Identification of human cytomegalovirus target sequences in the human immunodeficiency virus long terminal repeat - Potential role of IE2-86 binding to sequences between-120 and-20 in promoter transactivation

Objective: Because of the important medical consequences of human cytomegal ovirus (HCMV) infection in human immunodeficiency virus (HIV)-infected indi viduals, we wanted to understand the molecular interactions that occur duri ng coinfection. Specifically, in this study, we wanted to identify the tran sactivating target sequences on the HIV long terminal repeat (LTR) that res ponded to HCMV infection. Study Design/Methods: In this study, we transfected the HIV-LTR into human fibroblasts and then mapped the regulation of this promoter following HCMV infection and cotransfection with the HCMV immediate-early (IE) gene produc t IE2-86. In addition, we examined IE2-86 binding to specific sequences in the HIV-LTR by electrophoretic mobility shift assay. Results: Our results documented that HCMV and IE2-86 could transactivate th e HN-LTR. In mapping the regions of the HIV-LTR that IE2-86 transactivates, we identified discrete target sequences between -120 and -20 that are the major transactivating regions for the IE2-86-mediated effects and determine d that IE2-86 could specifically bind to several discrete sequences within this region of the HIV-LTR. Conclusions: Our discovery of the binding of IE2-86 to the HIV-LTR, coupled with its ability to transactivate the HIV-LTR and induce cellular transcri ption factors, points to potential molecular mechanisms used by HCMV to upr egulate the HIV life cycle and, consequently, exacerbate the conditions obs erved in individuals co-infected with HCMV and HIV.