Journal of Virology最新文献

{"title":"Tetraspanin CD81 serves as a functional entry factor for porcine circovirus type 2 infection.","authors":"Junshuo Li, Lin Lv, Yanni Gao, Yangyang Sun, Juan Bai, Xianwei Wang, Haifen Sun, Ping Jiang","doi":"10.1128/jvi.01408-24","DOIUrl":"https://doi.org/10.1128/jvi.01408-24","url":null,"abstract":"<p><p>Porcine circovirus type 2 (PCV2) is the primary causative agent of porcine circovirus-associated disease, clinically resulting in immunosuppression and co-infections with other pathogens in infected pigs. The mechanism of PCV2 infection remains unclear. In this study, we firstly found that the tetraspanin CD81 in PK-15 cells interacts with PCV2 Cap protein by using virus overlay protein-binding assay combined with mass spectrometry. Knockdown of the CD81 significantly reduces the levels of the viral Cap mRNA and protein, and viral internalization in PK-15 cells. The critical interaction regions locate in the large extracellular loop (LEL) domain of CD81 and the CD loop region (82-91aa) of the Cap protein, and a polyclonal antibody against the CD81 LEL domain significantly inhibits PCV2 infection. The transmembrane proteoglycan Syndecan-1 interacts with both CD81 and PCV2 Cap, and co-operates with CD81 to promote PCV2 infection in PK-15 cells. Furthermore, CD81 facilitates RhoA activation and enhances the viral internalization and replication in PK-15 cells. It was concluded that the tetraspanin CD81 is a key host factor for PCV2 invasion into PK-15 cells, thus providing new insights into PCV2 life cycle and identifying a potential target for antiviral drug development.IMPORTANCEPorcine circovirus type 2 (PCV2), a significant economic pathogen in the swine industry, presents persistent challenges in its prevention and treatment. Despite extensive research, the mechanism of PCV2 invading host cells remains unclear. In this study, we found and identified a novel interaction between the tetraspanin CD81 and the viral Cap protein during the PCV2 invading PK-15 cells. The transmembrane proteoglycan Syndecan-1 and RhoA are involved in the infection process through the CD81. Moreover, this is the first time that the role of Syndecan-1 in the PCV2 infection process has been demonstrated. Also, a polyclonal antibody against the CD81 extracellular domain significantly inhibits PCV2 infection in PK-15 cells. It not only enriches our understanding of PCV2 life cycle but also offers new perspectives for the development of antiviral therapeutics against circovirus.</p>","PeriodicalId":17583,"journal":{"name":"Journal of Virology","volume":" ","pages":"e0140824"},"PeriodicalIF":4.0,"publicationDate":"2024-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142914994","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Characteristics of viral ovarian tumor domain protease from two emerging orthonairoviruses and identification of Yezo virus human infections in northeastern China as early as 2012.","authors":"Zi-Yun Chen, Jie Zhang, Pei-Jun He, Tao Xiong, Dai-Yun Zhu, Wen-Jie Zhu, Xue-Bing Ni, Li-Feng Du, Qian Wang, Ya-Wei Zhang, Luo-Yuan Xia, Dong-Sheng Chen, Liang-Jing Li, Ming-Zhu Zhang, Xiao Ming Cui, Tian-Hong Wang, Juan Wang, Zhenfei Wang, Tian-Feng An, Wu-Chun Cao, Xiao-Hua Liu, En-Jiong Huang, Na Jia","doi":"10.1128/jvi.01727-24","DOIUrl":"https://doi.org/10.1128/jvi.01727-24","url":null,"abstract":"<p><p>Emerging tick-borne orthonairovirus infections pose a growing global concern, with limited understanding of the viral ovarian tumor-like cysteine proteases (vOTUs) encoded by novel orthonairoviruses. These vOTUs, a group of deubiquinylases (DUBs), disrupt the innate immune response. Yezo virus (YEZV), a recently discovered pathogenic orthonairovirus, was first reported in Japan in 2021. In this study, we successfully isolated and identified YEZV and a new orthonairovirus, Jiànchuān tick virus (JCTV), from <i>Ixodes persulcatus</i> and <i>Haemaphysalis montgomeryi</i> ticks, respectively, in China. We found that the vOTU domains encoded by YEZV and JCTV exhibited both DUB and deISGylase activities, though with potentially less broad deISGylation compared to that of Crimean-Congo hemorrhagic fever virus (CCHFV) during natural infection. Phylogenetic analysis of global vOTUs, including 