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Teo QW, Wang Y, Lv H, Mao KJ, Tan TJC, Huan YW, Rivera-Cardona J, Shao EK, Choi D, Dargani ZT, Brooke CB, Wu NC. Deep mutational scanning of influenza A virus NEP reveals pleiotropic mutations in its N-terminal domain. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.16.594574. [PMID: 38798526 PMCID: PMC11118461 DOI: 10.1101/2024.05.16.594574] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2024]
Abstract
The influenza A virus nuclear export protein (NEP) is a multifunctional protein that is essential for the viral life cycle and has very high sequence conservation. However, since the open reading frame of NEP largely overlaps with that of another influenza viral protein, non-structural protein 1, it is difficult to infer the functional constraints of NEP based on sequence conservation analysis. Besides, the N-terminal of NEP is structurally disordered, which further complicates the understanding of its function. Here, we systematically measured the replication fitness effects of >1,800 mutations of NEP. Our results show that the N-terminal domain has high mutational tolerance. Additional experiments demonstrate that N-terminal domain mutations pleiotropically affect viral transcription and replication dynamics, host cellular responses, and mammalian adaptation of avian influenza virus. Overall, our study not only advances the functional understanding of NEP, but also provides insights into its evolutionary constraints.
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Su G, Chen Y, Li X, Shao JW. Virus versus host: influenza A virus circumvents the immune responses. Front Microbiol 2024; 15:1394510. [PMID: 38817972 PMCID: PMC11137263 DOI: 10.3389/fmicb.2024.1394510] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2024] [Accepted: 04/23/2024] [Indexed: 06/01/2024] Open
Abstract
Influenza A virus (IAV) is a highly contagious pathogen causing dreadful losses to humans and animals around the globe. As is known, immune escape is a strategy that benefits the proliferation of IAVs by antagonizing, blocking, and suppressing immune surveillance. The HA protein binds to the sialic acid (SA) receptor to enter the cytoplasm and initiate viral infection. The conserved components of the viral genome produced during replication, known as the pathogen-associated molecular patterns (PAMPs), are thought to be critical factors for the activation of effective innate immunity by triggering dependent signaling pathways after recognition by pattern recognition receptors (PRRs), followed by a cascade of adaptive immunity. Viral infection-induced immune responses establish an antiviral state in the host to effectively inhibit virus replication and enhance viral clearance. However, IAV has evolved multiple mechanisms that allow it to synthesize and transport viral components by "playing games" with the host. At its heart, this review will describe how host and viral factors interact to facilitate the viral evasion of host immune responses.
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Affiliation(s)
- Guanming Su
- College of Veterinary Medicine, South China Agricultural University, Guangzhou, China
- Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety Evaluation, Guangzhou, China
| | - Yiqun Chen
- College of Veterinary Medicine, South China Agricultural University, Guangzhou, China
| | - Xiaowen Li
- College of Veterinary Medicine, South China Agricultural University, Guangzhou, China
- Key Laboratory of Zoonosis Prevention and Control of Guangdong Province, Guangzhou, China
| | - Jian-Wei Shao
- School of Life Science and Engineering, Foshan University, Foshan, China
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Li YJ, Chen CY, Kuo YS, Huang YW, Kuo RL, Chang LK, Yang JH, Lai CH, Shih SR, Chiu YF. OTUB1 contributes to the stability and function of Influenza A virus NS2. PLoS Pathog 2024; 20:e1012279. [PMID: 38814988 PMCID: PMC11166342 DOI: 10.1371/journal.ppat.1012279] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2023] [Revised: 06/11/2024] [Accepted: 05/20/2024] [Indexed: 06/01/2024] Open
Abstract
The influenza A virus (IAV) consists of 8 single-stranded, negative-sense viral RNA (vRNA) segments. After infection, vRNA is transcribed, replicated, and wrapped by viral nucleoprotein (NP) to form viral ribonucleoprotein (vRNP). The transcription, replication, and nuclear export of the viral genome are regulated by the IAV protein, NS2, which is translated from spliced mRNA transcribed from viral NS vRNA. This splicing is inefficient, explaining why NS2 is present in low abundance after IAV infection. The levels of NS2 and its subsequent accumulation are thought to influence viral RNA replication and vRNP nuclear export. Here we show that NS2 is ubiquitinated at the K64 and K88 residues by K48-linked and K63-linked polyubiquitin (polyUb) chains, leading to the degradation of NS2 by the proteasome. Additionally, we show that a host deubiquitinase, OTUB1, can remove polyUb chains conjugated to NS2, thereby stabilizing NS2. Accordingly, knock down of OTUB1 by siRNA reduces the nuclear export of vRNP, and reduces the overall production of IAV. These results collectively demonstrate that the levels of NS2 in IAV-infected cells are regulated by a ubiquitination-deubiquitination system involving OTUB1 that is necessary for optimal IAV replication.
