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Chakraborty A, Samant D, Sarkar R, Sangeet S, Prusty S, Roy S. RNA's Dynamic Conformational Selection and Entropic Allosteric Mechanism in Controlling Cascade Protein Binding Events. J Phys Chem Lett 2024; 15:6115-6125. [PMID: 38830201 DOI: 10.1021/acs.jpclett.4c00740] [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: 06/05/2024]
Abstract
In the TAR RNA of immunodeficiency viruses, an allosteric communication exists between a distant loop and a bulge. The bulge interacts with the TAT protein vital for transactivating viral RNA, while the loop interacts with cyclin-T1, contingent on TAT binding. Through extensive atomistic and free energy simulations, we investigate TAR-TAT binding in nonpathogenic bovine immunodeficiency virus (BIV) and pathogenic human immunodeficiency virus (HIV). Thermodynamic analysis reveals enthalpically driven binding in BIV and entropically favored binding in HIV. The broader global basin in HIV is attributed to binding-induced loop fluctuation, corroborated by nuclear magnetic resonance (NMR), indicating classical entropic allostery onset. While this loop fluctuation affects the TAT binding affinity, it generates a binding-competent conformation that aids subsequent effector (cyclin-T1) binding. This study underscores how two structurally similar apo-RNA scaffolds adopt distinct conformational selection mechanisms to drive enthalpic and entropic allostery, influencing protein affinity in the signaling cascade.
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Affiliation(s)
- Amrita Chakraborty
- Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata, Kolkata, West Bengal 741246, India
| | - Dibyamanjaree Samant
- Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata, Kolkata, West Bengal 741246, India
| | - Raju Sarkar
- Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata, Kolkata, West Bengal 741246, India
| | - Satyam Sangeet
- Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata, Kolkata, West Bengal 741246, India
| | - Sangram Prusty
- Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata, Kolkata, West Bengal 741246, India
| | - Susmita Roy
- Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata, Kolkata, West Bengal 741246, India
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Wicks SL, Morgan BS, Wilson AW, Hargrove AE. Probing Bioactive Chemical Space to Discover RNA-Targeted Small Molecules. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.31.551350. [PMID: 37577658 PMCID: PMC10418101 DOI: 10.1101/2023.07.31.551350] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/15/2023]
Abstract
Small molecules have become increasingly recognized as invaluable tools to study RNA structure and function and to develop RNA-targeted therapeutics. To rationally design RNA-targeting ligands, a comprehensive understanding and explicit testing of small molecule properties that govern molecular recognition is crucial. To date, most studies have primarily evaluated properties of small molecules that bind RNA in vitro, with little to no assessment of properties that are distinct to selective and bioactive RNA-targeted ligands. Therefore, we curated an RNA-focused library, termed the Duke RNA-Targeted Library (DRTL), that was biased towards the physicochemical and structural properties of biologically active and non-ribosomal RNA-targeted small molecules. The DRTL represents one of the largest academic RNA-focused small molecule libraries curated to date with more than 800 small molecules. These ligands were selected using computational approaches that measure similarity to known bioactive RNA ligands and that diversify the molecules within this space. We evaluated DRTL binding in vitro to a panel of four RNAs using two optimized fluorescent indicator displacement assays, and we successfully identified multiple small molecule hits, including several novel scaffolds for RNA. The DRTL has and will continue to provide insights into biologically relevant RNA chemical space, such as the identification of additional RNA-privileged scaffolds and validation of RNA-privileged molecular features. Future DRTL screening will focus on expanding both the targets and assays used, and we welcome collaboration from the scientific community. We envision that the DRTL will be a valuable resource for the discovery of RNA-targeted chemical probes and therapeutic leads.
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Affiliation(s)
- Sarah L. Wicks
- Department of Chemistry; Duke University; 124 Science Drive; Durham, NC 27708
| | - Brittany S. Morgan
- Department of Chemistry & Biochemistry; University of Notre Dame; 123 McCourtney Hall Notre Dame, IN 46556
| | - Alexander W. Wilson
- Department of Chemistry; Duke University; 124 Science Drive; Durham, NC 27708
| | - Amanda E. Hargrove
- Department of Chemistry; Duke University; 124 Science Drive; Durham, NC 27708
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Shin YH, Kim DE, Yu KL, Park CM, Kim HG, Kim KC, Bae S, Yoon CH. A Novel Time-Resolved Fluorescence Resonance Energy Transfer Assay for the Discovery of Small-Molecule Inhibitors of HIV-1 Tat-Regulated Transcription. Int J Mol Sci 2023; 24:ijms24119139. [PMID: 37298089 DOI: 10.3390/ijms24119139] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2023] [Revised: 05/17/2023] [Accepted: 05/18/2023] [Indexed: 06/12/2023] Open
Abstract
Human immunodeficiency virus-1 (HIV-1) transactivator (Tat)-mediated transcription is essential for HIV-1 replication. It is determined by the interaction between Tat and transactivation response (TAR) RNA, a highly conserved process representing a prominent therapeutic target against HIV-1 replication. However, owing to the limitations of current high-throughput screening (HTS) assays, no drug that disrupts the Tat-TAR RNA interaction has been uncovered yet. We designed a homogenous (mix-and-read) time-resolved fluorescence resonance energy transfer (TR-FRET) assay using europium cryptate as a fluorescence donor. It was optimized by evaluating different probing systems for Tat-derived peptides or TAR RNA. The specificity of the optimal assay was validated by mutants of the Tat-derived peptides and TAR RNA fragment, individually and by competitive inhibition with known TAR RNA-binding peptides. The assay generated a constant Tat-TAR RNA interaction signal, discriminating the compounds that disrupted the interaction. Combined with a functional assay, the TR-FRET assay identified two small molecules (460-G06 and 463-H08) capable of inhibiting Tat activity and HIV-1 infection from a large-scale compound library. The simplicity, ease of operation, and rapidity of our assay render it suitable for HTS to identify Tat-TAR RNA interaction inhibitors. The identified compounds may also act as potent molecular scaffolds for developing a new HIV-1 drug class.
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Affiliation(s)
- Young Hyun Shin
- Division of Chronic Viral Diseases, Center for Emerging Virus Research, Korea National Institute of Health, 187 Osongsaengmyeong 2-ro, Cheongju 363951, Republic of Korea
| | - Dong-Eun Kim
- Division of Chronic Viral Diseases, Center for Emerging Virus Research, Korea National Institute of Health, 187 Osongsaengmyeong 2-ro, Cheongju 363951, Republic of Korea
| | - Kyung Lee Yu
- Division of Chronic Viral Diseases, Center for Emerging Virus Research, Korea National Institute of Health, 187 Osongsaengmyeong 2-ro, Cheongju 363951, Republic of Korea
| | - Chul Min Park
- Department for Convergent Research of Emerging Virus Infection, Korea Research Institute of Chemical Technology, 141 Gajeong-ro, Daejeon 34114, Republic of Korea
| | - Hong Gi Kim
- Department for Convergent Research of Emerging Virus Infection, Korea Research Institute of Chemical Technology, 141 Gajeong-ro, Daejeon 34114, Republic of Korea
| | - Kyung-Chang Kim
- Division of Chronic Viral Diseases, Center for Emerging Virus Research, Korea National Institute of Health, 187 Osongsaengmyeong 2-ro, Cheongju 363951, Republic of Korea
| | - Songmee Bae
- Division of Chronic Viral Diseases, Center for Emerging Virus Research, Korea National Institute of Health, 187 Osongsaengmyeong 2-ro, Cheongju 363951, Republic of Korea
| | - Cheol-Hee Yoon
- Division of Chronic Viral Diseases, Center for Emerging Virus Research, Korea National Institute of Health, 187 Osongsaengmyeong 2-ro, Cheongju 363951, Republic of Korea
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Chowdhury MN, Jin H. The RGG motif proteins: Interactions, functions, and regulations. WILEY INTERDISCIPLINARY REVIEWS. RNA 2023; 14:e1748. [PMID: 35661420 PMCID: PMC9718894 DOI: 10.1002/wrna.1748] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Revised: 04/25/2022] [Accepted: 05/09/2022] [Indexed: 01/31/2023]
Abstract
Proteins with motifs rich in arginines and glycines were discovered decades ago and are functionally involved in a staggering range of essential processes in the cell. Versatile, specific, yet adaptable molecular interactions enabled by the unique combination of arginine and glycine, combined with multiplicity of molecular recognition conferred by repeated di-, tri-, and multiple peptide motifs, allow RGG motif proteins to interact with a broad range of proteins and nucleic acids. Furthermore, posttranslational modifications at the arginines in the motif extend the RGG protein's capacity for a fine-tuned regulation. In this review, we focus on the biochemical properties of the RGG motif, its molecular interactions with RNAs and proteins, and roles of the posttranslational modification in modulating their interactions. We discuss current knowledge of the RGG motif proteins involved in mRNA transport and translation, highlight our merging understanding of their molecular functions in translational regulation and summarize areas of research in the future critical in understanding this important family of proteins. This article is categorized under: RNA Interactions with Proteins and Other Molecules > Protein-RNA Recognition RNA Interactions with Proteins and Other Molecules > Protein-RNA Interactions: Functional Implications Translation > Mechanisms.
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Affiliation(s)
- Mashiat N. Chowdhury
- Department of Biochemistry, University of Illinois at Urbana-Champaign, 600 S. Mathews Avenue, Urbana, IL 61801
| | - Hong Jin
- Department of Biochemistry, University of Illinois at Urbana-Champaign, 600 S. Mathews Avenue, Urbana, IL 61801,Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, 600 S. Mathews Avenue, Urbana, IL 61801,Carl R. Woese Institute for Genomic Biology, 1206 West Gregory Drive, University of Illinois at Urbana-Champaign, 600 S. Mathews Avenue, Urbana, IL 61801,Corresponding author: Phone: (217)244-9493, Fax: (217)244-5858,
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Chaudhry T, Coxon CR, Ross K. Trading places: Peptide and small molecule alternatives to oligonucleotide-based modulation of microRNA expression. Drug Discov Today 2022; 27:103337. [PMID: 35995360 DOI: 10.1016/j.drudis.2022.08.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2022] [Revised: 06/13/2022] [Accepted: 08/09/2022] [Indexed: 11/03/2022]
Abstract
It is well established that microRNA (miRNA) dysregulation is involved in the development and progression of various diseases, especially cancer. Emerging evidence suggests that small molecule and peptide agents can interfere with miRNA disease pathways. Despite this, very little is known about structural features that drive drug-miRNA interactions and subsequent inhibition. In this review, we highlight the advances made in the development of small molecule and peptide inhibitors of miRNA processing. Specifically, we attempt to draw attention to peptide features that may be critical for interaction with the miRNA secondary structure to regulate miRNA expression. We hope that this review will help to establish peptides as exciting miRNA expression modulators and will contribute towards the development of the first miRNA-targeting peptide therapy.
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Affiliation(s)
- Talhat Chaudhry
- School of Pharmacy and Biomolecular Science, Liverpool John Moores University, Liverpool, UK; Institute for Health Research, Liverpool John Moores University, Liverpool, UK
| | - Christopher R Coxon
- EaStChem School of Chemistry, The University of Edinburgh, Joseph Black Building, David Brewster Road, Edinburgh EH14 4AS, UK
| | - Kehinde Ross
- School of Pharmacy and Biomolecular Science, Liverpool John Moores University, Liverpool, UK; Institute for Health Research, Liverpool John Moores University, Liverpool, UK.
