High Expression of the HNK-1/L2 Carbohydrate Epitope in the Major Glycoproteins of Shark Myelin |
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Authors: | Dina Zand Jeffrey Hammer Robert Gould Richard Quarles |
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Affiliation: | Myelin and Brain Development Section, NINDS, NIH, Bethesda, Maryland 20892. |
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Abstract: | The major 24- and 28-kDa glycoproteins in shark PNS and CNS myelin express high levels of the adhesion-associated HNK-1/L2 carbohydrate epitope. The 28-kDa protein, but not the 24-kDa protein, cross-reacts strongly with one of two anti-bovine P0 antisera not previously tested against fish myelin proteins. Shark PNS and CNS myelin also contains smaller amounts of high-molecular-weight HNK-1-positive proteins, including a prominent broad band in the 65-85-kDa range. Although myelin-associated glycoprotein (MAG) is well known to react with HNK-1 in some mammals, monoclonal and polyclonal anti-MAG antibodies did not react with the high-molecular-weight HNK-1-positive material in shark myelin, a result suggesting that it is not a MAG-like protein. The high expression of the HNK-1/L2 epitope in glycoproteins of shark myelin, including the major P0-related ones, suggests that this adhesion-related carbohydrate structure may have had an important role in the molecular evolution of the myelinating process. |
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Keywords: | Cartilaginous fish HNK-1/L2 epitope Myelin-associated glycoprotein Myelin evolution PO glycoprotein Sharks |
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