Use of Differential Display Reverse Transcription-PCR To Reveal Cellular Changes during Stimuli That Result in Herpes Simplex Virus Type 1 Reactivation from Latency: Upregulation of Immediate-Early Cellular Response Genes TIS7, Interferon, and Interferon Regulatory Factor-1

The detailed mechanism which governs the choice between herpes simplex virus (HSV) latency and reactivation remains to be elucidated. It is probable that altered expression of cellular factors in sensory neurons leads to induction of HSV gene expression resulting in reactivation. As an approach to identify novel cellular genes which are activated or repressed by stimuli that reactivate HSV from latency and hence may play a role in viral reactivation, RNA from explanted trigeminal ganglia (TG) was analyzed by differential display reverse transcription-PCR (DDRT-PCR). Nearly 50 cDNAs whose mRNA level was modified by the stress of explantation were isolated and sequenced. We present a listing of a spectrum of altered RNAs, including both known and unknown sequences. Five of those differentially displayed transcripts were identified as interferon-related murine TIS7 mRNA. These results were confirmed in both infected and uninfected ganglia by quantitative RNase protection assay and immunostaining. Alpha and beta interferons and interferon regulatory factor-1 (IRF-1) were also induced by explantation. In addition, we have identified sequences that correspond to IRF-1 consensus binding sites in both HSV type 1 origins of replication. Our findings suggest that physiological pathways that include these cellular factors may be involved in modulating HSV reactivation.