Gliolectin is a novel carbohydrate-binding protein expressed by a subset of glia in the embryonic Drosophila nervous system

Development ◽  
1996 ◽  
Vol 122 (3) ◽  
pp. 925-936
Author(s):  
M. Tiemeyer ◽  
C.S. Goodman
Keyword(s):  
Nervous System ◽  
Cell Surface ◽  
Neural Development ◽  
Small Subset ◽  
Carbohydrate Binding ◽  
Calculated Molecular Mass ◽  
Amino Terminal ◽  
Surface Carbohydrates ◽  
Drosophila Embryos ◽  
Cell Cell

Interactions between embryonic neural cells generate the specific patterns of connectivity observed in nervous systems. Cell surface carbohydrates have been proposed to function in cellular recognition events guiding such interactions. Carbohydrate-binding proteins (lectins) that recognize specific oligosaccharide ligands in embryonic neural tissue provide a molecular mechanism for carbohydrate-mediated cell-cell interactions in neural development. Therefore, we have screened an embryonic Drosophila melanogaster cDNA library, expressed in COS1 cells, for carbohydrate-binding activity. COS1 cells expressing putative Drosophila lectins were identified and recovered based on their adhesion to immobilized preparations of neutral and zwitterionic glycolipids extracted from Drosophila embryos. We have identified an endogenous lectin expressed during Drosophila embryogenesis. The cloned lectin, designated ‘gliolectin’, possesses a novel protein sequence with a calculated molecular mass of 24,993. When expressed in Drosophila S2 cells, the lectin mediates heterophilic cellular aggregation. In embryos, gliolectin is expressed by a subset of glial cells found at the midline of the developing nervous system. Expression is highest during the formation of the Drosophila embryonic axonal commissures, a process requiring midline glial cell funcion. Immunoprecipitation with a monoclonal antibody against gliolectin yields a protein of Mr=46,600 from Drosophila embryonic membranes, suggesting that post-translational modification of gliolectin is extensive. Epitope- tagged chimericproteins composed of the amino terminal one-half of gliolectin and the Fc region of human IgG bind a small subset of the total glycolipids extracted from Drosophila embryos, demonstrating that the lectin activity of gliolectin can discriminate between oligosaccharide structures. The presence of gliolectin in the developing Drosophila embryonic nervous system further supports a role for cell surface carbohydrates in cell-cell recognition and indicates that the molecular diversity of animal lectins is not yet completely defined.

scholarly journals Identification of Carbohydrate-Binding Domains in the Attachment Proteins of Type 1 and Type 3 Reoviruses

2000 ◽  
Vol 74 (18) ◽  
pp. 8472-8479 ◽  
Author(s):  
James D. Chappell ◽  
Joy L. Duong ◽  
Benjamin W. Wright ◽  
Terence S. Dermody
Keyword(s):  
Sialic Acid ◽  
Cell Surface ◽  
Receptor Binding ◽  
Binding Domain ◽  
Carbohydrate Binding ◽  
Tail Domain ◽  
Amino Terminal ◽  
Binding Domains ◽  
Type 3

ABSTRACT The reovirus attachment protein, ς1, is responsible for strain-specific patterns of viral tropism in the murine central nervous system and receptor binding on cultured cells. The ς1 protein consists of a fibrous tail domain proximal to the virion surface and a virion-distal globular head domain. To better understand mechanisms of reovirus attachment to cells, we conducted studies to identify the region of ς1 that binds cell surface carbohydrate. Chimeric and truncated ς1 proteins derived from prototype reovirus strains type 1 Lang (T1L) and type 3 Dearing (T3D) were expressed in insect cells by using a baculovirus vector. Assessment of expressed protein susceptibility to proteolytic cleavage, binding to anti-ς1 antibodies, and oligomerization indicates that the chimeric and truncated ς1 proteins are properly folded. To assess carbohydrate binding, recombinant ς1 proteins were tested for the capacity to agglutinate mammalian erythrocytes and to bind sialic acid presented on glycophorin, the cell surface molecule bound by type 3 reovirus on human erythrocytes. Using a panel of two wild-type and ten chimeric and truncated ς1 proteins, the sialic acid-binding domain of type 3 ς1 was mapped to a region of sequence proposed to form the more amino terminal of two predicted β-sheet structures in the tail. This unit corresponds to morphologic region T(iii) observed in computer-processed electron micrographs of ς1 protein purified from virions. In contrast, the homologous region of T1L ς1 sequence was not implicated in carbohydrate binding; rather, sequences in the distal portion of the tail known as the neck were required. Results of these studies demonstrate that a functional receptor-binding domain, which uses sialic acid as its ligand, is contained within morphologic region T(iii) of the type 3 ς1 tail. Furthermore, our findings indicate that T1L and T3D ς1 proteins contain different arrangements of receptor-binding domains.

