Recurrent infection with herpes simplex virus (HSV) may affect up to one-third of the world's population. In addition, recurrent corneal disease due to HSV is the leading cause of infectious corneal blindness in developed countries. An important concept in understanding the pathophysiology of disease due to HSV is that the virus establishes a latent infection in neurons, and that recurrent disease is due to reactivation of the virus from this latent state. Arriving at a solution for the problem of recurrent HSV disease will undoubtedly depend on an improved understanding of the molecular mechanisms that regulate latent infection with HSV. The overall goal of the proposed research is to identify neuronal signaling pathways and transcription factors that play a role in the establishment of herpes simplex virus (HSV) latent infection. Nerve growth factor, glial-cell-derived growth factor and artemin, potent neurotrophic factors that trigger intracellular signaling pathways important for neuronal survival, will be examined for their possible roles in promoting the establishment of HSV latent infection. Transgenic mice will be used to determine whether establishment of latent infection is due, in part, to the host neuron's ability to modulate expression of the key HSV immediate early (IE) regulatory genes, ICPO, ICP4 and ICP27. The gene expression profiles of two populations of ganglionic neurons with very different outcomes of HSV infection will be studied in order to identify host genes that are differentially expressed and may play a role in the establishment of latent infection. Finally, a neuronal cDNA expression library will be screened for host cell gene products that influence expression of key viral regulatory genes. These gene products will then be tested for their ability to repress HSV IE promoter activity in transient assays and HSV productive infection in vitro. Taken together, these studies will begin to elucidate mechanisms by which neurons survive HSV infection to become reservoirs of latent virus responsible for recurrent disease.