MYELIN BASIC PROTEIN-RELATED PROTEINS IN MOUSE-BRAIN AND IMMUNE TISSUES

Brain and immune system tissues express myelin basic protein (MBP) mRN As that contain novel exons upstream of those of the classic MBPs. We have generated antisera against a recombinant protein that includes th e deduced sequence for one of the predicted species of the new MBP-rel ated protein, hemopoietic HMBPR1. We report here the presence of multi ple proteins reactive to the antisera in a range of tissues. The princ ipal finding is that the antisera recognize a family of proteins of si milar to 25 kDa that are restricted to brain, thymus, and spleen, the only tissues in which the new MBP-related transcripts are present. The se antisera also detect other proteins of apparent molecular mass cons istent with other isoforms of predicted MBP-related proteins. The expr ession of MBP-retated proteins in immune system tissues may be importa nt for self-tolerance to CNS MBPs and the initiation of immune-associa ted demyelinating diseases.