1
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D'Orso I. The HIV-1 Transcriptional Program: From Initiation to Elongation Control. J Mol Biol 2025; 437:168690. [PMID: 38936695 DOI: 10.1016/j.jmb.2024.168690] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2024] [Revised: 06/20/2024] [Accepted: 06/21/2024] [Indexed: 06/29/2024]
Abstract
A large body of work in the last four decades has revealed the key pillars of HIV-1 transcription control at the initiation and elongation steps. Here, I provide a recount of this collective knowledge starting with the genomic elements (DNA and nascent TAR RNA stem-loop) and transcription factors (cellular and the viral transactivator Tat), and later transitioning to the assembly and regulation of transcription initiation and elongation complexes, and the role of chromatin structure. Compelling evidence support a core HIV-1 transcriptional program regulated by the sequential and concerted action of cellular transcription factors and Tat to promote initiation and sustain elongation, highlighting the efficiency of a small virus to take over its host to produce the high levels of transcription required for viral replication. I summarize new advances including the use of CRISPR-Cas9, genetic tools for acute factor depletion, and imaging to study transcriptional dynamics, bursting and the progression through the multiple phases of the transcriptional cycle. Finally, I describe current challenges to future major advances and discuss areas that deserve more attention to both bolster our basic knowledge of the core HIV-1 transcriptional program and open up new therapeutic opportunities.
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Affiliation(s)
- Iván D'Orso
- Department of Microbiology, The University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
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2
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Moezpoor MR, Stevenson M. Help or Hinder: Protein Host Factors That Impact HIV-1 Replication. Viruses 2024; 16:1281. [PMID: 39205255 PMCID: PMC11360189 DOI: 10.3390/v16081281] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2024] [Revised: 08/05/2024] [Accepted: 08/08/2024] [Indexed: 09/04/2024] Open
Abstract
Interactions between human immunodeficiency virus type 1 (HIV-1) and the host factors or restriction factors of its target cells determine the cell's susceptibility to, and outcome of, infection. Factors intrinsic to the cell are involved at every step of the HIV-1 replication cycle, contributing to productive infection and replication, or severely attenuating the chances of success. Furthermore, factors unique to certain cell types contribute to the differences in infection between these cell types. Understanding the involvement of these factors in HIV-1 infection is a key requirement for the development of anti-HIV-1 therapies. As the list of factors grows, and the dynamic interactions between these factors and the virus are elucidated, comprehensive and up-to-date summaries that recount the knowledge gathered after decades of research are beneficial to the field, displaying what is known so that researchers can build off the groundwork of others to investigate what is unknown. Herein, we aim to provide a review focusing on protein host factors, both well-known and relatively new, that impact HIV-1 replication in a positive or negative manner at each stage of the replication cycle, highlighting factors unique to the various HIV-1 target cell types where appropriate.
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Affiliation(s)
- Michael Rameen Moezpoor
- Department of Microbiology and Immunology, University of Miami Leonard M. Miller School of Medicine, Miami, FL 33136, USA
| | - Mario Stevenson
- Raymond F. Schinazi and Family Endowed Chair in Biomedicine; Professor of Medicine; Director, Institute of AIDS and Emerging Infectious Diseases; Department of Microbiology and Immunology, University of Miami Leonard M. Miller School of Medicine, Life Science Technology Park, 1951 NW 7th Avenue, Room 2331B, Suite 200, Miami, FL 33136, USA;
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3
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Patarca R, Haseltine WA. Bioinformatics Insights on Viral Gene Expression Transactivation: From HIV-1 to SARS-CoV-2. Int J Mol Sci 2024; 25:3378. [PMID: 38542351 PMCID: PMC10970485 DOI: 10.3390/ijms25063378] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2024] [Revised: 03/08/2024] [Accepted: 03/15/2024] [Indexed: 11/11/2024] Open
Abstract
Viruses provide vital insights into gene expression control. Viral transactivators, with other viral and cellular proteins, regulate expression of self, other viruses, and host genes with profound effects on infected cells, underlying inflammation, control of immune responses, and pathogenesis. The multifunctional Tat proteins of lentiviruses (HIV-1, HIV-2, and SIV) transactivate gene expression by recruiting host proteins and binding to transacting responsive regions (TARs) in viral and host RNAs. SARS-CoV-2 nucleocapsid participates in early viral transcription, recruits similar cellular proteins, and shares intracellular, surface, and extracellular distribution with Tat. SARS-CoV-2 nucleocapsid interacting with the replication-transcription complex might, therefore, transactivate viral and cellular RNAs in the transcription and reactivation of self and other viruses, acute and chronic pathogenesis, immune evasion, and viral evolution. Here, we show, by using primary and secondary structural comparisons, that the leaders of SARS-CoV-2 and other coronaviruses contain TAR-like sequences in stem-loops 2 and 3. The coronaviral nucleocapsid C-terminal domains harbor a region of similarity to TAR-binding regions of lentiviral Tat proteins, and coronaviral nonstructural protein 12 has a cysteine-rich metal binding, dimerization domain, as do lentiviral Tat proteins. Although SARS-CoV-1 nucleocapsid transactivated gene expression in a replicon-based study, further experimental evidence for coronaviral transactivation and its possible implications is warranted.
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Affiliation(s)
- Roberto Patarca
- ACCESS Health International, 384 West Lane, Ridgefield, CT 06877, USA;
- Feinstein Institutes for Medical Research, 350 Community Dr, Manhasset, NY 11030, USA
| | - William A. Haseltine
- ACCESS Health International, 384 West Lane, Ridgefield, CT 06877, USA;
- Feinstein Institutes for Medical Research, 350 Community Dr, Manhasset, NY 11030, USA
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4
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Palumbo RJ, Yang Y, Feigon J, Hanes SD. Catalytic activity of the Bin3/MePCE methyltransferase domain is dispensable for 7SK snRNP function in Drosophila melanogaster. Genetics 2024; 226:iyad203. [PMID: 37982586 PMCID: PMC10763541 DOI: 10.1093/genetics/iyad203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Revised: 10/27/2023] [Accepted: 11/13/2023] [Indexed: 11/21/2023] Open
Abstract
Methylphosphate Capping Enzyme (MePCE) monomethylates the gamma phosphate at the 5' end of the 7SK noncoding RNA, a modification thought to protect 7SK from degradation. 7SK serves as a scaffold for assembly of a snRNP complex that inhibits transcription by sequestering the positive elongation factor P-TEFb. While much is known about the biochemical activity of MePCE in vitro, little is known about its functions in vivo, or what roles-if any-there are for regions outside the conserved methyltransferase domain. Here, we investigated the role of Bin3, the Drosophila ortholog of MePCE, and its conserved functional domains in Drosophila development. We found that bin3 mutant females had strongly reduced rates of egg-laying, which was rescued by genetic reduction of P-TEFb activity, suggesting that Bin3 promotes fecundity by repressing P-TEFb. bin3 mutants also exhibited neuromuscular defects, analogous to a patient with MePCE haploinsufficiency. These defects were also rescued by genetic reduction of P-TEFb activity, suggesting that Bin3 and MePCE have conserved roles in promoting neuromuscular function by repressing P-TEFb. Unexpectedly, we found that a Bin3 catalytic mutant (Bin3Y795A) could still bind and stabilize 7SK and rescue all bin3 mutant phenotypes, indicating that Bin3 catalytic activity is dispensable for 7SK stability and snRNP function in vivo. Finally, we identified a metazoan-specific motif (MSM) outside of the methyltransferase domain and generated mutant flies lacking this motif (Bin3ΔMSM). Bin3ΔMSM mutant flies exhibited some-but not all-bin3 mutant phenotypes, suggesting that the MSM is required for a 7SK-independent, tissue-specific function of Bin3.
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Affiliation(s)
- Ryan J Palumbo
- Department of Biochemistry & Molecular Biology, SUNY Upstate Medical University, Syracuse, NY 13210, USA
| | - Yuan Yang
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095, USA
| | - Juli Feigon
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095, USA
| | - Steven D Hanes
- Department of Biochemistry & Molecular Biology, SUNY Upstate Medical University, Syracuse, NY 13210, USA
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5
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Khatkar P, Mensah G, Ning S, Cowen M, Kim Y, Williams A, Abulwerdi FA, Zhao Y, Zeng C, Le Grice SFJ, Kashanchi F. HIV-1 Transcription Inhibition Using Small RNA-Binding Molecules. Pharmaceuticals (Basel) 2023; 17:33. [PMID: 38256867 PMCID: PMC10819208 DOI: 10.3390/ph17010033] [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: 09/30/2023] [Revised: 12/11/2023] [Accepted: 12/19/2023] [Indexed: 01/24/2024] Open
Abstract
The HIV-1 transactivator protein Tat interacts with the transactivation response element (TAR) at the three-nucleotide UCU bulge to facilitate the recruitment of transcription elongation factor-b (P-TEFb) and induce the transcription of the integrated proviral genome. Therefore, the Tat-TAR interaction, unique to the virus, is a promising target for developing antiviral therapeutics. Currently, there are no FDA-approved drugs against HIV-1 transcription, suggesting the need to develop novel inhibitors that specifically target HIV-1 transcription. We have identified potential candidates that effectively inhibit viral transcription in myeloid and T cells without apparent toxicity. Among these candidates, two molecules showed inhibition of viral protein expression. A molecular docking and simulation approach was used to determine the binding dynamics of these small molecules on TAR RNA in the presence of the P-TEFb complex, which was further validated by a biotinylated RNA pulldown assay. Furthermore, we examined the effect of these molecules on transcription factors, including the SWI/SNF complex (BAF or PBAF), which plays an important role in chromatin remodeling near the transcription start site and hence regulates virus transcription. The top candidates showed significant viral transcription inhibition in primary cells infected with HIV-1 (98.6). Collectively, our study identified potential transcription inhibitors that can potentially complement existing cART drugs to address the current therapeutic gap in current regimens. Additionally, shifting of the TAR RNA loop towards Cyclin T1 upon molecule binding during molecular simulation studies suggested that targeting the TAR loop and Tat-binding UCU bulge together should be an essential feature of TAR-binding molecules/inhibitors to achieve complete viral transcription inhibition.
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Affiliation(s)
- Pooja Khatkar
- Laboratory of Molecular Virology, School of Systems Biology, George Mason University, Manassas, VA 20110, USA; (P.K.)
| | - Gifty Mensah
- Laboratory of Molecular Virology, School of Systems Biology, George Mason University, Manassas, VA 20110, USA; (P.K.)
| | - Shangbo Ning
- Institute of Biophysics and Department of Physics, Central China Normal University, Wuhan 430079, China
| | - Maria Cowen
- Laboratory of Molecular Virology, School of Systems Biology, George Mason University, Manassas, VA 20110, USA; (P.K.)
| | - Yuriy Kim
- Laboratory of Molecular Virology, School of Systems Biology, George Mason University, Manassas, VA 20110, USA; (P.K.)
| | - Anastasia Williams
- Laboratory of Molecular Virology, School of Systems Biology, George Mason University, Manassas, VA 20110, USA; (P.K.)
| | | | - Yunjie Zhao
- Institute of Biophysics and Department of Physics, Central China Normal University, Wuhan 430079, China
| | - Chen Zeng
- Physics Department, The George Washington University, Washington, DC 20052, USA
| | | | - Fatah Kashanchi
- Laboratory of Molecular Virology, School of Systems Biology, George Mason University, Manassas, VA 20110, USA; (P.K.)
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6
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Palumbo RJ, Hanes SD. Catalytic activity of the Bin3/MEPCE methyltransferase domain is dispensable for 7SK snRNP function in Drosophila melanogaster. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.01.543302. [PMID: 37333392 PMCID: PMC10274667 DOI: 10.1101/2023.06.01.543302] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/20/2023]
Abstract
Methylphosphate Capping Enzyme (MEPCE) monomethylates the gamma phosphate at the 5' end of the 7SK noncoding RNA, a modification thought to protect 7SK from degradation. 7SK serves as a scaffold for assembly of a snRNP complex that inhibits transcription by sequestering the positive elongation factor P-TEFb. While much is known about the biochemical activity of MEPCE in vitro, little is known about its functions in vivo, or what roles- if any-there are for regions outside the conserved methyltransferase domain. Here, we investigated the role of Bin3, the Drosophila ortholog of MEPCE, and its conserved functional domains in Drosophila development. We found that bin3 mutant females had strongly reduced rates of egg-laying, which was rescued by genetic reduction of P-TEFb activity, suggesting that Bin3 promotes fecundity by repressing P-TEFb. bin3 mutants also exhibited neuromuscular defects, analogous to a patient with MEPCE haploinsufficiency. These defects were also rescued by genetic reduction of P-TEFb activity, suggesting that Bin3 and MEPCE have conserved roles in promoting neuromuscular function by repressing P-TEFb. Unexpectedly, we found that a Bin3 catalytic mutant (Bin3Y795A) could still bind and stabilize 7SK and rescue all bin3 mutant phenotypes, indicating that Bin3 catalytic activity is dispensable for 7SK stability and snRNP function in vivo. Finally, we identified a metazoan-specific motif (MSM) outside of the methyltransferase domain and generated mutant flies lacking this motif (Bin3ΔMSM). Bin3ΔMSM mutant flies exhibited some-but not all-bin3 mutant phenotypes, suggesting that the MSM is required for a 7SK-independent, tissue-specific function of Bin3.
