The bovine subcommissural organ: cytochemical and immunochemical characterization of the secretory process.
Specific glycoproteins of the bovine subcommissural organ (SCO) were studied by means of various techniques: light and electron microscopy, immunoaffinity chromatography, electrophoresis and Western blotting. Use of lectins (Con A, WGA, PHA-E and -L, LCA) allowed to specify the synthesis and release of complex-type glycoproteins that bear high-mannose-carbohydrate chains in their precursor forms and probably triantennary carbohydrate chains in their mature forms. Antibodies raised against SCO extracts were characterized by means of various tests and used to purify specific compounds. Immunopurified fractions using A99 polyclonal antibody contained numerous polypeptides reactive with Con A, their apparent molecular weight (MW) ranging from 240 to 50 kDa. Only two glycopeptides were strongly labeled with WGA (98 and 52/54 kDa MW). Immunopurified fractions using C1B8A8 monoclonal antibody, specific of the complex-type glycoproteins at different steps of glycosylation, showed three specific Con A-reactive polypeptides at 88, 54 and 34 kDa MW. Only the 34 kDa glycopeptide was strongly labeled with WGA. The latter could correspond to the monomeric form of the secreted compound. Electrophoretical analyses of Reissner's fiber material allowed the detection of a WGA-positive smear in the upper part of the blots, suggesting that the complex-type glycoproteins, when released into the CSF, constitute a stable polymer.
Meiniel
A
A
Laboratoire de Biochimie Médicale, CJF INSERM 88.06, Université d'Auvergne, Clermont-Ferrand, France.
Meiniel
R
R
Karoumi
A
A
Duchier-Liris
N
N
Molat
J L
JL
D000818:Animals; D001923:Brain Chemistry; D002240:Carbohydrate Sequence; D002417:Cattle; D002846:Chromatography, Affinity; D006023:Glycoproteins / Q000032:analysis* / Q000302:isolation & purification; D007150:Immunohistochemistry; D037102:Lectins; D008969:Molecular Sequence Data; D009844:Oligosaccharides / Q000737:chemistry; D013351:Subcommissural Organ / Q000737:chemistry / Q000166:cytology* / Q000378:metabolism
D006023:Glycoproteins; D037102:Lectins; D009844:Oligosaccharides