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Affiliation(s)
- Yu-Jyun Li
- Department of Microbiology and Immunology, Chang Gung University, Taoyuan, Taiwan
- Graduate Institute of Biomedical Sciences, Chang Gung University, Taoyuan, Taiwan
| | - Chi-Yuan Chen
- Department of Microbiology and Immunology, Chang Gung University, Taoyuan, Taiwan
| | - Yu-Shen Kuo
- Department of Microbiology and Immunology, Chang Gung University, Taoyuan, Taiwan
- Graduate Institute of Biomedical Sciences, Chang Gung University, Taoyuan, Taiwan
| | - Yi-Wen Huang
- Department of Microbiology and Immunology, Chang Gung University, Taoyuan, Taiwan
- Graduate Institute of Biomedical Sciences, Chang Gung University, Taoyuan, Taiwan
| | - Rei-Lin Kuo
- Research Center for Emerging Viral Infections, Chang Gung University, Taoyuan, Taiwan
| | - Li-Kwan Chang
- Department of Biochemical Science and Technology, College of Life Science, National Taiwan University, Taipei, Taiwan
| | - Jeng-How Yang
- Division of Infectious Diseases, Department of Medicine, Chang Gung Memorial Hospital, New Taipei, Taiwan
| | - Chih-Ho Lai
- Department of Microbiology and Immunology, Chang Gung University, Taoyuan, Taiwan
- Graduate Institute of Biomedical Sciences, Chang Gung University, Taoyuan, Taiwan
| | - Shin-Ru Shih
- Research Center for Emerging Viral Infections, Chang Gung University, Taoyuan, Taiwan
| | - Ya-Fang Chiu
- Department of Microbiology and Immunology, Chang Gung University, Taoyuan, Taiwan
- Graduate Institute of Biomedical Sciences, Chang Gung University, Taoyuan, Taiwan
- Research Center for Emerging Viral Infections, Chang Gung University, Taoyuan, Taiwan
- Division of Infectious Diseases, Department of Medicine, Chang Gung Memorial Hospital, New Taipei, Taiwan
- Department of Laboratory Medicine, Linkou Chang Gung Memorial Hospital, Taoyuan, Taiwan
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Rashid F, Xie Z, Li M, Xie Z, Luo S, Xie L. Roles and functions of IAV proteins in host immune evasion. Front Immunol 2023; 14:1323560. [PMID: 38152399 PMCID: PMC10751371 DOI: 10.3389/fimmu.2023.1323560] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2023] [Accepted: 11/30/2023] [Indexed: 12/29/2023] Open
Abstract
Influenza A viruses (IAVs) evade the immune system of the host by several regulatory mechanisms. Their genomes consist of eight single-stranded segments, including nonstructural proteins (NS), basic polymerase 1 (PB1), basic polymerase 2 (PB2), hemagglutinin (HA), acidic polymerase (PA), matrix (M), neuraminidase (NA), and nucleoprotein (NP). Some of these proteins are known to suppress host immune responses. In this review, we discuss the roles, functions and underlying strategies adopted by IAV proteins to escape the host immune system by targeting different proteins in the interferon (IFN) signaling pathway, such as tripartite motif containing 25 (TRIM25), inhibitor of nuclear factor κB kinase (IKK), mitochondrial antiviral signaling protein (MAVS), Janus kinase 1 (JAK1), type I interferon receptor (IFNAR1), interferon regulatory factor 3 (IRF3), IRF7, and nuclear factor-κB (NF-κB). To date, the IAV proteins NS1, NS2, PB1, PB1-F2, PB2, HA, and PA have been well studied in terms of their roles in evading the host immune system. However, the detailed mechanisms of NS3, PB1-N40, PA-N155, PA-N182, PA-X, M42, NA, and NP have not been well studied with respect to their roles in immune evasion. Moreover, we also highlight the future perspectives of research on IAV proteins.