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Affiliation(s)
- Ryan J Palumbo
- Department of Biochemistry & Molecular Biology, SUNY Upstate Medical University 750 East Adams Street, 4283 Weiskotten Hall, Syracuse, New York, 13210
| | - Steven D Hanes
- Department of Biochemistry & Molecular Biology, SUNY Upstate Medical University 750 East Adams Street, 4283 Weiskotten Hall, Syracuse, New York, 13210
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7
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Sakamoto T, Ajiro M, Watanabe A, Matsushima S, Ueda K, Hagiwara M. Application of the CDK9 inhibitor FIT-039 for the treatment of KSHV-associated malignancy. BMC Cancer 2023; 23:71. [PMID: 36670405 PMCID: PMC9862866 DOI: 10.1186/s12885-023-10540-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Accepted: 01/11/2023] [Indexed: 01/21/2023] Open
Abstract
Chronic infection with Kaposi's sarcoma-associated herpes virus (KSHV) in B lymphocytes causes primary effusion lymphoma (PEL), the most aggressive form of KSHV-related cancer, which is resistant to conventional chemotherapy. In this study, we report that the BCBL-1 KSHV+ PEL cell line does not harbor oncogenic mutations responsible for its aggressive malignancy. Assuming that KSHV viral oncogenes play crucial roles in PEL proliferation, we examined the effect of cyclin-dependent kinase 9 (CDK9) inhibitor FIT-039 on KSHV viral gene expression and KSHV+ PEL proliferation. We found that FIT-039 treatment impaired the proliferation of KSHV+ PEL cells and the expression of KSHV viral genes in vitro. The effects of FIT-039 treatment on PEL cells were further evaluated in the PEL xenograft model that retains a more physiological environment for the growth of PEL growth and KSHV propagation, and we confirmed that FIT-039 administration drastically inhibited PEL growth in vivo. Our current study indicates that FIT-039 is a potential new anticancer drug targeting KSHV for PEL patients.
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Affiliation(s)
- Tetsunori Sakamoto
- grid.258799.80000 0004 0372 2033Department of Anatomy and Developmental Biology, Kyoto University Graduate School of Medicine, Building C, 3Rd Floor, Yoshida-Konoe Cho, Sakyo-Ku, Kyoto, 606-8501 Japan ,Present address: Japanese Red Cross Otsu Hospital, Otsu, 520-8511 Japan
| | - Masahiko Ajiro
- grid.258799.80000 0004 0372 2033Department of Anatomy and Developmental Biology, Kyoto University Graduate School of Medicine, Building C, 3Rd Floor, Yoshida-Konoe Cho, Sakyo-Ku, Kyoto, 606-8501 Japan ,grid.258799.80000 0004 0372 2033Department of Drug Discovery Medicine, Kyoto University Graduate School of Medicine, Kyoto, 606-8501 Japan
| | - Akira Watanabe
- grid.258799.80000 0004 0372 2033Medical Innovation Center, Kyoto University Graduate School of Medicine, Kyoto, 606-8397 Japan
| | - Shingo Matsushima
- grid.258799.80000 0004 0372 2033Department of Drug Discovery Medicine, Kyoto University Graduate School of Medicine, Kyoto, 606-8501 Japan
| | - Keiji Ueda
- grid.136593.b0000 0004 0373 3971Division of Virology, Osaka University Graduate School of Medicine, Suita, 565-0871 Japan
| | - Masatoshi Hagiwara
- grid.258799.80000 0004 0372 2033Department of Anatomy and Developmental Biology, Kyoto University Graduate School of Medicine, Building C, 3Rd Floor, Yoshida-Konoe Cho, Sakyo-Ku, Kyoto, 606-8501 Japan
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8
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Yan Y, Tang YD, Zheng C. When cyclin-dependent kinases meet viral infections, including SARS-CoV-2. J Med Virol 2022; 94:2962-2968. [PMID: 35288942 PMCID: PMC9088476 DOI: 10.1002/jmv.27719] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2022] [Revised: 02/18/2022] [Accepted: 02/25/2022] [Indexed: 11/16/2022]
Abstract
Cyclin‐dependent kinases (CDKs) are protein kinases that play a key role in cell division and transcriptional regulation. Recent studies have demonstrated the critical roles of CDKs in various viral infections. However, the molecular processes underpinning CDKs' roles in viral infection and host antiviral defense are unknown. This minireview briefly overviews CDKs' functions and highlights the most recent discoveries of CDKs' emerging roles during viral infections, thereby providing a scientific and theoretical foundation for antiviral regulation and shedding light on developing novel drug targets and therapeutic strategies against viral infection.
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Affiliation(s)
- Yan Yan
- Center of Clinical Laboratory, The Fifth People's Hospital of Wuxi, Affiliated Hospital of Jiangnan University, Wuxi, China
| | - Yan-Dong Tang
- Department of Immunology, School of Basic Medical Sciences, Fujian Medical University, Fuzhou, China.,State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute of Chinese Academy of Agricultural Sciences, Harbin, China
| | - Chunfu Zheng
- Department of Immunology, School of Basic Medical Sciences, Fujian Medical University, Fuzhou, China.,Department of Microbiology, Immunology and Infectious Diseases, University of Calgary, Calgary, Alberta, Canada
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9
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The Novel Protease Activities of JMJD5–JMJD6–JMJD7 and Arginine Methylation Activities of Arginine Methyltransferases Are Likely Coupled. Biomolecules 2022; 12:biom12030347. [PMID: 35327545 PMCID: PMC8945206 DOI: 10.3390/biom12030347] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Revised: 02/03/2022] [Accepted: 02/18/2022] [Indexed: 12/23/2022] Open
Abstract
The surreptitious discoveries of the protease activities on arginine-methylated targets of a subfamily of Jumonji domain-containing family including JMJD5, JMJD6, and JMJD7 pose several questions regarding their authenticity, function, purpose, and relations with others. At the same time, despite several decades of efforts and massive accumulating data regarding the roles of the arginine methyltransferase family (PRMTs), the exact function of this protein family still remains a mystery, though it seems to play critical roles in transcription regulation, including activation and inactivation of a large group of genes, as well as other biological activities. In this review, we aim to elucidate that the function of JMJD5/6/7 and PRMTs are likely coupled. Besides roles in the regulation of the biogenesis of membrane-less organelles in cells, they are major players in regulating stimulating transcription factors to control the activities of RNA Polymerase II in higher eukaryotes, especially in the animal kingdom. Furthermore, we propose that arginine methylation by PRMTs could be a ubiquitous action marked for destruction after missions by a subfamily of the Jumonji protein family.
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10
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Cheng D, Semmens K, McManus E, Chen Q, Meerzaman D, Wang X, Hafner M, Lewis BA, Takahashi H, Devaiah BN, Gegonne A, Singer DS. The nuclear transcription factor, TAF7, is a cytoplasmic regulator of protein synthesis. SCIENCE ADVANCES 2021; 7:eabi5751. [PMID: 34890234 PMCID: PMC8664259 DOI: 10.1126/sciadv.abi5751] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/20/2021] [Accepted: 10/22/2021] [Indexed: 06/13/2023]
Abstract
The TFIID component, TAF7, has been extensively characterized as essential for transcription and is critical for cell proliferation and differentiation. Here, we report that TAF7 is a previously unknown RNA chaperone that contributes to the regulation of protein synthesis. Mechanistically, TAF7 binds RNAs in the nucleus and delivers them to cytoplasmic polysomes. A broad spectrum of target RNA species, including the HIV-1 transactivation response element, binds TAF7 through consensus CUG motifs within the 3′ untranslated region. Export to the cytoplasm depends on a TAF7 nuclear export signal and occurs by an exportin 1–dependent pathway. Notably, disrupting either TAF7’s RNA binding or its export from the nucleus results in retention of target messenger RNAs in the nucleus and reduced levels of the protein products of TAF7-target RNAs. Thus, TAF7, an essential transcription factor, plays a key role in the regulation of RNA translation, thereby potentially connecting these processes.
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Affiliation(s)
- Dan Cheng
- Experimental Immunology Branch, National Cancer Institute, NIH, Bethesda, MD 20892, USA
| | - Kevin Semmens
- School of Medicine, University of Utah, Salt Lake City, UT 84132, USA
| | - Elizabeth McManus
- Experimental Immunology Branch, National Cancer Institute, NIH, Bethesda, MD 20892, USA
| | - Qingrong Chen
- Center for Biomedical Informatics and Information Technology, National Cancer Institute, NIH, Rockville, MD 20850, USA
| | - Daoud Meerzaman
- Center for Biomedical Informatics and Information Technology, National Cancer Institute, NIH, Rockville, MD 20850, USA
| | - Xiantao Wang
- Laboratory of Muscle Stem Cells and Gene Regulation, National Institute of Arthritis and Musculoskeletal and Skin Diseases, NIH, Bethesda, MD 20892, USA
| | - Markus Hafner
- Laboratory of Muscle Stem Cells and Gene Regulation, National Institute of Arthritis and Musculoskeletal and Skin Diseases, NIH, Bethesda, MD 20892, USA
| | - Brian A. Lewis
- Laboratory of Pathology, National Cancer Institute, NIH, Bethesda, MD 20892, USA
| | - Hidehisa Takahashi
- Department of Molecular Biology, Yokohama City University Graduate School of Medical Science, Fukuura 3-9, Kanazawa-ku, Yokohama, Kanagawa 216-0004, Japan
| | | | - Anne Gegonne
- Experimental Immunology Branch, National Cancer Institute, NIH, Bethesda, MD 20892, USA
| | - Dinah S. Singer
- Experimental Immunology Branch, National Cancer Institute, NIH, Bethesda, MD 20892, USA
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11
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Łukasik P, Załuski M, Gutowska I. Cyclin-Dependent Kinases (CDK) and Their Role in Diseases Development-Review. Int J Mol Sci 2021; 22:ijms22062935. [PMID: 33805800 PMCID: PMC7998717 DOI: 10.3390/ijms22062935] [Citation(s) in RCA: 90] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Revised: 03/07/2021] [Accepted: 03/09/2021] [Indexed: 12/13/2022] Open
Abstract
Cyclin-dependent kinases (CDKs) are involved in many crucial processes, such as cell cycle and transcription, as well as communication, metabolism, and apoptosis. The kinases are organized in a pathway to ensure that, during cell division, each cell accurately replicates its DNA, and ensure its segregation equally between the two daughter cells. Deregulation of any of the stages of the cell cycle or transcription leads to apoptosis but, if uncorrected, can result in a series of diseases, such as cancer, neurodegenerative diseases (Alzheimer’s or Parkinson’s disease), and stroke. This review presents the current state of knowledge about the characteristics of cyclin-dependent kinases as potential pharmacological targets.
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Affiliation(s)
- Paweł Łukasik
- Department of Medical Chemistry, Pomeranian Medical University in Szczecin, Powstancow Wlkp. 72 Av., 70-111 Szczecin, Poland;
| | - Michał Załuski
- Department of Pharmaceutical Chemistry, Pomeranian Medical University in Szczecin, Powstancow Wlkp. 72 Av., 70-111 Szczecin, Poland;
| | - Izabela Gutowska
- Department of Medical Chemistry, Pomeranian Medical University in Szczecin, Powstancow Wlkp. 72 Av., 70-111 Szczecin, Poland;
- Correspondence:
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12
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Dollinger R, Gilmour DS. Regulation of Promoter Proximal Pausing of RNA Polymerase II in Metazoans. J Mol Biol 2021; 433:166897. [PMID: 33640324 DOI: 10.1016/j.jmb.2021.166897] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 02/15/2021] [Accepted: 02/19/2021] [Indexed: 12/12/2022]
Abstract
Regulation of transcription is a tightly choreographed process. The establishment of RNA polymerase II promoter proximal pausing soon after transcription initiation and the release of Pol II into productive elongation are key regulatory processes that occur in early elongation. We describe the techniques and tools that have become available for the study of promoter proximal pausing and their utility for future experiments. We then provide an overview of the factors and interactions that govern a multipartite pausing process and address emerging questions surrounding the mechanism of RNA polymerase II's subsequent advancement into the gene body. Finally, we address remaining controversies and future areas of study.
