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Roesmann F, Müller L, Klaassen K, Heß S, Widera M. Interferon-Regulated Expression of Cellular Splicing Factors Modulates Multiple Levels of HIV-1 Gene Expression and Replication. Viruses 2024; 16:938. [PMID: 38932230 DOI: 10.3390/v16060938] [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: 04/30/2024] [Revised: 05/31/2024] [Accepted: 06/03/2024] [Indexed: 06/28/2024] Open
Abstract
Type I interferons (IFN-Is) are pivotal in innate immunity against human immunodeficiency virus I (HIV-1) by eliciting the expression of IFN-stimulated genes (ISGs), which encompass potent host restriction factors. While ISGs restrict the viral replication within the host cell by targeting various stages of the viral life cycle, the lesser-known IFN-repressed genes (IRepGs), including RNA-binding proteins (RBPs), affect the viral replication by altering the expression of the host dependency factors that are essential for efficient HIV-1 gene expression. Both the host restriction and dependency factors determine the viral replication efficiency; however, the understanding of the IRepGs implicated in HIV-1 infection remains greatly limited at present. This review provides a comprehensive overview of the current understanding regarding the impact of the RNA-binding protein families, specifically the two families of splicing-associated proteins SRSF and hnRNP, on HIV-1 gene expression and viral replication. Since the recent findings show specifically that SRSF1 and hnRNP A0 are regulated by IFN-I in various cell lines and primary cells, including intestinal lamina propria mononuclear cells (LPMCs) and peripheral blood mononuclear cells (PBMCs), we particularly discuss their role in the context of the innate immunity affecting HIV-1 replication.
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Affiliation(s)
- Fabian Roesmann
- Institute for Medical Virology, University Hospital Frankfurt, Goethe University Frankfurt, Paul-Ehrlich-Str. 40, 60596 Frankfurt am Main, Germany
| | - Lisa Müller
- Institute of Virology, Medical Faculty, University Hospital Düsseldorf, Heinrich-Heine-University Düsseldorf, Universitätsstr. 1, 40225 Düsseldorf, Germany
| | - Katleen Klaassen
- Institute for Medical Virology, University Hospital Frankfurt, Goethe University Frankfurt, Paul-Ehrlich-Str. 40, 60596 Frankfurt am Main, Germany
| | - Stefanie Heß
- Institute for Medical Virology, University Hospital Frankfurt, Goethe University Frankfurt, Paul-Ehrlich-Str. 40, 60596 Frankfurt am Main, Germany
| | - Marek Widera
- Institute for Medical Virology, University Hospital Frankfurt, Goethe University Frankfurt, Paul-Ehrlich-Str. 40, 60596 Frankfurt am Main, Germany
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2
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Yandrapally S, Sarkar S, Banerjee S. HIV-1 Tat commandeers nuclear export of Rev-viral RNA complex by controlling hnRNPA2-mediated splicing. J Virol 2023; 97:e0104423. [PMID: 37905837 PMCID: PMC10688328 DOI: 10.1128/jvi.01044-23] [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: 07/13/2023] [Accepted: 09/26/2023] [Indexed: 11/02/2023] Open
Abstract
IMPORTANCE HIV-infected host cells impose varied degrees of regulation on viral replication, from very high to abortive. Proliferation of HIV in astrocytes is limited when compared to immune cells, such as CD4+ T lymphocytes. Understanding such differential regulation is one of the key questions in the field as these cells permit HIV persistence and rebound viremia, challenging HIV treatment and clinical cure. This study focuses on understanding the molecular mechanism behind such cell-specific disparities. We show that one of the key mechanisms is the regulation of heterogenous nuclear ribonucleoprotein A2, a host factor involved in alternative splicing and RNA processing, by HIV-1 Tat in CD4+ T lymphocytes, not observed in astrocytes. This regulation causes an increase in the levels of unspliced/partially spliced viral RNA and nuclear export of Rev-RNA complexes which results in high viral propagation in CD4+ T lymphocytes. The study reveals a new mechanism imposed by HIV on host cells that determines the fate of infection.
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Affiliation(s)
- Sriram Yandrapally
- Department of Biochemistry, School of Life Sciences, University of Hyderabad, Hyderabad, Telangana, India
| | - Satarupa Sarkar
- Department of Biochemistry, School of Life Sciences, University of Hyderabad, Hyderabad, Telangana, India
| | - Sharmistha Banerjee
- Department of Biochemistry, School of Life Sciences, University of Hyderabad, Hyderabad, Telangana, India
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3
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Esser LM, Schmitz K, Hillebrand F, Erkelenz S, Schaal H, Stork B, Grimmler M, Wesselborg S, Peter C. Phosphorylation of pICln by the autophagy activating kinase ULK1 regulates snRNP biogenesis and splice activity of the cell. Comput Struct Biotechnol J 2023; 21:2100-2109. [PMID: 36968021 PMCID: PMC10034211 DOI: 10.1016/j.csbj.2023.03.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Revised: 03/10/2023] [Accepted: 03/11/2023] [Indexed: 03/18/2023] Open
Abstract
The spliceosome, responsible for all mature protein-coding transcripts of eukaryotic intron-containing genes, consists of small uridine-rich nuclear ribonucleoproteins (UsnRNPs). The assembly of UsnRNPs depends, on one hand, on the arginine methylation of Sm proteins catalyzed by the PRMT5 complex. On the other hand, it depends on the phosphorylation of the PRMT5 subunit pICln by the Uncoordinated Like Kinase 1 (ULK1). In consequence, phosphorylation of pICln affects the stability of the UsnRNP assembly intermediate, the so-called 6 S complex. The detailed mechanisms of phosphorylation-dependent integrity and subsequent UsnRNP assembly of the 6 S complex in vivo have not yet been analyzed. By using a phospho-specific antibody against ULK1-dependent phosphorylation sites of pICln, we visualize the intracellular distribution of phosphorylated pICln. Furthermore, we detect the colocaliphosphor-pICln1 with phospho-pICln by size-exclusion chromatography and immunofluorescence techniques. We also show that phosphorylated pICln is predominantly present in the 6 S complex. The addition of ULK1 to in vitro produced 6 S complex, as well as the reconstitution of ULK1 in ULK1-deficient cells, increases the efficiency of snRNP biogenesis. Accordingly, inhibition of ULK1 and the associated decreased pICln phosphorylation lead to accumulation of the 6 S complex and reduction in the spliceosomal activity of the cell.
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4
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Kim GN, Yu KL, Kim HI, You JC. Investigation of the effect of SRSF9 overexpression on HIV-1 production. BMB Rep 2022; 55:639-644. [PMID: 36330710 PMCID: PMC9813430] [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: 10/20/2022] [Indexed: 12/29/2022] Open
Abstract
Serine-arginine-rich splicing factors (SRSFs) are members of RNA processing proteins in the serine-arginine-rich (SR) family that could regulate the alternative splicing of the human immunodeficiency virus-1 (HIV-1). Whether SRSF9 has any effect on HIV-1 regulation requires elucidation. Here, we report for the first time the effects and mechanisms of SRSF9 on HIV-1 regulation. The overexpression of SRSF9 inhibits viral production and infectivity in both HEK293T and MT-4 cells. Deletion analysis of SRSF9 determined that the RNA regulation motif domain of SRSF9 is important for anti-HIV-1 effects. Furthermore, overexpression of SRSF9 increases multiple spliced forms of viral mRNA, such as Vpr mRNA. These data suggest that SRSF9 overexpression inhibits HIV-1 production by inducing the imbalanced HIV-1 mRNA splicing that could be exploited further for a novel HIV-1 therapeutic molecule. [BMB Reports 2022; 55(12): 639-644].
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Affiliation(s)
- Ga-Na Kim
- Department of Pathology, National Research Laboratory for Molecular Virology, College of Medicine, The Catholic University of Korea, Seoul 05505, Korea
| | - Kyung-Lee Yu
- Department of Pathology, National Research Laboratory for Molecular Virology, College of Medicine, The Catholic University of Korea, Seoul 05505, Korea
| | - Hae-In Kim
- Department of Pathology, National Research Laboratory for Molecular Virology, College of Medicine, The Catholic University of Korea, Seoul 05505, Korea
| | - Ji Chang You
- Department of Pathology, National Research Laboratory for Molecular Virology, College of Medicine, The Catholic University of Korea, Seoul 05505, Korea,Corresponding author. Tel: +82-2-3147-8734; Fax: +82-2-3147-9282; E-mail:
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5
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Chiu LY, Emery A, Jain N, Sugarman A, Kendrick N, Luo L, Ford W, Swanstrom R, Tolbert BS. Encoded Conformational Dynamics of the HIV Splice Site A3 Regulatory Locus: Implications for Differential Binding of hnRNP Splicing Auxiliary Factors. J Mol Biol 2022; 434:167728. [PMID: 35870649 PMCID: PMC9945881 DOI: 10.1016/j.jmb.2022.167728] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2022] [Revised: 07/07/2022] [Accepted: 07/07/2022] [Indexed: 01/19/2023]
Abstract
Alternative splicing of the HIV transcriptome is controlled through cis regulatory elements functioning as enhancers or silencers depending on their context and the type of host RNA binding proteins they recruit. Splice site acceptor A3 (ssA3) is one of the least used acceptor sites in the HIV transcriptome and its activity determines the levels of tat mRNA. Splice acceptor 3 is regulated by a combination of cis regulatory sequences, auxiliary splicing factors, and presumably RNA structure. The mechanisms by which these multiple regulatory components coordinate to determine the frequency in which ssA3 is utilized is poorly understood. By NMR spectroscopy and phylogenetic analysis, we show that the ssA3 regulatory locus is conformationally heterogeneous and that the sequences that encompass the locus are conserved across most HIV isolates. Despite the conformational heterogeneity, the major stem loop (A3SL1) observed in vitro folds to base pair the Polypyrimdine Tract (PPyT) to the Exon Splicing Silencer 2p (ESS2p) element and to a conserved downstream linker. The 3D structure as determined by NMR spectroscopy further reveals that the A3 consensus cleavage site is embedded within a unique stereochemical environment within the apical loop, where it is surrounded by alternating base-base interactions. Despite being described as a receptor for hnRNP H, the ESS2p element is sequestered by base pairing to the 3' end of the PPyT and within this context it cannot form a stable complex with hnRNP H. By comparison, hnRNP A1 directly binds to the A3 consensus cleavage site located within the apical loop, suggesting that it can directly modulate U2AF assembly. Sequence mutations designed to destabilize the PPyT:ESS2p helix results in an increase usage of ssA3 within HIV-infected cells, consistent with the PPyT becoming more accessible for U2AF recognition. Additional mutations introduced into the downstream ESS2 element synergize with ESS2p to cause further increases in ssA3 usage. When taken together, our work provides a unifying picture by which cis regulatory sequences, splicing auxiliary factors and RNA structure cooperate to provide stringent control over ssA3. We describe this as the pair-and-lock mechanism to restrict access of the PPyT, and posit that it operates to regulate a subset of the heterogenous structures encompassing the ssA3 regulatory locus.