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Affiliation(s)
- Farooq Rashid
- Department of Biotechnology, Guangxi Veterinary Research Institute, Nanning, China
- Guangxi Key Laboratory of Veterinary Biotechnology, Nanning, China
- Key Laboratory of China (Guangxi)-ASEAN Cross-border Animal Disease Prevention and Control, Ministry of Agriculture and Rural Affairs of China, Nanning, China
| | - Zhixun Xie
- Department of Biotechnology, Guangxi Veterinary Research Institute, Nanning, China
- Guangxi Key Laboratory of Veterinary Biotechnology, Nanning, China
- Key Laboratory of China (Guangxi)-ASEAN Cross-border Animal Disease Prevention and Control, Ministry of Agriculture and Rural Affairs of China, Nanning, China
| | - Meng Li
- Department of Biotechnology, Guangxi Veterinary Research Institute, Nanning, China
- Guangxi Key Laboratory of Veterinary Biotechnology, Nanning, China
- Key Laboratory of China (Guangxi)-ASEAN Cross-border Animal Disease Prevention and Control, Ministry of Agriculture and Rural Affairs of China, Nanning, China
| | - Zhiqin Xie
- Department of Biotechnology, Guangxi Veterinary Research Institute, Nanning, China
- Guangxi Key Laboratory of Veterinary Biotechnology, Nanning, China
- Key Laboratory of China (Guangxi)-ASEAN Cross-border Animal Disease Prevention and Control, Ministry of Agriculture and Rural Affairs of China, Nanning, China
| | - Sisi Luo
- Department of Biotechnology, Guangxi Veterinary Research Institute, Nanning, China
- Guangxi Key Laboratory of Veterinary Biotechnology, Nanning, China
- Key Laboratory of China (Guangxi)-ASEAN Cross-border Animal Disease Prevention and Control, Ministry of Agriculture and Rural Affairs of China, Nanning, China
| | - Liji Xie
- Department of Biotechnology, Guangxi Veterinary Research Institute, Nanning, China
- Guangxi Key Laboratory of Veterinary Biotechnology, Nanning, China
- Key Laboratory of China (Guangxi)-ASEAN Cross-border Animal Disease Prevention and Control, Ministry of Agriculture and Rural Affairs of China, Nanning, China
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Chen S, Jiang J, Li T, Huang L. PANoptosis: Mechanism and Role in Pulmonary Diseases. Int J Mol Sci 2023; 24:15343. [PMID: 37895022 PMCID: PMC10607352 DOI: 10.3390/ijms242015343] [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: 09/13/2023] [Revised: 10/09/2023] [Accepted: 10/12/2023] [Indexed: 10/29/2023] Open
Abstract
PANoptosis is a newly defined programmed cell death (PCD) triggered by a series of stimuli, and it engages three well-learned PCD forms (pyroptosis, apoptosis, necroptosis) concomitantly. Normally, cell death is recognized as a strategy to eliminate unnecessary cells, inhibit the proliferation of invaded pathogens and maintain homeostasis; however, vigorous cell death can cause excessive inflammation and tissue damage. Acute lung injury (ALI) and chronic obstructive pulmonary syndrome (COPD) exacerbation is related to several pathogens (e.g., influenza A virus, SARS-CoV-2) known to cause PANoptosis. An understanding of the mechanism and specific regulators may help to address the pathological systems of these diseases. This review presents our understanding of the potential mechanism of PANoptosis and the role of PANoptosis in different pulmonary diseases.
