Identification of the Protein Target of Myelin-Binding Ligands by Immunohistochemistry and Biochemical Analyses

The ability to visualize myelin is important in the diagnosis of demyelinating disordersand the detection of myelin-containing nerves during surgery. The development ofmyelin-selective imaging agents requires that a defined target for these agents beidentified and that a robust assay against the target be developed to allow for assessmentof structure-activity relationships. We describe an immunohistochemical analysis and afluorescence polarization binding assay using purified myelin basic protein (MBP) thatprovides quantitative evidence that MBP is the molecular binding partner of previouslydescribed myelin-selective fluorescent dyes such as BMB, GE3082, and GE3111.