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Affiliation(s)
- Liang-Yuan Chiu
- Department of Chemistry, Case Western Reserve University, Cleveland, OH 44106
| | - Ann Emery
- UNC Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC 27599
| | - Niyati Jain
- Department of Chemistry, Case Western Reserve University, Cleveland, OH 44106
| | - Andrew Sugarman
- Department of Chemistry, Case Western Reserve University, Cleveland, OH 44106
| | - Nashea Kendrick
- Department of Chemistry, Case Western Reserve University, Cleveland, OH 44106
| | - Le Luo
- Department of Chemistry, Case Western Reserve University, Cleveland, OH 44106
| | - William Ford
- Department of Chemistry, Case Western Reserve University, Cleveland, OH 44106
| | - Ronald Swanstrom
- UNC Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC 27599,Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, NC 27599,Center for AIDS Research, University of North Carolina, Chapel Hill, NC 27599
| | - Blanton S. Tolbert
- Department of Chemistry, Case Western Reserve University, Cleveland, OH 44106
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Dahal S, Clayton K, Been T, Fernet-Brochu R, Ocando AV, Balachandran A, Poirier M, Maldonado RK, Shkreta L, Boligan KF, Guvenc F, Rahman F, Branch D, Bell B, Chabot B, Gray-Owen SD, Parent LJ, Cochrane A. Opposing roles of CLK SR kinases in controlling HIV-1 gene expression and latency. Retrovirology 2022; 19:18. [PMID: 35986377 PMCID: PMC9389714 DOI: 10.1186/s12977-022-00605-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Accepted: 07/29/2022] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND The generation of over 69 spliced HIV-1 mRNAs from one primary transcript by alternative RNA splicing emphasizes the central role that RNA processing plays in HIV-1 replication. Control is mediated in part through the action of host SR proteins whose activity is regulated by multiple SR kinases (CLK1-4, SRPKs). METHODS Both shRNA depletion and small molecule inhibitors of host SR kinases were used in T cell lines and primary cells to evaluate the role of these factors in the regulation of HIV-1 gene expression. Effects on virus expression were assessed using western blotting, RT-qPCR, and immunofluorescence. RESULTS The studies demonstrate that SR kinases play distinct roles; depletion of CLK1 enhanced HIV-1 gene expression, reduction of CLK2 or SRPK1 suppressed it, whereas CLK3 depletion had a modest impact. The opposing effects of CLK1 vs. CLK2 depletion were due to action at distinct steps; reduction of CLK1 increased HIV-1 promoter activity while depletion of CLK2 affected steps after transcript initiation. Reduced CLK1 expression also enhanced the response to several latency reversing agents, in part, by increasing the frequency of responding cells, consistent with a role in regulating provirus latency. To determine whether small molecule modulation of SR kinase function could be used to control HIV-1 replication, we screened a GSK library of protein kinase inhibitors (PKIS) and identified several pyrazolo[1,5-b] pyridazine derivatives that suppress HIV-1 gene expression/replication with an EC50 ~ 50 nM. The compounds suppressed HIV-1 protein and viral RNA accumulation with minimal impact on cell viability, inhibiting CLK1 and CLK2 but not CLK3 function, thereby selectively altering the abundance of individual CLK and SR proteins in cells. CONCLUSIONS These findings demonstrate the unique roles played by individual SR kinases in regulating HIV-1 gene expression, validating the targeting of these functions to either enhance latency reversal, essential for "Kick-and-Kill" strategies, or to silence HIV protein expression for "Block-and-Lock" strategies.
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Affiliation(s)
- Subha Dahal
- grid.17063.330000 0001 2157 2938Dept. of Molecular Genetics, University of Toronto, 1 King’s College Circle, Toronto, ON M5S1A8 Canada
| | - Kiera Clayton
- grid.168645.80000 0001 0742 0364Department of Pathology, University of Massachusetts Medical School, Worcester, MA 01605 USA
| | - Terek Been
- grid.17063.330000 0001 2157 2938Dept. of Molecular Genetics, University of Toronto, 1 King’s College Circle, Toronto, ON M5S1A8 Canada
| | - Raphaële Fernet-Brochu
- grid.17063.330000 0001 2157 2938Dept. of Molecular Genetics, University of Toronto, 1 King’s College Circle, Toronto, ON M5S1A8 Canada
| | - Alonso Villasmil Ocando
- grid.461656.60000 0004 0489 3491Ragon Institute of MGH, MIT and Harvard, Cambridge, MA 02139 USA
| | - Ahalya Balachandran
- grid.17063.330000 0001 2157 2938Dept. of Molecular Genetics, University of Toronto, 1 King’s College Circle, Toronto, ON M5S1A8 Canada
| | - Mikaël Poirier
- grid.86715.3d0000 0000 9064 6198Dept. of Microbiology & Infectious Diseases, Université de Sherbrooke, Sherbrooke, QC Canada
| | - Rebecca Kaddis Maldonado
- grid.240473.60000 0004 0543 9901Department of Medicine, Penn State College of Medicine, Hershey, PA 17033 USA ,grid.240473.60000 0004 0543 9901Microbiology & Immunology, Penn State College of Medicine, Hershey, PA 17033 USA
| | - Lulzim Shkreta
- grid.86715.3d0000 0000 9064 6198Dept. of Microbiology & Infectious Diseases, Université de Sherbrooke, Sherbrooke, QC Canada
| | - Kayluz Frias Boligan
- grid.423370.10000 0001 0285 1288Center for Innovation, Canadian Blood Services, Toronto, ON Canada
| | - Furkan Guvenc
- grid.17063.330000 0001 2157 2938Dept. of Molecular Genetics, University of Toronto, 1 King’s College Circle, Toronto, ON M5S1A8 Canada
| | - Fariha Rahman
- grid.17063.330000 0001 2157 2938Dept. of Molecular Genetics, University of Toronto, 1 King’s College Circle, Toronto, ON M5S1A8 Canada
| | - Donald Branch
- grid.423370.10000 0001 0285 1288Center for Innovation, Canadian Blood Services, Toronto, ON Canada
| | - Brendan Bell
- grid.86715.3d0000 0000 9064 6198Dept. of Microbiology & Infectious Diseases, Université de Sherbrooke, Sherbrooke, QC Canada
| | - Benoit Chabot
- grid.86715.3d0000 0000 9064 6198Dept. of Microbiology & Infectious Diseases, Université de Sherbrooke, Sherbrooke, QC Canada
| | - Scott D. Gray-Owen
- grid.17063.330000 0001 2157 2938Dept. of Molecular Genetics, University of Toronto, 1 King’s College Circle, Toronto, ON M5S1A8 Canada
| | - Leslie J. Parent
- grid.240473.60000 0004 0543 9901Department of Medicine, Penn State College of Medicine, Hershey, PA 17033 USA ,grid.240473.60000 0004 0543 9901Microbiology & Immunology, Penn State College of Medicine, Hershey, PA 17033 USA
| | - Alan Cochrane
- grid.17063.330000 0001 2157 2938Dept. of Molecular Genetics, University of Toronto, 1 King’s College Circle, Toronto, ON M5S1A8 Canada
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7
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Müller L, Ptok J, Nisar A, Antemann J, Grothmann R, Hillebrand F, Brillen AL, Ritchie A, Theiss S, Schaal H. Modeling splicing outcome by combining 5'ss strength and splicing regulatory elements. Nucleic Acids Res 2022; 50:8834-8851. [PMID: 35947702 PMCID: PMC9410876 DOI: 10.1093/nar/gkac663] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 06/23/2022] [Accepted: 07/27/2022] [Indexed: 12/24/2022] Open
Abstract
Correct pre-mRNA processing in higher eukaryotes vastly depends on splice site recognition. Beyond conserved 5'ss and 3'ss motifs, splicing regulatory elements (SREs) play a pivotal role in this recognition process. Here, we present in silico designed sequences with arbitrary a priori prescribed splicing regulatory HEXplorer properties that can be concatenated to arbitrary length without changing their regulatory properties. We experimentally validated in silico predictions in a massively parallel splicing reporter assay on more than 3000 sequences and exemplarily identified some SRE binding proteins. Aiming at a unified 'functional splice site strength' encompassing both U1 snRNA complementarity and impact from neighboring SREs, we developed a novel RNA-seq based 5'ss usage landscape, mapping the competition of pairs of high confidence 5'ss and neighboring exonic GT sites along HBond and HEXplorer score coordinate axes on human fibroblast and endothelium transcriptome datasets. These RNA-seq data served as basis for a logistic 5'ss usage prediction model, which greatly improved discrimination between strong but unused exonic GT sites and annotated highly used 5'ss. Our 5'ss usage landscape offers a unified view on 5'ss and SRE neighborhood impact on splice site recognition, and may contribute to improved mutation assessment in human genetics.
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Affiliation(s)
| | | | - Azlan Nisar
- Institute of Virology, Medical Faculty, Heinrich-Heine-University Düsseldorf, Düsseldorf 40225, Germany,Institute for Bioinformatics and Chemoinformatics, Westphalian University of Applied Sciences, August-Schmidt-Ring 10, Recklinghausen 45665, Germany
| | - Jennifer Antemann
- Institute of Virology, Medical Faculty, Heinrich-Heine-University Düsseldorf, Düsseldorf 40225, Germany
| | - Ramona Grothmann
- Institute of Virology, Medical Faculty, Heinrich-Heine-University Düsseldorf, Düsseldorf 40225, Germany
| | - Frank Hillebrand
- Institute of Virology, Medical Faculty, Heinrich-Heine-University Düsseldorf, Düsseldorf 40225, Germany
| | - Anna-Lena Brillen
- Institute of Virology, Medical Faculty, Heinrich-Heine-University Düsseldorf, Düsseldorf 40225, Germany
| | - Anastasia Ritchie
- Institute of Virology, Medical Faculty, Heinrich-Heine-University Düsseldorf, Düsseldorf 40225, Germany
| | | | - Heiner Schaal
- To whom correspondence should be addressed. Tel: +49 211 81 12393; Fax: +49 211 81 10856;
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8
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Gallardo CM, Nguyen AVT, Routh AL, Torbett BE. Selective ablation of 3' RNA ends and processive RTs facilitate direct cDNA sequencing of full-length host cell and viral transcripts. Nucleic Acids Res 2022; 50:e98. [PMID: 35736235 PMCID: PMC9508845 DOI: 10.1093/nar/gkac516] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 04/25/2022] [Accepted: 06/01/2022] [Indexed: 11/13/2022] Open
Abstract
Alternative splicing (AS) is necessary for viral proliferation in host cells and a critical regulatory component of viral gene expression. Conventional RNA-seq approaches provide incomplete coverage of AS due to their short read lengths and are susceptible to biases and artifacts introduced in prevailing library preparation methodologies. Moreover, viral splicing studies are often conducted separately from host cell transcriptome analysis, precluding an assessment of the viral manipulation of host splicing machinery. To address current limitations, we developed a quantitative full-length direct cDNA sequencing strategy to simultaneously profile viral and host cell transcripts. This nanopore-based approach couples processive reverse transcriptases with a novel one-step chemical ablation of 3' RNA ends (termed CASPR), which decreases ribosomal RNA reads and enriches polyadenylated coding sequences. We extensively validate our approach using synthetic reference transcripts and show that CASPR doubles the breadth of coverage per transcript and increases detection of long transcripts (>4 kb), while being functionally equivalent to PolyA+ selection for transcript quantification. We used our approach to interrogate host cell and HIV-1 transcript dynamics during viral reactivation and identified novel putative HIV-1 host factors containing exon skipping or novel intron retentions and delineated the HIV-1 transcriptional state associated with these differentially regulated host factors.
