Expression of the 70 kdalton neurofilament protein in clonal lines of mouse neuroblastoma.

The expression of the neurofilament (NF) protein triplet (70, 150 and 200 k daltons (K)) was studied by immunofluorescence in two clones of murine C-1300 neuroblastoma. Clone 1 formed clumps of round cells with few processes, while in clone 2 the cells were more dispersed and extended many processes. In both clones selective decoration of tight bundles of filaments was only observed with anti-NF 70 K. Round cells contained curvilinear bundles with the appearance of whorls and ringlets , while in cells extending processes the bundles were more rectilinear in shape. Ringlets were the most prominent feature in large clumps of cells. Antisera to vimentin, the mesenchymal-type intermediate filament (IF) protein, decorated the neuroblastoma cells with a different pattern. Treatment of the two clones with dibutyryl cAMP, a neurite-inducing agent, did not result in the expression of NF 150 K and NF 200 K, although many cells had extended processes and the shape of the NF bundles had changed accordingly.