Cell interactions in preimplantation embryos: evidence for involvement of saccharides of the poly- N-acetyllactosamine series

Development ◽  
1985 ◽  
Vol 87 (1) ◽  
pp. 115-128
Author(s):  
S. Rastan ◽  
S. J. Thorpe ◽  
P. Scudder ◽  
S. Brown ◽  
H. C. Gooi ◽  
...  
Keyword(s):  
Cell Surface ◽  
Culture Medium ◽  
De Novo ◽  
Embryonic Cell ◽  
Preimplantation Embryos ◽  
Carbohydrate Binding ◽  
Cleavage Stage ◽  
Cell Stage ◽  
Antigen Activity ◽  
Surface Carbohydrates

Roles of cell surface carbohydrates containing the 3-fucosyl-N-acetyllactosamine and poly-Nacetyllactosamine sequences (SSEA-1 and I antigens, respectively) in the compaction of mouse embryos have been investigated using the endo-β-galactosidase of Bacteroides fragilis to modify the surface of cleavage-stage embryos. Treatment with this enzyme abolished SSEA-1 activity and diminished I antigen activity on the embryonic cell surface. Embryos cultured in the presence of endo-β-galactosidase from the 2- to 4-cell stage onwards, or treated with the enzyme at the compacting 8-cell stage, continued to compact and proceeded to form blastocysts at the normal rate. However, when compacted 8- to 16-cell embryos were experimentally decompacted in calcium-free medium, treated for 1 h with endo-β-galactosidase and returned to normal culture medium, the time taken for 50 % of the embryos to recompact was prolonged five-fold. There was an even greater delay if these embryos were maintained in culture medium containing the enzyme. Blastocysts were eventually formed under both conditions. Thus, endo-β-galactosidase did not affect compaction unless the embryos were first decompacted. On the assumption that recompaction and de novo compaction occur by similar mechanisms, we propose that carbohydrate-binding molecules are involved which have high affinities for poly-Nacetyllactosamine structures and protect them from digestion by endo-β-galactosidase.

scholarly journals Lymphocyte activation by monovalent fragments of antibodies reactive with cell surface carbohydrates.

1976 ◽  
Vol 143 (3) ◽  
pp. 665-671 ◽  
Author(s):  
B A Sela ◽  
J L Wang ◽  
G M Edelman
Keyword(s):  
Cell Surface ◽  
Thymidine Incorporation ◽  
Lymphocyte Activation ◽  
Carbohydrate Binding ◽  
Blast Transformation ◽  
Stringent Requirement ◽  
Chicken Serum ◽  
Fab Fragments ◽  
Cross Linkage ◽  
Surface Carbohydrates

Antibodies reactive with cell surface carbohydrates were isolated from normal chicken serum and were found to be mitogenic for mouse splenic lymphocytes as assayed by both blast transformation and [3H]thymidine incorporation. The Fab' fragments of these carbohydrate-binding immunoglobulins were just as mitogenic as the divalent native antibody. Moreover, succinylated Fab' fragments, which probably would not form self-associating aggregates, showed similar mitogenic properties. All of these results indicate that, at least for saccharide-specific ligands, multipoint attachment and receptor cross-linkage on the cell to which the ligand is attached may not be a stringent requirement for activation.

scholarly journals Sialic Acids in the Brain: Gangliosides and Polysialic Acid in Nervous System Development, Stability, Disease, and Regeneration

2014 ◽  
Vol 94 (2) ◽  
pp. 461-518 ◽  
Author(s):  
Ronald L. Schnaar ◽  
Rita Gerardy-Schahn ◽  
Herbert Hildebrandt
Keyword(s):  
Nervous System ◽  
Cell Surface ◽  
Polysialic Acid ◽  
Sialic Acids ◽  
Nervous System Development ◽  
Adult Brain ◽  
Surface Coat ◽  
Genetic Studies ◽  
The Brain ◽  
Cell Cell