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Affiliation(s)
- Roberta Dollinger
- Center for Eukaryotic Gene Regulation, Department of Biochemistry and Molecular Biology, The Pennsylvania State University, 462 North Frear, University Park, PA 16802, USA.
| | - David S Gilmour
- Center for Eukaryotic Gene Regulation, Department of Biochemistry and Molecular Biology, The Pennsylvania State University, 465A North Frear, University Park, PA 16802, USA.
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13
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Ramdas P, Sahu AK, Mishra T, Bhardwaj V, Chande A. From Entry to Egress: Strategic Exploitation of the Cellular Processes by HIV-1. Front Microbiol 2020; 11:559792. [PMID: 33343516 PMCID: PMC7746852 DOI: 10.3389/fmicb.2020.559792] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Accepted: 11/05/2020] [Indexed: 01/23/2023] Open
Abstract
HIV-1 employs a rich arsenal of viral factors throughout its life cycle and co-opts intracellular trafficking pathways. This exquisitely coordinated process requires precise manipulation of the host microenvironment, most often within defined subcellular compartments. The virus capitalizes on the host by modulating cell-surface proteins and cleverly exploiting nuclear import pathways for post entry events, among other key processes. Successful virus–cell interactions are indeed crucial in determining the extent of infection. By evolving defenses against host restriction factors, while simultaneously exploiting host dependency factors, the life cycle of HIV-1 presents a fascinating montage of an ongoing host–virus arms race. Herein, we provide an overview of how HIV-1 exploits native functions of the host cell and discuss recent findings that fundamentally change our understanding of the post-entry replication events.
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Affiliation(s)
- Pavitra Ramdas
- Molecular Virology Laboratory, Indian Institute of Science Education and Research (IISER) Bhopal, Bhopal, India
| | - Amit Kumar Sahu
- Molecular Virology Laboratory, Indian Institute of Science Education and Research (IISER) Bhopal, Bhopal, India
| | - Tarun Mishra
- Molecular Virology Laboratory, Indian Institute of Science Education and Research (IISER) Bhopal, Bhopal, India
| | - Vipin Bhardwaj
- Molecular Virology Laboratory, Indian Institute of Science Education and Research (IISER) Bhopal, Bhopal, India
| | - Ajit Chande
- Molecular Virology Laboratory, Indian Institute of Science Education and Research (IISER) Bhopal, Bhopal, India
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14
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Abstract
More than 30% of genes in higher eukaryotes are regulated by RNA polymerase II (Pol II) promoter proximal pausing. Pausing is released by the positive transcription elongation factor complex (P-TEFb). However, the exact mechanism by which this occurs and whether phosphorylation of the carboxyl-terminal domain of Pol II is involved in the process remains unknown. We previously reported that JMJD5 could generate tailless nucleosomes at position +1 from transcription start sites (TSS), thus perhaps enable progression of Pol II. Here we find that knockout of JMJD5 leads to accumulation of nucleosomes at position +1. Absence of JMJD5 also results in loss of or lowered transcription of a large number of genes. Interestingly, we found that phosphorylation, by CDK9, of Ser2 within two neighboring heptad repeats in the carboxyl-terminal domain of Pol II, together with phosphorylation of Ser5 within the second repeat, HR-Ser2p (1, 2)-Ser5p (2) for short, allows Pol II to bind JMJD5 via engagement of the N-terminal domain of JMJD5. We suggest that these events bring JMJD5 near the nucleosome at position +1, thus allowing JMJD5 to clip histones on this nucleosome, a phenomenon that may contribute to release of Pol II pausing.
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15
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Basu S, Nandy A, Biswas D. Keeping RNA polymerase II on the run: Functions of MLL fusion partners in transcriptional regulation. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2020; 1863:194563. [PMID: 32348849 DOI: 10.1016/j.bbagrm.2020.194563] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 01/13/2020] [Accepted: 04/13/2020] [Indexed: 12/21/2022]
Abstract
Since the identification of key MLL fusion partners as transcription elongation factors regulating expression of HOX cluster genes during hematopoiesis, extensive work from the last decade has resulted in significant progress in our overall mechanistic understanding of role of MLL fusion partner proteins in transcriptional regulation of diverse set of genes beyond just the HOX cluster. In this review, we are going to detail overall understanding of role of MLL fusion partner proteins in transcriptional regulation and thus provide mechanistic insights into possible MLL fusion protein-mediated transcriptional misregulation leading to aberrant hematopoiesis and leukemogenesis.
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Affiliation(s)
- Subham Basu
- Laboratory of Transcription Biology, Molecular Genetics Division, CSIR-Indian Institute of Chemical Biology, 4, Raja S. C. Mullick Road, Kolkata 32, India
| | - Arijit Nandy
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India
| | - Debabrata Biswas
- Laboratory of Transcription Biology, Molecular Genetics Division, CSIR-Indian Institute of Chemical Biology, 4, Raja S. C. Mullick Road, Kolkata 32, India.
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16
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Liu H, Lee S, Zhang Q, Chen Z, Zhang G. The potential underlying mechanism of the leukemia caused by MLL-fusion and potential treatments. Mol Carcinog 2020; 59:839-851. [PMID: 32329934 DOI: 10.1002/mc.23204] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Revised: 04/07/2020] [Accepted: 04/07/2020] [Indexed: 12/12/2022]
Abstract
A majority of infant and pediatric leukemias are caused by the mixed-lineage leukemia gene (MLL) fused with a variety of candidates. Several underlying mechanisms have been proposed. One currently popular view is that truncated MLL1 fusion and its associated complex constitutively hijacks super elongation complex, including positive transcription elongation factor b, CDK9, and cyclin T1 complex and DOT1L, to enhance the expression of transcription factors that maintain or restore stemness of leukocytes, as well as prevent the differentiation of hematopoietic progenitor cells. An alternative emerging view proposes that MLL1-fusion promotes the recruitment of TATA binding protein and RNA polymerase II (Pol II) initiation complex, so as to increase the expression levels of target genes. The fundamental mechanism of both theories are gain of function for truncated MLL1 fusions, either through Pol II elongation or initiation. Our recent progress in transcription regulation of paused Pol II through JMJD5, JMJD6, and JMJD7, combined with the repressive role of H3K4me3 revealed by others, prompted us to introduce a contrarian hypothesis: the failure to shut down transcribing units by MLL-fusions triggers the transformation: loss of function of truncated MLL1 fusions coupled with the loss of conversion of H3K4me1 to H3K4me3, leading to the constitutive expression of transcription factors that are in charge of maintenance of hematopoietic progenitor cells, may trigger the transformation of normal cells into cancer cells. Following this track, a potential treatment to eliminate these fusion proteins, which may ultimately cure the disease, is proposed.
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Affiliation(s)
- Haolin Liu
- Department of Biomedical Research, National Jewish Health, and Department of Immunology and Microbiology, Anschutz Medical Center, University of Colorado, Denver, Colorado
| | - Schuyler Lee
- Department of Biomedical Research, National Jewish Health, and Department of Immunology and Microbiology, Anschutz Medical Center, University of Colorado, Denver, Colorado
| | - Qianqian Zhang
- State Key Laboratory of Agrobiotechnology, College of Biological Sciences, Agriculture University, Beijing, China
| | - Zhongzhou Chen
- State Key Laboratory of Agrobiotechnology, College of Biological Sciences, Agriculture University, Beijing, China
| | - Gongyi Zhang
- Department of Biomedical Research, National Jewish Health, and Department of Immunology and Microbiology, Anschutz Medical Center, University of Colorado, Denver, Colorado
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17
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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: 1.8] [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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18
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Nguyen W, Jacobson J, Jarman KE, Blackmore TR, Sabroux HJ, Lewin SR, Purcell DF, Sleebs BE. Optimization of 5-substituted thiazolyl ureas and 6-substituted imidazopyridines as potential HIV-1 latency reversing agents. Eur J Med Chem 2020; 195:112254. [PMID: 32251744 DOI: 10.1016/j.ejmech.2020.112254] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2019] [Revised: 02/13/2020] [Accepted: 03/17/2020] [Indexed: 10/24/2022]
Abstract
A persistent latent reservoir of virus in CD4+ T cells is a major barrier to cure HIV. Activating viral transcription in latently infected cells using small molecules is one strategy being explored to eliminate latency. We previously described the use of a FlpIn.FM HEK293 cellular assay to identify and then optimize the 2-acylaminothiazole class to exhibit modest activation of HIV gene expression. Here, we implement two strategies to further improve the activation of viral gene expression and physicochemical properties of this class. Firstly, we explored rigidification of the central oxy-carbon linker with a variety of saturated heterocycles, and secondly, investigated bioisosteric replacement of the 2-acylaminothiazole moiety. The optimization process afforded lead compounds (74 and 91) from the 2-piperazinyl thiazolyl urea and the imidazopyridine class. The lead compounds from each class demonstrate potent activation of HIV gene expression in the FlpIn.FM HEK293 cellular assay (both with LTR EC50s of 80 nM) and in the Jurkat Latency 10.6 cell model (LTR EC50 220 and 320 nM respectively), but consequently activate gene expression non-specifically in the FlpIn.FM HEK293 cellular assay (CMV EC50 70 and 270 nM respectively) manifesting in cellular cytotoxicity. The lead compounds have potential for further development as novel latency reversing agents.
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Affiliation(s)
- William Nguyen
- The Walter and Eliza Hall Institute for Medical Research, Parkville, Victoria, 3052, Australia; Department of Medical Biology, University of Melbourne, Parkville, Victoria, 3052, Australia
| | - Jonathan Jacobson
- Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute of Infection and Immunity, University of Melbourne, Parkville, Victoria, 3000, Australia
| | - Kate E Jarman
- The Walter and Eliza Hall Institute for Medical Research, Parkville, Victoria, 3052, Australia; Department of Medical Biology, University of Melbourne, Parkville, Victoria, 3052, Australia
| | - Timothy R Blackmore
- The Walter and Eliza Hall Institute for Medical Research, Parkville, Victoria, 3052, Australia; Department of Medical Biology, University of Melbourne, Parkville, Victoria, 3052, Australia
| | - Helene Jousset Sabroux
- The Walter and Eliza Hall Institute for Medical Research, Parkville, Victoria, 3052, Australia; Department of Medical Biology, University of Melbourne, Parkville, Victoria, 3052, Australia
| | - Sharon R Lewin
- Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute of Infection and Immunity, University of Melbourne, Parkville, Victoria, 3000, Australia; The Peter Doherty Institute for Infection and Immunity, The University of Melbourne and Royal Melbourne Hospital, Parkville, Victoria, 3000, Australia; Department of Infectious Diseases, Alfred Health and Monash University, Melbourne, Victoria, 3004, Australia
| | - Damian F Purcell
- Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute of Infection and Immunity, University of Melbourne, Parkville, Victoria, 3000, Australia
| | - Brad E Sleebs
- The Walter and Eliza Hall Institute for Medical Research, Parkville, Victoria, 3052, Australia; Department of Medical Biology, University of Melbourne, Parkville, Victoria, 3052, Australia.
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19
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P-TEFb as A Promising Therapeutic Target. Molecules 2020; 25:molecules25040838. [PMID: 32075058 PMCID: PMC7070488 DOI: 10.3390/molecules25040838] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2020] [Revised: 02/06/2020] [Accepted: 02/07/2020] [Indexed: 01/19/2023] Open
Abstract
The positive transcription elongation factor b (P-TEFb) was first identified as a general factor that stimulates transcription elongation by RNA polymerase II (RNAPII), but soon afterwards it turned out to be an essential cellular co-factor of human immunodeficiency virus (HIV) transcription mediated by viral Tat proteins. Studies on the mechanisms of Tat-dependent HIV transcription have led to radical advances in our knowledge regarding the mechanism of eukaryotic transcription, including the discoveries that P-TEFb-mediated elongation control of cellular transcription is a main regulatory step of gene expression in eukaryotes, and deregulation of P-TEFb activity plays critical roles in many human diseases and conditions in addition to HIV/AIDS. P-TEFb is now recognized as an attractive and promising therapeutic target for inflammation/autoimmune diseases, cardiac hypertrophy, cancer, infectious diseases, etc. In this review article, I will summarize our knowledge about basic P-TEFb functions, the regulatory mechanism of P-TEFb-dependent transcription, P-TEFb’s involvement in biological processes and diseases, and current approaches to manipulating P-TEFb functions for the treatment of these diseases.
