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.

Sperm binding and formation of the fertilization envelope by surface complexes isolated from sea urchin eggs

1978 ◽  
Vol 36 (2) ◽  
pp. 578-579
Author(s):  
Glenn L. Decker
Keyword(s):  
Plasma Membrane ◽  
Sea Water ◽  
Secretory Vesicles ◽  
Surface Complexes ◽  
Exterior Surface ◽  
Sperm Binding ◽  
Acrosomal Reaction ◽  
Initial Interaction ◽  
Cortical Vesicles

During fertilization of the echinoderm egg the sperm cell undergoes the acrosomal reaction and binds species-specifically to the vitelline layer, which is attached to the exterior surface of the egg plasma membrane. Following initial interaction and fusion of the limiting membranes of the egg and the sperm, the cortical vesicles attached to the inner surface of the egg plasma membrane (Fig. 1) fuse and secrete components which appear to modify the vitelline layer, giving rise to the fertilization envelope.Recently, the surface and associated secretory vesicles of the egg were isolated from homogenates by differential centrifugation in sea water containing 25 mM EGTA (Fig. 2) (2). Determination of the extent to which this cell surface-secretory complex can be induced to mimic fertilization related events observed with intact eggs is currently in progress.

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 Different calcium-dependent pathways control fertilisation-triggered glycoside release and the cortical contraction in ascidian eggs

Zygote ◽  
1995 ◽  
Vol 3 (3) ◽  
pp. 251-258 ◽  
Author(s):  
Alex McDougall ◽  
Christian Sardet ◽  
Charles. C Lambert
Keyword(s):  
Intracellular Calcium ◽  
Sea Water ◽  
Calcium Influx ◽  
Protein Synthesis Inhibitor ◽  
Synthesis Inhibitor ◽  
Acetoxymethyl Ester ◽  
Calcium Dependent ◽  
Sperm Binding ◽  
Calcium Requirement ◽  
A Cell

SummaryFertilisation of ascidian eggs induces the rapid release of a cell surface N-acetylglycosaminidase that blocks sperm binding to vitelline coat sperm receptors resulting in a block to polyspermy. Fertilisation also triggers a large contraction of the egg (thus stimulating ooplasmic segregation) that is completed within 5 min of insemination. In eggs of the ascidian Phallusia mammillata, glycosidase release and cortical contractions are blocked by BAPTA-AM [bis-(o-aminophenoxy-ethane-N,N,N',N' -tetraacetic acid, tetra(acetoxymethyl)-ester], a cell-permeant calcium chelator, indicating that both processes are probaly dependent on a rise in intracellular calcium levels. Both glycosidase release and the cortical contraction are induced by treatment of the egg with the protein synthesis inhibitor emetine, while only the glycosidase release is induced by isoproterenol, carbachol or acetylcholine. Previous work with ryanodine demonstrated that ryanodine also caused glycosidase release but not the cortical contraction Inversely, activation by ionomycin in calcium-free sea water causes cortical contractions but not glycosidase release. Thus the two processes can be activated independently. Dextran-coupled (10kDa) calcium green-1 injected eggs show an increase in intracellular calcium 30–40s before the cortical contraction is triggered by fertilisation or ionomycin- induced activation. This confirms previous findings that the cortical contraction is a consequence of the activation calcium the triggered by te sperm. The extracellular calcium requirement for the glycosidase release suggests that calcium influx may be more important for this phase of egg activation. Thus activation eggs appears to involve two independent pathways involving calcium.

Immunogold and immunoblot studies on a cell surface protein found in primary mesenchyme cells and in the cortical secretory vesicles of the sea urchin egg

1987 ◽  
Vol 45 ◽  
pp. 832-833
Author(s):  
G.L. Decker ◽  
M.C. Valdizan
Keyword(s):  
Cell Surface ◽  
Sea Urchin ◽  
Surface Protein ◽  
Egg Cell ◽  
Secretory Vesicles ◽  
Cell Surface Protein ◽  
Surface Complexes ◽  
Mesenchyme Cells ◽  
Lowicryl K4m ◽  
Primary Mesenchyme Cells

