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D'Orso I. The HIV-1 Transcriptional Program: From Initiation to Elongation Control. J Mol Biol 2025; 437:168690. [PMID: 38936695 DOI: 10.1016/j.jmb.2024.168690] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2024] [Revised: 06/20/2024] [Accepted: 06/21/2024] [Indexed: 06/29/2024]
Abstract
A large body of work in the last four decades has revealed the key pillars of HIV-1 transcription control at the initiation and elongation steps. Here, I provide a recount of this collective knowledge starting with the genomic elements (DNA and nascent TAR RNA stem-loop) and transcription factors (cellular and the viral transactivator Tat), and later transitioning to the assembly and regulation of transcription initiation and elongation complexes, and the role of chromatin structure. Compelling evidence support a core HIV-1 transcriptional program regulated by the sequential and concerted action of cellular transcription factors and Tat to promote initiation and sustain elongation, highlighting the efficiency of a small virus to take over its host to produce the high levels of transcription required for viral replication. I summarize new advances including the use of CRISPR-Cas9, genetic tools for acute factor depletion, and imaging to study transcriptional dynamics, bursting and the progression through the multiple phases of the transcriptional cycle. Finally, I describe current challenges to future major advances and discuss areas that deserve more attention to both bolster our basic knowledge of the core HIV-1 transcriptional program and open up new therapeutic opportunities.
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Affiliation(s)
- Iván D'Orso
- Department of Microbiology, The University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
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Maikoo S, Palstra RJ, Dong KL, Mahmoudi T, Ndung'u T, Madlala P. Development of a latency model for HIV-1 subtype C and the impact of long terminal repeat element genetic variation on latency reversal. J Virus Erad 2024; 10:100575. [PMID: 39811575 PMCID: PMC11730875 DOI: 10.1016/j.jve.2024.100575] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2024] [Revised: 12/08/2024] [Accepted: 12/09/2024] [Indexed: 01/16/2025] Open
Abstract
Sub-Saharan Africa accounts for almost 70 % of people living with HIV (PLWH) worldwide, with the greatest numbers centred in South Africa where 98 % of infections are caused by subtype C (HIV-1C). However, HIV-1 subtype B (HIV-1B), prevalent in Europe and North America, has been the focus of most cure research and testing despite making up only 12 % of HIV-1 infections globally. Development of latency models for non-subtype B viruses is a necessary step to address this disproportionate focus. Furthermore, the impact of genetic variation between viral subtypes, specifically within the long terminal repeat (LTR) element of the viral transcriptional promoter on latency reversal, remains unclear. To address this scientific gap, we constructed a minimal genome retroviral vector expressing HIV-1C consensus transactivator of transcription protein (Tat) and green fluorescent protein (GFP) under the control of either HIV-1C consensus LTR (C731CC) or the transmitted/founder (T/F) LTRs derived from PLWH (CT/F731CC), produced corresponding LTR pseudotyped viruses using a vesicular stomatitis virus (VSV-G) pseudotyped Envelope vector and the pCMVΔR8.91 packaging vector containing HIV-1 accessory and rev genes. Viruses produced in this way were used to infect Jurkat E6 and primary CD4+ T cells in vitro. By enriching for latently infected cells, and treating them with different latency reversing agents, we developed an HIV-1C latency model that demonstrated that the HIV-1C consensus LTR has lower reactivation potential compared to its HIV-1B counterpart. Furthermore, HIV-1C T/F LTR pseudotyped proviral genetic variants exhibited a heterogenous reactivation response which was modulated by host cell (genetic) variation. Our data suggests that genetic variation both within and between HIV-1 subtypes influences latency reversal. Future studies should investigate the specific role of variation in host cellular environment on reactivation differences.