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T-cell evasion and invasion during HIV-1 infection: The role of HIV-1 Tat protein. Cell Immunol 2022; 377:104554. [DOI: 10.1016/j.cellimm.2022.104554] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Revised: 05/22/2022] [Accepted: 05/23/2022] [Indexed: 12/22/2022]
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Williams ME, Cloete R. Molecular Modeling of Subtype-Specific Tat Protein Signatures to Predict Tat-TAR Interactions That May Be Involved in HIV-Associated Neurocognitive Disorders. Front Microbiol 2022; 13:866611. [PMID: 35464972 PMCID: PMC9021916 DOI: 10.3389/fmicb.2022.866611] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Accepted: 03/16/2022] [Indexed: 12/30/2022] Open
Abstract
HIV-1 is responsible for a spectrum of neurocognitive deficits defined as HIV-associated neurocognitive disorders (HAND). The HIV transactivator of transcription (Tat) protein plays a key role in the neuropathophysiology of HAND. The Tat protein functions by transactivation of viral genes through its interaction with the transactivation response (TAR) RNA element. Subtype-specific Tat protein signatures including C31S, R57S and Q63E present in Tat subtype C has previously been linked to a lowered neuropathophysiology compared to Tat subtype B. In this study, we attempted to understand the molecular mechanism by which Tat subtype-specific variation, particularly, C31S, R57S, and Q63E influence the Tat-TAR interaction. We performed molecular modeling to generate accurate three-dimensional protein structures of the HIV-1 Tat subtypes C and B using the Swiss model webserver. Thereafter, we performed a molecular docking of the TAR RNA element to each of the Tat subtypes B and C protein structures using the HDOCK webserver. Our findings indicate that Tat subtype B had a higher affinity for the TAR RNA element compared to Tat subtype C based on a higher docking score of −187.37, a higher binding free energy value of −9834.63 ± 216.17 kJ/mol, and a higher number of protein–nucleotide interactions of 26. Furthermore, Tat subtype B displayed more flexible regions when bound to the TAR element and this flexibility could account for the stronger affinity of Tat subtype B to TAR. From the Tat signatures linked to neuropathogenesis, only R57/R57S are involved in Tat-TAR interaction. Due to the lack of electrostatic interactions observed between Tat subtype C and TAR, weaker affinity is observed, and this may contribute to a lower level of neuropathophysiology observed in subtype C infection.
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Affiliation(s)
- Monray E. Williams
- Human Metabolomics, North-West University, Potchefstroom, South Africa
- *Correspondence: Monray E. Williams,
| | - Ruben Cloete
- South African Medical Research Council Bioinformatics Unit, South African National Bioinformatics Institute, University of the Western Cape, Bellville, South Africa
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Satpathi S, Endoh T, Podbevšek P, Plavec J, Sugimoto N. Transcriptome screening followed by integrated physicochemical and structural analyses for investigating RNA-mediated berberine activity. Nucleic Acids Res 2021; 49:8449-8461. [PMID: 33784402 PMCID: PMC8421223 DOI: 10.1093/nar/gkab189] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Revised: 02/25/2021] [Accepted: 03/06/2021] [Indexed: 01/26/2023] Open
Abstract
Non-coding RNAs are regarded as promising targets for the discovery of innovative drugs due to their abundance in the genome and their involvement in many biological processes. Phytochemicals (PCs) are the primary source of ligand-based drugs due to their broad spectrum of biological activities. Since many PCs are heterocyclic and have chemical groups potentially involved in the interaction with nucleic acids, detailed interaction analysis between PCs and RNA is crucial to explore the effect of PCs on RNA functions. In this study, an integrated approach for investigating interactions between PCs and RNAs were demonstrated to verify the RNA-mediated PCs functions by using berberine (BRB) as a model PC. RNA screening of a transcriptome library followed by sequence refinement found minimal RNA motif consisting of a cytosine bulge with U-A and G-U neighbouring base pairs for interaction with BRB. NMR-based structure determination and physicochemical analyses using chemical analogues of BRB demonstrated the importance of electrostatic and stacking interactions for sequence selective interaction and RNA stabilization. The selective interaction with a relatively small RNA motif based on a chemical structure of a planer heterocyclic highlights the biological activities of various PCs mediated by the interactions with particular functional RNAs. In addition, the systematic and quantitative investigations demonstrated in this study could be useful for the development of therapeutic chemicals targeting functional RNAs, based on the PCs, in the future.
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Affiliation(s)
- Sagar Satpathi
- Frontier Institute for Biomolecular Engineering Research (FIBER), Konan University, 7-1-20 Minatojima-minamimachi, Kobe 650-0047, Japan
| | - Tamaki Endoh
- Frontier Institute for Biomolecular Engineering Research (FIBER), Konan University, 7-1-20 Minatojima-minamimachi, Kobe 650-0047, Japan
| | - Peter Podbevšek
- Slovenian NMR Centre, National Institute of Chemistry, Hajdrihova 19, Ljubljana SI-1000, Slovenia
| | - Janez Plavec
- Slovenian NMR Centre, National Institute of Chemistry, Hajdrihova 19, Ljubljana SI-1000, Slovenia
- EN→FIST Centre of Excellence, Trg OF 13, SI-1000 Ljubljana, Slovenia
- Faculty of Chemistry and Chemical Technology, University of Ljubljana, Večna pot 113, p. p. 537, SI-1000 Ljubljana, Slovenia
| | - Naoki Sugimoto
- Frontier Institute for Biomolecular Engineering Research (FIBER), Konan University, 7-1-20 Minatojima-minamimachi, Kobe 650-0047, Japan
- Graduate School of Frontiers of Innovative Research in Science and Technology (FIRST), Konan University, 7-1-20 Minatojima-minamimachi, Kobe 650-0047, Japan
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9
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de Almeida SM, Rotta I, Vidal LRR, Dos Santos JS, Nath A, Johnson K, Letendre S, Ellis RJ. HIV-1C and HIV-1B Tat protein polymorphism in Southern Brazil. J Neurovirol 2021; 27:126-136. [PMID: 33462791 PMCID: PMC8510567 DOI: 10.1007/s13365-020-00935-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Revised: 11/19/2020] [Accepted: 12/14/2020] [Indexed: 01/04/2023]
Abstract
The transactivator of transcription (Tat) is a key HIV regulatory protein. We aimed to identify the frequency of key polymorphisms in HIV-1C compared with HIV-1B Tat protein, chiefly in the cysteine-, arginine-, and glutamine-rich domains and identify novel point mutations in HIV-1B and C sequences from Southern Brazil. This study was the first to investigate the genetic diversity and point mutations within HIV-1 Tat C in a Brazilian cohort. This was an observational, cross-sectional study, which included sequences of HIV-1B (n = 20) and HIV-1C (n = 21) from Southern Brazil. Additionally, 344 HIV-1C sequences were obtained from the Los Alamos database: 29 from Brazil and 315 from Africa, Asia, and Europe. The frequency of C31S substitution on HIV-1 Tat C in Brazil was 82% vs. 10% in the HIV-1B group (p < 0.0001). The frequency of the R57S substitution among the HIV-1C sequences from Brazil was 74% vs. 20% in HIV-1B (p = 0.004), and that of substitution Q63E in HIV-1C was 80% and 20% in HIV-1B (p < 0.0001). The mutation P60Q was more frequent in HIV-1B than in HIV-1C (55% and 6.12%, respectively, p < 0.0001)). Novel point mutations in the HIV-1C and B Tat functional domains were described. The frequency of C31S and other key point mutations in HIV-1 Tat C in Brazil were similar to those described in Africa, although lower than those in India. The Tat-B and C sequences found in Southern Brazil are consistent with biological differences and have potential implications for HIV-1 subtype pathogenesis.
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Affiliation(s)
| | | | | | | | - Avindra Nath
- National Institute of Neurological Disorders and Stroke, NIH/NINDS, Bethesda, USA
| | - Kory Johnson
- National Institute of Neurological Disorders and Stroke, NIH/NINDS, Bethesda, USA
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Haniff HS, Knerr L, Chen JL, Disney MD, Lightfoot HL. Target-Directed Approaches for Screening Small Molecules against RNA Targets. SLAS DISCOVERY : ADVANCING LIFE SCIENCES R & D 2020; 25:869-894. [PMID: 32419578 PMCID: PMC7442623 DOI: 10.1177/2472555220922802] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
RNA molecules have a variety of cellular functions that can drive disease pathologies. They are without a doubt one of the most intriguing yet controversial small-molecule drug targets. The ability to widely target RNA with small molecules could be revolutionary, once the right tools, assays, and targets are selected, thereby defining which biomolecules are targetable and what constitutes drug-like small molecules. Indeed, approaches developed over the past 5-10 years have changed the face of small molecule-RNA targeting by addressing historic concerns regarding affinity, selectivity, and structural dynamics. Presently, selective RNA-protein complex stabilizing drugs such as branaplam and risdiplam are in clinical trials for the modulation of SMN2 splicing, compounds identified from phenotypic screens with serendipitous outcomes. Fully developing RNA as a druggable target will require a target engagement-driven approach, and evolving chemical collections will be important for the industrial development of this class of target. In this review we discuss target-directed approaches that can be used to identify RNA-binding compounds and the chemical knowledge we have today of small-molecule RNA binders.
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Affiliation(s)
- Hafeez S. Haniff
- Department of Chemistry, The Scripps Research Institute, Jupiter, FL, USA
| | - Laurent Knerr
- Medicinal Chemistry, Research and Early Development, Cardiovascular, Renal and Metabolism (CVRM), BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden
| | - Jonathan L. Chen
- Department of Chemistry, The Scripps Research Institute, Jupiter, FL, USA
| | - Matthew D. Disney
- Department of Chemistry, The Scripps Research Institute, Jupiter, FL, USA
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Khan N, Chen X, Geiger JD. Role of Divalent Cations in HIV-1 Replication and Pathogenicity. Viruses 2020; 12:E471. [PMID: 32326317 PMCID: PMC7232465 DOI: 10.3390/v12040471] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 04/09/2020] [Accepted: 04/18/2020] [Indexed: 12/22/2022] Open
Abstract
Divalent cations are essential for life and are fundamentally important coordinators of cellular metabolism, cell growth, host-pathogen interactions, and cell death. Specifically, for human immunodeficiency virus type-1 (HIV-1), divalent cations are required for interactions between viral and host factors that govern HIV-1 replication and pathogenicity. Homeostatic regulation of divalent cations' levels and actions appear to change as HIV-1 infection progresses and as changes occur between HIV-1 and the host. In people living with HIV-1, dietary supplementation with divalent cations may increase HIV-1 replication, whereas cation chelation may suppress HIV-1 replication and decrease disease progression. Here, we review literature on the roles of zinc (Zn2+), iron (Fe2+), manganese (Mn2+), magnesium (Mg2+), selenium (Se2+), and copper (Cu2+) in HIV-1 replication and pathogenicity, as well as evidence that divalent cation levels and actions may be targeted therapeutically in people living with HIV-1.
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Affiliation(s)
| | | | - Jonathan D. Geiger
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND 58203, USA; (N.K.); (X.C.)