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Affiliation(s)
- Christian M Gallardo
- Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, CA 92037, USA.,Center for Immunity and Immunotherapies, Seattle Children's Research Institute, Seattle, WA 98101, USA
| | - Anh-Viet T Nguyen
- Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Andrew L Routh
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX 77555, USA.,Sealy Center for Structural Biology and Molecular Biophysics, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Bruce E Torbett
- Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, CA 92037, USA.,Center for Immunity and Immunotherapies, Seattle Children's Research Institute, Seattle, WA 98101, USA.,Institute for Stem Cell & Regenerative Medicine, University of Washington, Seattle, WA 98109, USA.,Department of Laboratory Medicine and Pathology, University of Washington School of Medicine, Seattle, WA 98101, USA.,Department of Pediatrics, University of Washington School of Medicine, Seattle, WA 98101, USA
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9
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Crespo R, Rao S, Mahmoudi T. HibeRNAtion: HIV-1 RNA Metabolism and Viral Latency. Front Cell Infect Microbiol 2022; 12:855092. [PMID: 35774399 PMCID: PMC9237370 DOI: 10.3389/fcimb.2022.855092] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Accepted: 05/10/2022] [Indexed: 01/12/2023] Open
Abstract
HIV-1 infection remains non-curative due to the latent reservoir, primarily a small pool of resting memory CD4+ T cells bearing replication-competent provirus. Pharmacological reversal of HIV-1 latency followed by intrinsic or extrinsic cell killing has been proposed as a promising strategy to target and eliminate HIV-1 viral reservoirs. Latency reversing agents have been extensively studied for their role in reactivating HIV-1 transcription in vivo, although no permanent reduction of the viral reservoir has been observed thus far. This is partly due to the complex nature of latency, which involves strict intrinsic regulation at multiple levels at transcription and RNA processing. Still, the molecular mechanisms that control HIV-1 latency establishment and maintenance have been almost exclusively studied in the context of chromatin remodeling, transcription initiation and elongation and most known LRAs target LTR-driven transcription by manipulating these. RNA metabolism is a largely understudies but critical mechanistic step in HIV-1 gene expression and latency. In this review we provide an update on current knowledge on the role of RNA processing mechanisms in viral gene expression and latency and speculate on the possible manipulation of these pathways as a therapeutic target for future cure studies.
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Affiliation(s)
- Raquel Crespo
- Department of Biochemistry, Erasmus University Medical Center, Rotterdam, Netherlands
| | - Shringar Rao
- Department of Biochemistry, Erasmus University Medical Center, Rotterdam, Netherlands
| | - Tokameh Mahmoudi
- Department of Biochemistry, Erasmus University Medical Center, Rotterdam, Netherlands
- Department of Pathology, Erasmus University Medical Center, Rotterdam, Netherlands
- Department of Urology, Erasmus University Medical Center, Rotterdam, Netherlands
- *Correspondence: Tokameh Mahmoudi,
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10
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The Thiazole-5-Carboxamide GPS491 Inhibits HIV-1, Adenovirus, and Coronavirus Replication by Altering RNA Processing/Accumulation. Viruses 2021; 14:v14010060. [PMID: 35062264 PMCID: PMC8779516 DOI: 10.3390/v14010060] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2021] [Revised: 12/17/2021] [Accepted: 12/20/2021] [Indexed: 12/11/2022] Open
Abstract
Medicinal chemistry optimization of a previously described stilbene inhibitor of HIV-1, 5350150 (2-(2-(5-nitro-2-thienyl)vinyl)quinoline), led to the identification of the thiazole-5-carboxamide derivative (GPS491), which retained potent anti-HIV-1 activity with reduced toxicity. In this report, we demonstrate that the block of HIV-1 replication by GPS491 is accompanied by a drastic inhibition of viral gene expression (IC50 ~ 0.25 µM), and alterations in the production of unspliced, singly spliced, and multiply spliced HIV-1 RNAs. GPS491 also inhibited the replication of adenovirus and multiple coronaviruses. Low µM doses of GPS491 reduced adenovirus infectious yield ~1000 fold, altered virus early gene expression/viral E1A RNA processing, blocked viral DNA amplification, and inhibited late (hexon) gene expression. Loss of replication of multiple coronaviruses (229E, OC43, SARS-CoV2) upon GPS491 addition was associated with the inhibition of viral structural protein expression and the formation of virus particles. Consistent with the observed changes in viral RNA processing, GPS491 treatment induced selective alterations in the accumulation/phosphorylation/function of splicing regulatory SR proteins. Our study establishes that a compound that impacts the activity of cellular factors involved in RNA processing can prevent the replication of several viruses with minimal effect on cell viability.
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11
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She W, Shao J, Jia R. Targeting Splicing Factor SRSF6 for Cancer Therapy. Front Cell Dev Biol 2021; 9:780023. [PMID: 34917618 PMCID: PMC8669609 DOI: 10.3389/fcell.2021.780023] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Accepted: 11/12/2021] [Indexed: 01/19/2023] Open
Abstract
Aberrant alternative splicing of pre-mRNA is an emerging cancer hallmark. Many cancer-associated genes undergo alternative splicing to produce multiple isoforms with diverse or even antagonistic functions. Oncogenic isoforms are often up-regulated, whereas tumor suppressive isoforms are down-regulated during tumorigenesis. Serine/arginine-rich splicing factor 6 (SRSF6) is an important splicing factor that regulates the alternative splicing of hundreds of target genes, including many cancer-associated genes. The potential roles of SRSF6 in cancers have attracted increasing attentions in the past decade. Accumulated pieces of evidence have shown that SRSF6 is a potential oncogenic gene that promotes oncogenic splicing when overexpressed. Targeting SRSF6 may suppress tumorigenesis. In this review, we describe the gene, mRNA, and protein structure of SRSF6; summarize the current understanding of the expression, functions, and regulatory mechanisms of SRSF6 during tumorigenesis; and discuss the potential application of targeting SRSF6 in cancer treatment.
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Affiliation(s)
- Wenting She
- The State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) & Key Laboratory of Oral Biomedicine Ministry of Education, School & Hospital of Stomatology, Wuhan University, Wuhan, China
- Department of Stomatology, Renmin Hospital of Wuhan University, Wuhan University, Wuhan, China
| | - Jun Shao
- Department of Breast Surgery, Hubei Cancer Hospital, Tongji Medical College, Huazhong University of Science and Technology and Hubei Provincial Clinical Research Center for Breast Cancer, Wuhan, China
| | - Rong Jia
- The State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) & Key Laboratory of Oral Biomedicine Ministry of Education, School & Hospital of Stomatology, Wuhan University, Wuhan, China
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12
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Cellular Proteo-Transcriptomic Changes in the Immediate Early-Phase of Lentiviral Transduction. Microorganisms 2021; 9:microorganisms9112207. [PMID: 34835333 PMCID: PMC8625573 DOI: 10.3390/microorganisms9112207] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Revised: 10/15/2021] [Accepted: 10/19/2021] [Indexed: 11/28/2022] Open
Abstract
Lentivirus-based vectors derived from human immunodeficiency viruses type 1 and 2 (HIV-1 and 2) are widely used tools in research and may also be utilized in clinical settings. Like their parental virions, they are known to depend on the cellular machinery for successful gene delivery and integration. While most of the studies on cellular proteomic and transcriptomic changes have focused on the late phase of the transduction, studies of those changes in early time-points, especially in the case of HIV-2 based vectors, are widely lacking. Using second generation HIV-1 and 2 vesicular stomatitis virus G protein (VSV-G) pseudotyped lentiviral vectors, we transduced HEK-293T human embryonic kidney cells and carried out transcriptomic profiling at 0 and 2 h time points, with accompanying proteomic analysis at 2 h following transduction. Significant variations were observed in gene expression profile between HIV-1 and HIV-2 transduced samples. Thrombospondin 1 (THBS1), collagens (COL1A2, COL3A1), and eukaryotic translation factors (EIF3CL) in addition to various genes coding for long non-coding RNA (lncRNA) were significantly upregulated 2 h after HIV-2 transduction compared to HIV-1. Label-free quantification mass spectrometry (MS) indicated that seven proteins involved in RNA binding, mRNA transport, and chaperoning were significantly downregulated. The identification of cellular protein targets of lentiviral vectors and their effect on the cellular transcriptome will undoubtedly shed more light on their complex life cycle and may be utilized against infection by their parental lentiviruses. Furthermore, characterizing the early phase of HIV-2 infection may aid in the understanding of its pathomechanism and long incubation period.
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13
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Li K, Wang Z. Splicing factor SRSF2-centric gene regulation. Int J Biol Sci 2021; 17:1708-1715. [PMID: 33994855 PMCID: PMC8120470 DOI: 10.7150/ijbs.58888] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Accepted: 04/04/2021] [Indexed: 01/14/2023] Open
Abstract
Serine/arginine-rich splicing factor 2 (SRSF2) is a splicing factor that is widely expressed in a variety of mammalian cell types. Increasing evidence has confirmed that SRSF2 plays vital roles in a number of biological and pathological processes. Therefore, it is important to understand how its expression is regulated, and how it regulates the expression of its target genes. Recently, we found that SRSF2 expression could be upregulated by herpes simplex virus-1 (HSV-1) infection, and that altered SRSF2 expression, in turn, epigenetically regulates the transcription of HSV-1 genes. Further studies on T cell exhaustion demonstrated that upregulated SRSF2 in exhausted T cells elevated the levels of multiple immune checkpoint molecules by associating with the acyl-transferases, P300 and CBP, and by altering histone modification near the transcription start sites of these genes, thereby influencing signal transducer and activator of transcription 3 binding to these gene promoters. These findings suggest that SRSF2 acts as an important sensor and effector during disease progression. Here, we discuss the molecules that regulate SRSF2 gene expression and their associated mechanisms, and the mechanisms via which SRSF2 regulates the expression of target genes, thus providing novel insights into the central role of SRSF2 in gene regulation.
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Affiliation(s)
- Kun Li
- Department of Nuclear Medicine, The First Affiliated Hospital of Shandong First Medical University & Shandong Provincial Qianfoshan Hospital, Jinan 250014, China
| | - Ziqiang Wang
- Department of Nuclear Medicine, The First Affiliated Hospital of Shandong First Medical University & Shandong Provincial Qianfoshan Hospital, Jinan 250014, China.,Biomedical Sciences College & Shandong Medicinal Biotechnology Centre, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan 250062, China
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14
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Wan Q, Song D, Li H, He ML. Stress proteins: the biological functions in virus infection, present and challenges for target-based antiviral drug development. Signal Transduct Target Ther 2020; 5:125. [PMID: 32661235 PMCID: PMC7356129 DOI: 10.1038/s41392-020-00233-4] [Citation(s) in RCA: 68] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Revised: 05/26/2020] [Accepted: 06/13/2020] [Indexed: 02/06/2023] Open
Abstract
Stress proteins (SPs) including heat-shock proteins (HSPs), RNA chaperones, and ER associated stress proteins are molecular chaperones essential for cellular homeostasis. The major functions of HSPs include chaperoning misfolded or unfolded polypeptides, protecting cells from toxic stress, and presenting immune and inflammatory cytokines. Regarded as a double-edged sword, HSPs also cooperate with numerous viruses and cancer cells to promote their survival. RNA chaperones are a group of heterogeneous nuclear ribonucleoproteins (hnRNPs), which are essential factors for manipulating both the functions and metabolisms of pre-mRNAs/hnRNAs transcribed by RNA polymerase II. hnRNPs involve in a large number of cellular processes, including chromatin remodelling, transcription regulation, RNP assembly and stabilization, RNA export, virus replication, histone-like nucleoid structuring, and even intracellular immunity. Dysregulation of stress proteins is associated with many human diseases including human cancer, cardiovascular diseases, neurodegenerative diseases (e.g., Parkinson’s diseases, Alzheimer disease), stroke and infectious diseases. In this review, we summarized the biologic function of stress proteins, and current progress on their mechanisms related to virus reproduction and diseases caused by virus infections. As SPs also attract a great interest as potential antiviral targets (e.g., COVID-19), we also discuss the present progress and challenges in this area of HSP-based drug development, as well as with compounds already under clinical evaluation.