83 new sequences, revealed a high diversity of this domain. Interestingly, retrospective screening of tick-bite patients from 2012 to 2016 in northeastern China traced YEZV infections as far back as 2012, identifying four cases. Additionally, YEZV primarily infected <i>I. persulcatus</i> (31.4%) and <i>Dermacentor nuttalli</i> (10.5%) in northern China, while JCTV exhibited high infection rates in <i>H. montgomeryi</i> (81.3%) in southern China. In summary, our work emphasizes the active surveillance of orthonairovirus infections and the imperative need for the development of vOTU domain-targeted anti-virals, offering potential therapeutic solutions for a broad spectrum of orthonairoviruses.IMPORTANCEThe vOTUs, a group of DUBs, mimic the functions of host DUBs to enhance viral infectivity and may serve as potential drug targets. vOTUs from different orthonairoviruses exhibit distinct preferences toward ubiquitin (Ub) and ubiquitin-like protein interferon stimulated gene 15 (ISG15). In this study, we investigated the deubiquitinase and deISGylase functions of various orthonairoviral vOTUs using both an overexpression system and natural viral infections <i>in vitro</i>. Our findings illustrate that the vOTUs from YEZV and JCTV can cleave both Ub and ISG15 in an overexpression system, but these viruses exhibit potentially narrower deISGylation capacity than CCHFV during natural infection. This suggests that the diversity of vOTUs may have a potential relationship with the pathogenesis.</p>","PeriodicalId":17583,"journal":{"name":"Journal of Virology","volume":" ","pages":"e0172724"},"PeriodicalIF":4.0,"publicationDate":"2024-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142915280","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Post-translational modifications on protein VII are important during the early stages of adenovirus infection.","authors":"Edward A Arnold, Julian R Smith, Katie Leung, Daniel H Nguyen, Laurel E Kelnhofer-Millevolte, Monica S Guo, Jason G Smith, Daphne C Avgousti","doi":"10.1128/jvi.01462-24","DOIUrl":"https://doi.org/10.1128/jvi.01462-24","url":null,"abstract":"<p><p>Due to the importance of post-translational modification (PTM) in cellular function, viruses have evolved to both take advantage of and be susceptible to such modification. Adenovirus encodes a multifunctional protein called protein VII, which is packaged with the viral genome in the core of virions and disrupts host chromatin during infection. Protein VII has several PTMs whose addition contributes to the subnuclear localization of protein VII. Here, we used mutant viruses that abrogate or mimic these PTMs on protein VII to interrogate their impact on protein VII function during adenovirus infection. We discovered that acetylation of the lysine in positions 2 or 3 (K2 or K3) is deleterious during early infection as mutation to alanine led to greater intake of protein VII and viral DNA to the nucleus and enhanced early gene expression. Furthermore, we determined that protein VII is acetylated at alternative residues late during infection which may compensate for the mutated sites. Lastly, due to the role of the early viral protein E1A in viral gene activation, we investigated the interaction between protein VII and E1A and demonstrated that protein VII interacts with E1A through a chromatin-mediated interaction. Together, these results emphasize that the complexity of virus-host interactions is intimately tied to post-translational modification.</p><p><strong>Importance: </strong>Adenoviruses are ubiquitous human pathogens that cause a variety of diseases, such as respiratory infections, gastroenteritis, and conjunctivitis. While often viewed as a self-limiting infection in healthy individuals, adenoviruses are particularly harmful to immunocompromised patients. Here, we investigate the functional role of post-translational modifications (PTMs) on an essential adenovirus core protein, protein VII, describing how they regulate its function during the early and late stages of infection. Our study focuses on how specific PTMs on protein VII influence transcription, localization, and interactions with other proteins, highlighting how PTMs are employed by viruses to alter protein function.