Transactivation of human immunodeficiency virus by herpesviruses

We examined the interaction of human immunodeficiency virus (HIV) and herpes group viruses. For this purpose, a chimeric plasmid (pLTR-CAT) was constructed in which the long terminal repeat (LTR) sequences derived from a molecular clone of HIV were fused to a bacterial chloramphenicol acetyltransferase gene (CAT). Transient expression assays in transfected tissue culture cells were used to monitor the activity of the LTR. Basal levels of CAT activity were measured in HeLa and human lung fibroblast (HLF) cells transfected with pLTR-CAT. When HeLa or HLF cells transfected with pLTR-CAT were infected with herpesviruses, HIV LTR-directed expression of the CAT gene was detected. An enhancement of the HIV LTR-directed expression of CAT was observed for herpes simplex virus (HSV)-1 and HSV-2, cytomegalovirus and varicella zoster virus. Enhanced CAT expression directed by the LTR was also shown by cotransfection of recombinant plasmids containing two non-overlapping regions of HSV-1, a fragment from HSV-2 which is non-colinear with the regions used from HSV-1, the immediate early gene of pseudorabies virus and the adenovirus early gene EIA. HIV LTR-directed expression may be a useful model for studying the effects on HIV of various infectious agents known to be present in individuals with AIDS or HIV infection.