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Shivaprasad S, Qiao W, Weng KF, Umashankar P, Carette JE, Sarnow P. CRISPR Screen Reveals PACT as a Pro-Viral Factor for Dengue Viral Replication. Viruses 2024; 16:725. [PMID: 38793607 PMCID: PMC11125577 DOI: 10.3390/v16050725] [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: 03/13/2024] [Revised: 04/23/2024] [Accepted: 04/26/2024] [Indexed: 05/26/2024] Open
Abstract
The dengue virus is a single-stranded, positive-sense RNA virus that infects ~400 million people worldwide. Currently, there are no approved antivirals available. CRISPR-based screening methods have greatly accelerated the discovery of host factors that are essential for DENV infection and that can be targeted in host-directed antiviral interventions. In the present study, we performed a focused CRISPR (Clustered Regularly Interspaced Palindromic Repeats) library screen to discover the key host factors that are essential for DENV infection in human Huh7 cells and identified the Protein Activator of Interferon-Induced Protein Kinase (PACT) as a novel pro-viral factor for DENV. PACT is a double-stranded RNA-binding protein generally known to activate antiviral responses in virus-infected cells and block viral replication. However, in our studies, we observed that PACT plays a pro-viral role in DENV infection and specifically promotes viral RNA replication. Knockout of PACT resulted in a significant decrease in DENV RNA and protein abundances in infected cells, which was rescued upon ectopic expression of full-length PACT. An analysis of global gene expression changes indicated that several ER-associated pro-viral genes such as ERN1, DDIT3, HERPUD1, and EIF2AK3 are not upregulated in DENV-infected PACT knockout cells as compared to infected wildtype cells. Thus, our study demonstrates a novel role for PACT in promoting DENV replication, possibly through modulating the expression of ER-associated pro-viral genes.
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Affiliation(s)
- Shwetha Shivaprasad
- Department of Microbiology & Immunology, Stanford University SOM, Stanford, CA 94305, USA; (W.Q.); (J.E.C.); (P.S.)
- Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bengaluru 560064, Karnataka, India;
| | - Wenjie Qiao
- Department of Microbiology & Immunology, Stanford University SOM, Stanford, CA 94305, USA; (W.Q.); (J.E.C.); (P.S.)
| | - Kuo-Feng Weng
- Department of Microbiology & Immunology, Stanford University SOM, Stanford, CA 94305, USA; (W.Q.); (J.E.C.); (P.S.)
| | - Pavithra Umashankar
- Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bengaluru 560064, Karnataka, India;
| | - Jan E. Carette
- Department of Microbiology & Immunology, Stanford University SOM, Stanford, CA 94305, USA; (W.Q.); (J.E.C.); (P.S.)
| | - Peter Sarnow
- Department of Microbiology & Immunology, Stanford University SOM, Stanford, CA 94305, USA; (W.Q.); (J.E.C.); (P.S.)