</p>","PeriodicalId":17583,"journal":{"name":"Journal of Virology","volume":" ","pages":"e0146224"},"PeriodicalIF":4.0,"publicationDate":"2024-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142914968","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Induction of innate immunity and plant growth promotion in tomato unveils the antiviral nature of bacterial endophytes against groundnut bud necrosis virus.","authors":"R Sharanya, M Gayathri, P Renukadevi, N Saranya, M Suganthy, S Varanavasiappan, Amalendu Ghosh, S Nakkeeran","doi":"10.1128/jvi.01803-24","DOIUrl":"https://doi.org/10.1128/jvi.01803-24","url":null,"abstract":"<p><p>Tomato is an important crop worldwide, but groundnut bud necrosis virus (GBNV) often hampers its growth. This study investigates the antiviral potential of bacterial endophytes, including <i>Brucella melitensis</i> CNEB54, <i>Bacillus licheniformis</i> CNEB4, <i>Bacillus velezensis</i> CNEB26, and <i>Bacillus vallismortis</i> BAVE5 against GBNV, as well as their ability to enhance immunity and growth in tomato. All four bacterial isolates demonstrated a significant delay in GBNV symptom development 10 days post-inoculation, with disease incidence ranging from 18% to 36% compared to 84% in control. DAC-ELISA results indicated a noteworthy reduction in virus titer (0.32-0.96 OD) in treated tomato plants versus the control (3.26 OD). In addition, qPCR analysis revealed decreased viral copy numbers in plants treated with bacterial endophytes (1.3-3.1 × 10⁵) as against in untreated inoculated control (2.4 × 10⁶). Furthermore, these endophytes upregulated the expression of defense-associated genes, such as <i>MAPKK1</i>, <i>PAL</i>, <i>PPO</i>, <i>LOX1</i>, <i>JAR1</i>, and <i>PDF 1.2</i>. Field experiments with the application of <i>B. melitensis and B. velezensis</i> exhibited improved growth, with an average plant height of 123.70 cm, 14.87 flowers per plant, and a fruit weight of 549.3 g per plant, with a disease incidence of 18.1%. In comparison, the untreated control plants only reached a height of 104.73 cm, produced 11.17 flowers per plant, and yielded 267 g of fruit per plant, with a disease incidence of 30.1%. These findings strongly support the use of bacterial endophytes to reduce disease incidence and severity, enhance plant immunity and promote plant growth, resulting in overall crop productivity in sustainable agriculture.IMPORTANCEThe infection of GBNV in crops such as tomatoes, peanuts, and pulses leads to significant yield loss. Applying insecticides to control vector populations, can limit the spread of viruses carried by these vectors. The present study envisages a novel strategy to combat GBNV, with the help of bacterial endophytes. These bacterial endophytes have tremendously reduced the symptom expression of GBNV, induced the expression of defense genes during the tri-trophic interaction and promoted plant growth in tomatoes under field conditions. Hence, these bacteria are identified to be involved in immunity boosting, viral suppression and growth promotion.</p>","PeriodicalId":17583,"journal":{"name":"Journal of Virology","volume":" ","pages":"e0180324"},"PeriodicalIF":4.0,"publicationDate":"2024-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142914602","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Discovery of small molecules against porcine reproductive and respiratory syndrome virus replication by targeting NendoU activity.","authors":"Jiaqi Zhu, Yunqiang Lai, Mengqi Cheng, Radha Charan Dash, Shuangshuang Guo, Jintong Guo, Yue Su, Andrew Wolek, Brianna Issacs, Zhenming Liu, Qi Li, Neha Mishra, Antonio Garmendia, M Kyle Hadden, X Cindy Tian, Xin He, Young Tang","doi":"10.1128/jvi.02034-24","DOIUrl":"https://doi.org/10.1128/jvi.02034-24","url":null,"abstract":"<p><p>Porcine reproductive and respiratory syndrome (PRRS) remains a major threat to animal health and causes substantial economic losses worldwide. The nonstructural protein 11 (NSP11) of the causative agent, PRRS virus (PRRSV), contains a highly conserved nidoviral uridylate-specific endoribonuclease (NendoU) domain essential for viral replication and immune evasion. Targeting NSP11 offers a novel approach to antiviral intervention. Through <i>in silico</i> virtual screening followed by a fluorescence resonance energy