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12
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Parsonnet NV, Lammer NC, Holmes ZE, Batey RT, Wuttke DS. The glucocorticoid receptor DNA-binding domain recognizes RNA hairpin structures with high affinity. Nucleic Acids Res 2019; 47:8180-8192. [PMID: 31147715 DOI: 10.1093/nar/gkz486] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Revised: 05/17/2019] [Accepted: 05/21/2019] [Indexed: 01/04/2023] Open
Abstract
The glucocorticoid receptor (GR) binds the noncoding RNA Gas5 via its DNA-binding domain (DBD) with functional implications in pro-apoptosis signaling. Here, we report a comprehensive in vitro binding study where we have determined that GR-DBD is a robust structure-specific RNA-binding domain. GR-DBD binds to a diverse range of RNA hairpin motifs, both synthetic and biologically derived, with apparent mid-nanomolar affinity while discriminating against uniform dsRNA. As opposed to dimeric recognition of dsDNA, GR-DBD binds to RNA as a monomer and confers high affinity primarily through electrostatic contacts. GR-DBD adopts a discrete RNA-bound state, as assessed by NMR, distinct from both free and DNA-bound. NMR and alanine mutagenesis suggest a heightened involvement of the C-terminal α-helix of the GR-DBD in RNA-binding. RNA competes for binding with dsDNA and occurs in a similar affinity range as dimer binding to the canonical DNA element. Given the prevalence of RNA hairpins within the transcriptome, our findings strongly suggest that many RNAs have potential to impact GR biology.
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Affiliation(s)
- Nicholas V Parsonnet
- Department of Biochemistry, University of Colorado at Boulder, Campus Box 596, Boulder, CO 80309-0596, USA
| | - Nickolaus C Lammer
- Department of Biochemistry, University of Colorado at Boulder, Campus Box 596, Boulder, CO 80309-0596, USA
| | - Zachariah E Holmes
- Department of Biochemistry, University of Colorado at Boulder, Campus Box 596, Boulder, CO 80309-0596, USA
| | - Robert T Batey
- Department of Biochemistry, University of Colorado at Boulder, Campus Box 596, Boulder, CO 80309-0596, USA
| | - Deborah S Wuttke
- Department of Biochemistry, University of Colorado at Boulder, Campus Box 596, Boulder, CO 80309-0596, USA
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13
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Wicks SL, Hargrove AE. Fluorescent indicator displacement assays to identify and characterize small molecule interactions with RNA. Methods 2019; 167:3-14. [PMID: 31051253 DOI: 10.1016/j.ymeth.2019.04.018] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2019] [Revised: 04/25/2019] [Accepted: 04/26/2019] [Indexed: 01/15/2023] Open
Abstract
Fluorescent indicator displacement (FID) assays are an advantageous approach to convert receptors into optical sensors that can detect binding of various ligands. In particular, the identification of ligands that bind to RNA receptors has become of increasing interest as the roles of RNA in cellular processes and disease pathogenesis continue to be discovered. Small molecules have been validated as tools to elucidate unknown RNA functions, underscoring the critical need to rapidly identify and quantitatively characterize RNA:small molecule interactions for the development of chemical probes. The successful application of FID assays to evaluate interactions between diverse RNA receptors and small molecules has been facilitated by the characterization of distinct fluorescent indicators that reversibly bind RNA and modulate the fluorescence signal. The utility of RNA-based FID assays to both academia and industry has been demonstrated through numerous uses in high-throughput screening efforts, structure-activity relationship studies, and in vitro target engagement studies. Furthermore, the development, optimization, and validation of a variety of RNA-based FID assays has led to general guidelines that can be utilized for facile implementation of the method with new or underexplored RNA receptors. Altogether, the use of RNA-based FID assays as a general analysis tool has provided valuable insights into small molecule affinity and selectivity, furthering the fundamental understanding of RNA:small molecule recognition. In this review, we will summarize efforts to employ FID assays using RNA receptors and describe the significant contributions of the method towards the development of chemical probes to reveal unknown RNA functions.
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Affiliation(s)
- Sarah L Wicks
- Duke University, Department of Chemistry, Durham, NC 27705, United States
| | - Amanda E Hargrove
- Duke University, Department of Chemistry, Durham, NC 27705, United States.
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Patwardhan NN, Cai Z, Newson CN, Hargrove AE. Fluorescent peptide displacement as a general assay for screening small molecule libraries against RNA. Org Biomol Chem 2019; 17:1778-1786. [PMID: 30468226 DOI: 10.1039/c8ob02467g] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
A prominent hurdle in developing small molecule probes against RNA is the relative scarcity of general screening methods. In this study, we demonstrate the application of a fluorescent peptide displacement assay to screen small molecule probes against four different RNA targets. The designed experimental protocol combined with statistical analysis provides a fast and convenient method to simultaneously evaluate small molecule libraries against different RNA targets and classify them based on affinity and selectivity patterns.
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Affiliation(s)
- Neeraj N Patwardhan
- Department of Chemistry, 124 Science Drive, Box 90346, Durham, NC 27708, USA.
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15
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Kurnaeva MA, Sheval EV, Musinova YR, Vassetzky YS. Tat basic domain: A "Swiss army knife" of HIV-1 Tat? Rev Med Virol 2019; 29:e2031. [PMID: 30609200 DOI: 10.1002/rmv.2031] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Revised: 12/05/2018] [Accepted: 12/06/2018] [Indexed: 01/16/2023]
Abstract
Tat (transactivator of transcription) regulates transcription from the HIV provirus. It plays a crucial role in disease progression, supporting efficient replication of the viral genome. Tat also modulates many functions in the host genome via its interaction with chromatin and proteins. Many of the functions of Tat are associated with its basic domain rich in arginine and lysine residues. It is still unknown why the basic domain exhibits so many diverse functions. However, the highly charged basic domain, coupled with the overall structural flexibility of Tat protein itself, makes the basic domain a key player in binding to or associating with cellular and viral components. In addition, the basic domain undergoes diverse posttranslational modifications, which further expand and modulate its functions. Here, we review the current knowledge of Tat basic domain and its versatile role in the interaction between the virus and the host cell.
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Affiliation(s)
- Margarita A Kurnaeva
- Faculty of Bioengineering and Bioinformatics, Lomonosov Moscow State University, Moscow, Russia
| | - Eugene V Sheval
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russia.,Faculty of Biology, Lomonosov Moscow State University, Moscow, Russia.,LIA 1066 LFR2O French-Russian Joint Cancer Research Laboratory, CNRS, Villejuif, France
| | - Yana R Musinova
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russia.,LIA 1066 LFR2O French-Russian Joint Cancer Research Laboratory, CNRS, Villejuif, France.,Koltzov Institute of Developmental Biology, Russian Academy of Sciences, Moscow, Russia
| | - Yegor S Vassetzky
- LIA 1066 LFR2O French-Russian Joint Cancer Research Laboratory, CNRS, Villejuif, France.,Koltzov Institute of Developmental Biology, Russian Academy of Sciences, Moscow, Russia.,Nuclear Organization and Pathologies, CNRS, UMR8126, Université Paris-Sud, Institut Gustave Roussy, Villejuif, France
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16
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Structural mechanism for HIV-1 TAR loop recognition by Tat and the super elongation complex. Proc Natl Acad Sci U S A 2018; 115:12973-12978. [PMID: 30514815 DOI: 10.1073/pnas.1806438115] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Promoter-proximal pausing by RNA polymerase II (Pol II) is a key regulatory step in human immunodeficiency virus-1 (HIV-1) transcription and thus in the reversal of HIV latency. By binding to the nascent transactivating response region (TAR) RNA, HIV-1 Tat recruits the human super elongation complex (SEC) to the promoter and releases paused Pol II. Structural studies of TAR interactions have been largely focused on interactions between the TAR bulge and the arginine-rich motif (ARM) of Tat. Here, the crystal structure of the TAR loop in complex with Tat and the SEC core was determined at a 3.5-Å resolution. The bound TAR loop is stabilized by cross-loop hydrogen bonds. It makes structure-specific contacts with the side chains of the Cyclin T1 Tat-TAR recognition motif (TRM) and the zinc-coordinating loop of Tat. The TAR loop phosphate backbone forms electrostatic and VDW interactions with positively charged side chains of the CycT1 TRM. Mutational analysis showed that these interactions contribute importantly to binding affinity. The Tat ARM was present in the crystallized construct; however, it was not visualized in the electron density, and the TAR bulge was not formed in the RNA construct used in crystallization. Binding assays showed that TAR bulge-Tat ARM interactions contribute less to TAR binding affinity than TAR loop interactions with the CycT1 TRM and Tat core. Thus, the TAR loop evolved to make high-affinity interactions with the TRM while Tat has three roles: scaffolding and stabilizing the TRM, making specific interactions through its zinc-coordinating loop, and making electrostatic interactions through its ARM.
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17
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Warner KD, Hajdin CE, Weeks KM. Principles for targeting RNA with drug-like small molecules. Nat Rev Drug Discov 2018; 17:547-558. [PMID: 29977051 PMCID: PMC6420209 DOI: 10.1038/nrd.2018.93] [Citation(s) in RCA: 402] [Impact Index Per Article: 67.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Recent studies have indicated the potential to develop small-molecule drugs that act on RNA targets, leading to burgeoning interest in the field. This article discusses general principles for discovering small-molecule drugs that target RNA and argues that the overarching challenge is to identify appropriate target structures in disease-causing RNAs that have high information content and, consequently, appropriate ligand-binding pockets. RNA molecules are essential for cellular information transfer and gene regulation, and RNAs have been implicated in many human diseases. Messenger and non-coding RNAs contain highly structured elements, and evidence suggests that many of these structures are important for function. Targeting these RNAs with small molecules offers opportunities to therapeutically modulate numerous cellular processes, including those linked to 'undruggable' protein targets. Despite this promise, there is currently only a single class of human-designed small molecules that target RNA used clinically — the linezolid antibiotics. However, a growing number of small-molecule RNA ligands are being identified, leading to burgeoning interest in the field. Here, we discuss principles for discovering small-molecule drugs that target RNA and argue that the overarching challenge is to identify appropriate target structures — namely, in disease-causing RNAs that have high information content and, consequently, appropriate ligand-binding pockets. If focus is placed on such druggable binding sites in RNA, extensive knowledge of the typical physicochemical properties of drug-like small molecules could then enable small-molecule drug discovery for RNA targets to become (only) roughly as difficult as for protein targets.
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Affiliation(s)
| | | | - Kevin M Weeks
- Department of Chemistry, University of North Carolina, Chapel Hill, NC, USA
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18
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Jolley EA, Hardebeck LKE, Ren Y, Adams MS, Lewis M, Znosko BM. The effects of varying the substituent and DNA sequence on the stability of 4-substituted DNA-naphthalimide complexes. Biophys Chem 2018; 239:29-37. [PMID: 29804029 DOI: 10.1016/j.bpc.2018.04.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Revised: 04/22/2018] [Accepted: 04/26/2018] [Indexed: 11/30/2022]
Abstract
DNA duplexes are stabilized by many interactions, one of which is stacking interactions between the nucleic acid bases. These interactions are useful for designing small molecules that bind to DNA. Naphthalimide intercalators have been shown to be valuable anti-cancer agents that stack between the DNA bases and exhibit stabilizing effects. There is a continued need to design intercalators that will exhibit these stabilizing effects while being more selective toward DNA binding. This work investigates 4-substituted naphthalimides with varying functional groups and their interactions with nucleic acid duplexes. Mode of binding was determined via wavelength scans, circular dichroism, and viscosity measurements. Optical melting experiments were used to measure the absorbance of the sample as a function of temperature. The Tm values derived from the DNA duplexes were subtracted from the Tm values derived from the DNA-intercalator complexes, resulting in ΔTm values. The ΔTm values demonstrated that the substituents on the intercalator affect the stability of the DNA-intercalator complex. From the results of this study and comparison to results from previous work, we conclude that the substituent type and position on the core intercalator molecule affect the stability of the complex it forms with DNA.
