Expression of multiple proteins within single primary cortical neurons using a replication deficient HSV vector.

The study of protein-protein interactions in the nervous system has become dependent on the ability to express foreign proteins (or to overexpress endogenous proteins) within neurons. Often, multiple genes need to be overexpressed in the same cell. To investigate the simultaneous co-expression of more than one virally introduced gene in primary cortical neurons, we infected cultures with two different herpes simplex virus (HSV) vectors and analyzed the proportion of singly and doubly infected cells. The vast majority of neurons expressed both gene products, with a smaller number expressing one or the other protein alone. Increasing the quantity of virus caused an increase in the proportion of doubly labeled cells at the expense of singly labeled cells, which is consistent with a model in which infection with one viral vector is independent of infection with the other. We conclude that co-infection with HSV vectors is an efficient way to obtain expression of multiple gene products within individual primary culture neurons.