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Affiliation(s)
- Qianya Wan
- Department of Biomedical Sciences, City University of Hong Kong, Kowloon, Hong Kong, China
| | - Dan Song
- Department of Biomedical Sciences, City University of Hong Kong, Kowloon, Hong Kong, China
| | - Huangcan Li
- Department of Biomedical Sciences, City University of Hong Kong, Kowloon, Hong Kong, China
| | - Ming-Liang He
- Department of Biomedical Sciences, City University of Hong Kong, Kowloon, Hong Kong, China. .,CityU Shenzhen Research Institute, Shenzhen, China.
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15
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Trypsteen W, White CH, Mukim A, Spina CA, De Spiegelaere W, Lefever S, Planelles V, Bosque A, Woelk CH, Vandekerckhove L, Beliakova-Bethell N. Long non-coding RNAs and latent HIV - A search for novel targets for latency reversal. PLoS One 2019; 14:e0224879. [PMID: 31710657 PMCID: PMC6844474 DOI: 10.1371/journal.pone.0224879] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Accepted: 10/23/2019] [Indexed: 12/23/2022] Open
Abstract
The latent cellular reservoir of HIV is recognized as the major barrier to cure from HIV infection. Long non-coding RNAs (lncRNAs) are more tissue and cell type-specific than protein coding genes, and may represent targets of choice for HIV latency reversal. Using two in vitro primary T-cell models, we identified lncRNAs dysregulated in latency. PVT1 and RP11-347C18.3 were up-regulated in common between the two models, and RP11-539L10.2 was down-regulated. The major component of the latent HIV reservoir, memory CD4+ T-cells, had higher expression of these lncRNAs, compared to naïve T-cells. Guilt-by-association analysis demonstrated that lncRNAs dysregulated in latency were associated with several cellular pathways implicated in HIV latency establishment and maintenance: proteasome, spliceosome, p53 signaling, and mammalian target of rapamycin (MTOR). PVT1, RP11-347C18.3, and RP11-539L10.2 were down-regulated by latency reversing agents, suberoylanilide hydroxamic acid and Romidepsin, suggesting that modulation of lncRNAs is a possible secondary mechanism of action of these compounds. These results will facilitate prioritization of lncRNAs for evaluation as targets for HIV latency reversal. Importantly, our study provides insights into regulatory function of lncRNA during latent HIV infection.
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Affiliation(s)
- Wim Trypsteen
- HIV Cure Research Center, Department of Internal Medicine, Ghent University and Ghent University Hospital, Ghent, Belgium
| | - Cory H. White
- Faculty of Medicine, University of Southampton, Southampton, Hants, United Kingdom
| | - Amey Mukim
- San Diego VA Medical Center and Veterans Medical Research Foundation, San Diego, CA, United States of America
| | - Celsa A. Spina
- San Diego VA Medical Center and Veterans Medical Research Foundation, San Diego, CA, United States of America
- Department of Pathology, University of California San Diego, La Jolla, CA, United States of America
| | - Ward De Spiegelaere
- Department of Morphology, Faculty of Veterinary Sciences, Ghent University, Ghent, Belgium
| | - Steve Lefever
- Center for Medical Genetics, Ghent University, Ghent, Belgium
| | - Vicente Planelles
- Division of Microbiology and Immunology, Department of Pathology, University of Utah School of Medicine, Salt Lake City, UT, United States of America
| | - Alberto Bosque
- Department of Microbiology, Immunology and Tropical Medicine, The George Washington University, Washington, DC, United States of America
| | - Christopher H. Woelk
- Faculty of Medicine, University of Southampton, Southampton, Hants, United Kingdom
| | - Linos Vandekerckhove
- HIV Cure Research Center, Department of Internal Medicine, Ghent University and Ghent University Hospital, Ghent, Belgium
| | - Nadejda Beliakova-Bethell
- San Diego VA Medical Center and Veterans Medical Research Foundation, San Diego, CA, United States of America
- Department of Medicine, University of California San Diego, La Jolla, CA, United States of America
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16
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HIV Silencing and Inducibility Are Heterogeneous and Are Affected by Factors Intrinsic to the Virus. mBio 2019; 10:mBio.00188-19. [PMID: 31239371 PMCID: PMC6593397 DOI: 10.1128/mbio.00188-19] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Transcriptionally silent HIV proviruses form the major obstacle to eradicating HIV. Many studies of HIV latency have focused on the cellular mechanisms that maintain silencing of proviral DNA. Here we show that viral sequence variation affecting replicative ability leads to variable rates of silencing and ability to reactivate. We studied naturally occurring and engineered polymorphisms in a recently identified exonic splice enhancer (ESEtat) that regulates tat mRNA splicing and constructed viruses with increased (strain M1), reduced (strain M2), or completely absent (strain ERK) binding of splicing factors essential for optimal production of tat mRNA resulting in a corresponding change in Tat activity. The mutations affected viral replication, with M1 having wild-type (WT) kinetics, M2 exhibiting reduced kinetics, and ERK showing completely abrogated replication. Using single-round infection with green fluorescent protein (GFP)-expressing viruses to study proviral gene expression, we observed progressively greater rates of silencing relating to the degree of ESEtat disruption, with the WT strain at 53%, strain M2 at 69%, and strain ERK at 94%. By stimulating infected cells with a latency reversal agent (phorbol myristate acetate [PMA], panobinostat, or JQ1), we observed that the dose required to achieve 50% of the maximum signal was lowest in the WT, intermediate in M2, and highest in ERK, indicating progressively higher thresholds for reactivation. These results suggest that the ability of silent proviruses to reactivate from latency is variable and that minor differences in the viral sequence can alter the proportion of silenced viruses as well as the threshold required to induce silenced viruses to reactivate and express.IMPORTANCE A reservoir of infected cells in which the HIV genome is transcriptionally silent is acknowledged to be the principal barrier to eradicating the virus from an infected person. A number of cellular processes are implicated in this silencing; however, the viral factors that may contribute remain underexplored. Here we examined mutations altering the correct splicing of HIV gene products as a model to study whether differences in viral sequence can affect either the proportion of viruses that are active or silent or their ability to reactivate. We found that some naturally occurring variations result in viruses that are silenced at a higher rate and require a proportionally increased stimulus for reactivation from latency. These data suggest that the silencing and reactivation behavior of HIV exists in a spectrum, influenced by factors intrinsic to the virus.
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17
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Sajini AA, Choudhury NR, Wagner RE, Bornelöv S, Selmi T, Spanos C, Dietmann S, Rappsilber J, Michlewski G, Frye M. Loss of 5-methylcytosine alters the biogenesis of vault-derived small RNAs to coordinate epidermal differentiation. Nat Commun 2019; 10:2550. [PMID: 31186410 PMCID: PMC6560067 DOI: 10.1038/s41467-019-10020-7] [Citation(s) in RCA: 64] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Accepted: 04/09/2019] [Indexed: 12/20/2022] Open
Abstract
The presence and absence of RNA modifications regulates RNA metabolism by modulating the binding of writer, reader, and eraser proteins. For 5-methylcytosine (m5C) however, it is largely unknown how it recruits or repels RNA-binding proteins. Here, we decipher the consequences of m5C deposition into the abundant non-coding vault RNA VTRNA1.1. Methylation of cytosine 69 in VTRNA1.1 occurs frequently in human cells, is exclusively mediated by NSUN2, and determines the processing of VTRNA1.1 into small-vault RNAs (svRNAs). We identify the serine/arginine rich splicing factor 2 (SRSF2) as a novel VTRNA1.1-binding protein that counteracts VTRNA1.1 processing by binding the non-methylated form with higher affinity. Both NSUN2 and SRSF2 orchestrate the production of distinct svRNAs. Finally, we discover a functional role of svRNAs in regulating the epidermal differentiation programme. Thus, our data reveal a direct role for m5C in the processing of VTRNA1.1 that involves SRSF2 and is crucial for efficient cellular differentiation.
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Affiliation(s)
- Abdulrahim A Sajini
- Department of Genetics, University of Cambridge, Downing Street, Cambridge, CB2 3EH, UK
- Department of Biomedical Engineering, Khalifa University of Science and Technology, P.O. Box 127788, Abu Dhabi, United Arab Emirates
- Department of Medical Laboratory Technology, University of Tabuk, Tabuk, P.O. Box 71491, Saudi Arabia
| | - Nila Roy Choudhury
- Division of Infection and Pathway Medicine, University of Edinburgh, The Chancellor's Building, 49 Little France Crescent, Edinburgh, EH16 4SB, UK
| | - Rebecca E Wagner
- Department of Genetics, University of Cambridge, Downing Street, Cambridge, CB2 3EH, UK
| | - Susanne Bornelöv
- Wellcome MRC Cambridge Stem Cell Institute, Tennis Court Road, Cambridge, CB2 1QR, UK
| | - Tommaso Selmi
- Department of Genetics, University of Cambridge, Downing Street, Cambridge, CB2 3EH, UK
| | - Christos Spanos
- Wellcome Centre for Cell Biology, University of Edinburgh, Michael Swann Building, Max Born Crescent, Edinburgh, EH9 3BF, UK
| | - Sabine Dietmann
- Wellcome MRC Cambridge Stem Cell Institute, Tennis Court Road, Cambridge, CB2 1QR, UK
| | - Juri Rappsilber
- Wellcome Centre for Cell Biology, University of Edinburgh, Michael Swann Building, Max Born Crescent, Edinburgh, EH9 3BF, UK
- Department of Biotechnology, Technische Universität Berlin, Gustav-Meyer-Allee 25, 13355, Berlin, Germany
| | - Gracjan Michlewski
- Division of Infection and Pathway Medicine, University of Edinburgh, The Chancellor's Building, 49 Little France Crescent, Edinburgh, EH16 4SB, UK.
- Wellcome Centre for Cell Biology, University of Edinburgh, Michael Swann Building, Max Born Crescent, Edinburgh, EH9 3BF, UK.
- ZJU-UoE Institute, Zhejiang University, 718 East Haizhou Road, Haining, Zhejiang, 314400, P.R. China.
| | - Michaela Frye
- Department of Genetics, University of Cambridge, Downing Street, Cambridge, CB2 3EH, UK.
- German Cancer Research Centre (Deutsches Krebsforschungszentrum, DKFZ), Im Neuenheimer Feld 280, 69120, Heidelberg, Germany.
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18
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Hillebrand F, Ostermann PN, Müller L, Degrandi D, Erkelenz S, Widera M, Pfeffer K, Schaal H. Gymnotic Delivery of LNA Mixmers Targeting Viral SREs Induces HIV-1 mRNA Degradation. Int J Mol Sci 2019; 20:ijms20051088. [PMID: 30832397 PMCID: PMC6429378 DOI: 10.3390/ijms20051088] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Revised: 02/22/2019] [Accepted: 02/25/2019] [Indexed: 02/07/2023] Open
Abstract
Transcription of the HIV-1 provirus generates a viral pre-mRNA, which is alternatively spliced into more than 50 HIV-1 mRNAs encoding all viral proteins. Regulation of viral alternative splice site usage includes the presence of splicing regulatory elements (SREs) which can dramatically impact RNA expression and HIV-1 replication when mutated. Recently, we were able to show that two viral SREs, GI3-2 and ESEtat, are important players in the generation of viral vif, vpr and tat mRNAs. Furthermore, we demonstrated that masking these SREs by transfected locked nucleic acid (LNA) mixmers affect the viral splicing pattern and viral particle production. With regard to the development of future therapeutic LNA mixmer-based antiretroviral approaches, we delivered the GI3-2 and the ESEtat LNA mixmers “nakedly”, without the use of transfection reagents (gymnosis) into HIV-1 infected cells. Surprisingly, we observed that gymnotically-delivered LNA mixmers accumulated in the cytoplasm, and seemed to co-localize with GW bodies and induced degradation of mRNAs containing their LNA target sequence. The GI3-2 and the ESEtat LNA-mediated RNA degradation resulted in abrogation of viral replication in HIV-1 infected Jurkat and PM1 cells as well as in PBMCs.
