UPSTREAM STIMULATORY FACTOR FAMILY BINDS TO THE HERPES-SIMPLEX VIRUS TYPE-1 LATENCY-ASSOCIATED TRANSCRIPT PROMOTER

The herpes simplex Virus type 1 (HSV-1) latency-associated transcript (LAT) promoter 1 (LPI) is the only viral promoter that exhibits detect able transcriptional activity during a latent HSV infection. The LAT p romoter-binding factor (LPBF) regulatory sequence (nucleotides -65 to -72 relative to the transcriptional stat? site of the 8.3-kb primary t ranscript) closely resembles the core recognition sequence required fo r binding members of the upstream stimulatory factor (USF)/major late transcription factor (MLTF) family, In this analysis, we demonstrate t hat oligonucleotides containing either the LPBF recognition sequence o r the USF/MLTF recognition sequences from previously described promote rs bind cellular factors which exhibit very similar mobilities in elec trophoretic mobility shift (EMS) analyses. We also observe a high degr ee of similarity in competition profiles obtained in competition EMS a nalyses utilizing oligonucleotides containing recognition sequences fo r either LPBF or USF/MLTF. Furthermore, antibody supershift EMS analys es have demonstrated that the factors binding the LPBF or USF/MLTF rec ognition sites in these oligonucleotides are antigenically related, if not identical, and that greater than 90% of the LPBF-binding activity is antigenically related to USF. In addition, we demonstrate that bot h forms of in vitro-translated USF proteins (43 and 44 kDa) bind to th e LPBF recognition sequence within HSV-1 LPI. Taken together, these da ta indicate that USF is capable of binding to the HSV-I LPBF recogniti on sequence and that USF is a major LPBF-binding activity in cells of neuronal and nonneuronal lineage. These data further support the hypot hesis that USF may indeed play a significant role in the transcription al activity of HSV-I LPI. (C) 1997 Academic Press.