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20
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Shelton SB, Shah NM, Abell NS, Devanathan SK, Mercado M, Xhemalçe B. Crosstalk between the RNA Methylation and Histone-Binding Activities of MePCE Regulates P-TEFb Activation on Chromatin. Cell Rep 2019; 22:1374-1383. [PMID: 29425494 DOI: 10.1016/j.celrep.2018.01.028] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2017] [Revised: 12/14/2017] [Accepted: 01/10/2018] [Indexed: 10/18/2022] Open
Abstract
RNAP II switching from the paused to the productive transcription elongation state is a pivotal regulatory step that requires specific phosphorylations catalyzed by the P-TEFb kinase. Nucleosolic P-TEFb activity is inhibited by its interaction with the ribonuclear protein complex built around the 7SK small nuclear RNA (7SK snRNP). MePCE is the RNA methyltransferase that methylates and stabilizes 7SK in the nucleosol. Here, we report that MePCE also binds chromatin through the histone H4 tail to serve as a P-TEFb activator at specific genes important for cellular identity. Notably, this histone binding abolishes MePCE's RNA methyltransferase activity toward 7SK, which explains why MePCE-bound P-TEFb on chromatin may not be associated with the full 7SK snRNP and is competent for RNAP II activation. Overall, our results suggest that crosstalk between the histone-binding and RNA methylation activities of MePCE regulates P-TEFb activation on chromatin in a 7SK- and Brd4-independent manner.
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Affiliation(s)
- Samantha B Shelton
- Department of Molecular Biosciences, 2500 Speedway, Austin, TX 78712, USA
| | - Nakul M Shah
- Department of Molecular Biosciences, 2500 Speedway, Austin, TX 78712, USA
| | - Nathan S Abell
- Department of Molecular Biosciences, 2500 Speedway, Austin, TX 78712, USA; Department of Genetics, Stanford University School of Medicine, 300 Pasteur Drive, Stanford, CA 94305-5324, USA
| | | | - Marvin Mercado
- Department of Molecular Biosciences, 2500 Speedway, Austin, TX 78712, USA
| | - Blerta Xhemalçe
- Department of Molecular Biosciences, 2500 Speedway, Austin, TX 78712, USA.
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21
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Bunch H, Choe H, Kim J, Jo DS, Jeon S, Lee S, Cho DH, Kang K. P-TEFb Regulates Transcriptional Activation in Non-coding RNA Genes. Front Genet 2019; 10:342. [PMID: 31068966 PMCID: PMC6491683 DOI: 10.3389/fgene.2019.00342] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Accepted: 03/29/2019] [Indexed: 01/16/2023] Open
Abstract
Many non-coding RNAs (ncRNAs) serve as regulatory molecules in various physiological pathways, including gene expression in mammalian cells. Distinct from protein-coding RNA expression, ncRNA expression is regulated solely by transcription and RNA processing/stability. It is thus important to understand transcriptional regulation in ncRNA genes but is yet to be known completely. Previously, we identified that a subset of mammalian ncRNA genes is transcriptionally regulated by RNA polymerase II (Pol II) promoter-proximal pausing and in a tissue-specific manner. In this study, human ncRNA genes that are expressed in the early G1 phase, termed immediate early ncRNA genes, were monitored to assess the function of positive transcription elongation factor b (P-TEFb), a master Pol II pausing regulator for protein-coding genes, in ncRNA transcription. Our findings indicate that the expression of many ncRNA genes is induced in the G0–G1 transition and regulated by P-TEFb. Interestingly, a biphasic characteristic of P-TEFb-dependent transcription of serum responsive ncRNA genes was observed: Pol II carboxyl-terminal domain phosphorylated at serine 2 (S2) was largely increased in the transcription start site (TSS, -300 to +300) whereas overall, it was decreased in the gene body (GB, > +350) upon chemical inhibition of P-TEFb. In addition, the three representative, immediate early ncRNAs, whose expression is dependent on P-TEFb, metastasis-associated lung adenocarcinoma transcript 1 (MALAT1), nuclear enriched abundant transcript 1 (NEAT1), and X-inactive specific transcript (XIST), were further analyzed for determining P-TEFb association. Taken together, our data suggest that transcriptional activation of many human ncRNAs utilizes the pausing and releasing of Pol II, and that the regulatory mechanism of transcriptional elongation in these genes requires the function of P-TEFb. Furthermore, we propose that ncRNA and mRNA transcription are regulated by similar mechanisms while P-TEFb inhibition unexpectedly increases S2 Pol II phosphorylation in the TSSs in many ncRNA genes. One Sentence Summary: P-TEFb regulates Pol II phosphorylation for transcriptional activation in many stimulus-inducible ncRNA genes.
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Affiliation(s)
- Heeyoun Bunch
- Department of Applied Biosciences, College of Agriculture and Life Sciences, Kyungpook National University, Daegu, South Korea
| | - Hyeseung Choe
- Department of Applied Biosciences, College of Agriculture and Life Sciences, Kyungpook National University, Daegu, South Korea
| | - Jongbum Kim
- Department of Transcriptome & Epigenome, Macrogen Incorporated, Seoul, South Korea
| | - Doo Sin Jo
- Institute of Life Science and Biotechnology, College of Natural Science, Kyungpook National University, Daegu, South Korea
| | - Soyeon Jeon
- Department of Applied Biosciences, College of Agriculture and Life Sciences, Kyungpook National University, Daegu, South Korea
| | - Sanghwa Lee
- Department of Applied Biosciences, College of Agriculture and Life Sciences, Kyungpook National University, Daegu, South Korea
| | - Dong-Hyung Cho
- Department of Life Science, College of Natural Science, Kyungpook National University, Daegu, South Korea
| | - Keunsoo Kang
- Department of Microbiology, College of Natural Sciences, Dankook University, Cheonan, South Korea
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22
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Chen L, Keppler OT, Schölz C. Post-translational Modification-Based Regulation of HIV Replication. Front Microbiol 2018; 9:2131. [PMID: 30254620 PMCID: PMC6141784 DOI: 10.3389/fmicb.2018.02131] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Accepted: 08/20/2018] [Indexed: 12/13/2022] Open
Abstract
Human immunodeficiency virus (HIV) relies heavily on the host cellular machinery for production of viral progeny. To exploit cellular proteins for replication and to overcome host factors with antiviral activity, HIV has evolved a set of regulatory and accessory proteins to shape an optimized environment for its replication and to facilitate evasion from the immune system. Several cellular pathways are hijacked by the virus to modulate critical steps during the viral life cycle. Thereby, post-translational modifications (PTMs) of viral and cellular proteins gain increasingly attention as modifying enzymes regulate virtually every step of the viral replication cycle. This review summarizes the current knowledge of HIV-host interactions influenced by PTMs with a special focus on acetylation, ubiquitination, and phosphorylation of proteins linked to cellular signaling and viral replication. Insights into these interactions are surmised to aid development of new intervention strategies.
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Affiliation(s)
- Lin Chen
- Max von Pettenkofer-Institute and Gene Center, Virology, National Reference Center for Retroviruses, Faculty of Medicine, Ludwig-Maximilians-University Munich, Munich, Germany
| | - Oliver T Keppler
- Max von Pettenkofer-Institute and Gene Center, Virology, National Reference Center for Retroviruses, Faculty of Medicine, Ludwig-Maximilians-University Munich, Munich, Germany
| | - Christian Schölz
- Max von Pettenkofer-Institute and Gene Center, Virology, National Reference Center for Retroviruses, Faculty of Medicine, Ludwig-Maximilians-University Munich, Munich, Germany
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23
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Mok MT, Zhou J, Tang W, Zeng X, Oliver AW, Ward SE, Cheng AS. CCRK is a novel signalling hub exploitable in cancer immunotherapy. Pharmacol Ther 2018; 186:138-151. [PMID: 29360538 DOI: 10.1016/j.pharmthera.2018.01.008] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Cyclin-dependent kinase 20 (CDK20), or more commonly referred to as cell cycle-related kinase (CCRK), is the latest member of CDK family with strong linkage to human cancers. Accumulating studies have reported the consistent overexpression of CCRK in cancers arising from brain, colon, liver, lung and ovary. Such aberrant up-regulation of CCRK is clinically significant as it correlates with tumor staging, shorter patient survival and poor prognosis. Intriguingly, the signalling molecules perturbed by CCRK are divergent and cancer-specific, including the cell cycle regulators CDK2, cyclin D1, cyclin E and RB in glioblastoma, ovarian carcinoma and colorectal cancer, and KEAP1-NRF2 cytoprotective pathway in lung cancer. In hepatocellular carcinoma (HCC), CCRK mediates virus-host interaction to promote hepatitis B virus-associated tumorigenesis. Further mechanistic analyses reveal that CCRK orchestrates a self-reinforcing circuitry comprising of AR, GSK3β, β-catenin, AKT, EZH2, and NF-κB signalling for transcriptional and epigenetic regulation of oncogenes and tumor suppressor genes. Notably, EZH2 and NF-κB in this circuit have been recently shown to induce IL-6 production to facilitate tumor immune evasion. Concordantly, in a hepatoma preclinical model, ablation of Ccrk disrupts the immunosuppressive tumor microenvironment and enhances the therapeutic efficacy of immune checkpoint blockade via potentiation of anti-tumor T cell responses. In this review, we summarized the multifaceted tumor-intrinsic and -extrinsic functions of CCRK, which represents a novel signalling hub exploitable in cancer immunotherapy.
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Affiliation(s)
- Myth T Mok
- School of Biomedical Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Jingying Zhou
- School of Biomedical Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Wenshu Tang
- School of Biomedical Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Xuezhen Zeng
- School of Biomedical Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Antony W Oliver
- Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Falmer, UK
| | - Simon E Ward
- Medicines Discovery Institute, Cardiff University, Main Building, Cardiff, Wales, CF10 3AT, UK
| | - Alfred S Cheng
- School of Biomedical Sciences, The Chinese University of Hong Kong, Hong Kong, China; State Key Laboratory of Digestive Disease, The Chinese University of Hong Kong, Hong Kong, China.
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24
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Ser7 of RNAPII-CTD facilitates heterochromatin formation by linking ncRNA to RNAi. Proc Natl Acad Sci U S A 2017; 114:E11208-E11217. [PMID: 29237752 DOI: 10.1073/pnas.1714579115] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Some long noncoding RNAs (ncRNAs) transcribed by RNA polymerase II (RNAPII) are retained on chromatin, where they regulate RNAi and chromatin structure. The molecular basis of this retention remains unknown. We show that in fission yeast serine 7 (Ser7) of the C-terminal domain (CTD) of RNAPII is required for efficient siRNA generation for RNAi-dependent heterochromatin formation. Surprisingly, Ser7 facilitates chromatin retention of nascent heterochromatic RNAs (hRNAs). Chromatin retention of hRNAs and siRNA generation requires both Ser7 and an RNA-binding activity of the chromodomain of Chp1, a subunit of the RNA-induced transcriptional silencing (RITS) complex. Furthermore, RITS associates with RNAPII in a Ser7-dependent manner. We propose that Ser7 promotes cotranscriptional chromatin retention of hRNA by recruiting the RNA-chromatin connector protein Chp1, which facilitates RNAi-dependent heterochromatin formation. Our findings reveal a function of the CTD code: linking ncRNA transcription to RNAi for heterochromatin formation.
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25
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Bromodomain-containing Protein 4 Activates Voltage-gated Sodium Channel 1.7 Transcription in Dorsal Root Ganglia Neurons to Mediate Thermal Hyperalgesia in Rats. Anesthesiology 2017; 127:862-877. [DOI: 10.1097/aln.0000000000001809] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Abstract
Background
Bromodomain-containing protein 4 binds acetylated promoter histones and promotes transcription; however, the role of bromodomain-containing protein 4 in inflammatory hyperalgesia remains unclear.
Methods
Male Sprague–Dawley rats received hind paw injections of complete Freund’s adjuvant to induce hyperalgesia. The dorsal root ganglia were examined to detect changes in bromodomain-containing protein 4 expression and the activation of genes involved in the expression of voltage-gated sodium channel 1.7, which is a key pain-related ion channel.