transfer assay , we identified A8-A2 as a promising candidate that effectively inhibits NendoU activity. Molecular docking and mutational analysis revealed that A8-A2 and its analogs target the key catalytic residues His144 and Thr217 of NSP11, located within the NendoU enzyme activity loop and pocket region, respectively. A8-A2 demonstrated dose-dependent inhibition of PRRSV replication in porcine alveolar macrophages. Notably, the NendoU is conserved across PRRSV strains and other Nidoviruses, and A8-A2 exhibited antiviral activity against both type I and type II PRRSV strains, as well as the infectious bronchitis virus, a coronavirus in the order <i>Nidovirales</i>. Further investigations revealed that A8-A2 impedes viral replication early in infection and reverses NSP11-mediated suppression of Poly(I:C)-induced interferon production. However, this effect occurs independently of mRNA splicing inhibition. These findings indicate that A8-A2 could act as an effective antiviral agent against infections caused by diverse PRRSV strains and may serve as a broad-spectrum agent for other Nidoviruses.</p><p><strong>Importance: </strong>Porcine reproductive and respiratory syndrome virus (PRRSV) causes significant economic losses in the pig industry, and vaccination is the principal method to prevent this viral infection currently. However, vaccination often fails to provide protection against heterologous strains, highlighting the need for alternative strategies for broad protection. The nidoviral uridylate-specific endoribonuclease (NendoU) domain plays a crucial role in viral replication and evasion of host immune responses. In this study, we identified a group of new compounds with similar chemical structures that could interfere with NendoU enzyme activity. Among these compounds, A8-A2 significantly inhibited PRRSV replication in host cells with minimal cytotoxicity. Our findings provide a new direction for developing potent antiviral compounds that can offer broad protection against different PRRSV strains, thereby mitigating their impact on pig health and benefiting the husbandry industry.</p>","PeriodicalId":17583,"journal":{"name":"Journal of Virology","volume":" ","pages":"e0203424"},"PeriodicalIF":4.0,"publicationDate":"2024-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142914440","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Quorum sensing inhibits phage infection by regulating biofilm formation of <i>P. aeruginosa</i> PAO1.","authors":"Lei Cao, Jinhui Mi, Yile He, Guanhua Xuan, Jingxue Wang, Mengzhe Li, Yigang Tong","doi":"10.1128/jvi.01872-24","DOIUrl":"https://doi.org/10.1128/jvi.01872-24","url":null,"abstract":"<p><p>Quorum sensing (QS) can regulate diverse critical phenotypic responses in <i>Pseudomonas. aeruginosa</i> (<i>P. aeruginosa</i>), enabling bacterial adaptation to external environmental fluctuations and optimizing population advantages. While there is emerging evidence of QS's involvement in influencing phage infections, our current understanding remains limited, necessitating further investigation. In this study, we isolated and characterized a novel phage designated as BUCT640 that infected <i>P. aeruginosa</i> PAO1. This phage belonged to class <i>Caudoviricetes</i>, genus <i>Bruynoghevirus</i>, with a podovirus morphology, and its adsorption was dependent on Psl polysaccharides, a repeating pentamer used to support biofilm structure. Leveraging phage BUCT640 as a model, we analyzed the role of both <i>rhl</i> QS and <i>las</i> QS in bacteria-phage interactions. Based on its distinctive plaque formation performances on different QS-related mutants, we investigated the variations of phage sensitivity to these strains and ultimately elucidated the mechanism underlying how QS inhibited phage infection to PAO1. Specifically, we unveiled that the <i>las</i> QS could inhibit phage adsorption, which is related to the thickness change caused by biofilm differentiation. Our findings suggest that the inhibition of QS may enhance phage infectivity, potentially facilitating advanced phage therapy combined with QS interference.