Distribution and trafficking of JHM coronavirus structural proteins and virions in primary neurons and the OBL-21 neuronal cell line.

The neurotropic murine coronavirus JHM is capable of inducing various forms of neurologic diseases, including demyelination. Neurons have been shown to act as a repository site at the early stages of the disease process (O. Sorensen and S. Dales, J. Virol. 56:434-438, 1985). JHM virus (JHMV) replication and trafficking of viral proteins and virions in cultured rat hippocampal neurons and a neuronal cell line, OBL-21, were examined, with an emphasis placed on the role of the microtubular network. We show here that JHMV spread within the central nervous system occurs transneuronally and that virus protein trafficking was dependent upon microtubules. Viral trafficking occurred asymmetrically, involving both the somatodendritic and the axonal domains. Thus coronavirus can be disseminated from neurons at either the basolateral or the apical domains. A specific interaction between antibodies derived against the microtubule-associated protein tau and JHMV nucleocapsid protein (N) was observed, which can presumably be explained by an overall amino acid similarity of 44% and an identity of 20% between proteins N and tau, with optimal alignment at the microtubule binding domain of tau. Collectively, our data suggest an important role of the microtubule network in viral protein trafficking and distribution. They also draw attention to protein sequence mimicry of a cell component by this coronavirus as one strategy for making use of the host's functions on behalf of the virus.