Results
The intraplantar complete Freund’s adjuvant injections resulted in thermal hyperalgesia (4.0 ± 1.5 s; n = 7). The immunohistochemistry and immunoblotting results demonstrated an increase in the bromodomain-containing protein 4–expressing dorsal root ganglia neurons (3.78 ± 0.38 fold; n = 7) and bromodomain-containing protein 4 protein levels (2.62 ± 0.39 fold; n = 6). After the complete Freund’s adjuvant injection, histone H3 protein acetylation was enhanced in the voltage-gated sodium channel 1.7 promoter, and cyclin-dependent kinase 9 and phosphorylation of RNA polymerase II were recruited to this area. Furthermore, the voltage-gated sodium channel 1.7–mediated currents were enhanced in neurons of the complete Freund’s adjuvant rats (55 ± 11 vs. 19 ± 9 pA/pF; n = 4 to 6 neurons). Using bromodomain-containing protein 4–targeted antisense small interfering RNA to the complete Freund’s adjuvant–treated rats, the authors demonstrated a reduction in the expression of bromodomain-containing protein 4 (0.68 ± 0.16 fold; n = 7), a reduction in thermal hyperalgesia (7.5 ± 1.5 s; n = 7), and a reduction in the increased voltage-gated sodium channel 1.7 currents (21 ± 4 pA/pF; n = 4 to 6 neurons).
Conclusions
Complete Freund’s adjuvant triggers enhanced bromodomain-containing protein 4 expression, ultimately leading to the enhanced excitability of nociceptive neurons and thermal hyperalgesia. This effect is likely mediated by the enhanced expression of voltage-gated sodium channel 1.7.
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26
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Burenina OY, Oretskaya TS, Kubareva EA. Non-Coding RNAs As Transcriptional Regulators In Eukaryotes. Acta Naturae 2017; 9:13-25. [PMID: 29340213 PMCID: PMC5762824] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Indexed: 10/31/2022] Open
Abstract
Non-coding RNAs up to 1,000 nucleotides in length are widespread in eukaryotes and fulfil various regulatory functions, in particular during chromatin remodeling and cell proliferation. These RNAs are not translated into proteins: thus, they are non-coding RNAs (ncRNAs). The present review describes the eukaryotic ncRNAs involved in transcription regulation, first and foremost, targeting RNA polymerase II (RNAP II) and/or its major proteinaceous transcription factors. The current state of knowledge concerning the regulatory functions of SRA and TAR RNA, 7SK and U1 snRNA, GAS5 and DHFR RNA is summarized herein. Special attention is given to murine B1 and B2 RNAs and human Alu RNA, due to their ability to bind the active site of RNAP II. Discovery of bacterial analogs of the eukaryotic small ncRNAs involved in transcription regulation, such as 6S RNAs, suggests that they possess a common evolutionary origin.
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Affiliation(s)
- O. Y. Burenina
- Skolkovo Institute of Science and Technology, Nobel Str. 3, Moscow, 143026, Russia
- Lomonosov Moscow State University, Chemistry Department, Leninskie Gory 1, bld. 3, Moscow, 119991 , Russia
| | - T. S. Oretskaya
- Lomonosov Moscow State University, Chemistry Department, Leninskie Gory 1, bld. 3, Moscow, 119991 , Russia
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Leninskie Gory 1, bld. 40, Moscow, 119991, Russia
| | - E. A. Kubareva
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Leninskie Gory 1, bld. 40, Moscow, 119991, Russia
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27
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Paparidis NFDS, Durvale MC, Canduri F. The emerging picture of CDK9/P-TEFb: more than 20 years of advances since PITALRE. MOLECULAR BIOSYSTEMS 2017; 13:246-276. [PMID: 27833949 DOI: 10.1039/c6mb00387g] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
CDK9 is a prominent member of the transcriptional CDKs subfamily, a group of kinases whose function is to control the primary steps of mRNA synthesis and processing by eukaryotic RNA polymerase II. As a cyclin-dependent kinase, CDK9 activation in vivo depends upon its association with T-type cyclins to assemble the positive transcription elongation factor (P-TEFb). Although CDK9/P-TEFb phosphorylates the C-terminal domain of RNAP II in the same positions targeted by CDK7 (TFIIH) and CDK8 (Mediator), the former does not participate in the transcription initiation, but rather plays a unique role by driving the polymerase to productive elongation. In addition to RNAP II CTD, the negative transcription elongation factors DSIF and NELF also represent major CDK9 substrates, whose phosphorylation is required to overcome the proximal pause of the polymerase. CDK9 is recruited to specific genes through proteins that interact with both P-TEFb and distinct elements in DNA, RNA or chromatin, where it modulates the activity of individual RNAP II transcription complexes. The regulation of CDK9 function is an intricate network that includes post-translational modifications (phosphorylation/dephosphorylation and acetylation/deacetylation of key residues) as well as the association of P-TEFb with various proteins that can stimulate or inhibit its kinase activity. Several cases of CDK9 deregulation have been linked to important human diseases, including various types of cancer and also AIDS (due to its essential role in HIV replication). Not only HIV, but also many other human viruses have been shown to depend strongly on CDK9 activity to be transcribed within host cells. This review summarizes the main advances made on CDK9/P-TEFb field in more than 20 years, introducing the structural, functional and genetic aspects that have been elucidated ever since.
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Affiliation(s)
- Nikolas Ferreira Dos Santos Paparidis
- Department of Chemistry and Molecular Physics, Institute of Chemistry of Sao Carlos, Sao Paulo University, Av. Trabalhador Sãocarlense, 400, Zip Code 780, 13560-970, São Carlos-SP, Brazil.
| | - Maxwell Castro Durvale
- Department of Biochemistry, Institute of Chemistry, Sao Paulo University, Av. Prof. Lineu Prestes, 748, 05508-000, Butantã - São Paulo - SP, Brazil
| | - Fernanda Canduri
- Department of Chemistry and Molecular Physics, Institute of Chemistry of Sao Carlos, Sao Paulo University, Av. Trabalhador Sãocarlense, 400, Zip Code 780, 13560-970, São Carlos-SP, Brazil.
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Asamitsu K, Hirokawa T, Okamoto T. MD simulation of the Tat/Cyclin T1/CDK9 complex revealing the hidden catalytic cavity within the CDK9 molecule upon Tat binding. PLoS One 2017; 12:e0171727. [PMID: 28178316 PMCID: PMC5298246 DOI: 10.1371/journal.pone.0171727] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2016] [Accepted: 01/24/2017] [Indexed: 02/02/2023] Open
Abstract
In this study, we applied molecular dynamics (MD) simulation to analyze the dynamic behavior of the Tat/CycT1/CDK9 tri-molecular complex and revealed the structural changes of P-TEFb upon Tat binding. We found that Tat could deliberately change the local flexibility of CycT1. Although the structural coordinates of the H1 and H2 helices did not substantially change, H1', H2', and H3' exhibited significant changes en masse. Consequently, the CycT1 residues involved in Tat binding, namely Tat-recognition residues (TRRs), lost their flexibility with the addition of Tat to P-TEFb. In addition, we clarified the structural variation of CDK9 in complex with CycT1 in the presence or absence of Tat. Interestingly, Tat addition significantly reduced the structural variability of the T-loop, thus consolidating the structural integrity of P-TEFb. Finally, we deciphered the formation of the hidden catalytic cavity of CDK9 upon Tat binding. MD simulation revealed that the PITALRE signature sequence of CDK9 flips the inactive kinase cavity of CDK9 into the active form by connecting with Thr186, which is crucial for its activity, thus presumably recruiting the substrate peptide such as the C-terminal domain of RNA pol II. These findings provide vital information for the development of effective novel anti-HIV drugs with CDK9 catalytic activity as the target.
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Grants
- Ministry of Education, Culture, Sports, Science, and Technology "The Platform Project for Supporting Drug Discovery and Life Science Research (Platform for Drug Discovery, Informatics, and Structural Life Science)"
- Ministry of Education, Culture, Sports, Science, and Technology
- Asahi Grass Foundation
- Japan Agency for Medical Research and Development
- Junwakai Foundation
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Affiliation(s)
- Kaori Asamitsu
- Department of Molecular and Cellular Biology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Aichi, Japan
| | - Takatsugu Hirokawa
- Molecular Profiling Research Center for Drug Discovery (molprof), National Institute of Advanced Industrial Science and Technology (AIST), Tokyo, Japan
- Division of Biomedical Science, Faculty of Medicine, University of Tsukuba, Tsukuba, Ibaraki, Japan
- * E-mail: (TH); (TO)
| | - Takashi Okamoto
- Department of Molecular and Cellular Biology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Aichi, Japan
- * E-mail: (TH); (TO)
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Specific Inhibition of HIV Infection by the Action of Spironolactone in T Cells. J Virol 2016; 90:10972-10980. [PMID: 27681137 DOI: 10.1128/jvi.01722-16] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Accepted: 09/21/2016] [Indexed: 11/20/2022] Open
Abstract
Tat protein, the HIV transactivator, regulates transcription of the HIV genome by the host transcription machinery. Efficient inhibitors of HIV transcription that target Tat or the cellular cofactor NF-κB are well known. However, inhibition of HIV Tat-dependent transcription by targeting the general transcription and DNA repair factor II human (TFIIH) has not been reported. Here, we show that spironolactone (SP), an aldosterone antagonist approved for clinical use, inhibits HIV-1 and HIV-2 infection of permissive T cells by blocking viral Tat-dependent transcription from the long terminal repeat (LTR). We found that treatment of Jurkat and primary CD4+ T cells with SP induces degradation of the XPB cellular helicase, a component of the TFIIH complex, without affecting cellular mRNA levels, T cell viability, or T cell proliferation. We further demonstrate that the effect of SP on HIV infection is independent of its aldosterone antagonist function, since the structural analogue, eplerenone, does not induce XPB degradation and does not inhibit HIV infection. Rescue experiments showed that the SP-induced block of HIV infection relies, at least partially, on XPB degradation. In addition, we demonstrate that SP specifically inhibits Tat-dependent transcription, since basal transcription from the LTR is not affected. Our results demonstrate that SP is a specific inhibitor of HIV Tat-dependent transcription in T cells, which additionally suggests that XPB is a cofactor required for HIV infection. Targeting a cellular cofactor of HIV transcription constitutes an alternative strategy to inhibit HIV infection, together with the existing antiretroviral therapy. IMPORTANCE Transcription from the HIV promoter is regulated by the combined activities of the host transcription machinery and the viral transactivator Tat protein. Here, we report that the drug spironolactone-an antagonist of aldosterone-blocks viral Tat-dependent transcription, thereby inhibiting both HIV-1 and HIV-2 infection of permissive T cells. This inhibition relies on the degradation of the cellular helicase XPB, a component of the TFIIH transcription factor complex. Consequently, XPB appears to be a novel HIV cofactor. Our discovery of the HIV-inhibitory activity of spironolactone opens the way for the development of novel anti-HIV strategies targeting a cellular cofactor without the limitations of antiretroviral therapy of drug resistance and high cost.
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Knyazhanskaya ES, Shadrina OA, Anisenko AN, Gottikh MB. Role of DNA-dependent protein kinase in the HIV-1 replication cycle. Mol Biol 2016. [DOI: 10.1134/s0026893316040075] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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31
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Zaborowska J, Isa NF, Murphy S. P-TEFb goes viral. Bioessays 2016; 38 Suppl 1:S75-85. [DOI: 10.1002/bies.201670912] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2015] [Revised: 09/23/2015] [Accepted: 09/26/2015] [Indexed: 01/31/2023]
Affiliation(s)
| | - Nur F. Isa
- Sir William Dunn School of Pathology; University of Oxford; Oxford UK
- Department of Biotechnology; Kulliyyah of Science, IIUM; Kuantan Pahang Malaysia
| | - Shona Murphy
- Sir William Dunn School of Pathology; University of Oxford; Oxford UK
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McNamara RP, Bacon CW, D'Orso I. Transcription elongation control by the 7SK snRNP complex: Releasing the pause. Cell Cycle 2016; 15:2115-2123. [PMID: 27152730 DOI: 10.1080/15384101.2016.1181241] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The ability for the eukaryotic cell to transcriptionally respond to various stimuli is critical for the overall homeostasis of the cell, and in turn, the organism. The human RNA polymerase II complex (Pol II), which is responsible for the transcription of protein-encoding genes and non-coding RNAs, is paused at promoter-proximal regions to ensure their rapid activation. In response to stimulation, Pol II pause release is facilitated by the action of positive transcription elongation factors such as the P-TEFb kinase. However, the majority of P-TEFb is held in a catalytically inactivate state, assembled into the 7SK small nuclear ribonucleoprotein (snRNP) complex, and must be dislodged to become catalytically active. In this review, we discuss mechanisms of 7SK snRNP recruitment to promoter-proximal regions and P-TEFb disassembly from the inhibitory snRNP to regulate 'on site' kinase activation and Pol II pause release.
