DISTINCT SUBCELLULAR-LOCALIZATION OF BETA-TUBULIN EPITOPES IN THE ADULT-MOUSE BRAIN

A panel of monoclonal antibodies specific of alpha-tubulin (TU-01, TU- 09) and beta-tubulin (TU-06, TU-13) subunits was used to study the loc ation of N-terminal structural domains of tubulin in adult mouse brain . The specificity of antibodies was confirmed b immunoblotting experim ents. Immunohistochemical staining of vi bratome sections from cerebra l cortex, cerebellum, hippocampus, and corpus callosum showed that ant ibodies TU-01, TU-09, and TU13 reacted with neuronal and glial cells a nd their processes, whereas the TU-06 antibody stained only the perika rya. Dendrites and axons were either unstained or their staining was v ery weak. As the TU-06 epitope is located on the N-terminal structural domain of beta-tubulin, the observed staining pattern cannot be inter preted as evidence of a distinct subcellular localization of beta-tubu lin isotypes or known post-translational modifications. The limited di stribution of the epitope could, rather, reflect differences between t he conformations of tubulin molecules in microtubules of somata and ne urites or, alternatively, a specific masking of the corresponding regi on on the N-terminal domain of beta-tubulin by interacting protein(s) in dendrites and axons.