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Affiliation(s)
- Elizabeth A Jolley
- Department of Chemistry, Saint Louis University, 3501 Laclede Ave., St. Louis, MO 63103, United States
| | - Laura K E Hardebeck
- Department of Chemistry, Saint Louis University, 3501 Laclede Ave., St. Louis, MO 63103, United States
| | - Yi Ren
- Department of Chemistry, Saint Louis University, 3501 Laclede Ave., St. Louis, MO 63103, United States
| | - Miranda S Adams
- Department of Chemistry, Saint Louis University, 3501 Laclede Ave., St. Louis, MO 63103, United States
| | - Michael Lewis
- Department of Chemistry, Saint Louis University, 3501 Laclede Ave., St. Louis, MO 63103, United States
| | - Brent M Znosko
- Department of Chemistry, Saint Louis University, 3501 Laclede Ave., St. Louis, MO 63103, United States.
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19
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Tuma Sabah J, Zulkifli RM, Shahir S, Ahmed F, Abdul Kadir MR, Zakaria Z. In vitro selection and characterization of single stranded DNA aptamers for luteolin: A possible recognition tool. Anal Biochem 2018. [PMID: 29524380 DOI: 10.1016/j.ab.2018.03.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Distinctive bioactivities possessed by luteolin (3', 4', 5, 7-tetrahydroxy-flavone) are advantageous for sundry practical applications. This paper reports the in vitro selection and characterization of single stranded-DNA (ssDNA) aptamers, specific for luteolin (LUT). 76-mer library containing 1015 randomized ssDNA were screened via systematic evolution of ligands by exponential enrichment (SELEX). The recovered ssDNA pool from the 8th round was amplified with unlabeled primers and cloned into PSTBlue-1 vector prior to sequencing. 22 of LUT-binding aptamer variants were further classified into one of the seven groups based on their N40 random sequence regions, wherein one representative from each group was characterized. The dissociation constant of aptamers designated as LUT#28, LUT#20 and LUT#3 was discerned to be 107, 214 and 109 nM, respectively with high binding affinity towards LUT. Prediction analysis of the secondary structure suggested discrete features with typical loop and stem motifs. Furthermore, LUT#3 displayed higher specificity with insignificant binding toward kaempferol and quercetin despite its structural and functional similarity compared to LUT#28 and LUT#20. Further LUT#3 can detect free luteolin within 0.2-1 mM in solution. It was suggested that LUT#3 aptamer were the most suitable for LUT recognition tool at laboratory scale based on the condition tested.
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Affiliation(s)
- Jinan Tuma Sabah
- Faculty of Biosciences and Medical Engineering, Universiti Teknologi Malaysia, Malaysia
| | | | - Shafinaz Shahir
- Faculty of Biosciences and Medical Engineering, Universiti Teknologi Malaysia, Malaysia
| | - Farediah Ahmed
- Faculty of Biosciences and Medical Engineering, Universiti Teknologi Malaysia, Malaysia
| | | | - Zarita Zakaria
- Faculty of Biosciences and Medical Engineering, Universiti Teknologi Malaysia, Malaysia
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20
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Yang Y, Wang S. RNA Characterization by Solid-State NMR Spectroscopy. Chemistry 2018; 24:8698-8707. [DOI: 10.1002/chem.201705583] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2017] [Indexed: 02/05/2023]
Affiliation(s)
- Yufei Yang
- College of Chemistry and Molecular Engineering and Beijing NMR Center; Peking University; No.5 Yiheyuan Road, Haidian District Beijing 100871 P. R. China
| | - Shenlin Wang
- College of Chemistry and Molecular Engineering and Beijing NMR Center; Peking University; No.5 Yiheyuan Road, Haidian District Beijing 100871 P. R. China
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21
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Martinez-Zapien D, Legrand P, McEwen AG, Proux F, Cragnolini T, Pasquali S, Dock-Bregeon AC. The crystal structure of the 5΄ functional domain of the transcription riboregulator 7SK. Nucleic Acids Res 2017; 45:3568-3579. [PMID: 28082395 PMCID: PMC5389472 DOI: 10.1093/nar/gkw1351] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2016] [Accepted: 01/06/2017] [Indexed: 12/22/2022] Open
Abstract
In vertebrates, the 7SK RNA forms the scaffold of a complex, which regulates transcription pausing of RNA-polymerase II. By binding to the HEXIM protein, the complex comprising proteins LARP7 and MePCE captures the positive transcription elongation factor P-TEFb and prevents phosphorylation of pausing factors. The HEXIM-binding site embedded in the 5΄-hairpin of 7SK (HP1) encompasses a short signature sequence, a GAUC repeat framed by single-stranded uridines. The present crystal structure of HP1 shows a remarkably straight helical stack involving several unexpected triples formed at a central region. Surprisingly, two uridines of the signature sequence make triple interactions in the major groove of the (GAUC)2. The third uridine is turned outwards or inward, wedging between the other uridines, thus filling the major groove. A molecular dynamics simulation indicates that these two conformations of the signature sequence represent stable alternatives. Analyses of the interaction with the HEXIM protein confirm the importance of the triple interactions at the signature sequence. Altogether, the present structural analysis of 7SK HP1 highlights an original mechanism of swapping bases, which could represent a possible ‘7SK signature’ and provides new insight into the functional importance of the plasticity of RNA.
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Affiliation(s)
- Denise Martinez-Zapien
- Biotechnologie et signalisation cellulaire, CNRS UMR 7242, Ecole Supérieure de Biotechnologie de Strasbourg, F-67412 Illkirch, France
| | - Pierre Legrand
- Synchrotron SOLEIL, L'Orme des Merisiers, F-91190 Gif-sur-Yvette, France
| | - Alastair G McEwen
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France.,Centre National de la Recherche Scientifique, UMR7104, Illkirch, France.,Institut National de la Santé et de la Recherche Médicale, U964, Illkirch, France.,Université de Strasbourg, Illkirch, France
| | - Florence Proux
- Department of functional genomics, CNRS UMR 8197, Institut de Biologie de l΄Ecole Normale Supérieure F-75005 Paris, France.,Department of functional genomics, INSERM-U1024, Institut de Biologie de l΄Ecole Normale Supérieure F-75005 Paris, France
| | | | - Samuela Pasquali
- Laboratoire de Biochimie Théorique, IBPC, CNRS UPR 9080, Université Sorbonne Paris Cite, Paris Diderot, 75005 Paris, France
| | - Anne-Catherine Dock-Bregeon
- Department of functional genomics, CNRS UMR 8197, Institut de Biologie de l΄Ecole Normale Supérieure F-75005 Paris, France.,Department of functional genomics, INSERM-U1024, Institut de Biologie de l΄Ecole Normale Supérieure F-75005 Paris, France.,Sorbonne Universités UPMC, UMR 8227, Integrative Biology of Marine Models, Station Biologique de Roscoff, CS 90074, F-29688, Roscoff cedex, France.,CNRS, UMR 8227, Integrative Biology of Marine Models, Station Biologique de Roscoff, CS 90074, F-29688, Roscoff cedex, France
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22
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Kim JM, Choi HS, Seong BL. The folding competence of HIV-1 Tat mediated by interaction with TAR RNA. RNA Biol 2017; 14:926-937. [PMID: 28418268 DOI: 10.1080/15476286.2017.1311455] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
Abstract
The trans-activator Tat protein of HIV-1 belongs to the large family of intrinsically disordered proteins (IDPs), and is known to recruit various host proteins for the transactivation of viral RNA synthesis. Tat protein interacts with the transactivator response RNA (TAR RNA), exhibiting RNA chaperone activities for structural rearrangement of interacting RNAs. Here, considering that Tat-TAR RNA interaction is mutually cooperative, we examined the potential role of TAR RNA as Chaperna - RNA that provides chaperone function to proteins - for the folding of HIV-1 Tat. Using EGFP fusion as an indirect indicator for folding status, we monitored Tat-EGFP folding in HeLa cells via time-lapse fluorescence microscopy. The live cell imaging showed that the rate and the extent of folding of Tat-EGFP were stimulated by TAR RNA. The purified Tat-EGFP was denatured and the fluorescence was monitored in vitro under renaturation condition. The fluorescence was significantly increased by TAR RNA, and the mutations in TAR RNA that affected the interaction with Tat protein failed to promote Tat refolding. The results suggest that TAR RNA stabilizes Tat as unfolded, but prevents it from misfolding, and maintaining its folding competence for interaction with multiple host factors toward its transactivation. The Chaperna function of virally encoded RNA in establishing proteome link at the viral-host interface provides new insights to as yet largely unexplored RNA mediated protein folding in normal and dysregulated cellular metabolism.
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Affiliation(s)
- Jung Min Kim
- a Department of Biotechnology , College of Life Science and Biotechnology, Yonsei University , Seoul , South Korea.,b Vaccine Translational Research Center , Yonsei University , Seoul , South Korea
| | - Hee Sun Choi
- c Department of Pathology , Johns Hopkins University School of Medicine , Baltimore , MD , USA
| | - Baik Lin Seong
- a Department of Biotechnology , College of Life Science and Biotechnology, Yonsei University , Seoul , South Korea.,b Vaccine Translational Research Center , Yonsei University , Seoul , South Korea
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23
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Kamori D, Ueno T. HIV-1 Tat and Viral Latency: What We Can Learn from Naturally Occurring Sequence Variations. Front Microbiol 2017; 8:80. [PMID: 28194140 PMCID: PMC5276809 DOI: 10.3389/fmicb.2017.00080] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2016] [Accepted: 01/11/2017] [Indexed: 01/25/2023] Open
Abstract
Despite the effective use of antiretroviral therapy, the remainder of a latently HIV-1-infected reservoir mainly in the resting memory CD4+ T lymphocyte subset has provided a great setback toward viral eradication. While host transcriptional silencing machinery is thought to play a dominant role in HIV-1 latency, HIV-1 protein such as Tat, may affect both the establishment and the reversal of latency. Indeed, mutational studies have demonstrated that insufficient Tat transactivation activity can result in impaired transcription of viral genes and the establishment of latency in cell culture experiments. Because Tat protein is one of highly variable proteins within HIV-1 proteome, it is conceivable that naturally occurring Tat mutations may differentially modulate Tat functions, thereby influencing the establishment and/or the reversal of viral latency in vivo. In this mini review, we summarize the recent findings of Tat naturally occurring polymorphisms associating with host immune responses and we highlight the implication of Tat sequence variations in relation to HIV latency.