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Affiliation(s)
| | | | | | - Longshuang Huang
- Shanghai Frontiers Science Center of Drug Target Identification and Delivery, School of Pharmacy, Shanghai Jiao Tong University, Shanghai 200240, China; (S.C.); (J.J.); (T.L.)
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Charostad J, Rezaei Zadeh Rukerd M, Mahmoudvand S, Bashash D, Hashemi SMA, Nakhaie M, Zandi K. A comprehensive review of highly pathogenic avian influenza (HPAI) H5N1: An imminent threat at doorstep. Travel Med Infect Dis 2023; 55:102638. [PMID: 37652253 DOI: 10.1016/j.tmaid.2023.102638] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Revised: 08/13/2023] [Accepted: 08/27/2023] [Indexed: 09/02/2023]
Abstract
Avian influenza viruses (AIVs) are globally challenging due to widespread circulation and high mortality rates. Highly pathogenic avian influenza (HPAI) strains like H5N1 have caused significant outbreaks in birds. Since 2003 to 14 July 2023, the World Health Organization (WHO) has documented 878 cases of HPAI H5N1 infection in humans and 458 (52.16%) fatalities in 23 countries. Recent outbreaks in wild birds, domestic birds, sea lions, minks, and etc., and the occurrence of genetic variations among HPAI H5N1 strains raise concerns about potential transmission and public health risks. This paper aims to provide a comprehensive overview of the current understanding and new insights into HPAI H5N1. It begins with an introduction to the significance of studying this virus and highlighting the need for updated knowledge. The origin and evaluation of HPAI H5N1 are examined, shedding light on its emergence, and spread across different geographic regions. The genome organization and structural biology of the H5N1 virus are explored, providing insights into its molecular composition and key structural features. This manuscript also delves into the phylogeny, evolution, mutational trends, reservoirs, and transmission routes of HPAI H5N1. The immune response against HPAI H5N1 and its implications for vaccine development are analyzed, along with an exploration of the pathogenesis and clinical manifestations of HPAI H5N1 in human cases. Furthermore, diagnostic tools and preventive and therapeutic strategies are discussed, highlighting the current approaches and potential future directions for better management of the potential pandemic.
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Affiliation(s)
- Javad Charostad
- Department of Microbiology, Faculty of Medicine, Shahid Sadoghi University of Medical Science, Yazd, Iran
| | - Mohammad Rezaei Zadeh Rukerd
- Gastroenterology and Hepatology Research Center, Institute of Basic and Clinical Physiology Sciences, Kerman University of Medical Sciences, Kerman, Iran; Universal Scientific Education and Research Network (USERN), Tehran, Iran
| | - Shahab Mahmoudvand
- Research Center for Molecular Medicine, Hamadan University of Medical Sciences, Hamadan, Iran; Department of Virology, School of Medicine, Hamadan University of Medical Science, Hamadan, Iran
| | - Davood Bashash
- Department of Hematology and Blood Banking, School of Allied Medical Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Seyed Mohammad Ali Hashemi
- Department of Bacteriology & Virology, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Mohsen Nakhaie
- Gastroenterology and Hepatology Research Center, Institute of Basic and Clinical Physiology Sciences, Kerman University of Medical Sciences, Kerman, Iran.
| | - Keivan Zandi
- Arrowhead Pharmaceuticals, San Diego, CA, USA; Tropical Infectious Diseases Research and Education Center (TIDREC), University of Malaya, Kuala Lumpur, Malaysia.