</p><p><strong>Importance: </strong>Phage therapy is a powerful solution to combat drug-resistant pathogenic bacterial infections and has earned remarkable success in clinical treatment. However, recent insights underscore the potential impact of bacterial QS on phage infection dynamics. Here, we reported a unique phenomenon wherein QS, particularly in the <i>las</i> QS pathway, showed distinctive plaque formation behaviors by enlarging halos around plaques in mutant strains. In addition to this, we first elucidated the correlation between biofilm formation and phage infection. Notably, the <i>las</i> QS could inhibit phage adsorption, an effect closely related to biofilm thickness. Such research could be the evidence to steer bacterial QS toward favorable therapeutical outcomes. Therefore, our work can extend the comprehension of the interactions between bacteria and phages influenced by QS, thereby providing new perspectives on leveraging QS interference to enhance the efficacy of phage therapy for clinical applications.</p>","PeriodicalId":17583,"journal":{"name":"Journal of Virology","volume":" ","pages":"e0187224"},"PeriodicalIF":4.0,"publicationDate":"2024-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142914936","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Induction of PD-1 and CD44 in CD4⁺ T cells by circulatory extracellular vesicles from severe dengue patients drives endothelial damage via the NF-kB signaling pathway.","authors":"Sharda Kumari, Ankit Biswas, Tushar Kanti Maiti, Bhaswati Bandyopadhyay, Arup Banerjee","doi":"10.1128/jvi.01861-24","DOIUrl":"https://doi.org/10.1128/jvi.01861-24","url":null,"abstract":"<p><p>Extracellular vesicles (EVs) emerged as critical contributors to the pathogenesis of vascular endothelial barrier dysfunction during the inflammatory response to infection. However, the contribution of circulating EVs to modifying endothelial function during dengue virus infection remains unclear. In this study, we showed that severe dengue patients' plasma-derived EV (SD-EV) were found to carry elevated levels of different protein cargos, e.g., immunoregulatory proteins (PD-L1, CD44). Further, we demonstrated that SD-EV induces PD-1 and CD44 expression on CD4⁺ T cells. SD-EV-modulated CD4⁺ T (SD-EV-CD4) cells released secretome delayed endothelial cell (EC) migration, arrested them in the G1 phase, and augmented the expression of PD-L1 and ICAM-1 expression on EC through the Notch signaling pathway. Blocking SD-EV and CD4⁺ T-cell interaction through the PD-1/PD-L1 pathway partially rescued the CD4⁺ T cell's effect on EC but did not alter ICAM-1 expression on EC. We observed that the ICAM-1 expression on EC and hyaluronic acid (HA) release from EC was mediated by CD44, which was elevated on SD-EV-modulated CD4⁺ T cells (SD-EV-CD4), indicating a permeability defect. Blocking of CD44 on SD-EV-CD4 significantly reduced ICAM-1 expression on EC. Further, depletion of specific cytokines, e.g., TNF-α and not IFN-γ from the SD-EV-CD4 secretome, reduced ICAM-1 expression, decreased transendothelial electrical resistance, and induced apoptosis on EC significantly. Treatment with NF-kB inhibitor before secretome addition to EC reduced ICAM-1 expression on EC. In conclusion, we provided evidence that SD-EV-CD4 carrying PD-1 and CD44, when interacting with EC, significantly affected endothelial cell properties and may be significant in dengue-mediated endothelial dysfunction.IMPORTANCEExtracellular vesicles (EVs) are small membrane vesicles secreted into biological fluids, including plasma from living cells, holding insights into pathological processes. Studying EVs under pathological conditions is extremely important as they play a selective role in intercellular communication and modulation of immune response under diverse pathological conditions. However, there is less clarity on how circulatory extracellular vesicles influence immune cells during dengue virus (DV) infection and impact pathogenesis. Our present study highlights the impact of severe dengue patients' plasma-derived EV (SD-EV) on CD4⁺ T cells and together induce endothelial barrier dysfunction. We provided evidence that SD-EV induces PD-1 and CD44 on CD4⁺ T cells and, when interacting with endothelial cells (EC), drives endothelial damage through direct interaction or secretome and may be significant in dengue-mediated endothelial dysfunction.