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Affiliation(s)
- Ryan P McNamara
- a Department of Microbiology , The University of Texas Southwestern Medical Center , Dallas , TX , USA
| | - Curtis W Bacon
- a Department of Microbiology , The University of Texas Southwestern Medical Center , Dallas , TX , USA
| | - Iván D'Orso
- a Department of Microbiology , The University of Texas Southwestern Medical Center , Dallas , TX , USA
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López-Huertas MR, Li J, Zafar A, Rodríguez-Mora S, García-Domínguez C, Mateos E, Alcamí J, Rao S, Coiras M. PKCθ and HIV-1 Transcriptional Regulator Tat Co-exist at the LTR Promoter in CD4(+) T Cells. Front Immunol 2016; 7:69. [PMID: 26973648 PMCID: PMC4770193 DOI: 10.3389/fimmu.2016.00069] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2015] [Accepted: 02/15/2016] [Indexed: 11/17/2022] Open
Abstract
PKCθ is essential for the activation of CD4+ T cells. Upon TCR/CD28 stimulation, PKCθ is phosphorylated and migrates to the immunological synapse, inducing the activation of cellular transcription factors such as NF-κB and kinases as ERK that are critical for HIV-1 replication. We previously demonstrated that PKCθ is also necessary for HIV-1 replication but the precise mechanism is unknown. Efficient HIV-1 transcription and elongation are absolutely dependent on the synergy between NF-κB and the viral regulator Tat. Tat exerts its function by binding a RNA stem-loop structure proximal to the viral mRNA cap site termed TAR. Besides, due to its effect on cellular metabolic pathways, Tat causes profound changes in infected CD4+ T cells such as the activation of NF-κB and ERK. We hypothesized that the aberrant upregulation of Tat-mediated activation of NF-κB and ERK occurred through PKCθ signaling. In fact, Jurkat TetOff cells with stable and doxycycline-repressible expression of Tat (Jurkat-Tat) expressed high levels of mRNA for PKCθ. In these cells, PKCθ located at the plasma membrane was phosphorylated at T538 residue in undivided cells, in the absence of stimulation. Treatment with doxycycline inhibited PKCθ phosphorylation in Jurkat-Tat, suggesting that Tat expression was directly related to the activation of PKCθ. Both NF-κB and Ras/Raf/MEK/ERK signaling pathway were significantly activated in Jurkat-Tat cells, and this correlated with high transactivation of HIV-1 LTR promoter. RNA interference for PKCθ inhibited NF-κB and ERK activity, as well as LTR-mediated transactivation even in the presence of Tat. In addition to Tat-mediated activation of PKCθ in the cytosol, we demonstrated by sequential ChIP that Tat and PKCθ coexisted in the same complex bound at the HIV-1 LTR promoter, specifically at the region containing TAR loop. In conclusion, PKCθ-Tat interaction seemed to be essential for HIV-1 replication in CD4+ T cells and could be used as a therapeutic target.
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Affiliation(s)
- María Rosa López-Huertas
- AIDS Immunopathology Unit, National Center of Microbiology, Instituto de Salud Carlos III , Madrid , Spain
| | - Jasmine Li
- Department of Microbiology and Immunology, The Doherty Institute for Infection and Immunity, University of Melbourne , Melbourne, VIC , Australia
| | - Anjum Zafar
- Biomedical Sciences, Faculty of Education, Science, Technology and Mathematics, University of Canberra , Canberra, ACT , Australia
| | - Sara Rodríguez-Mora
- AIDS Immunopathology Unit, National Center of Microbiology, Instituto de Salud Carlos III , Madrid , Spain
| | - Carlota García-Domínguez
- Functional Research Unit in Chronic Diseases, National Center of Microbiology, Instituto de Salud Carlos III , Madrid , Spain
| | - Elena Mateos
- AIDS Immunopathology Unit, National Center of Microbiology, Instituto de Salud Carlos III , Madrid , Spain
| | - José Alcamí
- AIDS Immunopathology Unit, National Center of Microbiology, Instituto de Salud Carlos III , Madrid , Spain
| | - Sudha Rao
- Biomedical Sciences, Faculty of Education, Science, Technology and Mathematics, University of Canberra , Canberra, ACT , Australia
| | - Mayte Coiras
- AIDS Immunopathology Unit, National Center of Microbiology, Instituto de Salud Carlos III , Madrid , Spain
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Shadrina OA, Knyazhanskaya ES, Korolev S, Gottikh MB. Host Proteins Ku and HMGA1 As Participants of HIV-1 Transcription. Acta Naturae 2016; 8:34-47. [PMID: 27099783 PMCID: PMC4837570] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
Human immunodeficiency virus type 1 is known to use the transcriptional machinery of the host cell for viral gene transcription, and the only viral protein that partakes in this process is Tat, the viral trans-activator of transcription. During acute infection, the binding of Tat to the hairpin at the beginning of the transcribed viral RNA recruits the PTEFb complex, which in turn hyperphosphorylates RNA-polymerase II and stimulates transcription elongation. Along with acute infection, HIV-1 can also lead to latent infection that is characterized by a low level of viral transcription. During the maintenance and reversal of latency, there are no detectable amounts of Tat protein in the cell and the mechanism of transcription activation in the absence of Tat protein remains unclear. The latency maintenance is also a problematic question. It seems evident that cellular proteins with a yet unknown nature or role regulate both transcriptional repression in the latent phase and its activation during transition into the lytic phase. The present review discusses the role of cellular proteins Ku and HMGA1 in the initiation of transcription elongation of the HIV-1 provirus. The review presents data regarding Ku-mediated HIV-1 transcription and its dependence on the promoter structure and the shape of viral DNA. We also describe the differential influence of the HMGA1 protein on the induced and basal transcription of HIV-1. Finally, we offer possible mechanisms for Ku and HMGA1 proteins in the proviral transcription regulation.
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Affiliation(s)
- O. A. Shadrina
- Faculty of Bioengineering and Bioinformatics, Lomonosov Moscow State University, Leninskie Gory, Moscow, 119991, Russia
| | - E. S. Knyazhanskaya
- Chemistry Department, Lomonosov Moscow State University, Leninskie Gory, Moscow, 119991, Russia
| | - S.P. Korolev
- Chemistry Department, Lomonosov Moscow State University, Leninskie Gory, Moscow, 119991, Russia
| | - M. B. Gottikh
- Belozersky Institute of Physical-Chemical Biology, Lomonosov Moscow State University, Leninskie Gory, Moscow, Russia; 119991
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35
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Zaborowska J, Isa NF, Murphy S. P-TEFb goes viral. ACTA ACUST UNITED AC 2015; 1:106-116. [PMID: 27398404 PMCID: PMC4863834 DOI: 10.1002/icl3.1037] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2015] [Revised: 09/23/2015] [Accepted: 09/26/2015] [Indexed: 01/30/2023]
Abstract
Positive transcription elongation factor b (P‐TEFb), which comprises cyclin‐dependent kinase 9 (CDK9) kinase and cyclin T subunits, is an essential kinase complex in human cells. Phosphorylation of the negative elongation factors by P‐TEFb is required for productive elongation of transcription of protein‐coding genes by RNA polymerase II (pol II). In addition, P‐TEFb‐mediated phosphorylation of the carboxyl‐terminal domain (CTD) of the largest subunit of pol II mediates the recruitment of transcription and RNA processing factors during the transcription cycle. CDK9 also phosphorylates p53, a tumor suppressor that plays a central role in cellular responses to a range of stress factors. Many viral factors affect transcription by recruiting or modulating the activity of CDK9. In this review, we will focus on how the function of CDK9 is regulated by viral gene products. The central role of CDK9 in viral life cycles suggests that drugs targeting the interaction between viral products and P‐TEFb could be effective anti‐viral agents.
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Affiliation(s)
| | - Nur F Isa
- Sir William Dunn School of Pathology University of Oxford Oxford UK; Department of Biotechnology Kulliyyah of Science, IIUM Kuantan Pahang Malaysia
| | - Shona Murphy
- Sir William Dunn School of Pathology University of Oxford Oxford UK
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Wang C, Yang S, Lu H, You H, Ni M, Shan W, Lin T, Gao X, Chen H, Zhou Q, Xue Y. A Natural Product from Polygonum cuspidatum Sieb. Et Zucc. Promotes Tat-Dependent HIV Latency Reversal through Triggering P-TEFb's Release from 7SK snRNP. PLoS One 2015; 10:e0142739. [PMID: 26569506 PMCID: PMC4646521 DOI: 10.1371/journal.pone.0142739] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2015] [Accepted: 10/25/2015] [Indexed: 01/22/2023] Open
Abstract
The latent reservoirs of HIV represent a major impediment to eradication of HIV/AIDS. To overcome this problem, agents that can activate latent HIV proviruses have been actively sought after, as they can potentially be used in combination with the highly active antiretroviral therapy (HAART) to eliminate the latent reservoirs. Although several chemical compounds have been shown to activate latency, they are of limited use due to high toxicity and poor clinical outcomes. In an attempt to identify natural products as effective latency activators from traditional Chinese medicinal herbs that have long been widely used in human population, we have isolated procyanidin C-13,3',3"-tri-O-gallate (named as REJ-C1G3) from Polygonum cuspidatum Sieb. et Zucc., that can activate HIV in latently infected Jurkat T cells. REJ-C1G3 preferentially stimulates HIV transcription in a process that depends on the viral encoded Tat protein and acts synergistically with prostratin (an activator of the NF-κB pathway) or JQ1 (an inhibitor of Brd4) to activate HIV latency. Our mechanistic analyses further show that REJ-C1G3 accomplishes these tasks by inducing the release of P-TEFb, a host cofactor essential for Tat-activation of HIV transcription, from the cellular P-TEFb reservoir 7SK snRNP.
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Affiliation(s)
- Cong Wang
- School of Pharmaceutical Sciences, Xiamen University, Xiamen, Fujian, China
| | - Shuiyuan Yang
- School of Pharmaceutical Sciences, Xiamen University, Xiamen, Fujian, China
| | - Huasong Lu
- School of Pharmaceutical Sciences, Xiamen University, Xiamen, Fujian, China
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, United States of America
| | - Hongchao You
- School of Pharmaceutical Sciences, Xiamen University, Xiamen, Fujian, China
| | - Man Ni
- School of Pharmaceutical Sciences, Xiamen University, Xiamen, Fujian, China
| | - Wenjun Shan
- School of Pharmaceutical Sciences, Xiamen University, Xiamen, Fujian, China
| | - Ting Lin
- School of Pharmaceutical Sciences, Xiamen University, Xiamen, Fujian, China
| | - Xiang Gao
- School of Pharmaceutical Sciences, Xiamen University, Xiamen, Fujian, China
| | - Haifeng Chen
- School of Pharmaceutical Sciences, Xiamen University, Xiamen, Fujian, China
| | - Qiang Zhou
- School of Pharmaceutical Sciences, Xiamen University, Xiamen, Fujian, China
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, United States of America
| | - Yuhua Xue
- School of Pharmaceutical Sciences, Xiamen University, Xiamen, Fujian, China
- * E-mail:
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Storch K, Cordes N. The impact of CDK9 on radiosensitivity, DNA damage repair and cell cycling of HNSCC cancer cells. Int J Oncol 2015; 48:191-8. [PMID: 26573875 DOI: 10.3892/ijo.2015.3246] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Accepted: 10/09/2015] [Indexed: 11/06/2022] Open
Abstract
Cyclin-dependent kinase 9 (CDK9), mainly involved in regulation of transcription, has recently been shown to impact on cell cycling and DNA repair. Despite the fact that CDK9 has been proposed as potential cancer target, it remains largely elusive whether CDK9 targeting alters tumor cell radiosensitivity. Five human head and neck squamous cell carcinoma (HNSCC) cell lines (SAS, FaDu, HSC4, Cal33, UTSCC5) as well as SAS cells stably transfected with CDK9-EGFP-N1 plasmid or empty vector controls were used. Upon either CDK9 small interfering RNA knockdown or treatment with a pan-CDK inhibitor (ZK304709), colony formation, DNA double strand breaks (DSBs), apoptosis, cell cycling, and expression and phosphorylation of major cell cycle and DNA damage repair proteins were examined. While CDK9 overexpression mediated radioprotection, CDK9 depletion clearly enhanced the radiosensitivity of HNSCC cells without an induction of apoptosis. While the cell cycle and cell cycle proteins were significantly modulated by CDK9 depletion, no further alterations in these parameters were observed after combined CDK9 knockdown with irradiation. ZK304709 showed concentration-dependent cytotoxicity but failed to radiosensitize HNSCC cells. Our findings suggest a potential role of CDK9 in the radiation response of HNSCC cells. Additional studies are warranted to clarify the usefulness to target CDK9 in the clinic.