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Chen X, Li RT, Chen RY, Shi PD, Liu ZX, Lou YN, Wu M, Zhang RR, Tang W, Li XF, Qin CF. The subgenomic flaviviral RNA suppresses RNA interference through competing with siRNAs for binding RISC components. J Virol 2024; 98:e0195423. [PMID: 38289102 PMCID: PMC10878275 DOI: 10.1128/jvi.01954-23] [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: 12/15/2023] [Accepted: 12/17/2023] [Indexed: 02/21/2024] Open
Abstract
During the life cycle of mosquito-borne flaviviruses, substantial subgenomic flaviviral RNA (sfRNA) is produced via incomplete degradation of viral genomic RNA by host XRN1. Zika virus (ZIKV) sfRNA has been detected in mosquito and mammalian somatic cells. Human neural progenitor cells (hNPCs) in the developing brain are the major target cells of ZIKV, and antiviral RNA interference (RNAi) plays a critical role in hNPCs. However, whether ZIKV sfRNA was produced in ZIKV-infected hNPCs as well as its function remains not known. In this study, we demonstrate that abundant sfRNA was produced in ZIKV-infected hNPCs. RNA pulldown and mass spectrum assays showed ZIKV sfRNA interacted with host proteins RHA and PACT, both of which are RNA-induced silencing complex (RISC) components. Functionally, ZIKV sfRNA can antagonize RNAi by outcompeting small interfering RNAs (siRNAs) in binding to RHA and PACT. Furthermore, the 3' stem loop (3'SL) of sfRNA was responsible for RISC components binding and RNAi inhibition, and 3'SL can enhance the replication of a viral suppressor of RNAi (VSR)-deficient virus in a RHA- and PACT-dependent manner. More importantly, the ability of binding to RISC components is conversed among multiple flaviviral 3'SLs. Together, our results identified flavivirus 3'SL as a potent VSR in RNA format, highlighting the complexity in virus-host interaction during flavivirus infection.IMPORTANCEZika virus (ZIKV) infection mainly targets human neural progenitor cells (hNPCs) and induces cell death and dysregulated cell-cycle progression, leading to microcephaly and other central nervous system abnormalities. RNA interference (RNAi) plays critical roles during ZIKV infections in hNPCs, and ZIKV has evolved to encode specific viral proteins to antagonize RNAi. Herein, we first show that abundant sfRNA was produced in ZIKV-infected hNPCs in a similar pattern to that in other cells. Importantly, ZIKV sfRNA acts as a potent viral suppressor of RNAi (VSR) by competing with siRNAs for binding RISC components, RHA and PACT. The 3'SL of sfRNA is responsible for binding RISC components, which is a conserved feature among mosquito-borne flaviviruses. As most known VSRs are viral proteins, our findings highlight the importance of viral non-coding RNAs during the antagonism of host RNAi-based antiviral innate immunity.
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Affiliation(s)
- Xiang Chen
- Department of Virology, State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
| | - Rui-Ting Li
- Department of Virology, State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
| | - Ru-Yi Chen
- Department of Virology, State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
| | - Pan-Deng Shi
- Department of Virology, State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
| | - Zi-Xin Liu
- Department of Virology, State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
| | - Ya-Nan Lou
- Department of Virology, State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
| | - Mei Wu
- Department of Virology, State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
| | - Rong-Rong Zhang
- Department of Virology, State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
| | - Wei Tang
- Department of Virology, State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
| | - Xiao-Feng Li
- Department of Virology, State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
| | - Cheng-Feng Qin
- Department of Virology, State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
- Research Unit of Discovery and Tracing of Natural Focus Diseases, Chinese Academy of Medical Sciences, Beijing, China
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Liu Y, Guan W, Liu H. Subgenomic Flaviviral RNAs of Dengue Viruses. Viruses 2023; 15:2306. [PMID: 38140548 PMCID: PMC10747610 DOI: 10.3390/v15122306] [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: 10/24/2023] [Revised: 11/15/2023] [Accepted: 11/22/2023] [Indexed: 12/24/2023] Open
Abstract
Subgenomic flaviviral RNAs (sfRNAs) are produced during flavivirus infections in both arthropod and vertebrate cells. They are undegraded products originating from the viral 3' untranslated region (3' UTR), a result of the action of the host 5'-3' exoribonuclease, Xrn1, when it encounters specific RNA structures known as Xrn1-resistant RNAs (xrRNAs) within the viral 3' UTR. Dengue viruses generate three to four distinct species of sfRNAs through the presence of two xrRNAs and two dumbbell structures (DBs). The tertiary structures of xrRNAs have been characterized to form a ringlike structure around the 5' end of the viral RNA, effectively inhibiting the activity of Xrn1. The most important role of DENV sfRNAs is to inhibit host antiviral responses by interacting with viral and host proteins, thereby influencing viral pathogenicity, replicative fitness, epidemiological fitness, and transmission. In this review, we aimed to summarize the biogenesis, structures, and functions of DENV sfRNAs, exploring their implications for viral interference.