</p>","PeriodicalId":17583,"journal":{"name":"Journal of Virology","volume":" ","pages":"e0186124"},"PeriodicalIF":4.0,"publicationDate":"2024-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142914867","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Role of mouse adenovirus type 1 E4orf6-induced degradation of protein kinase R in pathogenesis.","authors":"Daniel F Edwards Iii, Estela A Pereira, Luiza A Castro-Jorge, Juan M Nevarez, Oded Foreman, Katherine R Spindler","doi":"10.1128/jvi.01545-24","DOIUrl":"https://doi.org/10.1128/jvi.01545-24","url":null,"abstract":"<p><p>Protein kinase R (PKR) is an interferon-induced antiviral protein activated by autophosphorylation in response to double strand DNA (dsRNA) and other stimuli. Activated PKR causes translation inhibition and apoptosis, and it contributes to proinflammatory responses, cell growth, and differentiation. Mouse adenovirus type 1 (MAV-1) counteracts PKR by causing its degradation via a viral protein, early region 4 open reading frame 6 (E4orf6). Degradation is dependent on E4orf6 binding to Cullin 2, a component of the MAV-1 E4orf6 ubiquitin ligase. We investigated the importance of E4orf6 for induction of PKR degradation by exploiting the ability to infect the natural host with the adenovirus MAV-1. First, we used a new PKR-deficient mouse strain, PKR-TKO. PKR-TKO mouse embryo fibroblasts (MEFs) produced higher levels of MAV-1 upon infection than did wild-type (WT) MEFs. PKR-TKO mice had significantly reduced survival, and MAV-1 had a lower LD₅₀ than in WT control mice. However, virus loads in brains and spleens, key organs infected by MAV-1, were similar between PKR-TKO and WT mice. Second, we constructed a virus, E4orf6TMC2, that has three amino acid changes in the E4orf6 domain involved in Cullin 2 binding. In cell culture infection, compared to WT virus, E4orf6TMC2 resulted in reduced PKR degradation, but its growth was equivalent to WT virus. However, E4orf6TMC2 was avirulent in three mouse strains, including the PKR-TKO mice. The results indicate that PKR is an essential antiviral protein that protects against MAV-1 infection. We confirmed that the viral E4orf6 protein is a virulence protein important for PKR degradation during virus infection, and our results suggest its function is not limited to PKR degradation.IMPORTANCEProtein kinase R (PKR) is a host protein that is central to many aspects of the cellular stress response. PKR protects against viral infection by inhibiting viral and host protein synthesis. Most animal viruses have developed ways to circumvent PKR effects by at least one of a variety of means, including inducing its degradation. A new mouse strain knocked out for PKR expression has enabled us to show the importance of PKR for protection from mouse adenovirus type 1 infection in the natural host, which is not possible for human adenoviruses. Mouse adenovirus type 1 induces degradation of PKR through an interaction with host protein Cullin 2. We generated a mutant virus that is defective in its ability to interact with Cullin 2 and showed that the virus does not cause pathogenesis in mice. This work provides critical evidence from mouse studies supporting the importance of PKR for adenovirus pathogenesis.</p>","PeriodicalId":17583,"journal":{"name":"Journal of Virology","volume":" ","pages":"e0154524"},"PeriodicalIF":4.0,"publicationDate":"2024-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142914990","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"YBX1 is required for assembly of viral replication complexes of chikungunya virus and replication of multiple alphaviruses.","authors":"Zhen-Qi Li, Li-Xin Zhao, Su-Yun Wang, Chu-Yu Hu, Yan-Yi Wang, Yan Yang","doi":"10.1128/jvi.02015-24","DOIUrl":"https://doi.org/10.1128/jvi.02015-24","url":null,"abstract":"<p><p>Chikungunya virus (CHIKV), an enveloped positive-sense RNA virus, is a member of the alphaviruses and cause fever and arthralgia in humans. We performed genome-wide CRISPR/Cas9-based screens and identified Y-box binding protein 1 (YBX1) as an essential cellular factor for CHIKV. Deficiency of YBX1 inhibited CHIKV RNA replication and impaired virus production. Upon CHIKV infection, YBX1 showed a striking re-localization to viral replication complexes (vRCs), where it co-localized