Morphology of the nucleoprotein component of rabies virus.

The intracytoplasmic ground substance, or matrix, associated with the development of rabies virus and the nucleocapsid of the virus were investigated. The filaments of the matrix were identified as virus-specific by means of ferritin-labeled antibodies. In thin sections, the diameter was 15 nm and the strands seemed to be incorporated into virions during morphogenesis of the virus. The nucleocapsid was isolated from purified virus preparations and was studied in negative contrast. The rabies nucleocapsid appeared as a single-stranded helix with a diameter of 16 nm and a periodicity of 7.5 nm; its length was in excess of 1 mum.