?-dystroglycan isoforms are differentially distributed in adult rat retina

✍ Scribed by Moukhles, Hakima; Roque, Rouel; Carbonetto, Salvatore

• Publisher: John Wiley and Sons
• Year: 2000
• Tongue: English
• Weight: 498 KB
• Volume: 420
• Category: Article
• ISSN: 0021-9967
• DOI: 10.1002/(sici)1096-9861(20000501)420:2<182::aid-cne3>3.0.co;2-2

✦ Synopsis

␣-Dystroglycan (␣ -DG) is a laminin/agrin receptor expressed in skeletal muscle as well as in nervous system and other tissues. Glycosylation of the core protein of ␣-DG is extensive, variable from tissue to tissue, and functionally relevant. To address differential glycosylation of ␣-DG in the retina, we have investigated the distribution of this protein using two different antibodies: 1B7 directed against the core protein of ␣-dystroglycan, and IIH6 directed against a carbohydrate moiety (Ervasti and Campbell [1993] J Cell Biol 122:809 -823). Monoclonal antibody 1B7 recognizes a broader band than IIH6, which seems to recognize only a subset of ␣-DG forms in retina. These data reflect the existence of differentially glycosylated isoforms of ␣-DG. Monoclonal antibody 1B7 shows an extensive staining for ␣-DG in the inner limiting membrane as well as in the ganglion cell and inner plexiform layers labeling Mu ¨ller cell processes, whereas monoclonal antibody IIH6 staining is restricted to the inner limiting membrane and blood vessels. Our data indicate that there are distinct isoforms of ␣-DG that are localized in apposition to basal lamina in the inner limiting membrane and blood vessels or within the parenchyma of the retina along Mu ¨ller glia. Both isoforms are expressed in a Mu ¨ller cell line in culture and coimmunoprecipitate with ␤-dystroglycan. These data suggest that DGs may participate in organizing synapses and basement membrane assembly in the retina.