Mechanism of Latency of Herpes Simplex Virus Project 4. HSV-1 interactions with NGF differentiated cellsThis project will determine if and how the herpes simplex virus type 1 (HSV-1) genome, in quiescentlyinfected cells, accumulates mutations and is repaired or otherwise physically managed. Establishment of,and reactivation from, latently infected cells is dependent upon the integrity of the viral genome, and mutantscan be a serous problem during therapy. During the viral life cycle, the genome exists in multiple physicalstates ranging from linear to circular forms, and is exposed to potentially damaging genotoxins. Informationabout how neuronal cells repair their cellular DNA is limited, but neuronal cell repair appears to be morerestricted than is repair of DNA in other tissue. Since neuronal cells are not likely to replicate, restrictedrepair has not been thought to present serious consequences to the organism. The latent HSV viral genomeis a special case for the neuron, since the quiescent genomes can be reactivated and must thereforemaintain considerable sequence integrity to be viable. There is very little information about if and how theviral genome becomes damaged, mutated and/or repaired, during latency. This proposal addressestheseimportant questions by comparing the DNA lesion incidence of HSV genomes derived from latently infectedcells maintained in the presence and absence of mutagen with each other, and with the viral DNA from theinoculum used to establish the infection. Observations made using quiescently infected NGF differentiatedPC12 cells will be validated using in vivo systems. The results will have important implications regardingviral pathogenesis as well as neuronal cell biology.