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Affiliation(s)
- Doreen Kamori
- Center for AIDS Research, Kumamoto University Kumamoto, Japan
| | - Takamasa Ueno
- Center for AIDS Research, Kumamoto UniversityKumamoto, Japan; International Research Center for Medical Sciences, Kumamoto UniversityKumamoto, Japan
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24
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Pandey S, Agarwala P, Maiti S. Targeting RNA G-Quadruplexes for Potential Therapeutic Applications. TOPICS IN MEDICINAL CHEMISTRY 2017. [DOI: 10.1007/7355_2016_22] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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25
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Bourbigot S, Dock-Bregeon AC, Eberling P, Coutant J, Kieffer B, Lebars I. Solution structure of the 5'-terminal hairpin of the 7SK small nuclear RNA. RNA (NEW YORK, N.Y.) 2016; 22:1844-1858. [PMID: 27852926 PMCID: PMC5113205 DOI: 10.1261/rna.056523.116] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2016] [Accepted: 09/10/2016] [Indexed: 05/10/2023]
Abstract
The small nuclear 7SK RNA regulates RNA polymerase II (RNA Pol II) transcription, by sequestering and inhibiting the positive transcription elongation factor b (P-TEFb). P-TEFb is stored in the 7SK ribonucleoprotein (RNP) that contains the three nuclear proteins Hexim1, LaRP7, and MePCE. P-TEFb interacts with the protein Hexim1 and the 7SK RNA. Once P-TEFb is released from the 7SK RNP, it activates transcription by phosphorylating the C-terminal domain of RNA Pol II. P-TEFb also plays a crucial role in the replication of the human immunodeficiency virus HIV-1, through its recruitment by the viral transactivator Tat. Previous work demonstrated that the protein Tat promotes the release of P-TEFb from the 7SK RNP through direct binding to the 7SK RNA. Hexim1 and Tat proteins both comprise conserved and similar arginine-rich motifs that were identified to bind the 7SK RNA at a repeated GAUC site located at the top of the 5'-terminal hairpin (HPI). Here, we report the solution structure of this region as determined by nuclear magnetic resonance, to identify HPI structural features recognized by Hexim1 and Tat. The HPI solution structure displays an elongated shape featuring four helical segments interrupted by one internal loop and three bulges with distinct folds. In particular, the repeated GAUC motif adopts a pre-organized geometry. Our results suggest that the binding of Hexim1 and Tat to the 7SK RNA could originate from a conformational selection of this motif, highlighting how RNA local structure could lead to an adaptive recognition of their partners.
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Affiliation(s)
- Sarah Bourbigot
- Department of Integrated Structural Biology, Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), CNRS UMR 7104, INSERM U964, Université de Strasbourg, 67404 Illkirch Cedex, France
| | - Anne-Catherine Dock-Bregeon
- Department of Functional Genomics, Institut de Biologie de l'Ecole Normale Supérieure (IBENS), CNRS UMR 8197, INSERM U1024, 75005 Paris, France
| | - Pascal Eberling
- Department of Integrated Structural Biology, Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), CNRS UMR 7104, INSERM U964, Université de Strasbourg, 67404 Illkirch Cedex, France
| | - Jérôme Coutant
- Bruker BioSpin SAS, BP 10002, 67166 Wissembourg Cedex, France
| | - Bruno Kieffer
- Department of Integrated Structural Biology, Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), CNRS UMR 7104, INSERM U964, Université de Strasbourg, 67404 Illkirch Cedex, France
| | - Isabelle Lebars
- Department of Integrated Structural Biology, Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), CNRS UMR 7104, INSERM U964, Université de Strasbourg, 67404 Illkirch Cedex, France
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26
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Schulze-Gahmen U, Echeverria I, Stjepanovic G, Bai Y, Lu H, Schneidman-Duhovny D, Doudna JA, Zhou Q, Sali A, Hurley JH. Insights into HIV-1 proviral transcription from integrative structure and dynamics of the Tat:AFF4:P-TEFb:TAR complex. eLife 2016; 5. [PMID: 27731797 PMCID: PMC5072841 DOI: 10.7554/elife.15910] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2016] [Accepted: 10/07/2016] [Indexed: 01/04/2023] Open
Abstract
HIV-1 Tat hijacks the human superelongation complex (SEC) to promote proviral transcription. Here we report the 5.9 Å structure of HIV-1 TAR in complex with HIV-1 Tat and human AFF4, CDK9, and CycT1. The TAR central loop contacts the CycT1 Tat-TAR recognition motif (TRM) and the second Tat Zn2+-binding loop. Hydrogen-deuterium exchange (HDX) shows that AFF4 helix 2 is stabilized in the TAR complex despite not touching the RNA, explaining how it enhances TAR binding to the SEC 50-fold. RNA SHAPE and SAXS data were used to help model the extended (Tat Arginine-Rich Motif) ARM, which enters the TAR major groove between the bulge and the central loop. The structure and functional assays collectively support an integrative structure and a bipartite binding model, wherein the TAR central loop engages the CycT1 TRM and compact core of Tat, while the TAR major groove interacts with the extended Tat ARM. DOI:http://dx.doi.org/10.7554/eLife.15910.001
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Affiliation(s)
- Ursula Schulze-Gahmen
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States.,California Institute of Quantitative Biosciences, University of California, Berkeley, Berkeley, United States
| | - Ignacia Echeverria
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, San Francisco, United States.,Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, United States.,California Institute of Quantitative Biosciences, University of California San, Francisco, San Francisco, United States
| | - Goran Stjepanovic
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States.,California Institute of Quantitative Biosciences, University of California, Berkeley, Berkeley, United States.,Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, United States
| | - Yun Bai
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States.,California Institute of Quantitative Biosciences, University of California, Berkeley, Berkeley, United States
| | - Huasong Lu
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States.,California Institute of Quantitative Biosciences, University of California, Berkeley, Berkeley, United States
| | - Dina Schneidman-Duhovny
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, San Francisco, United States.,Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, United States.,California Institute of Quantitative Biosciences, University of California San, Francisco, San Francisco, United States
| | - Jennifer A Doudna
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States.,California Institute of Quantitative Biosciences, University of California, Berkeley, Berkeley, United States.,Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, United States.,Howard Hughes Medical Institute, University of California, Berkeley, Berkeley, United States.,Department of Chemistry, University of California, Berkeley, Berkeley, United States
| | - Qiang Zhou
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States.,California Institute of Quantitative Biosciences, University of California, Berkeley, Berkeley, United States
| | - Andrej Sali
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, San Francisco, United States.,Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, United States.,California Institute of Quantitative Biosciences, University of California San, Francisco, San Francisco, United States
| | - James H Hurley
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States.,California Institute of Quantitative Biosciences, University of California, Berkeley, Berkeley, United States.,Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, United States
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27
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Musinova YR, Sheval EV, Dib C, Germini D, Vassetzky YS. Functional roles of HIV-1 Tat protein in the nucleus. Cell Mol Life Sci 2016; 73:589-601. [PMID: 26507246 PMCID: PMC11108392 DOI: 10.1007/s00018-015-2077-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2015] [Revised: 09/01/2015] [Accepted: 10/16/2015] [Indexed: 02/06/2023]
Abstract
Human immunodeficiency virus-1 (HIV-1) Tat protein is one of the most important regulatory proteins for viral gene expression in the host cell and can modulate different cellular processes. In addition, Tat is secreted by the infected cell and can be internalized by neighboring cells; therefore, it affects both infected and uninfected cells. Tat can modulate cellular processes by interacting with different cellular structures and signaling pathways. In the nucleus, Tat might be localized either in the nucleoplasm or the nucleolus depending on its concentration. Here we review the distinct functions of Tat in the nucleoplasm and the nucleolus in connection with viral infection and HIV-induced oncogenesis.
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Affiliation(s)
- Yana R Musinova
- A.N. Belozersky Institute of Physico-Chemical Biology, M.V. Lomonosov Moscow State University, 119991, Moscow, Russia
- LIA 1066 French-Russian Joint Cancer Research Laboratory, 94805, Villejuif, France
| | - Eugene V Sheval
- A.N. Belozersky Institute of Physico-Chemical Biology, M.V. Lomonosov Moscow State University, 119991, Moscow, Russia
- LIA 1066 French-Russian Joint Cancer Research Laboratory, 94805, Villejuif, France
| | - Carla Dib
- LIA 1066 French-Russian Joint Cancer Research Laboratory, 94805, Villejuif, France
- UMR8126, Université Paris-Sud, CNRS, Institut de cancérologie Gustave Roussy, 94805, Villejuif, France
| | - Diego Germini
- LIA 1066 French-Russian Joint Cancer Research Laboratory, 94805, Villejuif, France
- UMR8126, Université Paris-Sud, CNRS, Institut de cancérologie Gustave Roussy, 94805, Villejuif, France
| | - Yegor S Vassetzky
- A.N. Belozersky Institute of Physico-Chemical Biology, M.V. Lomonosov Moscow State University, 119991, Moscow, Russia.
- LIA 1066 French-Russian Joint Cancer Research Laboratory, 94805, Villejuif, France.
- UMR8126, Université Paris-Sud, CNRS, Institut de cancérologie Gustave Roussy, 94805, Villejuif, France.
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28
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Abstract
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Influenza A is an RNA virus with
a genome of eight negative sense
segments. Segment 7 mRNA contains a 3′ splice site for alternative
splicing to encode the essential M2 protein. On the basis of sequence
alignment and chemical mapping experiments, the secondary structure
surrounding the 3′ splice site has an internal loop, adenine
bulge, and hairpin loop when it is in the hairpin conformation that
exposes the 3′ splice site. We report structural features of
a three-dimensional model of the hairpin derived from nuclear magnetic
resonance spectra and simulated annealing with restrained molecular
dynamics. Additional insight was provided by modeling based on 1H chemical shifts. The internal loop containing the 3′
splice site has a dynamic guanosine and a stable imino (cis Watson–Crick/Watson–Crick) GA pair. The adenine bulge
also appears to be dynamic with the A either stacked in the stem or
forming a base triple with a Watson–Crick GC pair. The hairpin
loop is a GAAA tetraloop closed by an AC pair.