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Affiliation(s)
- Frank Hillebrand
- Institute of Virology, Medical Faculty, Heinrich-Heine-University Düsseldorf, 40225 Düsseldorf, Germany.
| | - Philipp Niklas Ostermann
- Institute of Virology, Medical Faculty, Heinrich-Heine-University Düsseldorf, 40225 Düsseldorf, Germany.
| | - Lisa Müller
- Institute of Virology, Medical Faculty, Heinrich-Heine-University Düsseldorf, 40225 Düsseldorf, Germany.
| | - Daniel Degrandi
- Institute of Medical Microbiology and Hospital Hygiene, Medical Faculty, Heinrich-Heine-University Düsseldorf, 40225 Düsseldorf, Germany.
| | - Steffen Erkelenz
- Institute of Virology, Medical Faculty, Heinrich-Heine-University Düsseldorf, 40225 Düsseldorf, Germany.
| | - Marek Widera
- Institute of Virology, Medical Faculty, Heinrich-Heine-University Düsseldorf, 40225 Düsseldorf, Germany.
| | - Klaus Pfeffer
- Institute of Medical Microbiology and Hospital Hygiene, Medical Faculty, Heinrich-Heine-University Düsseldorf, 40225 Düsseldorf, Germany.
| | - Heiner Schaal
- Institute of Virology, Medical Faculty, Heinrich-Heine-University Düsseldorf, 40225 Düsseldorf, Germany.
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19
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Levengood JD, Tolbert BS. Idiosyncrasies of hnRNP A1-RNA recognition: Can binding mode influence function. Semin Cell Dev Biol 2019; 86:150-161. [PMID: 29625167 PMCID: PMC6177329 DOI: 10.1016/j.semcdb.2018.04.001] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Revised: 03/27/2018] [Accepted: 04/03/2018] [Indexed: 12/21/2022]
Abstract
The heterogeneous nuclear ribonucleoproteins (hnRNPs) are a diverse family of RNA binding proteins that function in most stages of RNA metabolism. The prototypical member, hnRNP A1, is composed of three major domains; tandem N-terminal RNA Recognition Motifs (RRMs) and a C-terminal mostly intrinsically disordered region. HnRNP A1 is broadly implicated in basic cellular RNA processing events such as splicing, stability, nuclear export and translation. Due to its ubiquity and abundance, hnRNP A1 is also frequently usurped to control viral gene expression. Deregulation of the RNA metabolism functions of hnRNP A1 in neuronal cells contributes to several neurodegenerative disorders. Because of these roles in human pathologies, the study of hnRNP A1 provides opportunities for the development of novel therapeutics, with disruption of its RNA binding capabilities being the most promising target. The functional diversity of hnRNP A1 is reflected in the complex nature by which it interacts with various RNA targets. Indeed, hnRNP A1 binds both structured and unstructured RNAs with binding affinities that span several magnitudes. Available structures of hnRNP A1-RNA complexes also suggest a degree of plasticity in molecular recognition. Given the reinvigoration in hnRNP A1, the goal of this review is to use the available structural biochemical developments as a framework to interpret its wide-range of RNA functions.
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Affiliation(s)
- Jeffrey D Levengood
- Department of Chemistry, Case Western Reserve University, Cleveland, OH, United States
| | - Blanton S Tolbert
- Department of Chemistry, Case Western Reserve University, Cleveland, OH, United States.
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20
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Dominguez-Valentin M, Nakken S, Tubeuf H, Vodak D, Ekstrøm PO, Nissen AM, Morak M, Holinski-Feder E, Martins A, Møller P, Hovig E. Potentially pathogenic germline CHEK2 c.319+2T>A among multiple early-onset cancer families. Fam Cancer 2019; 17:141-153. [PMID: 28608266 DOI: 10.1007/s10689-017-0011-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
To study the potential contribution of genes other than BRCA1/2, PTEN, and TP53 to the biological and clinical characteristics of multiple early-onset cancers in Norwegian families, including early-onset breast cancer, Cowden-like and Li-Fraumeni-like syndromes (BC, CSL and LFL, respectively). The Hereditary Cancer Biobank from the Norwegian Radium Hospital was used to identify early-onset BC, CSL or LFL for whom no pathogenic variants in BRCA1/2, PTEN, or TP53 had been found in routine diagnostic DNA sequencing. Forty-four cancer susceptibility genes were selected and analyzed by our in-house designed TruSeq amplicon-based assay for targeted sequencing. Protein- and RNA splicing-dedicated in silico analyses were performed for all variants of unknown significance (VUS). Variants predicted as the more likely to affect splicing were experimentally analyzed by minigene assay. We identified a CSL individual carrying a variant in CHEK2 (c.319+2T>A, IVS2), here considered as likely pathogenic. Out of the five VUS (BRCA2, CDH1, CHEK2, MAP3K1, NOTCH3) tested in the minigene splicing assay, only NOTCH3 c.14090C>T (p.Ser497Leu) showed a significant effect on RNA splicing, notably by inducing partial skipping of exon 9. Among 13 early-onset BC, CSL and LFL patients, gene panel sequencing identified a potentially pathogenic variant in CHEK2 that affects a canonical RNA splicing signal. Our study provides new information on genetic loci that may affect the risk of developing cancer in these patients and their families, demonstrating that genes presently not routinely tested in molecular diagnostic settings may be important for capturing cancer predisposition in these families.
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Affiliation(s)
- Mev Dominguez-Valentin
- Department of Tumor Biology, Institute for Cancer Research, Oslo University Hospital, Oslo, Norway.
| | - Sigve Nakken
- Department of Tumor Biology, Institute for Cancer Research, Oslo University Hospital, Oslo, Norway
| | - Hélène Tubeuf
- Normandy Centre for Genomic and Personalized Medicine, Inserm-U1245, UNIROUEN, Normandie Univ, Rouen, France.,Interactive Biosoftware, Rouen, France
| | - Daniel Vodak
- Department of Tumor Biology, Institute for Cancer Research, Oslo University Hospital, Oslo, Norway
| | - Per Olaf Ekstrøm
- Department of Tumor Biology, Institute for Cancer Research, Oslo University Hospital, Oslo, Norway
| | - Anke M Nissen
- Medizinische Klinik und Poliklinik IV, Campus Innenstadt, Klinikum der Universität München, Ziemssenstr. 1, Munich, Germany.,MGZ-Medizinisch Genetisches Zentrum, Munich, Germany
| | - Monika Morak
- Medizinische Klinik und Poliklinik IV, Campus Innenstadt, Klinikum der Universität München, Ziemssenstr. 1, Munich, Germany.,MGZ-Medizinisch Genetisches Zentrum, Munich, Germany
| | - Elke Holinski-Feder
- Medizinische Klinik und Poliklinik IV, Campus Innenstadt, Klinikum der Universität München, Ziemssenstr. 1, Munich, Germany.,MGZ-Medizinisch Genetisches Zentrum, Munich, Germany
| | - Alexandra Martins
- Normandy Centre for Genomic and Personalized Medicine, Inserm-U1245, UNIROUEN, Normandie Univ, Rouen, France
| | - Pål Møller
- Department of Tumor Biology, Institute for Cancer Research, Oslo University Hospital, Oslo, Norway.,Department of Human Medicine, Universität Witten/Herdecke, Witten, Germany.,Department of Medical Genetics, Oslo University Hospital, Oslo, Norway
| | - Eivind Hovig
- Department of Tumor Biology, Institute for Cancer Research, Oslo University Hospital, Oslo, Norway.,Department of Informatics, University of Oslo, Oslo, Norway.,Instituteof Cancer Genetics and Informatics, Oslo University Hospital, Oslo, Norway
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21
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Sertznig H, Hillebrand F, Erkelenz S, Schaal H, Widera M. Behind the scenes of HIV-1 replication: Alternative splicing as the dependency factor on the quiet. Virology 2018; 516:176-188. [PMID: 29407375 DOI: 10.1016/j.virol.2018.01.011] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Revised: 01/10/2018] [Accepted: 01/11/2018] [Indexed: 01/31/2023]
Abstract
Alternative splicing plays a key role in the HIV-1 life cycle and is essential to maintain an equilibrium of mRNAs that encode viral proteins and polyprotein-isoforms. In particular, since all early HIV-1 proteins are expressed from spliced intronless and late enzymatic and structural proteins from intron containing, i.e. splicing repressed viral mRNAs, cellular splicing factors and splicing regulatory proteins are crucial for the replication capacity. In this review, we will describe the complex network of cis-acting splicing regulatory elements (SREs), which are mainly localized in the neighbourhoods of all HIV-1 splice sites and warrant the proper ratio of individual transcript isoforms. Since SREs represent binding sites for trans-acting cellular splicing factors interacting with the cellular spliceosomal apparatus we will review the current knowledge of interactions between viral RNA and cellular proteins as well as their impact on viral replication. Finally, we will discuss potential therapeutic approaches targeting HIV-1 alternative splicing.
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Affiliation(s)
- Helene Sertznig
- Institute for Virology, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
| | - Frank Hillebrand
- Institute of Virology, Heinrich Heine University, University Hospital, Düsseldorf, Germany
| | - Steffen Erkelenz
- Institute for Genetics, Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Germany
| | - Heiner Schaal
- Institute of Virology, Heinrich Heine University, University Hospital, Düsseldorf, Germany
| | - Marek Widera
- Institute for Virology, University Hospital Essen, University of Duisburg-Essen, Essen, Germany.
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22
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van der Kuyl AC, Vink M, Zorgdrager F, Bakker M, Wymant C, Hall M, Gall A, Blanquart F, Berkhout B, Fraser C, Cornelissen M. The evolution of subtype B HIV-1 tat in the Netherlands during 1985-2012. Virus Res 2018; 250:51-64. [PMID: 29654800 DOI: 10.1016/j.virusres.2018.04.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Revised: 04/05/2018] [Accepted: 04/05/2018] [Indexed: 12/18/2022]
Abstract
For the production of viral genomic RNA, HIV-1 is dependent on an early viral protein, Tat, which is required for high-level transcription. The quantity of viral RNA detectable in blood of HIV-1 infected individuals varies dramatically, and a factor involved could be the efficiency of Tat protein variants to stimulate RNA transcription. HIV-1 virulence, measured by set-point viral load, has been observed to increase over time in the Netherlands and elsewhere. Investigation of tat gene evolution in clinical isolates could discover a role of Tat in this changing virulence. A dataset of 291 Dutch HIV-1 subtype B tat genes, derived from full-length HIV-1 genome sequences from samples obtained between 1985-2012, was used to analyse the evolution of Tat. Twenty-two patient-derived tat genes, and the control TatHXB2 were analysed for their capacity to stimulate expression of an LTR-luciferase reporter gene construct in diverse cell lines, as well as for their ability to complement a tat-defective HIV-1LAI clone. Analysis of 291 historical tat sequences from the Netherlands showed ample amino acid (aa) variation between isolates, although no specific mutations were selected for over time. Of note, however, the encoded protein varied its length over the years through the loss or gain of stop codons in the second exon. In transmission clusters, a selection against the shorter Tat86 ORF was apparent in favour of the more common Tat101 version, likely due to negative selection against Tat86 itself, although random drift, transmission bottlenecks, or linkage to other variants could also explain the observation. There was no correlation between Tat length and set-point viral load; however, the number of non-intermediate variants in our study was small. In addition, variation in the length of Tat did not significantly change its capacity to stimulate transcription. From 1985 till 2012, variation in the length of the HIV-1 subtype B tat gene is increasingly found in the Dutch epidemic. However, as Tat proteins did not differ significantly in their capacity to stimulate transcription elongation in vitro, the increased HIV-1 virulence seen in recent years could not be linked to an evolving viral Tat protein.
