Segregation of viral structural proteins in cultured neurons of rat spinal ganglia and cord

Cultured spinal ganglion and spinal cord neurons were used to examine the intraneuronal distribution of five structural proteins of Sendai virus by immunohistochemistry. In spinal ganglion cells the internal, cytosolic viral proteins (the nucleocapsid, polymerase and matrix proteins) were confined to the perikarya, while the envelope glycoproteins (the haemagglutinin-neuraminidase and fusion proteins) also appeared in the axon-like processes. All five proteins occurred in the dendrite-like processes of spinal cord neurons. In both types of neuron the cytosolic viral proteins showed a pattern of distribution similar to that observed for the microtubule-associated protein MAP2. The segregated occurrence of the viral envelope and cytosolic proteins in axons may prevent virus assembly in axons and limit long-distance spread of paramyxoviruses in the nervous system.