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Affiliation(s)
- Shreyal Maikoo
- HIV Pathogenesis Programme, The Doris Duke Medical Research Institute, Nelson R. Mandela School of Medicine, University of KwaZulu-Natal, Durban, South Africa
- School of Laboratory Medicine and Medical Sciences, University of KwaZulu-Natal, Durban, South Africa
| | - Robert-Jan Palstra
- Department of Biochemistry, Erasmus University Medical Center, PO Box 2040, 3000CA, Rotterdam, the Netherlands
- Department of Pathology, Erasmus University Medical Center, the Netherlands
- Department of Urology, Erasmus University Medical Center, the Netherlands
| | - Krista L. Dong
- Ragon Institute of Mass General, MIT and Harvard, Cambridge, MA, USA
- Massachusetts General Hospital, Infectious Disease Division, Boston, MA, USA
- Harvard Medical School, Cambridge, MA, USA
| | - Tokameh Mahmoudi
- Department of Biochemistry, Erasmus University Medical Center, PO Box 2040, 3000CA, Rotterdam, the Netherlands
- Department of Pathology, Erasmus University Medical Center, the Netherlands
- Department of Urology, Erasmus University Medical Center, the Netherlands
| | - Thumbi Ndung'u
- HIV Pathogenesis Programme, The Doris Duke Medical Research Institute, Nelson R. Mandela School of Medicine, University of KwaZulu-Natal, Durban, South Africa
- School of Laboratory Medicine and Medical Sciences, University of KwaZulu-Natal, Durban, South Africa
- Ragon Institute of Mass General, MIT and Harvard, Cambridge, MA, USA
- Africa Health Research Institute, Durban, KwaZulu-Natal, South Africa
- Division of Infection and Immunity, University College London, London, United Kingdom
| | - Paradise Madlala
- HIV Pathogenesis Programme, The Doris Duke Medical Research Institute, Nelson R. Mandela School of Medicine, University of KwaZulu-Natal, Durban, South Africa
- School of Laboratory Medicine and Medical Sciences, University of KwaZulu-Natal, Durban, South Africa
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Ranga U, Panchapakesan A, Saini C. HIV-1 subtypes and latent reservoirs. Curr Opin HIV AIDS 2024; 19:87-92. [PMID: 38169308 DOI: 10.1097/coh.0000000000000835] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
Abstract
PURPOSE OF REVIEW We explore the current status of research on HIV-1 subtype-specific variations and their impact on HIV-1 latency. We also briefly address the controversy surrounding the decision-making process governing the ON/OFF states of HIV-1 transcription, specifically focusing on the regulatory elements, the long terminal repeat (LTR), and Tat. Understanding the decision-making process is crucial for developing effective intervention strategies, such as the 'shock-and-kill' approach, to reactivate latent HIV-1. RECENT FINDINGS Attention has been drawn to subtype-specific transcription factor binding site (TFBS) variations and the possible impact of these variations on viral latency. Further, diverse subtype-specific assays have been developed to quantify the latent viral reservoirs. One interesting observation is the relatively larger latent reservoirs in HIV-1B infection than those of other viral subtypes, which needs rigorous validation. The emergence of LTR-variant viral strains in HIV-1C demonstrating significantly higher levels of latency reversal has been reported. SUMMARY Despite persistent and substantial efforts, latent HIV-1 remains a formidable challenge to a functional cure. Determined and continued commitment is needed to understand the ON/OFF decision-making process of HIV-1 latency, develop rigorous assays for accurately quantifying the latent reservoirs, and identify potent latency-reversing agents and cocktails targeting multiple latency stages. The review emphasizes the importance of including diverse viral subtypes in future latency research.
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Affiliation(s)
- Udaykumar Ranga
- HIV-AIDS Laboratory, Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, Karnataka
| | - Arun Panchapakesan
- Molecular Biology Laboratory, Y R Gaitonde Centre for AIDS Research and Education (YRG CARE), Chennai, Tamil Nadu, India
| | - Chhavi Saini
- HIV-AIDS Laboratory, Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, Karnataka
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Damour A, Slaninova V, Radulescu O, Bertrand E, Basyuk E. Transcriptional Stochasticity as a Key Aspect of HIV-1 Latency. Viruses 2023; 15:1969. [PMID: 37766375 PMCID: PMC10535884 DOI: 10.3390/v15091969] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Revised: 09/16/2023] [Accepted: 09/18/2023] [Indexed: 09/29/2023] Open
Abstract
This review summarizes current advances in the role of transcriptional stochasticity in HIV-1 latency, which were possible in a large part due to the development of single-cell approaches. HIV-1 transcription proceeds in bursts of RNA production, which stem from the stochastic switching of the viral promoter between ON and OFF states. This switching is caused by random binding dynamics of transcription factors and nucleosomes to the viral promoter and occurs at several time scales from minutes to hours. Transcriptional bursts are mainly controlled by the core transcription factors TBP, SP1 and NF-κb, the chromatin status of the viral promoter and RNA polymerase II pausing. In particular, spontaneous variability in the promoter chromatin creates heterogeneity in the response to activators such as TNF-α, which is then amplified by the Tat feedback loop to generate high and low viral transcriptional states. This phenomenon is likely at the basis of the partial and stochastic response of latent T cells from HIV-1 patients to latency-reversing agents, which is a barrier for the development of shock-and-kill strategies of viral eradication. A detailed understanding of the transcriptional stochasticity of HIV-1 and the possibility to precisely model this phenomenon will be important assets to develop more effective therapeutic strategies.
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Affiliation(s)
- Alexia Damour
- MFP UMR 5234 CNRS, Université de Bordeaux, 33076 Bordeaux, France;
| | - Vera Slaninova
- IGH UMR 9002 CNRS, Université de Montpellier, 34094 Montpellier, France;
| | - Ovidiu Radulescu
- LPHI, UMR 5294 CNRS, University of Montpellier, 34095 Montpellier, France;
| | - Edouard Bertrand
- IGH UMR 9002 CNRS, Université de Montpellier, 34094 Montpellier, France;
| | - Eugenia Basyuk
- MFP UMR 5234 CNRS, Université de Bordeaux, 33076 Bordeaux, France;
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