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Affiliation(s)
- Antoinette C van der Kuyl
- Laboratory of Experimental Virology, Department of Medical Microbiology, Academic Medical Center, University of Amsterdam, Meibergdreef 15, 1105 AZ, Amsterdam, The Netherlands.
| | - Monique Vink
- Laboratory of Experimental Virology, Department of Medical Microbiology, Academic Medical Center, University of Amsterdam, Meibergdreef 15, 1105 AZ, Amsterdam, The Netherlands
| | - Fokla Zorgdrager
- Laboratory of Experimental Virology, Department of Medical Microbiology, Academic Medical Center, University of Amsterdam, Meibergdreef 15, 1105 AZ, Amsterdam, The Netherlands
| | - Margreet Bakker
- Laboratory of Experimental Virology, Department of Medical Microbiology, Academic Medical Center, University of Amsterdam, Meibergdreef 15, 1105 AZ, Amsterdam, The Netherlands
| | - Chris Wymant
- Medical Research Council Centre for Outbreak Analysis and Modelling, Department of Infectious Disease Epidemiology, School of Public Health, Imperial College London, London, W21PG, United Kingdom; Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Matthew Hall
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Astrid Gall
- Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, CB10 1SA, United Kingdom
| | - François Blanquart
- Medical Research Council Centre for Outbreak Analysis and Modelling, Department of Infectious Disease Epidemiology, School of Public Health, Imperial College London, London, W21PG, United Kingdom; Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Ben Berkhout
- Laboratory of Experimental Virology, Department of Medical Microbiology, Academic Medical Center, University of Amsterdam, Meibergdreef 15, 1105 AZ, Amsterdam, The Netherlands
| | - Christophe Fraser
- Medical Research Council Centre for Outbreak Analysis and Modelling, Department of Infectious Disease Epidemiology, School of Public Health, Imperial College London, London, W21PG, United Kingdom; Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Marion Cornelissen
- Laboratory of Experimental Virology, Department of Medical Microbiology, Academic Medical Center, University of Amsterdam, Meibergdreef 15, 1105 AZ, Amsterdam, The Netherlands
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Dominguez-Valentin M, Nakken S, Tubeuf H, Vodak D, Ekstrøm PO, Nissen AM, Morak M, Holinski-Feder E, Martins A, Møller P, Hovig E. Identification of genetic variants for clinical management of familial colorectal tumors. BMC MEDICAL GENETICS 2018; 19:26. [PMID: 29458332 PMCID: PMC5819082 DOI: 10.1186/s12881-018-0533-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Accepted: 01/24/2018] [Indexed: 12/22/2022]
Abstract
Background The genetic mechanisms for families who meet the clinical criteria for Lynch syndrome (LS) but do not carry pathogenic variants in the mismatch repair (MMR) genes are still undetermined. We aimed to study the potential contribution of genes other than MMR genes to the biological and clinical characteristics of Norwegian families fulfilling Amsterdam (AMS) criteria or revised Bethesda guidelines. Methods The Hereditary Cancer Biobank of the Norwegian Radium Hospital was interrogated to identify individuals with a high risk of developing colorectal cancer (CRC) for whom no pathogenic variants in MMR genes had been found in routine diagnostic DNA sequencing. Forty-four cancer susceptibility genes were selected and analyzed by using our in-house designed TruSeq amplicon-based assay for targeted sequencing. RNA splicing- and protein-dedicated in silico analyses were performed for all variants of unknown significance (VUS). Variants predicted as likely to affect splicing were experimentally analyzed by resorting to minigene assays. Results We identified a patient who met the revised Bethesda guidelines and carried a likely pathogenic variant in CHEK2 (c.470 T > C, p.I157T). In addition, 25 unique VUS were identified in 18 individuals, of which 2 exonic variants (MAP3K1 c.764A > G and NOTCH3 c.5854G >A) were analyzed in the minigene splicing assay and found not to have an effect on RNA splicing. Conclusions Among high-risk CRC patients that fulfill the AMS criteria or revised Bethesda guidelines, targeted gene sequencing identified likely pathogenic variant and VUS in other genes than the MMR genes (CHEK2, NOTCH3 and MAP3K1). Our study suggests that the analysis of genes currently excluded from routine molecular diagnostic screens may confer cancer susceptibility. Electronic supplementary material The online version of this article (10.1186/s12881-018-0533-9) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Mev Dominguez-Valentin
- Department of Tumor Biology, Institute for Cancer Research, Oslo University Hospital, Oslo, Norway.
| | - Sigve Nakken
- Department of Tumor Biology, Institute for Cancer Research, Oslo University Hospital, Oslo, Norway
| | - Hélène Tubeuf
- Inserm-U1245, UNIROUEN, Normandie Univ, Normandy Centre for Genomic and Personalized Medicine, Rouen, France.,Interactive Biosoftware, Rouen, France
| | - Daniel Vodak
- Department of Tumor Biology, Institute for Cancer Research, Oslo University Hospital, Oslo, Norway
| | - Per Olaf Ekstrøm
- Department of Tumor Biology, Institute for Cancer Research, Oslo University Hospital, Oslo, Norway
| | - Anke M Nissen
- Medizinische Klinik und Poliklinik IV, Campus Innenstadt, Klinikum der Universität München, Ziemssenstr. 1, Munich, Germany.,MGZ-Medizinisch Genetisches Zentrum, Munich, Germany
| | - Monika Morak
- Medizinische Klinik und Poliklinik IV, Campus Innenstadt, Klinikum der Universität München, Ziemssenstr. 1, Munich, Germany.,MGZ-Medizinisch Genetisches Zentrum, Munich, Germany
| | - Elke Holinski-Feder
- Medizinische Klinik und Poliklinik IV, Campus Innenstadt, Klinikum der Universität München, Ziemssenstr. 1, Munich, Germany.,MGZ-Medizinisch Genetisches Zentrum, Munich, Germany
| | - Alexandra Martins
- Inserm-U1245, UNIROUEN, Normandie Univ, Normandy Centre for Genomic and Personalized Medicine, Rouen, France
| | - Pål Møller
- Department of Tumor Biology, Institute for Cancer Research, Oslo University Hospital, Oslo, Norway.,Department of Human Medicine, Universität Witten, Herdecke, Germany.,Department of Medical Genetics, Oslo University Hospital, Oslo, Norway
| | - Eivind Hovig
- Department of Tumor Biology, Institute for Cancer Research, Oslo University Hospital, Oslo, Norway.,Department of Informatics, University of Oslo, Oslo, Norway.,Institute of Cancer Genetics and Informatics, Oslo University Hospital, Oslo, Norway
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24
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Dominguez-Valentin M, Evans DGR, Nakken S, Tubeuf H, Vodak D, Ekstrøm PO, Nissen AM, Morak M, Holinski-Feder E, Martins A, Møller P, Hovig E. Genetic variants of prospectively demonstrated phenocopies in BRCA1/2 kindreds. Hered Cancer Clin Pract 2018; 16:4. [PMID: 29371908 PMCID: PMC5769521 DOI: 10.1186/s13053-018-0086-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Accepted: 01/10/2018] [Indexed: 01/03/2023] Open
Abstract
Background In kindreds carrying path_BRCA1/2 variants, some women in these families will develop cancer despite testing negative for the family’s pathogenic variant. These families may have additional genetic variants, which not only may increase the susceptibility of the families’ path_BRCA1/2, but also be capable of causing cancer in the absence of the path_BRCA1/2 variants. We aimed to identify novel genetic variants in prospectively detected breast cancer (BC) or gynecological cancer cases tested negative for their families’ pathogenic BRCA1/2 variant (path_BRCA1 or path_BRCA2). Methods Women with BC or gynecological cancer who had tested negative for path_BRCA1 or path_BRCA2 variants were included. Forty-four cancer susceptibility genes were screened for genetic variation through a targeted amplicon-based sequencing assay. Protein- and RNA splicing-dedicated in silico analyses were performed for all variants of unknown significance (VUS). Variants predicted as the ones most likely affecting pre-mRNA splicing were experimentally analyzed in a minigene assay. Results We identified 48 women who were tested negative for their family’s path_BRCA1 (n = 13) or path_BRCA2 (n = 35) variants. Pathogenic variants in the ATM, BRCA2, MSH6 and MUTYH genes were found in 10% (5/48) of the cases, of whom 15% (2/13) were from path_BRCA1 and 9% (3/35) from path_BRCA2 families. Out of the 26 unique VUS, 3 (12%) were predicted to affect RNA splicing (APC c.721G > A, MAP3K1 c.764A > G and MSH2 c.815C > T). However, by using a minigene, assay we here show that APC c.721G > A does not cause a splicing defect, similarly to what has been recently reported for the MAP3K1 c.764A > G. The MSH2 c.815C > T was previously described as causing partial exon skipping and it was identified in this work together with the path_BRCA2 c.9382C > T (p.R3128X). Conclusion All women in breast or breast/ovarian cancer kindreds would benefit from being offered genetic testing irrespective of which causative genetic variants have been demonstrated in their relatives. Electronic supplementary material The online version of this article (10.1186/s13053-018-0086-0) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Mev Dominguez-Valentin
- 1Department of Tumor Biology, Institute for Cancer Research, Oslo University Hospital, Oslo, Norway
| | - D Gareth R Evans
- 2Department of Genetic Medicine, The University of Manchester, Manchester Academic Health Science Centre, St. Mary's Hospital, Manchester, UK.,3Genesis Prevention Centre, University Hospital of South Manchester, Southmoor Road, Wythenshawe, UK
| | - Sigve Nakken
- 1Department of Tumor Biology, Institute for Cancer Research, Oslo University Hospital, Oslo, Norway
| | - Hélène Tubeuf
- 4Inserm-U1245, UNIROUEN, Normandie Univ, Normandy Centre for Genomic and Personalized Medicine, Rouen, France.,Interactive Biosoftware, Rouen, France
| | - Daniel Vodak
- 1Department of Tumor Biology, Institute for Cancer Research, Oslo University Hospital, Oslo, Norway
| | - Per Olaf Ekstrøm
- 1Department of Tumor Biology, Institute for Cancer Research, Oslo University Hospital, Oslo, Norway
| | - Anke M Nissen
- 6Medizinische Klinik und Poliklinik IV, Campus Innenstadt, Klinikum der Universität München, Ziemssenstr. 1, Munich, Germany.,MGZ-Medizinisch Genetisches Zentrum, Munich, Germany
| | - Monika Morak
- 6Medizinische Klinik und Poliklinik IV, Campus Innenstadt, Klinikum der Universität München, Ziemssenstr. 1, Munich, Germany.,MGZ-Medizinisch Genetisches Zentrum, Munich, Germany
| | - Elke Holinski-Feder
- 6Medizinische Klinik und Poliklinik IV, Campus Innenstadt, Klinikum der Universität München, Ziemssenstr. 1, Munich, Germany.,MGZ-Medizinisch Genetisches Zentrum, Munich, Germany
| | - Alexandra Martins
- 4Inserm-U1245, UNIROUEN, Normandie Univ, Normandy Centre for Genomic and Personalized Medicine, Rouen, France
| | - Pål Møller
- 1Department of Tumor Biology, Institute for Cancer Research, Oslo University Hospital, Oslo, Norway.,8Department of Human Medicine, Universität Witten/Herdecke, Witten, Germany.,9Department of Medical Genetics, Oslo University Hospital, Oslo, Norway
| | - Eivind Hovig
- 1Department of Tumor Biology, Institute for Cancer Research, Oslo University Hospital, Oslo, Norway.,10Department of Informatics, University of Oslo, Oslo, Norway.,11Institute of Cancer Genetics and Informatics, Oslo University Hospital, Oslo, Norway
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Brillen AL, Schöneweis K, Walotka L, Hartmann L, Müller L, Ptok J, Kaisers W, Poschmann G, Stühler K, Buratti E, Theiss S, Schaal H. Succession of splicing regulatory elements determines cryptic 5΄ss functionality. Nucleic Acids Res 2017; 45:4202-4216. [PMID: 28039323 PMCID: PMC5397162 DOI: 10.1093/nar/gkw1317] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2016] [Accepted: 12/19/2016] [Indexed: 12/25/2022] Open
Abstract
A critical step in exon definition is the recognition of a proper splice donor (5΄ss) by the 5’ end of U1 snRNA. In the selection of appropriate 5΄ss, cis-acting splicing regulatory elements (SREs) are indispensable. As a model for 5΄ss recognition, we investigated cryptic 5΄ss selection within the human fibrinogen Bβ-chain gene (FGB) exon 7, where we identified several exonic SREs that simultaneously acted on up- and downstream cryptic 5΄ss. In the FGB exon 7 model system, 5΄ss selection iteratively proceeded along an alternating sequence of U1 snRNA binding sites and interleaved SREs which in principle supported different 3’ exon ends. Like in a relay race, SREs either suppressed a potential 5΄ss and passed the splicing baton on or splicing actually occurred. From RNA-Seq data, we systematically selected 19 genes containing exons with silent U1 snRNA binding sites competing with nearby highly used 5΄ss. Extensive SRE analysis by different algorithms found authentic 5΄ss significantly more supported by SREs than silent U1 snRNA binding sites, indicating that our concept may permit generalization to a model for 5΄ss selection and 3’ exon end definition.
