MOLECULAR-CLONING OF OLFACTOMEDIN, AN EXTRACELLULAR-MATRIX PROTEIN-SPECIFIC TO OLFACTORY NEUROEPITHELIUM

The extracellular mucous matrix of olfactory neuroepithelium is a high ly organized structure in intimate contact with chemosensory cilia tha t house the olfactory transduction machinery. Here we describe the mol ecular cloning and primary structure of olfactomedin, which is the maj or component of this extracellular matrix. Olfactomedin is expressed e xclusively in olfactory neuroepithelium and its amino acid sequence sh ows no homologies to any known protein. This olfactory tissue-specific glycoprotein contains cysteines which form disulfide-linked polymers that constitute the primary architecture of the olfactory extracellula r matrix. By analogy to other extracellular matrix proteins of the ner vous system, olfactomedin may influence the maintenance, growth, or di fferentiation of chemosensory cilia on the apical dendrites of olfacto ry neurons.