable genes, Fimp, Sof1, Spaca6, or Tmem95. Collectively, our data suggest that IZUMO1 is required for the sperm-oolemma binding prior to fusion at least in rat.

Differences between antigenic determinants of pig and cat zona pellucida proteins

Reproduction ◽  
2000 ◽  
pp. 15-23 ◽  
Author(s):  
K Jewgenow ◽  
M Rohleder ◽  
I Wegner
Keyword(s):  
In Vitro Fertilization ◽  
Zona Pellucida ◽  
Antigenic Determinants ◽  
Vitro Fertilization ◽  
Contraceptive Vaccine ◽  
Sperm Binding ◽  
Dependent Inhibition ◽  
Dose Dependent Inhibition ◽  
Dose Dependent

Despite many efforts, the control of reproduction in feral cat populations is still a problem in urban regions around the world. Immunocontraception is a promising approach; thus the present study examined the suitability of the widely used pig zona pellucida proteins (pZP) for contraception in feral domestic cats. Purified zona pellucida proteins obtained from pig and cat ovaries were used to produce highly specific antisera in rabbits. Antibodies against pZP raised in rabbits or lions were not effective inhibitors of either in vitro sperm binding (cat spermatozoa to cat oocytes) or in vitro fertilization in cats, whereas antibodies against feline zona pellucida proteins (fZP) raised in rabbits showed a dose-dependent inhibition of in vitro fertilization. Immunoelectrophoresis, ELISA and immunohistology of ovaries confirmed these results, showing crossreactivity of anti-fZP sera to fZP and to a lesser extent to pZP, but no interaction of anti-pZP sera with fZP. It is concluded that cat and pig zonae pellucidae express a very small number of shared antigenic determinants, making the use of pZP vaccine in cats questionable. A contraceptive vaccine based on feline zona pellucida determinants will be a better choice for the control of reproduction in feral cats if immunogenity can be achieved.

Combination of ribosome and phage display for fast selection of high affinity VHH antibody fragments

2019 ◽  
pp. 27-33
Author(s):  
YuE Kravchenko ◽  
SV Ivanov ◽  
DS Kravchenko ◽  
EI Frolova ◽  
SP Chumakov
Keyword(s):  
Phage Display ◽  
Selection Procedure ◽  
Free System ◽  
Phage Displays ◽  
High Affinity ◽  
Binding Domains ◽  
A Cell ◽  
Vhh Antibodies ◽  
Efficiency Of Selection ◽  
Selection Of

Selection of antibodies using phage display involves the preliminary cloning of the repertoire of sequences encoding antigen-binding domains into phagemid, which is considered the bottleneck of the method, limiting the resulting diversity of libraries and leading to the loss of poorly represented variants before the start of the selection procedure. Selection in cell-free conditions using a ribosomal display is devoid from this drawback, however is highly sensitive to PCR artifacts and the RNase contamination. The aim of the study was to test the efficiency of a combination of both methods, including pre-selection in a cell-free system to enrich the source library, followed by cloning and final selection using phage display. This approach may eliminate the shortcomings of each method and increase the efficiency of selection. For selection, alpaca VHH antibody sequences suitable for building an immune library were used due to the lack of VL domains. Analysis of immune libraries from the genes of the VH3, VHH3 and VH4 families showed that the VHH antibodies share in the VH3 and VH4 gene groups is insignificant, and selection from the combined library is less effective than from the VHH3 family of sequences. We found that the combination of ribosomal and phage displays leads to a higher enrichment of high-affinity fragments and avoids the loss of the original diversity during cloning. The combined method allowed us to obtain a greater number of different high-affinity sequences, and all the tested VHH fragments were able to specifically recognize the target, including the total protein extracts of cell cultures.

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