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Affiliation(s)
- Anna-Lena Brillen
- Institute for Virology, Heinrich-Heine-University Düsseldorf, 40225 Düsseldorf, Germany
| | - Katrin Schöneweis
- Department of Infectious Diseases, Molecular Virology, University Hospital Heidelberg, 69120 Heidelberg, Germany
| | - Lara Walotka
- Institute for Virology, Heinrich-Heine-University Düsseldorf, 40225 Düsseldorf, Germany
| | - Linda Hartmann
- Institute for Virology, Heinrich-Heine-University Düsseldorf, 40225 Düsseldorf, Germany
| | - Lisa Müller
- Institute for Virology, Heinrich-Heine-University Düsseldorf, 40225 Düsseldorf, Germany
| | - Johannes Ptok
- Institute for Virology, Heinrich-Heine-University Düsseldorf, 40225 Düsseldorf, Germany
| | - Wolfgang Kaisers
- Department of Anesthesiology, University Hospital Düsseldorf, Heinrich-Heine-University Düsseldorf, 40225 Düsseldorf, Germany
| | - Gereon Poschmann
- Molecular Proteomics Laboratory, BMFZ, Heinrich-Heine-University Düsseldorf, 40225 Düsseldorf, Germany
| | - Kai Stühler
- Molecular Proteomics Laboratory, BMFZ, Heinrich-Heine-University Düsseldorf, 40225 Düsseldorf, Germany.,Institute for Molecular Medicine, University Hospital Düsseldorf, Heinrich-Heine-University Düsseldorf, 40225 Düsseldorf, Germany
| | - Emanuele Buratti
- International Centre for Genetic Engineering and Biotechnology (ICGEB), Area Science Park, 34149 Trieste, Italy
| | - Stephan Theiss
- Institute of Clinical Neuroscience and Medical Psychology, Heinrich-Heine-University Düsseldorf, 40225
| | - Heiner Schaal
- Institute for Virology, Heinrich-Heine-University Düsseldorf, 40225 Düsseldorf, Germany
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26
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Screening for small molecule inhibitors of HIV-1 Gag expression. Methods 2017; 126:201-208. [DOI: 10.1016/j.ymeth.2017.06.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2017] [Revised: 05/08/2017] [Accepted: 06/05/2017] [Indexed: 01/03/2023] Open
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27
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Control of HIV-1 gene expression by SR proteins. Biochem Soc Trans 2017; 44:1417-1425. [PMID: 27911724 DOI: 10.1042/bst20160113] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Revised: 07/08/2016] [Accepted: 07/12/2016] [Indexed: 12/24/2022]
Abstract
Cellular proteins are required for all steps of human immunodeficiency virus type 1 (HIV-1) gene expression including transcription, splicing, 3'-end formation/polyadenylation, nuclear export and translation. SR proteins are a family of cellular RNA-binding proteins that regulate and functionally integrate multiple steps of gene expression. Specific SR proteins are best characterised for regulating HIV-1 RNA splicing by binding specific locations in the viral RNA, though recently they have also been shown to control transcription, 3'-end formation, and translation. Due to their importance in regulating HIV-1 gene expression, SR proteins and their regulatory factors are potential antiviral drug targets.
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28
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Analysis of Competing HIV-1 Splice Donor Sites Uncovers a Tight Cluster of Splicing Regulatory Elements within Exon 2/2b. J Virol 2017; 91:JVI.00389-17. [PMID: 28446664 DOI: 10.1128/jvi.00389-17] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2017] [Accepted: 04/18/2017] [Indexed: 12/24/2022] Open
Abstract
The HIV-1 accessory protein Vif is essential for viral replication by counteracting the host restriction factor APOBEC3G (A3G), and balanced levels of both proteins are required for efficient viral replication. Noncoding exons 2/2b contain the Vif start codon between their alternatively used splice donors 2 and 2b (D2 and D2b). For vif mRNA, intron 1 must be removed while intron 2 must be retained. Thus, splice acceptor 1 (A1) must be activated by U1 snRNP binding to either D2 or D2b, while splicing at D2 or D2b must be prevented. Here, we unravel the complex interactions between previously known and novel components of the splicing regulatory network regulating HIV-1 exon 2/2b inclusion in viral mRNAs. In particular, using RNA pulldown experiments and mass spectrometry analysis, we found members of the heterogeneous nuclear ribonucleoparticle (hnRNP) A/B family binding to a novel splicing regulatory element (SRE), the exonic splicing silencer ESS2b, and the splicing regulatory proteins Tra2/SRSF10 binding to the nearby exonic splicing enhancer ESE2b. Using a minigene reporter, we performed bioinformatics HEXplorer-guided mutational analysis to narrow down SRE motifs affecting splice site selection between D2 and D2b. Eventually, the impacts of these SREs on the viral splicing pattern and protein expression were exhaustively analyzed in viral particle production and replication experiments. Masking of these protein binding sites by use of locked nucleic acids (LNAs) impaired Vif expression and viral replication.IMPORTANCE Based on our results, we propose a model in which a dense network of SREs regulates vif mRNA and protein expression, crucial to maintain viral replication within host cells with varying A3G levels and at different stages of infection. This regulation is maintained by several serine/arginine-rich splicing factors (SRSF) and hnRNPs binding to those elements. Targeting this cluster of SREs with LNAs may lead to the development of novel effective therapeutic strategies.
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Balachandran A, Wong R, Stoilov P, Pan S, Blencowe B, Cheung P, Harrigan PR, Cochrane A. Identification of small molecule modulators of HIV-1 Tat and Rev protein accumulation. Retrovirology 2017; 14:7. [PMID: 28122580 PMCID: PMC5267425 DOI: 10.1186/s12977-017-0330-0] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Accepted: 01/04/2017] [Indexed: 11/10/2022] Open
Abstract
Background HIV-1 replication is critically dependent upon controlled processing of its RNA and the activities provided by its encoded regulatory factors Tat and Rev. A screen of small molecule modulators of RNA processing identified several which inhibited virus gene expression, affecting both relative abundance of specific HIV-1 RNAs and the levels of Tat and Rev proteins. Results The screen for small molecules modulators of HIV-1 gene expression at the post-transcriptional level identified three (a pyrimidin-7-amine, biphenylcarboxamide, and benzohydrazide, designated 791, 833, and 892, respectively) that not only reduce expression of HIV-1 Gag and Env and alter the accumulation of viral RNAs, but also dramatically decrease Tat and Rev levels. Analyses of viral RNA levels by qRTPCR and RTPCR indicated that the loss of either protein could not be attributed to changes in abundance of the mRNAs encoding these factors. However, addition of the proteasome inhibitor MG132 did result in significant restoration of Tat expression, indicating that the compounds are affecting Tat synthesis and/or degradation. Tests in the context of replicating HIV-1 in PBMCs confirmed that 791 significantly reduced virus replication. Parallel analyses of the effect of the compounds on host gene expression revealed only minor changes in either mRNA abundance or alternative splicing. Subsequent tests suggest that 791 may function by reducing levels of the Tat/Rev chaperone Nap1. Conclusions The three compounds examined (791, 833, 892), despite their lack of structural similarity, all suppressed HIV-1 gene expression by preventing accumulation of two key HIV-1 regulatory factors, Tat and Rev. These findings demonstrate that selective disruption of HIV-1 gene expression can be achieved. Electronic supplementary material The online version of this article (doi:10.1186/s12977-017-0330-0) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Ahalya Balachandran
- Department of Molecular Genetics, University of Toronto, 1 King's College Circle, Toronto, ON, M5S1A8, Canada
| | - Raymond Wong
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada
| | - Peter Stoilov
- Department of Biochemistry, University of West Virginia, Morgantown, WV, USA
| | - Sandy Pan
- Donnelly Centre, University of Toronto, Toronto, ON, Canada
| | - Benjamin Blencowe
- Department of Molecular Genetics, University of Toronto, 1 King's College Circle, Toronto, ON, M5S1A8, Canada.,Donnelly Centre, University of Toronto, Toronto, ON, Canada
| | - Peter Cheung
- British Columbia Centre for Excellence in HIV/AIDS, 608-1081 Burrard St., Vancouver, BC, Canada
| | - P Richard Harrigan
- British Columbia Centre for Excellence in HIV/AIDS, 608-1081 Burrard St., Vancouver, BC, Canada.,Department of Medicine, University of British Columbia, Vancouver, BC, Canada
| | - Alan Cochrane
- Department of Molecular Genetics, University of Toronto, 1 King's College Circle, Toronto, ON, M5S1A8, Canada.