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Affiliation(s)
- Yi Liu
- Hubei Jiangxia Laboratory, Wuhan 430200, China
| | - Wuxiang Guan
- Hubei Jiangxia Laboratory, Wuhan 430200, China
- Center for Emerging Infectious Diseases, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan 430207, China
| | - Haibin Liu
- Hubei Jiangxia Laboratory, Wuhan 430200, China
- Center for Emerging Infectious Diseases, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan 430207, China
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Jansen S, Smlatic E, Copmans D, Debaveye S, Tangy F, Vidalain PO, Neyts J, Dallmeier K. Identification of host factors binding to dengue and Zika virus subgenomic RNA by efficient yeast three-hybrid screens of the human ORFeome. RNA Biol 2021; 18:732-744. [PMID: 33459164 PMCID: PMC8086697 DOI: 10.1080/15476286.2020.1868754] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Revised: 12/15/2020] [Accepted: 12/17/2020] [Indexed: 10/26/2022] Open
Abstract
Flaviviruses such as the dengue (DENV) and the Zika virus (ZIKV) are important human pathogens causing around 100 million symptomatic infections each year. During infection, small subgenomic flavivirus RNAs (sfRNAs) are formed inside the infected host cell as a result of incomplete degradation of the viral RNA genome by cellular exoribonuclease XRN1. Although the full extent of sfRNA functions is to be revealed, these non-coding RNAs are key virulence factors and their detrimental effects on multiple cellular processes seem to consistently involve molecular interactions with RNA-binding proteins (RBPs). Discovery of such sfRNA-binding host-factors has followed established biochemical pull-down approaches skewed towards highly abundant proteins hampering proteome-wide coverage. Yeast three-hybrid (Y3H) systems represent an attractive alternative approach. To facilitate proteome-wide screens for RBP, we revisited and improved existing RNA-Y3H methodology by (1) implementing full-length ORF libraries in combination with (2) efficient yeast mating to increase screening depth and sensitivity, and (3) stringent negative controls to eliminate over-representation of non-specific RNA-binders. These improvements were validated employing the well-characterized interaction between DDX6 (DEAD-box helicase 6) and sfRNA of DENV as paradigm. Our advanced Y3H system was used to screen for human proteins binding to DENV and ZIKV sfRNA, resulting in a list of 69 putative sfRNA-binders, including several previously reported as well as numerous novel RBP host factors. Our methodology requiring no sophisticated infrastructure or analytic pipeline may be employed for the discovery of meaningful RNA-protein interactions at large scale in other fields.
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Affiliation(s)
- Sander Jansen
- KU Leuven Department of Microbiology, Immunology and Transplantation, Rega Institute, Laboratory of Virology and Chemotherapy, Leuven, Belgium
| | - Enisa Smlatic
- KU Leuven Department of Microbiology, Immunology and Transplantation, Rega Institute, Laboratory of Virology and Chemotherapy, Leuven, Belgium
- Division of Paediatric Infectious Diseases, Ludwig-Maximilians-University Munich, Dr. Von Hauner Children’s Hospital, Munich, Germany
| | - Daniëlle Copmans
- KU Leuven Department of Microbiology, Immunology and Transplantation, Rega Institute, Laboratory of Virology and Chemotherapy, Leuven, Belgium
- KU Leuven Department of Pharmaceutical and Pharmacological Sciences, Laboratory for Molecular Biodiscovery, Leuven, Belgium
| | - Sarah Debaveye
- KU Leuven Department of Microbiology, Immunology and Transplantation, Rega Institute, Laboratory of Virology and Chemotherapy, Leuven, Belgium
| | - Frédéric Tangy
- Unité de Génomique Virale et Vaccination, Institut Pasteur, CNRS, Paris, France
| | - Pierre-Olivier Vidalain
- Unité de Génomique Virale et Vaccination, Institut Pasteur, CNRS, Paris, France
- CIRI, Centre International de Recherche en Infectiologie, Univ Lyon, Inserm U1111, Université Claude Bernard Lyon 1, Lyon, France
| | - Johan Neyts
- KU Leuven Department of Microbiology, Immunology and Transplantation, Rega Institute, Laboratory of Virology and Chemotherapy, Leuven, Belgium
| | - Kai Dallmeier
- KU Leuven Department of Microbiology, Immunology and Transplantation, Rega Institute, Laboratory of Virology and Chemotherapy, Leuven, Belgium
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