A monoclonal antibody designated MAb 1223 has been used to show that primary mesenchyme cells of the sea urchin embryo express a 130-kDa cell surface protein that may be directly involved in Ca2+ uptake required for growth of skeletal spicules. Other studies from this laboratory have shown that the 1223 antigen, although in relatively low abundance, is also expressed on the cell surfaces of unfertilized eggs and on the majority of blastomeres formed prior to differentiation of the primary mesenchyme cells.We have studied the distribution of 1223 antigen in S. purpuratus eggs and embryos and in isolated egg cell surface complexes that contain the cortical secretory vesicles. Specimens were fixed in 1.0% paraformaldehyde and 1.0% glutaraldehyde and embedded in Lowicryl K4M as previously reported. Colloidal gold (8nm diameter) was prepared by the method of Mulpfordt.

scholarly journals Human TRIM5α: Autophagy Connects Cell-Intrinsic HIV-1 Restriction and Innate Immune Sensor Functioning

Viruses ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 320 ◽  
Author(s):  
Alexandra P. M. Cloherty ◽  
Anusca G. Rader ◽  
Brandon Compeer ◽  
Carla M. S. Ribeiro
Keyword(s):  
Therapeutic Potential ◽  
Innate Immune ◽  
Health Concern ◽  
Restriction Factor ◽  
Viral Reservoirs ◽  
Minimal Restriction ◽  
Immunodeficiency Virus ◽  
A Cell ◽  
Species Specific ◽  
Hiv 1

Human immunodeficiency virus-1 (HIV-1) persists as a global health concern, with an incidence rate of approximately 2 million, and estimated global prevalence of over 35 million. Combination antiretroviral treatment is highly effective, but HIV-1 patients that have been treated still suffer from chronic inflammation and residual viral replication. It is therefore paramount to identify therapeutically efficacious strategies to eradicate viral reservoirs and ultimately develop a cure for HIV-1. It has been long accepted that the restriction factor tripartite motif protein 5 isoform alpha (TRIM5α) restricts HIV-1 infection in a species-specific manner, with rhesus macaque TRIM5α strongly restricting HIV-1, and human TRIM5α having a minimal restriction capacity. However, several recent studies underscore human TRIM5α as a cell-dependent HIV-1 restriction factor. Here, we present an overview of the latest research on human TRIM5α and propose a novel conceptualization of TRIM5α as a restriction factor with a varied portfolio of antiviral functions, including mediating HIV-1 degradation through autophagy- and proteasome-mediated mechanisms, and acting as a viral sensor and effector of antiviral signaling. We have also expanded on the protective antiviral roles of autophagy and outline the therapeutic potential of autophagy modulation to intervene in chronic HIV-1 infection.

scholarly journals Syntaxin 1A Gene Is Negatively Regulated in a Cell/Tissue Specific Manner by YY1 Transcription Factor, Which Binds to the −183 to −137 Promoter Region Together with Gene Silencing Factors Including Histone Deacetylase

Biomolecules ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 146
Author(s):  
Takahiro Nakayama ◽  
Toshiyuki Fukutomi ◽  
Yasuo Terao ◽  
Kimio Akagawa
Keyword(s):  
Transcription Factor ◽  
Gene Silencing ◽  
Protein Complex ◽  
Promoter Region ◽  
Neuronal Cell ◽  
Syntaxin 1A ◽  
Tissue Specific ◽  
Cell Tissue ◽  
Specific Manner ◽  
A Cell

The HPC-1/syntaxin 1A (Stx1a) gene, which is involved in synaptic transmission and neurodevelopmental disorders, is a TATA-less gene with several transcription start sites. It is activated by the binding of Sp1 and acetylated histone H3 to the −204 to +2 core promoter region (CPR) in neuronal cell/tissue. Furthermore, it is depressed by the association of class 1 histone deacetylases (HDACs) to Stx1a–CPR in non-neuronal cell/tissue. To further clarify the factors characterizing Stx1a gene silencing in non-neuronal cell/tissue not expressing Stx1a, we attempted to identify the promoter region forming DNA–protein complex only in non-neuronal cells. Electrophoresis mobility shift assays (EMSA) demonstrated that the −183 to −137 OL2 promoter region forms DNA–protein complex only in non-neuronal fetal rat skin keratinocyte (FRSK) cells which do not express Stx1a. Furthermore, the Yin-Yang 1 (YY1) transcription factor binds to the −183 to −137 promoter region of Stx1a in FRSK cells, as shown by competitive EMSA and supershift assay. Chromatin immunoprecipitation assay revealed that YY1 in vivo associates to Stx1a–CPR in cell/tissue not expressing Stx1a and that trichostatin A treatment in FRSK cells decreases the high-level association of YY1 to Stx1a-CPR in default. Reporter assay indicated that YY1 negatively regulates Stx1a transcription. Finally, mass spectrometry analysis showed that gene silencing factors, including HDAC1, associate onto the −183 to −137 promoter region together with YY1. The current study is the first to report that Stx1a transcription is negatively regulated in a cell/tissue-specific manner by YY1 transcription factor, which binds to the −183 to −137 promoter region together with gene silencing factors, including HDAC.