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Affiliation(s)
- Jonathan L Chen
- †Department of Chemistry, University of Rochester, Rochester, New York 14627, United States
| | - Scott D Kennedy
- ‡Department of Biochemistry and Biophysics, University of Rochester School of Medicine and Dentistry, Rochester, New York 14642, United States
| | - Douglas H Turner
- †Department of Chemistry, University of Rochester, Rochester, New York 14627, United States.,§Center for RNA Biology, University of Rochester, Rochester, New York 14627, United States
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29
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Fragment based search for small molecule inhibitors of HIV-1 Tat-TAR. Bioorg Med Chem Lett 2014; 24:5576-5580. [DOI: 10.1016/j.bmcl.2014.11.004] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2014] [Revised: 10/28/2014] [Accepted: 11/01/2014] [Indexed: 01/06/2023]
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30
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Schulze-Gahmen U, Lu H, Zhou Q, Alber T. AFF4 binding to Tat-P-TEFb indirectly stimulates TAR recognition of super elongation complexes at the HIV promoter. eLife 2014; 3:e02375. [PMID: 24843025 PMCID: PMC4013717 DOI: 10.7554/elife.02375] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Superelongation complexes (SECs) are essential for transcription elongation of many human genes, including the integrated HIV-1 genome. At the HIV-1 promoter, the viral Tat protein binds simultaneously to the nascent TAR RNA and the CycT1 subunit of the P-TEFb kinase in a SEC. To understand the preferential recruitment of SECs by Tat and TAR, we determined the crystal structure of a quaternary complex containing Tat, P-TEFb, and the SEC scaffold, AFF4. Tat and AFF4 fold on the surface of CycT1 and interact directly. Interface mutations in the AFF4 homolog AFF1 reduced Tat–AFF1 affinity in vivo and Tat-dependent transcription from the HIV promoter. AFF4 binding in the presence of Tat partially orders the CycT1 Tat–TAR recognition motif and increases the affinity of Tat-P-TEFb for TAR 30-fold. These studies indicate that AFF4 acts as a two-step filter to increase the selectivity of Tat and TAR for SECs over P-TEFb alone. DOI:http://dx.doi.org/10.7554/eLife.02375.001 The rate at which many genes are expressed as proteins depends on a process called transcriptional elongation. This process takes place as the region of DNA that defines the gene is transcribed into an RNA molecule, and it is catalyzed by an enzyme called RNA polymerase II. However, this process often stalls shortly after it starts, and another enzyme called a positive transcription elongation factor is needed to restart it. The human immunodeficiency virus (HIV) is a retrovirus that hijacks the gene expression machinery inside immune cells in order to replicate itself. To do this as efficiently as possible, the elongation factor needs to restart the transcription process as quickly as possible. To ensure that this happens the virus produces a protein called Tat that binds to the short region of RNA that has already been made. At the same time the Tat protein also combines with other proteins to form a multi-protein machine called the super elongation complex. Other proteins in the super elongation complex include a ‘scaffold’ protein called AFF4, a positive elongation factor called P-TEFb, and at least two additional transcription factors. Until recently researchers did not know how the Tat protein was able to recruit super elongation complexes to the correct location without recruiting other complexes that contained similar protein subunits. Now Schulze-Gahmen et al. have shed new light on this mystery by working out the crystal structure of the complex formed by the elongation factor P-TEFb when it forms a complex with the Tat protein and a scaffold protein called AFF4. The results show that direct interactions between the Tat and scaffold proteins help to recruit the super elongation complex to the correct location. The three-way interactions between Tat, AFF4, and P-TEFb form a binding surface that encourages the complex to bind to the RNA. Overall, Schulze-Gahmen et al. show that the super elongation complex is much more likely to be recognized by the Tat protein and then bind to RNA than just the elongation factor on its own. DOI:http://dx.doi.org/10.7554/eLife.02375.002
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Affiliation(s)
- Ursula Schulze-Gahmen
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States
| | - Huasong Lu
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States
| | - Qiang Zhou
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States
| | - Tom Alber
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States California Institute for Quantitative Biosciences, QB3, University of California, Berkeley, Berkeley, United States
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31
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Rijal K, Bao X, Chow CS. Amino acid-linked platinum(II) analogues have altered specificity for RNA compared to cisplatin. Chem Commun (Camb) 2014; 50:3918-20. [PMID: 24413091 DOI: 10.1039/c3cc49035a] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Cisplatin can be modified with various ligands to alter the size and charge distribution of the complex. Several amino acid-linked platinum(II) complexes were synthesized, and a reactivity study with 16S ribosomal RNA was carried out. The amino acid-linked analogues show altered specificity compared to the parental compound cisplatin.
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Affiliation(s)
- Keshab Rijal
- Department of Chemistry, Wayne State University, 5101 Cass Ave., Detroit, MI 48202, USA.
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32
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Ding Y, Tang Y, Kwok CK, Zhang Y, Bevilacqua PC, Assmann SM. In vivo genome-wide profiling of RNA secondary structure reveals novel regulatory features. Nature 2013; 505:696-700. [DOI: 10.1038/nature12756] [Citation(s) in RCA: 587] [Impact Index Per Article: 53.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2013] [Accepted: 10/09/2013] [Indexed: 12/18/2022]
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33
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Kumar S, Maiti S. The effect of N-acetylation and N-methylation of lysine residue of Tat peptide on its interaction with HIV-1 TAR RNA. PLoS One 2013; 8:e77595. [PMID: 24147034 PMCID: PMC3798303 DOI: 10.1371/journal.pone.0077595] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2013] [Accepted: 09/06/2013] [Indexed: 12/25/2022] Open
Abstract
Post-translational modification (PTM) of RNA binding proteins (RBPs) play a very important role in determining their binding to cognate RNAs and therefore regulate the downstream effects. Lysine can undergo various PTMs and thereby contribute to the regulation of different cellular processes. It can be reversibly acetylated and methylated using a pool of respective enzymes, to act as a switch for controlling the binding efficiency of RBPs. Here we have delineated the thermodynamic and kinetic effects of N-acetylation and N-monomethylation of lysine on interaction between HIV-1 TAR RNA and its cognate binder Tat peptide ( a model system). Our results indicate that acetylation of lysine 50 (K50), leads to eight- fold reduction in binding affinity, originating exclusively from entropy changes whereas, lysine 51 (K51) acetylation resulted only in three fold decrease with large enthalpy-entropy compensation. The measurement of kinetic parameters indicated major change (4.5 fold) in dissociation rate in case of K50 acetylation however, K51 acetylation showed similar effect on both association and dissociation rates. In contrast, lysine methylation did not affect the binding affinity of Tat peptide to TAR RNA at K50, nonetheless three fold enhancement in binding affinity was observed at K51 position. In spite of large enthalpy-entropy compensation, lysine methylation seems to have more pronounced position specific effect on the kinetic parameters. In case of K50 methylation, simultaneous increase was observed in the rate of association and dissociation leaving binding affinity unaffected. The increased binding affinity for methylated Tat at K51 stems from faster association rate with slightly slower dissociation rate.
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Affiliation(s)
- Santosh Kumar
- Proteomics and Structural Biology Unit, CSIR-Institute of Genomics and Integrative Biology, CSIR, Delhi, India
| | - Souvik Maiti
- Proteomics and Structural Biology Unit, CSIR-Institute of Genomics and Integrative Biology, CSIR, Delhi, India
- CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, CSIR, Pune, India
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34
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Muse O, Zengeya T, Mwaura J, Hnedzko D, McGee DW, Grewer CT, Rozners E. Sequence selective recognition of double-stranded RNA at physiologically relevant conditions using PNA-peptide conjugates. ACS Chem Biol 2013; 8:1683-6. [PMID: 23721369 DOI: 10.1021/cb400144x] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Conjugation of short peptide nucleic acids (PNA) with tetralysine peptides strongly enhanced triple helical binding to RNA at physiologically relevant conditions. The PNA hexamers and heptamers carrying cationic nucleobase and tetralysine modifications displayed high binding affinity for complementary double-stranded RNA without compromising sequence selectivity. The PNA-peptide conjugates had unique preference for binding double-stranded RNA, while having little, if any, affinity for double-stranded DNA. The cationic PNAs were efficiently taken up by HEK293 cells, whereas little uptake was observed for unmodified PNA.
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Affiliation(s)
- Oluwatoyosi Muse
- Departments of †Chemistry and ‡Biological Sciences, Binghamton University, The State University
of New York, Binghamton, New York 13902, United
States
| | - Thomas Zengeya
- Departments of †Chemistry and ‡Biological Sciences, Binghamton University, The State University
of New York, Binghamton, New York 13902, United
States
| | - Juddy Mwaura
- Departments of †Chemistry and ‡Biological Sciences, Binghamton University, The State University
of New York, Binghamton, New York 13902, United
States
| | - Dziyana Hnedzko
- Departments of †Chemistry and ‡Biological Sciences, Binghamton University, The State University
of New York, Binghamton, New York 13902, United
States
| | - Dennis W. McGee
- Departments of †Chemistry and ‡Biological Sciences, Binghamton University, The State University
of New York, Binghamton, New York 13902, United
States
| | - Christof T. Grewer
- Departments of †Chemistry and ‡Biological Sciences, Binghamton University, The State University
of New York, Binghamton, New York 13902, United
States
| | - Eriks Rozners
- Departments of †Chemistry and ‡Biological Sciences, Binghamton University, The State University
of New York, Binghamton, New York 13902, United
States
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35
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Quy VC, Pantano S, Rossetti G, Giacca M, Carloni P. HIV-1 Tat Binding to PCAF Bromodomain: Structural Determinants from Computational Methods. BIOLOGY 2012; 1:277-96. [PMID: 24832227 PMCID: PMC4009784 DOI: 10.3390/biology1020277] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/08/2012] [Revised: 07/09/2012] [Accepted: 07/26/2012] [Indexed: 12/13/2022]
Abstract
The binding between the HIV-1 trans-activator of transcription (Tat) and p300/(CREB-binding protein)-associated factor (PCAF) bromodomain is a crucial step in the HIV-1 life cycle. However, the structure of the full length acetylated Tat bound to PCAF has not been yet determined experimentally. Acetylation of Tat residues can play a critical role in enhancing HIV-1 transcriptional activation. Here, we have combined a fully flexible protein-protein docking approach with molecular dynamics simulations to predict the structural determinants of the complex for the common HIV-1BRU variant. This model reproduces all the crucial contacts between the Tat peptide 46SYGR(AcK)KRRQRC56 and the PCAF bromodomain previously reported by NMR spectroscopy. Additionally, inclusion of the entire Tat protein results in additional contact points at the protein-protein interface. The model is consistent with the available experimental data reported and adds novel information to our previous structural predictions of the PCAF bromodomain in complex with the rare HIVZ2 variant, which was obtained with a less accurate computational method. This improved characterization of Tat.PCAF bromodomain binding may help in defining the structural determinants of other protein interactions involving lysine acetylation.
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Affiliation(s)
- Vo Cam Quy
- Computational Biophysics, German Research School for Simulation Sciences, Computational Biomedicine, Institute for Advanced Simulation (IAS-5), Forschungszentrum Jülich, Jülich D-52425, Germany.
| | - Sergio Pantano
- Institut Pasteur de Montevideo, Mataojo 2020, Montevideo CP 11400, Uruguay.
| | - Giulia Rossetti
- Computational Biophysics, German Research School for Simulation Sciences, Computational Biomedicine, Institute for Advanced Simulation (IAS-5), Forschungszentrum Jülich, Jülich D-52425, Germany.
| | - Mauro Giacca
- International Centre for Genetic Engineering and Biotechnology, Trieste 34149, Italy.
| | - Paolo Carloni
- Computational Biophysics, German Research School for Simulation Sciences, Computational Biomedicine, Institute for Advanced Simulation (IAS-5), Forschungszentrum Jülich, Jülich D-52425, Germany.
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36
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Impact of Tat Genetic Variation on HIV-1 Disease. Adv Virol 2012; 2012:123605. [PMID: 22899925 PMCID: PMC3414192 DOI: 10.1155/2012/123605] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2012] [Accepted: 05/14/2012] [Indexed: 01/08/2023] Open
Abstract
The human immunodeficiency virus type 1 (HIV-1) promoter or long-terminal repeat (LTR) regulates viral gene expression by interacting with multiple viral and host factors. The viral transactivator protein Tat plays an important role in transcriptional activation of HIV-1 gene expression. Functional domains of Tat and its interaction with transactivation response element RNA and cellular transcription factors have been examined. Genetic variation within tat of different HIV-1 subtypes has been shown to affect the interaction of the viral transactivator with cellular and/or viral proteins, influencing the overall level of transcriptional activation as well as its action as a neurotoxic protein. Consequently, the genetic variability within tat may impact the molecular architecture of functional domains of the Tat protein that may impact HIV pathogenesis and disease. Tat as a therapeutic target for anti-HIV drugs has also been discussed.