Every cell in nature carries a rich surface coat of glycans, its glycocalyx, which constitutes the cell's interface with its environment. In eukaryotes, the glycocalyx is composed of glycolipids, glycoproteins, and proteoglycans, the compositions of which vary among different tissues and cell types. Many of the linear and branched glycans on cell surface glycoproteins and glycolipids of vertebrates are terminated with sialic acids, nine-carbon sugars with a carboxylic acid, a glycerol side-chain, and an N-acyl group that, along with their display at the outmost end of cell surface glycans, provide for varied molecular interactions. Among their functions, sialic acids regulate cell-cell interactions, modulate the activities of their glycoprotein and glycolipid scaffolds as well as other cell surface molecules, and are receptors for pathogens and toxins. In the brain, two families of sialoglycans are of particular interest: gangliosides and polysialic acid. Gangliosides, sialylated glycosphingolipids, are the most abundant sialoglycans of nerve cells. Mouse genetic studies and human disorders of ganglioside metabolism implicate gangliosides in axon-myelin interactions, axon stability, axon regeneration, and the modulation of nerve cell excitability. Polysialic acid is a unique homopolymer that reaches >90 sialic acid residues attached to select glycoproteins, especially the neural cell adhesion molecule in the brain. Molecular, cellular, and genetic studies implicate polysialic acid in the control of cell-cell and cell-matrix interactions, intermolecular interactions at cell surfaces, and interactions with other molecules in the cellular environment. Polysialic acid is essential for appropriate brain development, and polymorphisms in the human genes responsible for polysialic acid biosynthesis are associated with psychiatric disorders including schizophrenia, autism, and bipolar disorder. Polysialic acid also appears to play a role in adult brain plasticity, including regeneration. Together, vertebrate brain sialoglycans are key regulatory components that contribute to proper development, maintenance, and health of the nervous system.

scholarly journals Zika Virus Infection Leads to Demyelination and Axonal Injury in Mature CNS Cultures

Viruses ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 91
Author(s):  
Verena Schultz ◽  
Stephanie L. Cumberworth ◽  
Quan Gu ◽  
Natasha Johnson ◽  
Claire L. Donald ◽  
...  
Keyword(s):  
Nervous System ◽  
Neural Development ◽  
Zika Virus ◽  
Developmental Stages ◽  
Cell Types ◽  
Neural Cells ◽  
Zikv Infection ◽  
Axonal Pathology ◽  
Time Frames

Understanding how Zika virus (Flaviviridae; ZIKV) affects neural cells is paramount in comprehending pathologies associated with infection. Whilst the effects of ZIKV in neural development are well documented, impact on the adult nervous system remains obscure. Here, we investigated the effects of ZIKV infection in established mature myelinated central nervous system (CNS) cultures. Infection incurred damage to myelinated fibers, with ZIKV-positive cells appearing when myelin damage was first detected as well as axonal pathology, suggesting the latter was a consequence of oligodendroglia infection. Transcriptome analysis revealed host factors that were upregulated during ZIKV infection. One such factor, CCL5, was validated in vitro as inhibiting myelination. Transferred UV-inactivated media from infected cultures did not damage myelin and axons, suggesting that viral replication is necessary to induce the observed effects. These data show that ZIKV infection affects CNS cells even after myelination—which is critical for saltatory conduction and neuronal function—has taken place. Understanding the targets of this virus across developmental stages including the mature CNS, and the subsequent effects of infection of cell types, is necessary to understand effective time frames for therapeutic intervention.

scholarly journals The role of CPEB family proteins in the nervous system function in the norm and pathology

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Eugene Kozlov ◽  
Yulii V. Shidlovskii ◽  
Rudolf Gilmutdinov ◽  
Paul Schedl ◽  
Mariya Zhukova
Keyword(s):  
Nervous System ◽  
Gene Regulation ◽  
Neural Development ◽  
Fragile X ◽  
Autism Spectrum ◽  
Mrna Transport ◽  
Ribonucleoprotein Complexes ◽  
Posttranscriptional Gene Regulation ◽  
Nervous System Function ◽  
Functional Features

AbstractPosttranscriptional gene regulation includes mRNA transport, localization, translation, and regulation of mRNA stability. CPEB (cytoplasmic polyadenylation element binding) family proteins bind to specific sites within the 3′-untranslated region and mediate poly- and deadenylation of transcripts, activating or repressing protein synthesis. As part of ribonucleoprotein complexes, the CPEB proteins participate in mRNA transport and localization to different sub-cellular compartments. The CPEB proteins are evolutionarily conserved and have similar functions in vertebrates and invertebrates. In the nervous system, the CPEB proteins are involved in cell division, neural development, learning, and memory. Here we consider the functional features of these proteins in the nervous system of phylogenetically distant organisms: Drosophila, a well-studied model, and mammals. Disruption of the CPEB proteins functioning is associated with various pathologies, such as autism spectrum disorder and brain cancer. At the same time, CPEB gene regulation can provide for a recovery of the brain function in patients with fragile X syndrome and Huntington's disease, making the CPEB genes promising targets for gene therapy.

scholarly journals Keratin 19 maintains E-cadherin localization at the cell surface and stabilizes cell-cell adhesion of MCF7 cells

2021 ◽  
Vol 15 (1) ◽  
pp. 1-17
Author(s):  
Sarah Alsharif ◽  
Pooja Sharma ◽  
Karina Bursch ◽  
Rachel Milliken ◽  
Van Lam ◽  
...  
Keyword(s):  
Cell Adhesion ◽  
Cell Surface ◽  
Mcf7 Cells ◽  
Keratin 19 ◽  
E Cadherin ◽  
Cell Cell
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