Transcriptional regulatory mechanisms shaping HIV proviral fate

PROJECT SUMMARY Although HIV-1 infection can be controlled through long-term treatment with anti-retroviral therapy (ART), a true cure has been elusive. Reservoir cells persist over time and support latent HIV-1 reactivation upon therapy cessation, yet little is known about the underlying mechanisms. Our lab has recently identified previously unknown facets in the “core” HIV-1 transcriptional program that we will explore in this proposal to help fill this knowledge gap, and may offer key insights into HIV-1 biology as well as cure strategies. The major goal of this grant application is to understand transcriptional regulatory mechanisms shaping HIV-1 latency maintenance and reactivation. We will accomplish this goal by leveraging genetic, genomic and microscopy approaches to explore HIV-1 transcription at high-resolution in several immortalized and primary models of latency as well as in aviremic participants samples. We will focus on the cycle of RNA polymerase II (Pol II) transcription, which is essential for the process of latency reactivation in reservoir cells. Specifically, we will explore the hypothesis that HIV-1 transcription is initially activated by de novo Pol II recruitment through the action of viral enhancers and eukaryotic transcription factors -TFs- (host phase) and later sustained through Tat-dependent Pol II re-initiation (viral phase). We propose to build on our recent findings to gain a deeper understanding of how the viral enhancers promote HIV-1 transcription for latency reactivation in the host and viral phases of the HIV-1 transcriptional program. These goals are reflected in two Specific Aims: to define the viral enhancers that drive HIV-1 transcription and latency reactivation (Aim 1), and to determine how eukaryotic TFs and Tat function with the viral enhancers to facilitate HIV-1 transcription and latency reactivation. If successful, this project will yield a better understanding of the molecular mechanisms by which eukaryotic TFs and Tat converge to promote efficient HIV-1 transcription and latency reactivation, collectively having a sustained impact in the field. In keeping with NIAID’s mission of ending the HIV-1 epidemic, our long-term objective is to leverage the basic discoveries to devise novel and alternative cure strategies. As such, the fundamental knowledge gained by this research could be used in the future studies beyond the scope of this focused grant application, to exploit an enhancer-based strategy to permanently silence HIV-1 to achieve the long-awaited HIV-1 remission.