Ranjbar, ShahinTsytsykova, Alla V.Lee, Sang-KyungRajsbaum, RicardoFalvo, James V.Lieberman, JudyShankar, PremlataGoldfeld, Anne E.Ross, Susan2019-10-052006Ranjbar, Shahin, Alla V. Tsytsykova, Sang-Kyung Lee, Ricardo Rajsbaum, James V. Falvo, Judy Lieberman, Premlata Shankar, and Anne E. Goldfeld. 2006. “NFAT5 Regulates HIV-1 in Primary Monocytes via a Highly Conserved Long Terminal Repeat Site.” PLoS Pathogens 2 (12): e130. https://doi.org/10.1371/journal.ppat.0020130.1553-73661553-7374http://nrs.harvard.edu/urn-3:HUL.InstRepos:41483442To replicate, HIV-1 capitalizes on endogenous cellular activation pathways resulting in recruitment of key host transcription factors to its viral enhancer. RNA interference has been a powerful tool for blocking key checkpoints in HIV-1 entry into cells. Here we apply RNA interference to HIV-1 transcription in primary macrophages, a major reservoir of the virus, and specifically target the transcription factor NFAT5 (nuclear factor of activated T cells 5), which is the most evolutionarily divergent NFAT protein. By molecularly cloning and sequencing isolates from multiple viral subtypes, and performing DNase I footprinting, electrophoretic mobility shift, and promoter mutagenesis transfection assays, we demonstrate that NFAT5 functionally interacts with a specific enhancer binding site conserved in HIV-1, HIV-2, and multiple simian immunodeficiency viruses. Using small interfering RNA to ablate expression of endogenous NFAT5 protein, we show that the replication of three major HIV-1 viral subtypes (B, C, and E) is dependent upon NFAT5 in human primary differentiated macrophages. Our results define a novel host factor-viral enhancer interaction that reveals a new regulatory role for NFAT5 and defines a functional DNA motif conserved across HIV-1 subtypes and representative simian immunodeficiency viruses. Inhibition of the NFAT5-LTR interaction may thus present a novel therapeutic target to suppress HIV-1 replication and progression of AIDS.en-USJournal Article2019-10-0510.1371/journal.ppat.0020130