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Affiliation(s)
- Katja Storch
- OncoRay - National Center for Radiation Research in Oncology, Medical Faculty Carl Gustav Carus, Dresden University of Technology, D-01307 Dresden, Germany
| | - Nils Cordes
- OncoRay - National Center for Radiation Research in Oncology, Medical Faculty Carl Gustav Carus, Dresden University of Technology, D-01307 Dresden, Germany
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38
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Srivastava R, Ahn SH. Modifications of RNA polymerase II CTD: Connections to the histone code and cellular function. Biotechnol Adv 2015; 33:856-72. [PMID: 26241863 DOI: 10.1016/j.biotechadv.2015.07.008] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2015] [Revised: 07/08/2015] [Accepted: 07/28/2015] [Indexed: 12/24/2022]
Abstract
At the onset of transcription, many protein machineries interpret the cellular signals that regulate gene expression. These complex signals are mostly transmitted to the indispensable primary proteins involved in transcription, RNA polymerase II (RNAPII) and histones. RNAPII and histones are so well coordinated in this cellular function that each cellular signal is precisely allocated to specific machinery depending on the stage of transcription. The carboxy-terminal domain (CTD) of RNAPII in eukaryotes undergoes extensive posttranslational modification, called the 'CTD code', that is indispensable for coupling transcription with many cellular processes, including mRNA processing. The posttranslational modification of histones, known as the 'histone code', is also critical for gene transcription through the reversible and dynamic remodeling of chromatin structure. Notably, the histone code is closely linked with the CTD code, and their combinatorial effects enable the delicate regulation of gene transcription. This review elucidates recent findings regarding the CTD modifications of RNAPII and their coordination with the histone code, providing integrative pathways for the fine-tuned regulation of gene expression and cellular function.
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Affiliation(s)
- Rakesh Srivastava
- Division of Molecular and Life Sciences, College of Science and Technology, Hanyang University, Ansan, Republic of Korea
| | - Seong Hoon Ahn
- Division of Molecular and Life Sciences, College of Science and Technology, Hanyang University, Ansan, Republic of Korea.
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Jin HX, Go ML, Yin P, Qiu XT, Zhu P, Yan XJ. Determining the Functions of HIV-1 Tat and a Second Magnesium Ion in the CDK9/Cyclin T1 Complex: A Molecular Dynamics Simulation Study. PLoS One 2015; 10:e0124673. [PMID: 25909811 PMCID: PMC4409394 DOI: 10.1371/journal.pone.0124673] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2014] [Accepted: 03/16/2015] [Indexed: 11/18/2022] Open
Abstract
The current paradigm of cyclin-dependent kinase (CDK) regulation based on the well-established CDK2 has been recently expanded. The determination of CDK9 crystal structures suggests the requirement of an additional regulatory protein, such as human immunodeficiency virus type 1 (HIV-1) Tat, to exert its physiological functions. In most kinases, the exact number and roles of the cofactor metal ions remain unappreciated, and the repertoire has thus gained increasing attention recently. Here, molecular dynamics (MD) simulations were implemented on CDK9 to explore the functional roles of HIV-1 Tat and the second Mg2+ ion at site 1 (Mg12+). The simulations unveiled that binding of HIV-1 Tat to CDK9 not only stabilized hydrogen bonds (H-bonds) between ATP and hinge residues Asp104 and Cys106, as well as between ATP and invariant Lys48, but also facilitated the salt bridge network pertaining to the phosphorylated Thr186 at the activation loop. By contrast, these H-bonds cannot be formed in CDK9 owing to the absence of HIV-1 Tat. MD simulations further revealed that the Mg12+ ion, coupled with the Mg22+ ion, anchored to the triphosphate moiety of ATP in its catalytic competent conformation. This observation indicates the requirement of the Mg12+ ion for CDK9 to realize its function. Overall, the introduction of HIV-1 Tat and Mg12+ ion resulted in the active site architectural characteristics of phosphorylated CDK9. These data highlighted the functional roles of HIV-1 Tat and Mg12+ ion in the regulation of CDK9 activity, which contributes an important complementary understanding of CDK molecular underpinnings.
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Affiliation(s)
- Hai-Xiao Jin
- Key Laboratory of Applied Marine Biotechnology Ministry of Education, School of Marine Sciences, Ningbo University, Ningbo, China
| | - Mei-Lin Go
- Department of Pharmacy, National University of Singapore, Singapore, Singapore
| | - Peng Yin
- Key Laboratory of Chemical Biology and Traditional Chinese Medicine Research (Ministry of Education), College of Chemistry and Chemical Engineering, Hunan Normal University, Changsha, China
| | - Xiao-Ting Qiu
- Key Laboratory of Applied Marine Biotechnology Ministry of Education, School of Marine Sciences, Ningbo University, Ningbo, China
| | - Peng Zhu
- Key Laboratory of Applied Marine Biotechnology Ministry of Education, School of Marine Sciences, Ningbo University, Ningbo, China
| | - Xiao-Jun Yan
- Key Laboratory of Applied Marine Biotechnology Ministry of Education, School of Marine Sciences, Ningbo University, Ningbo, China
- * E-mail:
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Eifler TT, Shao W, Bartholomeeusen K, Fujinaga K, Jäger S, Johnson JR, Luo Z, Krogan NJ, Peterlin BM. Cyclin-dependent kinase 12 increases 3' end processing of growth factor-induced c-FOS transcripts. Mol Cell Biol 2015; 35:468-78. [PMID: 25384976 PMCID: PMC4272423 DOI: 10.1128/mcb.01157-14] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2014] [Revised: 10/07/2014] [Accepted: 11/01/2014] [Indexed: 01/05/2023] Open
Abstract
Transcriptional cyclin-dependent kinases (CDKs) regulate RNA polymerase II initiation and elongation as well as cotranscriptional mRNA processing. In this report, we describe an important role for CDK12 in the epidermal growth factor (EGF)-induced c-FOS proto-oncogene expression in mammalian cells. This kinase was found in the exon junction complexes (EJC) together with SR proteins and was thus recruited to RNA polymerase II. In cells depleted of CDK12 or eukaryotic translation initiation factor 4A3 (eIF4A3) from the EJC, EGF induced fewer c-FOS transcripts. In these cells, phosphorylation of serines at position 2 in the C-terminal domain (CTD) of RNA polymerase II, as well as levels of cleavage-stimulating factor 64 (Cstf64) and 73-kDa subunit of cleavage and polyadenylation specificity factor (CPSF73), was reduced at the c-FOS gene. These effects impaired 3' end processing of c-FOS transcripts. Mutant CDK12 proteins lacking their Arg-Ser-rich (RS) domain or just the RS domain alone acted as dominant negative proteins. Thus, CDK12 plays an important role in cotranscriptional processing of c-FOS transcripts.
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Affiliation(s)
- Tristan T Eifler
- Department of Medicine, Microbiology and Immunology, University of California at San Francisco, San Francisco, California, USA
| | - Wei Shao
- Department of Medicine, Microbiology and Immunology, University of California at San Francisco, San Francisco, California, USA
| | - Koen Bartholomeeusen
- Department of Medicine, Microbiology and Immunology, University of California at San Francisco, San Francisco, California, USA
| | - Koh Fujinaga
- Department of Medicine, Microbiology and Immunology, University of California at San Francisco, San Francisco, California, USA
| | - Stefanie Jäger
- Department of Cellular and Molecular Pharmacology, University of California at San Francisco, San Francisco, California, USA California Institute for Quantitative Biosciences, QB3, San Francisco, California, USA
| | - Jeff R Johnson
- Department of Cellular and Molecular Pharmacology, University of California at San Francisco, San Francisco, California, USA California Institute for Quantitative Biosciences, QB3, San Francisco, California, USA
| | - Zeping Luo
- Department of Medicine, Microbiology and Immunology, University of California at San Francisco, San Francisco, California, USA
| | - Nevan J Krogan
- Department of Cellular and Molecular Pharmacology, University of California at San Francisco, San Francisco, California, USA California Institute for Quantitative Biosciences, QB3, San Francisco, California, USA
| | - B Matija Peterlin
- Department of Medicine, Microbiology and Immunology, University of California at San Francisco, San Francisco, California, USA
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41
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Bowman EA, Kelly WG. RNA polymerase II transcription elongation and Pol II CTD Ser2 phosphorylation: A tail of two kinases. Nucleus 2014; 5:224-36. [PMID: 24879308 DOI: 10.4161/nucl.29347] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The transition between initiation and productive elongation during RNA Polymerase II (Pol II) transcription is a well-appreciated point of regulation across many eukaryotes. Elongating Pol II is modified by phosphorylation of serine 2 (Ser2) on its carboxy terminal domain (CTD) by two kinases, Bur1/Ctk1 in yeast and Cdk9/Cdk12 in metazoans. Here, we discuss the roles and regulation of these kinases and their relationship to Pol II elongation control, and focus on recent data from work in C. elegans that point out gaps in our current understand of transcription elongation.
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Affiliation(s)
- Elizabeth A Bowman
- National Institute of Environmental Health Sciences; Research Triangle Park, NC USA
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42
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Nowarski R, Prabhu P, Kenig E, Smith Y, Britan-Rosich E, Kotler M. APOBEC3G inhibits HIV-1 RNA elongation by inactivating the viral trans-activation response element. J Mol Biol 2014; 426:2840-53. [PMID: 24859335 DOI: 10.1016/j.jmb.2014.05.012] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2014] [Revised: 05/14/2014] [Accepted: 05/15/2014] [Indexed: 10/25/2022]
Abstract
Deamination of cytidine residues in viral DNA is a major mechanism by which APOBEC3G (A3G) inhibits vif-deficient human immunodeficiency virus type 1 (HIV-1) replication. dC-to-dU transition following RNase-H activity leads to viral cDNA degradation, production of non-functional proteins, formation of undesired stop codons and decreased viral protein synthesis. Here, we demonstrate that A3G provides an additional layer of defense against HIV-1 infection dependent on inhibition of proviral transcription. HIV-1 transcription elongation is regulated by the trans-activation response (TAR) element, a short stem-loop RNA structure required for elongation factors binding. Vif-deficient HIV-1-infected cells accumulate short viral transcripts and produce lower amounts of full-length HIV-1 transcripts due to A3G deamination of the TAR apical loop cytidine, highlighting the requirement for TAR loop integrity in HIV-1 transcription. We further show that free single-stranded DNA (ssDNA) termini are not essential for A3G activity and a gap of CCC motif blocked with juxtaposed DNA or RNA on either or 3'+5' ends is sufficient for A3G deamination. These results identify A3G as an efficient mutator and that deamination of (-)SSDNA results in an early block of HIV-1 transcription.
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Affiliation(s)
- Roni Nowarski
- Department of Pathology and Lautenberg Center for General and Tumor Immunology, Jerusalem 91120, Israel
| | - Ponnandy Prabhu
- Department of Pathology and Lautenberg Center for General and Tumor Immunology, Jerusalem 91120, Israel
| | - Edan Kenig
- Department of Pathology and Lautenberg Center for General and Tumor Immunology, Jerusalem 91120, Israel
| | - Yoav Smith
- Genomic Data Analysis Unit, The Hebrew University Hadassah Medical School, Jerusalem 91120, Israel
| | - Elena Britan-Rosich
- Department of Pathology and Lautenberg Center for General and Tumor Immunology, Jerusalem 91120, Israel
| | - Moshe Kotler
- Department of Pathology and Lautenberg Center for General and Tumor Immunology, Jerusalem 91120, Israel.
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43
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Zhao W, Liu Y, Timani KA, He JJ. Tip110 protein binds to unphosphorylated RNA polymerase II and promotes its phosphorylation and HIV-1 long terminal repeat transcription. J Biol Chem 2013; 289:190-202. [PMID: 24217245 DOI: 10.1074/jbc.m113.529784] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Transcription plays an important role in both HIV-1 gene expression and replication and mandates complicated but coordinated interactions between the host and virus. Our previous studies have shown that an HIV-1 Tat-interacting protein of 110 kDa, Tip110, binds to and enhances Tat function in Tat-mediated HIV-1 gene transcription and replication (Liu, Y., Li, J., Kim, B. O., Pace, B. S., and He, J. J. (2002) HIV-1 Tat protein-mediated transactivation of the HIV-1 long terminal repeat promoter is potentiated by a novel nuclear Tat-interacting protein of 110 kDa, Tip110. J. Biol. Chem. 277, 23854-23863). However, the underlying molecular mechanisms by which this takes place were not understood. In this study, we demonstrated that Tip110 bound to unphosphorylated RNA polymerase II (RNAPII) in a direct and specific manner. In addition, we detected Tip110 at the HIV-1 long terminal repeat (LTR) promoter and found that Tip110 expression was associated with increased phosphorylation of serine 2 of the heptapeptide repeats within the RNAPII C-terminal domain and increased recruitment of positive transcription elongation factor b to the LTR promoter. Consistent with these findings, we showed that Tip110 interaction with Tat directly enhanced transcription elongation of the LTR promoter. Taken together, these findings have provided additional and mechanistic evidence to support Tip110 function in HIV-1 transcription.