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Wei L, Wang X, Zhou H. Interaction among inflammasome, PANoptosise, and innate immune cells in infection of influenza virus: Updated review. Immun Inflamm Dis 2023; 11:e997. [PMID: 37773712 PMCID: PMC10521376 DOI: 10.1002/iid3.997] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Revised: 08/15/2023] [Accepted: 08/18/2023] [Indexed: 10/01/2023] Open
Abstract
BACKGROUND Influenza virus (IV) is a leading cause of respiratory tract infections, eliciting responses from key innate immune cells such as Macrophages (MQs), Neutrophils, and Dendritic Cells (DCs). These cells employ diverse mechanisms to combat IV, with Inflammasomes playing a pivotal role in viral infection control. Cellular death mechanisms, including Pyroptosis, Apoptosis, and Necroptosis (collectively called PANoptosis), significantly contribute to the innate immune response. METHODS In this updated review, we delve into the intricate relationship between PANoptosis and Inflammasomes within innate immune cells (MQs, Neutrophils, and DCs) during IV infections. We explore the strategies employed by IV to evade these immune defenses and the consequences of unchecked PANoptosis and inflammasome activation, including the potential development of severe complications such as cytokine storms and tissue damage. RESULTS Our analysis underscores the interplay between PANoptosis and Inflammasomes as a critical aspect of the innate immune response against IV. We provide insights into IV's various mechanisms to subvert these immune pathways and highlight the importance of understanding these interactions to develop effective antiviral medications. CONCLUSION A comprehensive understanding of the dynamic interactions between PANoptosis, Inflammasomes, and IV is essential for advancing our knowledge of innate immune responses to viral infections. This knowledge will be invaluable in developing targeted antiviral therapies to combat IV and mitigate potential complications, including cytokine storms and tissue damage.
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Affiliation(s)
- Li Wei
- Intensive Care Unit, Huzhou Third Municipal hospitalThe Affiliated hospital of Huzhou UniversityHuzhouChina
| | - Xufang Wang
- Intensive Care Unit, Huzhou Third Municipal hospitalThe Affiliated hospital of Huzhou UniversityHuzhouChina
| | - Huifei Zhou
- Intensive Care Unit, Huzhou Third Municipal hospitalThe Affiliated hospital of Huzhou UniversityHuzhouChina
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Ma W, Huang G, Wang Z, Wang L, Gao Q. IRF7: role and regulation in immunity and autoimmunity. Front Immunol 2023; 14:1236923. [PMID: 37638030 PMCID: PMC10449649 DOI: 10.3389/fimmu.2023.1236923] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2023] [Accepted: 07/25/2023] [Indexed: 08/29/2023] Open
Abstract
Interferon regulatory factor (IRF) 7 was originally identified as master transcriptional factor that produced IFN-I and regulated innate immune response, subsequent studies have revealed that IRF7 performs a multifaceted and versatile functions in multiple biological processes. In this review, we provide a comprehensive overview on the current knowledge of the role of IRF7 in immunity and autoimmunity. We focus on the latest regulatory mechanisms of IRF7 in IFN-I, including signaling pathways, transcription, translation, and post-translational levels, the dimerization and nuclear translocation, and the role of IRF7 in IFN-III and COVID-19. In addition to antiviral immunity, we also discuss the role and mechanism of IRF7 in autoimmunity, and the further research will expand our understanding of IRF7.
