Detection of O-mannosyl glycans in rabbit skeletal muscle alpha-dystroglycan

alpha-Dystroglycan, which is a cell surface component of dystroglycan compl ex, is known to bind laminin in basal lamina of muscle cells and Schwann ce lls. We found previously that a novel O-glycan, Sia alpha 2-3Gal beta 1-4Gl cNAc beta 1-2Man, is the major oligosaccharide in bovine peripheral nerve a lpha-dystroglycan, and that this structure might mediate the binding of lam inin. In order to determine whether this structure is specific for peripher al nerve alpha-dystroglycan or present on different forms of alpha-dystrogl ycan, we analyzed the structures of the sialylated O-glycans of rabbit skel etal muscle alpha-dystroglycan. Their structures were elucidated to be a mi xture of a core 1 O-glycan and the same O-mannosyl glycan that we found in bovine peripheral nerve. These results indicate that alpha-dystroglycan in different species and tissues share a common structure of its major O-linke d acidic carbohydrate, suggesting its relevance to the basic functional rol e of alpha-dystroglycan. (C) 1998 Published by Elsevier Science B.V. All ri ghts reserved.