Rat osteopontin antibody is cross-reactive to a novel myelin-associated protein in chick

Osteopontin (OPN) was initially identified as glycosylated phosphoprotein i n bones of vertebrates. Recently, OPN is reported to express in the primiti ve neuroepithelia of early chick embryonic hindbrain. We have demonstrated that rat OPN is immunohistochemically localized in the white matter of chic k CNS. We have further confirmed the specificity of OPN cross-immunoreactio n in myelin using demyelinated optic nerve induced by lysophosphatidylcholi ne (LPC), where the intensity of immunoreaction was closely related to the degree of demyelination. Immunoblot analyses showed that rat OPN antibody r ecognized a protein with molecular weights of similar to 47 kDa from chick CNS. Our data suggest that the antigen recognized by rat OPN is a previousl y undescribed myelin-associated protein in the chick CNS. (C) 1999 Elsevier Science B.V. All rights reserved.