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30
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Hillebrand F, Peter JO, Brillen AL, Otte M, Schaal H, Erkelenz S. Differential hnRNP D isoform incorporation may confer plasticity to the ESSV-mediated repressive state across HIV-1 exon 3. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2016; 1860:205-217. [PMID: 27919832 DOI: 10.1016/j.bbagrm.2016.12.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Revised: 11/22/2016] [Accepted: 12/01/2016] [Indexed: 11/27/2022]
Abstract
Even though splicing repression by hnRNP complexes bound to exonic sequences is well-documented, the responsible effector domains of hnRNP proteins have been described for only a select number of hnRNP constituents. Thus, there is only limited information available for possible varying silencer activities amongst different hnRNP proteins and composition changes within possible hnRNP complex assemblies. In this study, we identified the glycine-rich domain (GRD) of hnRNP proteins as a unifying feature in splice site repression. We also show that all four hnRNP D isoforms can act as genuine splicing repressors when bound to exonic positions. The presence of an extended GRD, however, seemed to potentiate the hnRNP D silencer activity of isoforms p42 and p45. Moreover, we demonstrate that hnRNP D proteins associate with the HIV-1 ESSV silencer complex, probably through direct recognition of "UUAG" sequences overlapping with the previously described "UAGG" motifs bound by hnRNP A1. Consequently, this spatial proximity seems to cause mutual interference between hnRNP A1 and hnRNP D. This interplay between hnRNP A1 and D facilitates a dynamic regulation of the repressive state of HIV-1 exon 3 which manifests as fluctuating relative levels of spliced vpr- and unspliced gag/pol-mRNAs.
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Affiliation(s)
- Frank Hillebrand
- Institute of Virology, Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany
| | - Jan Otto Peter
- Institute of Virology, Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany
| | - Anna-Lena Brillen
- Institute of Virology, Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany
| | - Marianne Otte
- Institute of Evolutionary Genetics, Heinrich-Heine-University Duesseldorf, Duesseldorf, Germany
| | - Heiner Schaal
- Institute of Virology, Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany
| | - Steffen Erkelenz
- Institute of Virology, Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany; Institute for Genetics and Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany.
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31
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Wang Z, Liu Q, Lu J, Fan P, Xie W, Qiu W, Wang F, Hu G, Zhang Y. Serine/Arginine-rich Splicing Factor 2 Modulates Herpes Simplex Virus Type 1 Replication via Regulating Viral Gene Transcriptional Activity and Pre-mRNA Splicing. J Biol Chem 2016; 291:26377-26387. [PMID: 27784784 DOI: 10.1074/jbc.m116.753046] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2016] [Revised: 10/17/2016] [Indexed: 11/06/2022] Open
Abstract
Once it enters the host cell, herpes simplex virus type 1 (HSV-1) recruits a series of host cell factors to facilitate its life cycle. Here, we demonstrate that serine/arginine-rich splicing factor 2 (SRSF2), which is an important component of the splicing speckle, mediates HSV-1 replication by regulating viral gene expression at the transcriptional and posttranscriptional levels. Our results indicate that SRSF2 functions as a transcriptional activator by directly binding to infected cell polypeptide 0 (ICP0), infected cell polypeptide 27 (ICP27), and thymidine kinase promoters. Moreover, SRSF2 participates in ICP0 pre-mRNA splicing by recognizing binding sites in ICP0 exon 3. These findings provide insight into the functions of SRSF2 in HSV-1 replication and gene expression.
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Affiliation(s)
- Ziqiang Wang
- From the School of Life Sciences, Tsinghua University, Beijing 100084, China.,the Key Lab in Healthy Science and Technology, Division of Life Science, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055, China
| | - Qing Liu
- From the School of Life Sciences, Tsinghua University, Beijing 100084, China.,the Key Lab in Healthy Science and Technology, Division of Life Science, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055, China
| | - Jinhua Lu
- Shenzhen South China Pharmaceutical Co., Ltd., Shenzhen 518055, China, and
| | - Ping Fan
- From the School of Life Sciences, Tsinghua University, Beijing 100084, China.,the Key Lab in Healthy Science and Technology, Division of Life Science, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055, China
| | - Weidong Xie
- the Key Lab in Healthy Science and Technology, Division of Life Science, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055, China
| | - Wei Qiu
- From the School of Life Sciences, Tsinghua University, Beijing 100084, China.,the Key Lab in Healthy Science and Technology, Division of Life Science, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055, China
| | - Fan Wang
- From the School of Life Sciences, Tsinghua University, Beijing 100084, China.,the Key Lab in Healthy Science and Technology, Division of Life Science, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055, China
| | - Guangnan Hu
- the Department of Medicine, University of Massachusetts Medical School, Worcester, Massachusetts 01655
| | - Yaou Zhang
- the Key Lab in Healthy Science and Technology, Division of Life Science, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055, China,
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32
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Vega Y, Delgado E, de la Barrera J, Carrera C, Zaballos Á, Cuesta I, Mariño A, Ocampo A, Miralles C, Pérez-Castro S, Álvarez H, López-Miragaya I, García-Bodas E, Díez-Fuertes F, Thomson MM. Sequence Analysis of In Vivo-Expressed HIV-1 Spliced RNAs Reveals the Usage of New and Unusual Splice Sites by Viruses of Different Subtypes. PLoS One 2016; 11:e0158525. [PMID: 27355361 PMCID: PMC4927154 DOI: 10.1371/journal.pone.0158525] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2016] [Accepted: 06/16/2016] [Indexed: 11/18/2022] Open
Abstract
HIV-1 RNAs are generated through a complex splicing mechanism, resulting in a great diversity of transcripts, which are classified in three major categories: unspliced, singly spliced (SS), and doubly spliced (DS). Knowledge on HIV-1 RNA splicing in vivo and by non-subtype B viruses is scarce. Here we analyze HIV-1 RNA splice site usage in CD4+CD25+ lymphocytes from HIV-1-infected individuals through pyrosequencing. HIV-1 DS and SS RNAs were amplified by RT-PCR in 19 and 12 samples, respectively. 13,108 sequences from HIV-1 spliced RNAs, derived from viruses of five subtypes (A, B, C, F, G), were identified. In four samples, three of non-B subtypes, five 3' splice sites (3'ss) mapping to unreported positions in the HIV-1 genome were identified. Two, designated A4i and A4j, were used in 22% and 25% of rev RNAs in two viruses of subtypes B and A, respectively. Given their close proximity (one or two nucleotides) to A4c and A4d, respectively, they could be viewed as variants of these sites. Three 3'ss, designated A7g, A7h, and A7i, located 20, 32, and 18 nucleotides downstream of A7, respectively, were identified in a subtype C (A7g, A7h) and a subtype G (A7i) viruses, each in around 2% of nef RNAs. The new splice sites or variants of splice sites were associated with the usual sequence features of 3'ss. Usage of unusual 3'ss A4d, A4e, A5a, A7a, and A7b was also detected. A4f, previously identified in two subtype C viruses, was preferentially used by rev RNAs of a subtype C virus. These results highlight the great diversity of in vivo splice site usage by HIV-1 RNAs. The fact that four of five newly identified splice sites or variants of splice sites were detected in non-subtype B viruses allows anticipating an even greater diversity of HIV-1 splice site usage than currently known.
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Affiliation(s)
- Yolanda Vega
- HIV Biology and Variability Unit, Centro Nacional de Microbiología, Instituto de Salud Carlos III. Majadahonda, Madrid, Spain
| | - Elena Delgado
- HIV Biology and Variability Unit, Centro Nacional de Microbiología, Instituto de Salud Carlos III. Majadahonda, Madrid, Spain
| | - Jorge de la Barrera
- Bioinformatics Unit, Centro Nacional de Microbiología, Instituto de Salud Carlos III. Majadahonda, Madrid, Spain
| | - Cristina Carrera
- HIV Biology and Variability Unit, Centro Nacional de Microbiología, Instituto de Salud Carlos III. Majadahonda, Madrid, Spain
| | - Ángel Zaballos
- Genomics Unit, Centro Nacional de Microbiología, Instituto de Salud Carlos III. Majadahonda, Madrid, Spain
| | - Isabel Cuesta
- Bioinformatics Unit, Centro Nacional de Microbiología, Instituto de Salud Carlos III. Majadahonda, Madrid, Spain
| | - Ana Mariño
- Hospital Arquitecto Marcide. Ferrol, A Coruña, Spain
| | - Antonio Ocampo
- Complejo Hospitalario Universitario de Vigo. Vigo, Pontevedra, Spain
| | - Celia Miralles
- Complejo Hospitalario Universitario de Vigo. Vigo, Pontevedra, Spain
| | | | | | | | - Elena García-Bodas
- HIV Biology and Variability Unit, Centro Nacional de Microbiología, Instituto de Salud Carlos III. Majadahonda, Madrid, Spain
| | - Francisco Díez-Fuertes
- AIDS Immunopathogenesis Unit. Centro Nacional de Microbiología, Instituto de Salud Carlos III. Majadahonda, Madrid, Spain
| | - Michael M. Thomson
- HIV Biology and Variability Unit, Centro Nacional de Microbiología, Instituto de Salud Carlos III. Majadahonda, Madrid, Spain
- * E-mail:
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33
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Goering W, Schmitt K, Dostert M, Schaal H, Deenen R, Mayer J, Schulz WA. Human endogenous retrovirus HERV-K(HML-2) activity in prostate cancer is dominated by a few loci. Prostate 2015; 75:1958-71. [PMID: 26384005 DOI: 10.1002/pros.23095] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/14/2015] [Accepted: 09/02/2015] [Indexed: 11/11/2022]
Abstract
BACKGROUND Increased expression of human endogenous retroviruses, especially HERV-K(HML-2) proviruses, has recently been associated with prostate carcinoma progression. In particular, a HML-2 locus in chromosome 22q11.23 (H22q) is upregulated in many cases. We therefore aimed at delineating the extent and repertoire of HML-2 transcription in prostate cancer tissues and cell lines and to define the transcription pattern and biological effects of H22q. METHODS Sanger and high throughput amplicon sequencing was used to define the repertoire of expressed HML-2 in a selected set of samples. qRT-PCR was used to quantify expression of selected proviruses in an extended set of prostate cancer tissues. Transcription factor binding sites (TFBS) were compared bioinformatically using the Transfac database. Expression of H22q was further characterized by siRNA-mediated knockdown, 5' RACE mapping of transcriptional start sites (TSS) and identification of splice sites. Functional effects of H22q knockdown were investigated by viability and apoptosis assays. RESULTS In addition to H22q, a limited number of other proviruses were found expressed by sequencing. Of these, provirus ERVK-5 and to a lesser degree ERVK-15 were frequently upregulated in prostate cancer. In contrast, expression of ERVK-24, predominant in germ cell tumors, was not detectable in prostatic tissues. While HML-2 LTRs contain binding sites for the androgen receptor and cofactors, no consistent differences in transcription factor binding sites were found between expressed and non-expressed proviruses. The H22q locus contains two 5'-LTRs of which the upstream LTR is predominantly used in prostatic cells, with an imprecise TSS. Splicing of H22q transcripts is complex, generating, among others, a transcript with an Np9-like ORF. Knockdown of H22q did not significantly affect proliferation or apoptosis of prostate cancer cells. CONCLUSIONS Our findings further underline that HML-2 expression is commonly highly tissue-specific. In prostate cancer, a limited number of loci become activated, especially H22q and ERVK-5. As expressed and non-expressed proviruses do not differ significantly in TFBS, tissue- and tumor-specific expression may be governed primarily by chromatin context. Overexpression of HML-2 H22q is more likely consequence than cause of prostate cancer progression.
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Affiliation(s)
- Wolfgang Goering
- Department of Urology, Medical Faculty, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Katja Schmitt
- Institute of Human Genetics, Center of Human and Molecular Biology, Medical Faculty, Saarland University, Homburg, Germany
| | - Melanie Dostert
- Department of Urology, Medical Faculty, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Heiner Schaal
- Institute of Virology, Medical Faculty, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - René Deenen
- GTL, Biomedical Research Center, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Jens Mayer
- Institute of Human Genetics, Center of Human and Molecular Biology, Medical Faculty, Saarland University, Homburg, Germany
| | - Wolfgang A Schulz
- Department of Urology, Medical Faculty, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
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