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- Oohashi, T, et al.
(författare)
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Mouse ten-m/Odz is a new family of dimeric type II transmembrane proteins expressed in many tissues
- 1999
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Ingår i: Journal of Cell Biology. - 0021-9525. ; 145:3, s. 563-577
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Tidskriftsartikel (refereegranskat)abstract
- The Drosophila gene ten-m/odz is the only pair rule gene identified to date which is not a transcription factor. In an attempt to analyze the structure and the function of ten-m/odz in mouse, we isolated four murine ten-m cDNAs which code for proteins of 2,700-2, 800 amino acids. All four proteins (Ten-m1-4) lack signal peptides at the NH2 terminus, but contain a short hydrophobic domain characteristic of transmembrane proteins, 300-400 amino acids after the NH2 terminus. About 200 amino acids COOH-terminal to this hydrophobic region are eight consecutive EGF-like domains. Cell transfection, biochemical, and electronmicroscopic studies suggest that Ten-m1 is a dimeric type II transmembrane protein. Expression of fusion proteins composed of the NH2-terminal and hydrophobic domain of ten-m1 attached to the alkaline phosphatase reporter gene resulted in membrane-associated staining of the alkaline phosphatase. Electronmicroscopic and electrophoretic analysis of a secreted form of the extracellular domain of Ten-m1 showed that Ten-m1 is a disulfide-linked dimer and that the dimerization is mediated by EGF-like modules 2 and 5 which contain an odd number of cysteines. Northern blot and immunohistochemical analyses revealed widespread expression of mouse ten-m genes, with most prominent expression in brain. All four ten-m genes can be expressed in variously spliced mRNA isoforms. The extracellular domain of Ten-m1 fused to an alkaline phosphatase reporter bound to specific regions in many tissues which were partially overlapping with the Ten-m1 immunostaining. Far Western assays and electronmicroscopy demonstrated that Ten-m1 can bind to itself.
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| 2. |
- Sancho Pelluz, Javier, et al.
(författare)
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Sialoadhesin Expression in Intact Degenerating Retinas and Following Transplantation.
- 2008
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Ingår i: Investigative Ophthalmology & Visual Science. - : Association for Research in Vision and Ophthalmology (ARVO). - 1552-5783. ; 49, s. 5602-5610
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: Resident microglial cells normally do not express sialoadhesin (a sialic acid binding receptor), whereas recruited inflammatory macrophages have been shown to do so. The expression of sialoadhesin was examined here in the course of photoreceptor cell degeneration and following transplantation. Methods: Sialoadhesin expression was analyzed in retinas of rd1 and rds mice. For transplantation studies, neonatal (P2) retinal cells derived from GFP mice were injected intraocularly in adult rd1 mice and controls. Antibodies recognizing different sialoadhesin epitopes, CD11b, and MHC-II were used to identify activated microglial cells in intact retinas and 21 days post-transplantation. Results: In rd1 mice, a few CD11b-positive cells were observed in the outer nuclear layer in the central retina at postnatal day (P) 11 and in increasing numbers between P12 21. In rds mice, CD11b-expressing cells were found from P16 and onwards. No sialoadhesin expressing cells were observed within the rd1 or rds mouse retinas at any of the ages examined (up to P150). Specific staining was only observed in cells found in the vitreal margin of the retina and in surrounding tissues (sclera, cornea, ciliary body, choroid). Following transplantation to normal and rd1 mice, a variable number of sialoadhesin-positive cells were detected within the grafts, in the graft-host interface, and in the subretinal space. Conclusions: The significant activation of microglia/macrophages observed in the various stages of degeneration in rd1 and rds mouse retinas is not accompanied by sialoadhesin expression. However, sialoadhesin-expressing cells are observed following transplantation. The occurrence of such cells could be of significance for the integration and long term survival of retinal grafts, as expression of sialoadhesin could facilitate other phagocytic receptors.
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| 3. |
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| 4. |
- Zhang, Yiqin, et al.
(författare)
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Integration between abutting retinas: Role of glial structures and associated molecules at the interface
- 2004
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Ingår i: Investigative Ophthalmology & Visual Science. - : Association for Research in Vision and Ophthalmology (ARVO). - 1552-5783. ; 45:12, s. 4440-4449
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE. Integration between subretinal grafts and the host retina is limited in part by the presence of a barrier at the graft-host interface. This study was conducted to identify factors that may contribute to this barrier, by examining the distribution of glial structures and associated molecules in different setups of overlapping retinal pieces. METHODS. Neuroretinal tissue derived from mice that express green fluorescent protein (GFP) was fragmented and transplanted into the subretinal space of adult rd1 mice. In an in vitro system, two retinal pieces, derived from GFP and rd1 mice, respectively, were placed overlapping each other and forming either laminar-laminar pairs or fragment-laminar pairs. The glia-associated markers analyzed included glial fibrillary acidic protein (GFAP), cellular retinaldehyde-binding protein ( CRALBP), and two molecules known to inhibit neurite outgrowth: CD44 and neurocan. Bridging fibers and migrated cells were visualized with GFP fluorescence and retinal cell markers. RESULTS. A thick CRALBP-immunolabeled band was observed in the interface in cultured laminar-laminar pairs, whereas a thinner band was seen in cultured fragment-laminar pairs and in transplants. Accumulation of CD44 and neurocan was also observed in the interface between abutting retinal pieces in all setups. GFP(+) bridging fibers and GFP(+) cells (some of which coexpressed neuronal markers) were observed within the abutting rd1 retina in some areas. However, such integration occurred exclusively where CRALBP, CD44, and neurocan immunolabeling appeared disrupted in the interface, but coincided with high GFAP expression within the rd1 retina. CONCLUSIONS. The results demonstrate that, on the one hand, an accumulation of glial-associated inhibitory molecules in the interface correlates with limited integration between overlapping retinal pieces. On the other hand, glial reactivity within the rd1 retina does not appear to be incompatible with integration.
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