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37
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Jalalirad M, Saadatmand J, Laughrea M. Dominant role of the 5' TAR bulge in dimerization of HIV-1 genomic RNA, but no evidence of TAR-TAR kissing during in vivo virus assembly. Biochemistry 2012; 51:3744-58. [PMID: 22482513 DOI: 10.1021/bi300111p] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The 5' untranslated region of HIV-1 genomic RNA (gRNA) contains two stem-loop structures that appear to be equally important for gRNA dimerization: the 57-nucleotide 5' TAR, at the very 5' end, and the 35-nucleotide SL1 (nucleotides 243-277). SL1 is well-known for containing the dimerization initiation site (DIS) in its apical loop. The DIS is a six-nucleotide palindrome. Here, we investigated the mechanism of TAR-directed gRNA dimerization. We found that the trinucleotide bulge (UCU24) of the 5' TAR has dominant impacts on both formation of HIV-1 RNA dimers and maturation of the formed dimers. The ΔUCU trinucleotide deletion strongly inhibited the first process and blocked the other, thus impairing gRNA dimerization as severely as deletion of the entire 5' TAR, and more severely than deletion of the DIS, inactivation of the viral protease, or most severe mutations in the nucleocapsid protein. The apical loop of TAR contains a 10-nucleotide palindrome that has been postulated to stimulate gRNA dimerization by a TAR-TAR kissing mechanism analogous to the one used by SL1 to stimulate dimerization. Using mutations that strongly destabilize formation of the TAR palindrome duplex, as well as compensatory mutations that restore duplex formation to a wild-type-like level, we found no evidence of TAR-TAR kissing, even though mutations nullifying the kissing potential of the TAR palindrome could impair dimerization by a mechanism other than hindering of SL1. However, nullifying the kissing potential of TAR had much less severe effects than ΔUCU. By not uncovering a dimerization mechanism intrinsic to TAR, our data suggest that TAR mutations exert their effect 3' of TAR, yet not on SL1, because TAR and SL1 mutations have synergistic effects on gRNA dimerization.
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Affiliation(s)
- Mohammad Jalalirad
- McGill AIDS Center, Lady Davis Institute for Medical Research, Jewish General Hospital, Montreal, QC, Canada
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38
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Bullwinkle TJ, Samorodnitsky D, Rosati RC, Koudelka GB. Determinants of bacteriophage 933W repressor DNA binding specificity. PLoS One 2012; 7:e34563. [PMID: 22509323 PMCID: PMC3317979 DOI: 10.1371/journal.pone.0034563] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2011] [Accepted: 03/06/2012] [Indexed: 11/22/2022] Open
Abstract
We reported previously that 933W repressor apparently does not cooperatively bind to adjacent sites on DNA and that the relative affinities of 933W repressor for its operators differ significantly from that of any other lambdoid bacteriophage. These findings indicate that the operational details of the lysis-lysogeny switch of bacteriophage 933W are unique among lambdoid bacteriophages. Since the functioning of the lysis-lysogeny switch in 933W bacteriophage uniquely and solely depends on the order of preference of 933W repressor for its operators, we examined the details of how 933W repressor recognizes its DNA sites. To identify the specificity determinants, we first created a molecular model of the 933W repressor-DNA complex and tested the predicted protein-DNA interactions. These results of these studies provide a picture of how 933W repressor recognizes its DNA sites. We also show that, opposite of what is normally observed for lambdoid phages, 933W operator sequences have evolved in such a way that the presence of the most commonly found base sequences at particular operator positions serves to decrease, rather than increase, the affinity of the protein for the site. This finding cautions against assuming that a consensus sequence derived from sequence analysis defines the optimal, highest affinity DNA binding site for a protein.
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Affiliation(s)
- Tammy J. Bullwinkle
- Department of Biological Sciences, University at Buffalo, Buffalo, New York, United States of America
| | - Daniel Samorodnitsky
- Department of Biological Sciences, University at Buffalo, Buffalo, New York, United States of America
| | - Rayna C. Rosati
- Department of Biological Sciences, University at Buffalo, Buffalo, New York, United States of America
| | - Gerald B. Koudelka
- Department of Biological Sciences, University at Buffalo, Buffalo, New York, United States of America
- * E-mail:
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39
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Huang W, Varani G, Drobny GP. Interactions of protein side chains with RNA defined with REDOR solid state NMR. JOURNAL OF BIOMOLECULAR NMR 2011; 51:347-356. [PMID: 21947838 DOI: 10.1007/s10858-011-9573-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2011] [Accepted: 08/11/2011] [Indexed: 05/31/2023]
Abstract
Formation of the complex between human immunodeficiency virus type-1 Tat protein and the transactivation response region (TAR) RNA is vital for transcriptional elongation, yet the structure of the Tat-TAR complex remains to be established. The NMR structures of free TAR, and TAR bound to Tat-derived peptides have been obtained by solution NMR, but only a small number of intermolecular NOEs could be identified unambiguously, preventing the determination of a complete structure. Here we show that a combination of multiple solid state NMR REDOR experiments can be used to obtain multiple distance constraints from (15)N to (13)C spins within the backbone and side chain guanidinium groups of arginine in a Tat-derived peptide, using (19)F spins incorporated into the base of U23 in TAR and (31)P spins in the P22 and P23 phosphate groups. Distances between the side chain of Arg52 and the base and phosphodiester backbone near U23 measured by REDOR NMR are comparable to distances observed in solution NMR-derived structural models, indicating that interactions of TAR RNA with key amino acid side chains in Tat are the same in the amorphous solid state as in solution. This method is generally applicable to other protein-RNA complexes where crystallization or solution NMR has failed to provide high resolution structural information.
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Affiliation(s)
- Wei Huang
- Department of Chemistry, University of Washington, Box 351700, Seattle, Washington, DC 98195, USA
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40
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Lu J, Kadakkuzha BM, Zhao L, Fan M, Qi X, Xia T. Dynamic ensemble view of the conformational landscape of HIV-1 TAR RNA and allosteric recognition. Biochemistry 2011; 50:5042-57. [PMID: 21553929 DOI: 10.1021/bi200495d] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
RNA conformational dynamics and the resulting structural heterogeneity play an important role in RNA functions, e.g., recognition. Recognition of HIV-1 TAR RNA has been proposed to occur via a conformational capture mechanism. Here, using ultrafast time-resolved fluorescence spectroscopy, we have probed the complexity of the conformational landscape of HIV-1 TAR RNA and monitored the position-dependent changes in the landscape upon binding of a Tat protein-derived peptide and neomycin B. In the ligand-free state, the TAR RNA samples multiple families of conformations with various degrees of base stacking around the three-nucleotide bulge region. Some subpopulations partially resemble those ligand-bound states, but the coaxially stacked state is below the detection limit. When Tat or neomycin B binds, the bulge region as an ensemble undergoes a conformational transition in a position-dependent manner. Tat and neomycin B induce mutually exclusive changes in the TAR RNA underlying the mechanism of allosteric inhibition at an ensemble level with residue-specific details. Time-resolved anisotropy decay measurements revealed picosecond motions of bases in both ligand-free and ligand-bound states. Mutation of a base pair at the bulge--stem junction has differential effects on the conformational distributions of the bulge bases. A dynamic model of the ensemble view of the conformational landscape for HIV-1 TAR RNA is proposed, and the implication of the general mechanism of RNA recognition and its impact on RNA-based therapeutics are discussed.
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Affiliation(s)
- Jia Lu
- Department of Molecular and Cell Biology, The University of Texas at Dallas, Richardson, Texas 75080, United States
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41
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Jeong JG, Kim DS, Kim YS, Kwon MH. A Tat-grafted anti-nucleic acid antibody acquires nuclear-localization property and a preference for TAR RNA. Biochem Biophys Res Commun 2011; 406:403-7. [PMID: 21329654 DOI: 10.1016/j.bbrc.2011.02.054] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2011] [Accepted: 02/11/2011] [Indexed: 11/24/2022]
Abstract
The 3D8 single chain variable fragment (3D8 scFv) is an anti-nucleic acid antibody that can hydrolyze nucleic acids and enter the cytosol of cells without reaching the nucleus. The Tat peptide, derived from the basic region of the HIV-1 Tat protein, translocates to cell nuclei and has TAR RNA binding activity. In this study, we generated a Tat-grafted antibody ((H₃)Tat-3D8) by replacing complementarity-determining region 3 (CDR3) within the VH domain of the 3D8 scFv with a Tat₄₈₋₆₀ peptide (GRKKRRQRRRPPQ). (H₃)Tat-3D8 retained the DNA-binding and DNA-hydrolyzing activity of the scFv, and translocated to the nuclei of HeLa cells and preferentially recognized TAR RNA. Thus, the properties associated with the Tat peptide were transferred to the antibody via Tat-grafting without loss of the intrinsic DNA-binding and hydrolyzing activities of the 3D8 scFv antibody.
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Affiliation(s)
- Jong-Geun Jeong
- Department of Microbiology, Ajou University School of Medicine, Suwon 443-749, South Korea
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42
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Cardarelli F, Serresi M, Albanese A, Bizzarri R, Beltram F. Quantitative analysis of Tat peptide binding to import carriers reveals unconventional nuclear transport properties. J Biol Chem 2011; 286:12292-9. [PMID: 21321119 DOI: 10.1074/jbc.m110.203083] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
A detailed study of nuclear import mediated by the HIV-1 Tat peptide (47YGRKKRRQRRR57, TatRRR) is reported. Fluorescence-based measurements, calibration of protein concentrations, and binding assays are exploited to address the physicochemical mechanisms of Tat peptide recognition by the classical importin α (Impα) and importin β (Impβ) receptors both in vitro and in intact cells. We show that TatRRR is an unconventional nuclear localization sequence that binds directly to both Impα and Impβ carriers in the absence of competitors (in vitro), whereas this property is silenced in the actual cellular environment. In the latter case, Impα/β-dependent nuclear import can be successfully restored by replacing the "RRR" stretch with "GGG". We apply a recently developed method to determine quantitatively TatGGG affinity for each receptor. Based on these results, we can rationalize previous controversial reports on the Tat peptide and provide coherent guidelines for the design of novel intracellular targeting sequences.
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Affiliation(s)
- Francesco Cardarelli
- Center for Nanotechnology Innovation @NEST, Istituto Italiano di TecnologiaConsiglio Nazionale delle Ricerche, Scuola Normale Superiore, Pisa, Italy.
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43
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Ryazanova AY, Kubareva EA, Grman I, Lavrova NV, Ryazanova EM, Oretskaya TS, Hianik T. The study of the interaction of (cytosine-5)-DNA methyltransferase SsoII with DNA by acoustic method. Analyst 2011; 136:1227-33. [PMID: 21274469 DOI: 10.1039/c0an00545b] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The interaction of (cytosine-5)-DNA methyltransferase SsoII (M.SsoII) with double-stranded DNA was studied by means of thickness shear mode acoustic method (TSM) and gel electrophoresis. M.SsoII recognizes in double-stranded DNA the methylation site 5'-CCNGG-3' (N=A, C, G, T) and methylates the inner cytosine residue. M.SsoII also acts as a transcription factor via binding to the regulatory site 5'-AGGACAAATTGTCCT-3' in the promoter region of SsoII restriction-modification system. We designed three 60-mer biotinylated DNA duplexes: with the methylation site (60met), with the regulatory site (60reg), and without a specific binding site (60oct). A strong binding of M.SsoII with each one of the studied DNA immobilized on the TSM transducer has been shown. The equilibrium dissociation constants, K(D), of the M.SsoII-DNA complexes decreased in the order 60oct>60reg>60met, suggesting a higher stability of M.SsoII-60met complex in comparison with the others. The association rate constant, k(a), was also higher for 60met, while similar values were obtained for 60reg and 60oct. The difference in the kinetic parameters for 60met and 60reg suggested a possible way of coordination between the two M.SsoII functions in a cell.