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Affiliation(s)
- Weina Zhao
- From the Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, Indiana 46202 and
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44
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Dahiya S, Irish BP, Nonnemacher MR, Wigdahl B. Genetic variation and HIV-associated neurologic disease. Adv Virus Res 2013; 87:183-240. [PMID: 23809924 DOI: 10.1016/b978-0-12-407698-3.00006-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
HIV-associated neurologic disease continues to be a significant complication in the era of highly active antiretroviral therapy. A substantial subset of the HIV-infected population shows impaired neuropsychological performance as a result of HIV-mediated neuroinflammation and eventual central nervous system (CNS) injury. CNS compartmentalization of HIV, coupled with the evolution of genetically isolated populations in the CNS, is responsible for poor prognosis in patients with AIDS, warranting further investigation and possible additions to the current therapeutic strategy. This chapter reviews key advances in the field of neuropathogenesis and studies that have highlighted how molecular diversity within the HIV genome may impact HIV-associated neurologic disease. We also discuss the possible functional implications of genetic variation within the viral promoter and possibly other regions of the viral genome, especially in the cells of monocyte-macrophage lineage, which are arguably key cellular players in HIV-associated CNS disease.
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Affiliation(s)
- Satinder Dahiya
- Department of Microbiology and Immunology, Center for Molecular Virology and Translational Neuroscience, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, Philadelphia, Pennsylvania, USA
| | - Bryan P Irish
- Department of Microbiology and Immunology, Center for Molecular Virology and Translational Neuroscience, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, Philadelphia, Pennsylvania, USA
| | - Michael R Nonnemacher
- Department of Microbiology and Immunology, Center for Molecular Virology and Translational Neuroscience, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, Philadelphia, Pennsylvania, USA
| | - Brian Wigdahl
- Department of Microbiology and Immunology, Center for Molecular Virology and Translational Neuroscience, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, Philadelphia, Pennsylvania, USA
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45
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Ou M, Sandri-Goldin RM. Inhibition of cdk9 during herpes simplex virus 1 infection impedes viral transcription. PLoS One 2013; 8:e79007. [PMID: 24205359 PMCID: PMC3799718 DOI: 10.1371/journal.pone.0079007] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2013] [Accepted: 09/26/2013] [Indexed: 01/01/2023] Open
Abstract
During herpes simplex virus 1 (HSV-1) infection there is a loss of the serine-2 phosphorylated form of RNA polymerase II (RNAP II) found in elongation complexes. This occurs in part because RNAP II undergoes ubiquitination and proteasomal degradation during times of highly active viral transcription, which may result from stalled elongating complexes. In addition, a viral protein, ICP22, was reported to trigger a loss of serine-2 RNAP II. These findings have led to some speculation that the serine-2 phosphorylated form of RNAP II may not be required for HSV-1 transcription, although this form is required for cellular transcription elongation and RNA processing. Cellular kinase cdk9 phosphorylates serine-2 in the C-terminal domain (CTD) of RNAP II. To determine if serine-2 phosphorylated RNAP II is required for HSV-1 transcription, we inhibited cdk9 during HSV-1 infection and measured viral gene expression. Inhibition was achieved by adding cdk9 inhibitors 5,6-dichlorobenzimidazone-1-β-D-ribofuranoside (DRB) or flavopiridol (FVP) or by expression of a dominant–negative cdk9 or HEXIM1, which in conjunction with 7SK snRNA inhibits cdk9 in complex with cyclin 1. Here we report that inhibition of cdk9 resulted in decreased viral yields and levels of late proteins, poor formation of viral transcription-replication compartments, reduced levels of poly(A)+ mRNA and decreased RNA synthesis as measured by uptake of 5-bromouridine into nascent RNA. Importantly, a global reduction in viral mRNAs was seen as determined by microarray analysis. We conclude that serine-2 phosphorylation of the CTD of RNAP II is required for HSV-1 transcription.
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Affiliation(s)
- Mark Ou
- Department of Microbiology and Molecular Genetics, University of California, Irvine, California, United States of America
| | - Rozanne M. Sandri-Goldin
- Department of Microbiology and Molecular Genetics, University of California, Irvine, California, United States of America
- * E-mail:
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46
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Affiliation(s)
- Dirk Eick
- Department of Molecular Epigenetics, Helmholtz Center Munich and Center for Integrated Protein Science Munich (CIPSM), Marchioninistrasse 25, 81377 Munich,
Germany
| | - Matthias Geyer
- Center of Advanced European Studies and Research, Group Physical Biochemistry,
Ludwig-Erhard-Allee 2, 53175 Bonn, Germany
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47
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Miller-Jensen K, Skupsky R, Shah PS, Arkin AP, Schaffer DV. Genetic selection for context-dependent stochastic phenotypes: Sp1 and TATA mutations increase phenotypic noise in HIV-1 gene expression. PLoS Comput Biol 2013; 9:e1003135. [PMID: 23874178 PMCID: PMC3708878 DOI: 10.1371/journal.pcbi.1003135] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2012] [Accepted: 05/16/2013] [Indexed: 12/13/2022] Open
Abstract
The sequence of a promoter within a genome does not uniquely determine gene expression levels and their variability; rather, promoter sequence can additionally interact with its location in the genome, or genomic context, to shape eukaryotic gene expression. Retroviruses, such as human immunodeficiency virus-1 (HIV), integrate their genomes into those of their host and thereby provide a biomedically-relevant model system to quantitatively explore the relationship between promoter sequence, genomic context, and noise-driven variability on viral gene expression. Using an in vitro model of the HIV Tat-mediated positive-feedback loop, we previously demonstrated that fluctuations in viral Tat-transactivating protein levels generate integration-site-dependent, stochastically-driven phenotypes, in which infected cells randomly ‘switch’ between high and low expressing states in a manner that may be related to viral latency. Here we extended this model and designed a forward genetic screen to systematically identify genetic elements in the HIV LTR promoter that modulate the fraction of genomic integrations that specify ‘Switching’ phenotypes. Our screen identified mutations in core promoter regions, including Sp1 and TATA transcription factor binding sites, which increased the Switching fraction several fold. By integrating single-cell experiments with computational modeling, we further investigated the mechanism of Switching-fraction enhancement for a selected Sp1 mutation. Our experimental observations demonstrated that the Sp1 mutation both impaired Tat-transactivated expression and also altered basal expression in the absence of Tat. Computational analysis demonstrated that the observed change in basal expression could contribute significantly to the observed increase in viral integrations that specify a Switching phenotype, provided that the selected mutation affected Tat-mediated noise amplification differentially across genomic contexts. Our study thus demonstrates a methodology to identify and characterize promoter elements that affect the distribution of stochastic phenotypes over genomic contexts, and advances our understanding of how promoter mutations may control the frequency of latent HIV infection. The sequence of a gene within a cellular genome does not uniquely determine its expression level, even for a single type of cell under fixed conditions. Numerous other factors, including gene location on the chromosome and random gene-expression “noise,” can alter expression patterns and cause differences between otherwise identical cells. This poses new challenges for characterizing the genotype–phenotype relationship. Infection by the human immunodeficiency virus-1 (HIV-1) provides a biomedically important example in which transcriptional noise and viral genomic location impact the decision between viral replication and latency, a quiescent but reversible state that cannot be eliminated by anti-viral therapies. Here, we designed a forward genetic screen to systematically identify mutations in the HIV promoter that alter the fraction of genomic integrations that specify noisy/reactivating expression phenotypes. The mechanisms by which the selected mutations specify the observed phenotypic enrichments are investigated through a combination of single-cell experiments and computational modeling. Our study provides a framework for identifying genetic sequences that alter the distribution of stochastic expression phenotypes over genomic locations and for characterizing their mechanisms of regulation. Our results also may yield further insights into the mechanisms by which HIV sequence evolution can alter the propensity for latent infections.
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Affiliation(s)
- Kathryn Miller-Jensen
- Department of Biomedical Engineering, Yale University, New Haven, Connecticut, United States of America
- California Institute for Quantitative Biosciences, University of California, Berkeley, Berkeley, California, United States of America
- * E-mail: (KMJ); (DVS)
| | - Ron Skupsky
- California Institute for Quantitative Biosciences, University of California, Berkeley, Berkeley, California, United States of America
| | - Priya S. Shah
- California Institute for Quantitative Biosciences, University of California, Berkeley, Berkeley, California, United States of America
| | - Adam P. Arkin
- California Institute for Quantitative Biosciences, University of California, Berkeley, Berkeley, California, United States of America
- Department of Bioengineering, University of California, Berkeley, California, United States of America
- Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, California, United States of America
| | - David V. Schaffer
- California Institute for Quantitative Biosciences, University of California, Berkeley, Berkeley, California, United States of America
- Department of Bioengineering, University of California, Berkeley, California, United States of America
- Department of Chemical and Biomolecular Engineering, University of California, Berkeley, California, United States of America
- * E-mail: (KMJ); (DVS)
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48
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Lu H, Li Z, Xue Y, Zhou Q. Viral-host interactions that control HIV-1 transcriptional elongation. Chem Rev 2013; 113:8567-82. [PMID: 23795863 DOI: 10.1021/cr400120z] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Huasong Lu
- School of Pharmaceutical Sciences, Xiamen University , Xiamen, Fujian 361005, China
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49
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Dhamija N, Rawat P, Mitra D. Epigenetic regulation of HIV-1 persistence and evolving strategies for virus eradication. Subcell Biochem 2013; 61:479-505. [PMID: 23150264 DOI: 10.1007/978-94-007-4525-4_21] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Despite the intense effort put by researchers globally to understand Human Immunodeficiency Virus (HIV-1) pathogenesis since its discovery 30 years ago, the acquired knowledge till date is not good enough to eradicate HIV-1 from an infected individual. HIV-1 infects cells of the human immune system and integrates into the host cell genome thereby leading to persistent infection in these cells. Based on the activation status of the cells, the infection could be productive or result in latent infection. The current regimen used to treat HIV-1 infection in an AIDS patient includes combination of antiretroviral drugs called Highly Active Anti-Retroviral Therapy (HAART). A major challenge for the success of HAART has been these latent reservoirs of HIV which remain hidden and pose major hurdle for the eradication of virus. Combination of HAART therapy with simultaneous activation of latent reservoirs of HIV-1 seems to be the future of anti-retroviral therapy; however, this will require a much better understanding of the mechanisms and regulation of HIV-1 latency. In this chapter, we have tried to elaborate on HIV-1 latency, highlighting the strategies employed by the virus to ensure persistence in the host with specific focus on epigenetic regulation of latency. A complete understanding of HIV-1 latency will be extremely essential for ultimate eradication of HIV-1 from the human host.
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Affiliation(s)
- Neeru Dhamija
- National Centre for Cell Science, NCCS Complex, Pune University Campus, Ganeshkhind, Pune, 411007, India
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50
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Hsin JP, Manley JL. The RNA polymerase II CTD coordinates transcription and RNA processing. Genes Dev 2012; 26:2119-37. [PMID: 23028141 DOI: 10.1101/gad.200303.112] [Citation(s) in RCA: 484] [Impact Index Per Article: 37.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The C-terminal domain (CTD) of the RNA polymerase II largest subunit consists of multiple heptad repeats (consensus Tyr1-Ser2-Pro3-Thr4-Ser5-Pro6-Ser7), varying in number from 26 in yeast to 52 in vertebrates. The CTD functions to help couple transcription and processing of the nascent RNA and also plays roles in transcription elongation and termination. The CTD is subject to extensive post-translational modification, most notably phosphorylation, during the transcription cycle, which modulates its activities in the above processes. Therefore, understanding the nature of CTD modifications, including how they function and how they are regulated, is essential to understanding the mechanisms that control gene expression. While the significance of phosphorylation of Ser2 and Ser5 residues has been studied and appreciated for some time, several additional modifications have more recently been added to the CTD repertoire, and insight into their function has begun to emerge. Here, we review findings regarding modification and function of the CTD, highlighting the important role this unique domain plays in coordinating gene activity.
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Affiliation(s)
- Jing-Ping Hsin
- Department of Biological Sciences, Columbia University, New York, New York 10027, USA
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