OLFACTORY NEURONAL CELL-LINES GENERATED BY RETROVIRAL INSERTION OF THE N-MYC ONCOGENE DISPLAY DIFFERENT DEVELOPMENTAL PHENOTYPES

Being genetically homogeneous, clonal cell lines are potentially impor tant for investigating many aspects of cellular differentiation. We de scribe here the creation of clonal cell lines by immortalization of ne uronal precursor cells from the adult mouse olfactory epithelium. Unli ke neurons elsewhere in the vertebrate nervous system, the olfactory s ensory neuron can be replaced throughout the lifespan of the animal, H owever, little is known about the molecular aspects of olfactory neuro genesis. Continuous cell lines were generated by retroviral transducti on of the n-myc proto-oncogene into the mitotically active basal cells of the olfactory epithelium which give rise to the sensory neuron, Tw enty-one clonal cell lines were produced which could be divided into t hree distinct morphological classes: one with flat, epithelial-like ce lls only; another with round, flat, and bipolar cells; and a third wit h large flat and large bipolar cells, These morphological classes had different patterns of intermediate filament expression, as shown by im munocytochemistry and immunoblot analysis, All cells in all cell lines expressed the intermediate filament protein vimentin, Most bipolar ce lls, but not other cell types, expressed neurofilament protein and in one morphological class the bipolar cells co-expressed neurofilament a nd glial fibrillary acidic protein, Several cell lines expressed mRNA for OMP, a marker of mature olfactory sensory neurons, and G(OLF), a g uanine nucleotide binding protein involved in olfactory sensory transd uction, It is concluded that these cell lines were immortalized from s ensory neuron precursors late in the lineage pathway, Other cell lines appear to have been immortalized at earlier stages in the lineage pat hway, These cell lines therefore provide useful tools for the investig ation of neuronal differentiation and sensory transduction in the olfa ctory epithelium. (C) 1996 Wiley-Liss, Inc.