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Affiliation(s)
- A Yu Ryazanova
- Faculty of Bioengineering and Bioinformatics, Chemistry Department, and Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Leninskie Gory 1, 119991 Moscow, Russia
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Huang W, Varani G, Drobny GP. 13C/15N-19F intermolecular REDOR NMR study of the interaction of TAR RNA with Tat peptides. J Am Chem Soc 2010; 132:17643-5. [PMID: 21105680 PMCID: PMC3238802 DOI: 10.1021/ja1051439] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The complex of the HIV TAR RNA with the viral regulatory protein Tat is of considerable interest, but the plasticity of this interaction has made it impossible so far to establish the structure of that complex. In order to explore a new approach to obtain structural information on protein-RNA complexes, we performed (13)C/(15)N-(19)F REDOR NMR experiments in the solid state on TAR bound to a peptide comprising the RNA-binding section of Tat. A critical arginine in the peptide was uniformly (13)C and (15)N labeled, and 5-fluorouridine was incorporated at the U23 position of TAR. REDOR irradiation resulted in dephasing of the (13)C and (15)N resonances, indicating the proximity of the U23(5F)-C and U23(5F)-N spin pairs. Best fits to the REDOR data show the U23(5F)-C distances and the U23(5F)-N distances are in good agreement with the distances obtained from solution NMR structures of partial complexes of Tat with TAR. These results demonstrate that it is possible to study protein-RNA complexes using solid-state REDOR NMR measurements, adding to a growing list of solid state techniques for studying protein-nucleic acid complexes.
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Affiliation(s)
- Wei Huang
- Department of Chemistry, University of Washington, Box 351700, Seattle, Washington 98195, United States
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Muniz L, Egloff S, Ughy B, Jády BE, Kiss T. Controlling cellular P-TEFb activity by the HIV-1 transcriptional transactivator Tat. PLoS Pathog 2010; 6:e1001152. [PMID: 20976203 PMCID: PMC2954905 DOI: 10.1371/journal.ppat.1001152] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2010] [Accepted: 09/13/2010] [Indexed: 11/18/2022] Open
Abstract
The human immunodeficiency virus 1 (HIV-1) transcriptional transactivator (Tat) is essential for synthesis of full-length transcripts from the integrated viral genome by RNA polymerase II (Pol II). Tat recruits the host positive transcription elongation factor b (P-TEFb) to the HIV-1 promoter through binding to the transactivator RNA (TAR) at the 5′-end of the nascent HIV transcript. P-TEFb is a general Pol II transcription factor; its cellular activity is controlled by the 7SK small nuclear RNA (snRNA) and the HEXIM1 protein, which sequester P-TEFb into transcriptionally inactive 7SK/HEXIM/P-TEFb snRNP. Besides targeting P-TEFb to HIV transcription, Tat also increases the nuclear level of active P-TEFb through promoting its dissociation from the 7SK/HEXIM/P-TEFb RNP by an unclear mechanism. In this study, by using in vitro and in vivo RNA-protein binding assays, we demonstrate that HIV-1 Tat binds with high specificity and efficiency to an evolutionarily highly conserved stem-bulge-stem motif of the 5′-hairpin of human 7SK snRNA. The newly discovered Tat-binding motif of 7SK is structurally and functionally indistinguishable from the extensively characterized Tat-binding site of HIV TAR and importantly, it is imbedded in the HEXIM-binding elements of 7SK snRNA. We show that Tat efficiently replaces HEXIM1 on the 7SK snRNA in vivo and therefore, it promotes the disassembly of the 7SK/HEXIM/P-TEFb negative transcriptional regulatory snRNP to augment the nuclear level of active P-TEFb. This is the first demonstration that HIV-1 specifically targets an important cellular regulatory RNA, most probably to promote viral transcription and replication. Demonstration that the human 7SK snRNA carries a TAR RNA-like Tat-binding element that is essential for the normal transcriptional regulatory function of 7SK questions the viability of HIV therapeutic approaches based on small drugs blocking the Tat-binding site of HIV TAR. Expression and replication of the human immunodeficiency virus (HIV) is supported by the viral transcriptional transactivator (Tat) that recruits the host positive transcription elongation factor b (P-TEFb) to the promoter of the integrated viral genome. Here, we demonstrate that HIV Tat specifically and efficiently binds to the host 7SK small nuclear RNA (snRNA) that is a negative regulator of P-TEFb. Although HIV Tat has been reported to interact with a plethora of host factors, our results indicate that the 7SK transcriptional regulatory snRNA is a major and important cellular target of HIV Tat. We demonstrate that binding of Tat to the 7SK snRNA disrupts the 7SK-P-TEFb negative transcriptional regulatory complex and releases active P-TEFb. Thus, we propose that Tat not only targets P-TEFb for HIV transcription, but also modulates the nuclear level of active P-TEFb in HIV-infected cells.
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Affiliation(s)
- Lisa Muniz
- Laboratoire de Biologie Moléculaire Eucaryote du CNRS, UMR5099, IFR109 CNRS, Université Paul Sabatier, Toulouse, France
| | - Sylvain Egloff
- Laboratoire de Biologie Moléculaire Eucaryote du CNRS, UMR5099, IFR109 CNRS, Université Paul Sabatier, Toulouse, France
| | - Bettina Ughy
- Laboratoire de Biologie Moléculaire Eucaryote du CNRS, UMR5099, IFR109 CNRS, Université Paul Sabatier, Toulouse, France
- Biological Research Centre, Hungarian Academy of Sciences, Szeged, Hungary
| | - Beáta E. Jády
- Laboratoire de Biologie Moléculaire Eucaryote du CNRS, UMR5099, IFR109 CNRS, Université Paul Sabatier, Toulouse, France
| | - Tamás Kiss
- Laboratoire de Biologie Moléculaire Eucaryote du CNRS, UMR5099, IFR109 CNRS, Université Paul Sabatier, Toulouse, France
- Biological Research Centre, Hungarian Academy of Sciences, Szeged, Hungary
- * E-mail:
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Lebars I, Martinez-Zapien D, Durand A, Coutant J, Kieffer B, Dock-Bregeon AC. HEXIM1 targets a repeated GAUC motif in the riboregulator of transcription 7SK and promotes base pair rearrangements. Nucleic Acids Res 2010; 38:7749-63. [PMID: 20675720 PMCID: PMC2995076 DOI: 10.1093/nar/gkq660] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
7SK snRNA, an abundant RNA discovered in human nucleus, regulates transcription by RNA polymerase II (RNAPII). It sequesters and inhibits the transcription elongation factor P-TEFb which, by phosphorylation of RNAPII, switches transcription from initiation to processive elongation and relieves pauses of transcription. This regulation process depends on the association between 7SK and a HEXIM protein, neither isolated partner being able to inhibit P-TEFb alone. In this work, we used a combined NMR and biochemical approach to determine 7SK and HEXIM1 elements that define their binding properties. Our results demonstrate that a repeated GAUC motif located in the upper part of a hairpin on the 5'-end of 7SK is essential for specific HEXIM1 recognition. Binding of a peptide comprising the HEXIM Arginine Rich Motif (ARM) induces an opening of the GAUC motif and stabilization of an internal loop. A conserved proline-serine sequence in the middle of the ARM is shown to be essential for the binding specificity and the conformational change of the RNA. This work provides evidences for a recognition mechanism involving a first event of induced fit, suggesting that 7SK plasticity is involved in the transcription regulation.
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Affiliation(s)
- Isabelle Lebars
- IGBMC, BP10142, 1 rue Laurent Fries, 67404 Illkirch Cedex, France.
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Guendel I, Agbottah ET, Kehn-Hall K, Kashanchi F. Inhibition of human immunodeficiency virus type-1 by cdk inhibitors. AIDS Res Ther 2010; 7:7. [PMID: 20334651 PMCID: PMC2852372 DOI: 10.1186/1742-6405-7-7] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2009] [Accepted: 03/24/2010] [Indexed: 11/14/2022] Open
Abstract
Current therapy for human immunodeficiency virus (HIV-1) infection relies primarily on the administration of anti-retroviral nucleoside analogues, either alone or in combination with HIV-protease inhibitors. Although these drugs have a clinical benefit, continuous therapy with the drugs leads to drug-resistant strains of the virus. Recently, significant progress has been made towards the development of natural and synthetic agents that can directly inhibit HIV-1 replication or its essential enzymes. We previously reported on the pharmacological cyclin-dependent kinase inhibitor (PCI) r-roscovitine as a potential inhibitor of HIV-1 replication. PCIs are among the most promising novel antiviral agents to emerge over the past few years. Potent activity on viral replication combined with proliferation inhibition without the emergence of resistant viruses, which are normally observed in HAART patients; make PCIs ideal candidates for HIV-1 inhibition. To this end we evaluated twenty four cdk inhibitors for their effect on HIV-1 replication in vitro. Screening of these compounds identified alsterpaullone as the most potent inhibitor of HIV-1 with activity at 150 nM. We found that alsterpaullone effectively inhibits cdk2 activity in HIV-1 infected cells with a low IC50 compared to control uninfected cells. The effects of alsterpaullone were associated with suppression of cdk2 and cyclin expression. Combining both alsterpaullone and r-roscovitine (cyc202) in treatment exhibited even stronger inhibitory activities in HIV-1 infected PBMCs.
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Ferner J, Suhartono M, Breitung S, Jonker HRA, Hennig M, Wöhnert J, Göbel M, Schwalbe H. Structures of HIV TAR RNA-ligand complexes reveal higher binding stoichiometries. Chembiochem 2009; 10:1490-4. [PMID: 19444830 DOI: 10.1002/cbic.200900220] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Target TAR by NMR: Tripeptides containing arginines as terminal residues and non-natural amino acids as central residues are good leads for drug design to target the HIV trans-activation response element (TAR). The structural characterization of the RNA-ligand complex by NMR spectroscopy reveals two specific binding sites that are located at bulge residue U23 and around the pyrimidine-stretch U40-C41-U42 directly adjacent to the bulge.
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Affiliation(s)
- Jan Ferner
- Institut für Organische Chemie und Chemische Biologie, Zentrum für Biomolekulare Magnetische Resonanz (BMRZ), Johann Wolfgang Goethe-Universität Frankfurt am Main, Max-von-Laue-Strasse 7, 60438 Frankfurt am Main, Germany
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Keene FR, Smith JA, Collins JG. Metal complexes as structure-selective binding agents for nucleic acids. Coord Chem Rev 2009. [DOI: 10.1016/j.ccr.2009.01.004] [Citation(s) in RCA: 167] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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Ramaswamy P, Woodson SA. Global stabilization of rRNA structure by ribosomal proteins S4, S17, and S20. J Mol Biol 2009; 392:666-77. [PMID: 19616559 DOI: 10.1016/j.jmb.2009.07.032] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2009] [Revised: 07/01/2009] [Accepted: 07/09/2009] [Indexed: 10/20/2022]
Abstract
Ribosomal proteins stabilize the folded structure of the ribosomal RNA and enable the recruitment of further proteins to the complex. Quantitative hydroxyl radical footprinting was used to measure the extent to which three different primary assembly proteins, S4, S17, and S20, stabilize the three-dimensional structure of the Escherichia coli 16S 5' domain. The stability of the complexes was perturbed by varying the concentration of MgCl(2). Each protein influences the stability of the ribosomal RNA tertiary interactions beyond its immediate binding site. S4 and S17 stabilize the entire 5' domain, while S20 has a more local effect. Multistage folding of individual helices within the 5' domain shows that each protein stabilizes a different ensemble of structural intermediates that include nonnative interactions at low Mg(2+) concentration. We propose that the combined interactions of S4, S17, and S20 with different helical junctions bias the free-energy landscape toward a few RNA conformations that are competent to add the secondary assembly protein S16 in the next step of assembly.
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