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- Brakebusch, Cord, et al.
(författare)
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Brevican-deficient mice display impaired hippocampal CA1 long-term potentiation but show no obvious deficits in learning and memory
- 2002
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Ingår i: Molecular and Cellular Biology. - 0270-7306. ; 22:21, s. 7417-7427
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Tidskriftsartikel (refereegranskat)abstract
- Brevican is a brain-specific proteoglycan which is found in specialized extracellular matrix structures called perineuronal nets. Brevican increases the invasiveness of glioma cells in vivo and has been suggested to play a role in central nervous system fiber tract development. To study the role of brevican in the development and function of the brain, we generated mice lacking a functional brevican gene. These mice are viable and fertile and have a normal life span. Brain anatomy was normal, although alterations in the expression of neurocan were detected. Perineuronal nets formed but appeared to be less prominent in mutant than in wild-type mice. Brevican-deficient mice showed significant deficits in the maintenance of hippocampal long-term potentiation (LTP). However, no obvious impairment of excitatory and inhibitory synaptic transmission was found, suggesting a complex cause for the LTP defect. Detailed behavioral analysis revealed no statistically significant deficits in learning and memory. These data indicate that brevican is not crucial for brain development but has restricted structural and functional roles.
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| 2. |
- Feng, Kang, et al.
(författare)
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All four members of the Ten-m/Odz family of transmembrane proteins form dimers.
- 2002
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Ingår i: Journal of Biological Chemistry. - 1083-351X. ; 277:29, s. 26128-26135
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Tidskriftsartikel (refereegranskat)abstract
- Ten-m/Odz/teneurins are a new family of four distinct type II transmembrane molecules. Their extracellular domains are composed of an array of eight consecutive EGF modules followed by a large globular domain. Two of the eight modules contain only 5 instead of the typical 6 cysteine residues and have the capability to dimerize in a covalent, disulfide-linked fashion. The structural properties of the extracellular domains of all four mouse Ten-m proteins have been analyzed using secreted, recombinant molecules produced by mammalian HEK-293 cells. Electron microscopic analysis supported by analytical ultracentrifugation data revealed that the recombinant extracellular domains of all Ten-m proteins formed homodimers. SDS-PAGE analysis under nonreducing conditions as well as negative staining after partial denaturation of the molecules indicated that the globular COOH-terminal domains of Ten-m1 and -m4 contained subdomains with a pronounced stability against denaturing agents, especially when compared with the homologous domains of Ten-m2 and -m3. Cotransfection experiments of mammalian cells with two different extracellular domains revealed that Ten-m molecules have also the ability to form heterodimers, a property that, combined with alternative splicing events, allows the formation of a multitude of molecules with different characteristics from a limited set of genes.
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| 3. |
- Kappler, J, et al.
(författare)
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Tenascins are associated with lipid rafts isolated from mouse brain
- 2002
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Ingår i: Biochemical and Biophysical Research Communications. - 1090-2104. ; 294:3, s. 742-747
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Tidskriftsartikel (refereegranskat)abstract
- Lipid rafts are microdomains of the plasma membrane which are enriched in glycosphingolipids and specific proteins. The reported interactions of several raft-associated proteins (such as, e.g., F3) with tenascin C and tenascin R prompted us to consider that these oligomeric multidomain glycoproteins of the extracellular matrix (ECM) could associate with rafts. Here, we show punctate immunocytochemical distributions of tenascin C (TN-C) and tenascin R (TN-R) at the membrane surface of neural cells resembling the pattern reported for raft-associated proteins. Moreover, cholesterol depletion with methyl-beta-cyclodextrin reduced the punctate surface staining of TN-C. Consistently, TN-C was associated with lipid rafts of neonatal mouse brain according to sucrose density gradient centrifugation experiments. Furthermore, TN-R was also found in rafts prepared from myelin of adult mice. Thus, brain-derived tenascins are able to associate with lipid rafts. (C) 2002 Elsevier Science (USA). All rights reserved.
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| 5. |
- Oohashi, T, et al.
(författare)
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Bral1, a brain-specific link protein, colocalizing with the versican V2 isoform at the nodes of Ranvier in developing and adult, mouse central nervous systems
- 2002
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Ingår i: Molecular and Cellular Neuroscience. - : Elsevier BV. - 1044-7431. ; 19:1, s. 43-57
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Tidskriftsartikel (refereegranskat)abstract
- Bral1, a brain-specific hyaluronan-binding protein, has been cloned recently. To gain insight into the role of Bral1, we generated a specific antibody against this protein. We have examined the detailed localization pattern of Bral1 protein and compared it with that of other members of the lectican proteoglycan family, such as brevican and versican, with which Bral1 is predicted to interact. The immunoreactivity of Bral1 antibody was predominantly observed in myelinated fiber tracts in the adult brain and could be detected at P20 in the white matter of the developing cerebellum, suggesting that expression starts when axonal myelination takes place. Furthermore, immunostaining demonstrated that Bral1 colocalized with the versican V2 isoform at the nodes of Ranvier. The present data suggest that Bral1 may play a pivotal role in the formation of the hyaluronan-associated matrix in the CNS that facilitates neuronal conduction by forming an ion diffusion barrier at the nodes.
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