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Affiliation(s)
- Wei Ma
- Department of Cell Biology, College of Basic Medical Sciences, Army Medical University (Third Military Medical University), Chongqing, China
- Department of Wound Infection and Drug, State Key Laboratory of Trauma, Burn and Combined Injury, Daping Hospital, Army Medical University (Third Military Medical University), Chongqing, China
| | - Gang Huang
- Department of Oncology, The Second Affiliated Hospital of Zunyi Medical University, Zunyi, Guizhou, China
| | - Zhi Wang
- Department of Cell Biology, College of Basic Medical Sciences, Army Medical University (Third Military Medical University), Chongqing, China
| | - Li Wang
- Department of Cell Biology, College of Basic Medical Sciences, Army Medical University (Third Military Medical University), Chongqing, China
| | - Qiangguo Gao
- Department of Cell Biology, College of Basic Medical Sciences, Army Medical University (Third Military Medical University), Chongqing, China
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Li R, Gao S, Chen H, Zhang X, Yang X, Zhao J, Wang Z. Virus usurps alternative splicing to clear the decks for infection. Virol J 2023; 20:131. [PMID: 37340420 DOI: 10.1186/s12985-023-02098-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Accepted: 06/12/2023] [Indexed: 06/22/2023] Open
Abstract
Since invasion, there will be a tug-of-war between host and virus to scramble cellular resources, for either restraining or facilitating infection. Alternative splicing (AS) is a conserved and critical mechanism of processing pre-mRNA into mRNAs to increase protein diversity in eukaryotes. Notably, this kind of post-transcriptional regulatory mechanism has gained appreciation since it is widely involved in virus infection. Here, we highlight the important roles of AS in regulating viral protein expression and how virus in turn hijacks AS to antagonize host immune response. This review will widen the understandings of host-virus interactions, be meaningful to innovatively elucidate viral pathogenesis, and provide novel targets for developing antiviral drugs in the future.
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Affiliation(s)
- Ruixue Li
- College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, People's Republic of China
| | - Shenyan Gao
- College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, People's Republic of China
| | - Huayuan Chen
- College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, People's Republic of China
| | - Xiaozhan Zhang
- College of Veterinary Medicine, Henan University of Animal Husbandry and Economy, Zhengzhou, People's Republic of China
| | - Xia Yang
- College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, People's Republic of China
| | - Jun Zhao
- College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, People's Republic of China
| | - Zeng Wang
- College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, People's Republic of China.
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Strategies of Influenza A Virus to Ensure the Translation of Viral mRNAs. Pathogens 2022; 11:pathogens11121521. [PMID: 36558855 PMCID: PMC9783940 DOI: 10.3390/pathogens11121521] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Revised: 12/08/2022] [Accepted: 12/09/2022] [Indexed: 12/14/2022] Open
Abstract
Viruses are obligatorily intracellular pathogens. To generate progeny virus particles, influenza A viruses (IAVs) have to divert the cellular machinery to ensure sufficient translation of viral mRNAs. To this end, several strategies have been exploited by IAVs, such as host gene shutoff, suppression of host innate immune responses, and selective translation of viral mRNAs. Various IAV proteins are responsible for host gene shutoff, e.g., NS1, PA-X, and RdRp, through inhibition of cellular gene transcription, suppression of cellular RNA processing, degradation of cellular RNAs, and blockage of cellular mRNA export from the nucleus. Host shutoff should suppress the innate immune responses and also increase the translation of viral mRNAs indirectly due to the reduced competition from cellular mRNAs for cellular translational machinery. However, many other mechanisms are also responsible for the suppression of innate immune responses by IAV, such as prevention of the detection of the viral RNAs by the RLRs, inhibition of the activities of proteins involved in signaling events of interferon production, and inhibition of the activities of interferon-stimulated genes, mainly through viral NS1, PB1-F2, and PA-X proteins. IAV mRNAs may be selectively translated in favor of cellular mRNAs through interacting with viral and/or cellular proteins, such as NS1, PABPI, and/or IFIT2, in the 5'-UTR of viral mRNAs. This review briefly summarizes the strategies utilized by IAVs to ensure sufficient translation of viral mRNAs focusing on recent developments.
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