High expression of the HNK-1/L2 carbohydrate epitope in the major glycoproteins of shark myelin.
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.
Zand
D
D
Myelin and Brain Development Section, NINDS, NIH, Bethesda, Maryland 20892.
Hammer
J
J
Gould
R
R
Quarles
R
R
D000818:Animals; D000943:Antigens, Differentiation / Q000276:immunology*; D005075:Biological Evolution; D018959:CD57 Antigens; D004284:Dogfish / Q000378:metabolism*; D000939:Epitopes / Q000235:genetics* / Q000276:immunology; D015870:Gene Expression; D006023:Glycoproteins / Q000032:analysis / Q000235:genetics* / Q000276:immunology / Q000378:metabolism; D006801:Humans; D009186:Myelin Sheath / Q000737:chemistry* / Q000378:metabolism; D010525:Peripheral Nerves / Q000737:chemistry / Q000378:metabolism
D000943:Antigens, Differentiation; D018959:CD57 Antigens; D000939:Epitopes; D006023:Glycoproteins