A latent, nonpathogenic HSV-1-derived vector stably expresses beta-galactosidase in mouse neurons.

A genetically engineered herpes simplex virus variant was constructed for use as a stable gene vector for neurons. To inhibit replication, the agent possessed a deletion in the immediate early gene ICP4, and to minimize reactivation from the latent state, the gene encoding the latency-associated transcript was deleted. The E. coli beta-galactosidase gene under the control of the Maloney murine leukemia virus long terminal repeat promoter was inserted into the ICP4 region. When introduced into the peripheral nervous system, this virus established latent infections and stably expressed beta-galactosidase in primary sensory neurons. Expression of beta-galactosidase over a more limited time period was observed when the latent infection was established in motor neurons of the hypoglossal nucleus. Agents of this general design have considerable potential for use as gene vectors for studies of neuronal function and correction of genetic defects affecting neurons.