scholarly journals Pig zona pellucida 2 (pZP2) protein does not participate in zona pellucida formation in transgenic mice

Reproduction ◽  
2006 ◽  
Vol 132 (3) ◽  
pp. 455-464 ◽  
Author(s):  
Akiko Hasegawa ◽  
Nozomi Kanazawa ◽  
Hideaki Sawai ◽  
Shinji Komori ◽  
Koji Koyama
Keyword(s):  
Extracellular Matrix ◽  
Transgenic Mice ◽  
Molecular Species ◽  
Zona Pellucida ◽  
Transgenic Protein ◽  
Specific Manner ◽  
Species Specific ◽  
Deficient Mice

The zona pellucida, an extracellular matrix surrounding mammalian oocytes, is composed of three or four glycoproteins. It is well known that the zona pellucida plays several critical roles during fertilization, but there is little knowledge about its formation. The purpose of this study is to examine whether a pig zona pellucida glycoprotein 2 (pZP2) would assemble with mouse zona pellucida. A transgene construct was prepared by placing a minigene encoding pZP2 downstream from the promoter of mouse ZP2. The result showed that the transgenic protein was synthesized in growing oocytes but not incorporated into the zona pellucida. Furthermore, the pZP2 transgene did not rescue the phenotype in ZP2-knockout zona-deficient mice. These results indicate that pZP2 does not participate in mouse zona pellucida formation and the zona pellucida is constituted from its component proteins in a molecular species-specific manner between mice and pigs.

Localization and expression of msp130, a primary mesenchyme lineage-specific cell surface protein in the sea urchin embryo

Development ◽  
1987 ◽  
Vol 101 (2) ◽  
pp. 255-265 ◽  
Author(s):  
J.A. Anstrom ◽  
J.E. Chin ◽  
D.S. Leaf ◽  
A.L. Parks ◽  
R.A. Raff
Keyword(s):  
Cell Surface ◽  
Sea Urchin ◽  
Sea Water ◽  
Surface Protein ◽  
Specific Cell ◽  
Cell Surface Protein ◽  
Sea Urchin Embryo ◽  
A Cell ◽  
Mesenchyme Cells ◽  
Primary Mesenchyme Cells

In this report, we use a monoclonal antibody (B2C2) and antibodies against a fusion protein (Leaf et al. 1987) to characterize msp130, a cell surface protein specific to the primary mesenchyme cells of the sea urchin embryo. This protein first appears on the surface of these cells upon ingression into the blastocoel. Immunoelectronmicroscopy shows that msp130 is present in the trans side of the Golgi apparatus and on the extracellular surface of primary mesenchyme cells. Four precursor proteins to msp130 are identified and we show that B2C2 recognizes only the mature form of msp130. We demonstrate that msp130 contains N-linked carbohydrate groups and that the B2C2 epitope is sensitive to endoglycosidase F digestion. Evidence that msp130 is apparently a sulphated glycoprotein is presented. The recognition of the B2C2 epitope of msp130 is disrupted when embryos are cultured in sulphate-free sea water. In addition, two-dimensional immunoblots show that msp130 is an acidic protein that becomes substantially less acidic in the absence of sulphate. We also show that two other independently derived monoclonal antibodies, IG8 (McClay et al. 1983; McClay, Matranga & Wessel, 1985) and 1223 (Carson et al. 1985), recognize msp130, and suggest this protein to be a major cell surface antigen of primary mesenchyme cells.

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