with CHIKV nsP3 and dsRNA intermediates. YBX1 directly interacted with CHIKV nsP3, and mutation of the YBX1-binding motif in CHIKV nsP3 suppressed viral replication in host cells. Furthermore, YBX1 bound to viral RNA and increased the viral RNA-binding activity of CHIKV nsP3. Consistently, the RNA-binding activity of YBX1, as well as the ability of nsP3 to bind to YBX1, was required for efficient CHIKV replication. In addition to CHIKV, YBX1 was also essential for replication of all examined alphaviruses including the prototypic alphavirus. Our findings suggest that YBX1 acts as a scaffold for assembly of chikungunya vRCs and an important factor for replication of multiple alphaviruses, which may serve as a potential target for the development of anti-alphavirus therapies.IMPORTANCEAlphaviruses are a group of mosquito-transmitted, enveloped, positive-strand RNA viruses in the <i>Togaviridae</i> family. Most alphaviruses are important pathogens that continue to cause human disease ranging from severe and potentially fatal neurological disease to chronic arthritic disease on a global scale. Here, we found that YBX1 promotes binding of CHIKV genomic RNA to nsP3, which is a key component of the replication complex, and is therefore pivotal for CHIKV replication. Deficiency of YBX1 results in reduced replication of multiple alphaviruses, including arthritogenic and encephalitic alphaviruses. These findings suggest that YBX1 is an important cellular factor for multiple alphaviruses and a potential target for preventing alphavirus infections.</p>","PeriodicalId":17583,"journal":{"name":"Journal of Virology","volume":" ","pages":"e0201524"},"PeriodicalIF":4.0,"publicationDate":"2024-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142914999","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Dengue and Zika virus NS4B proteins differ in topology and in determinants of ER membrane protein complex dependency.","authors":"Samuel S Porter, Talon M Gilchrist, Samantha Schrodel, Andrew W Tai","doi":"10.1128/jvi.01443-24","DOIUrl":"https://doi.org/10.1128/jvi.01443-24","url":null,"abstract":"<p><p>Flaviviruses utilize the cellular endoplasmic reticulum (ER) for all aspects of their lifecycle. Genome replication and other viral activities take place in structures called replication organelles (ROs), which are invaginations induced in the ER membrane. Among the required elements for RO formation is the biogenesis of viral nonstructural proteins NS4A and NS4B. We have previously shown that NS4A and NS4B from Dengue virus (DENV) and Zika virus (ZIKV) depend on the cellular ER membrane protein complex (EMC) for biogenesis. Here, we find that this dependency extends to the NS4A and NS4B proteins of Yellow Fever virus (YFV) and West Nile virus (WNV), which share similar computationally predicted membrane topologies. However, we demonstrate that ZIKV NS4B has different determinants of its dependency on the EMC than those for DENV NS4B, as well as a different membrane topology. Furthermore, we characterize mutant isolates of DENV and ZIKV that were serially passaged in EMC knockout cells and find that none are completely independent of the EMC for infection, and that mutant NS4B proteins remain sensitive to EMC depletion, suggesting a high genetic barrier to EMC depletion. Collectively, our findings are consistent with a model in which the EMC recognizes multiple determinants in the NS4B protein to support infection in several flaviviruses of critical public health importance.IMPORTANCEThe NS4A and NS4B proteins of flaviviruses are critically important to replication, but little is known about their function. It has been previously reported that the cellular EMC supports the biogenesis of NS4A and NS4B from Dengue and Zika virus. In this work, we demonstrate that this dependency on the EMC for NS4A and NS4B biogenesis extends to the West Nile and Yellow Fever viruses. Furthermore, we examine the features of ZIKV NS4B and find that its membrane topology of ZIKV NS4B and its determinants of dependency on the EMC are different from those previously described in DENV NS4B. Finally, we present evidence that there is a high genetic barrier for Dengue and Zika viruses to overcome EMC depletion.</p>","PeriodicalId":17583,"journal":{"name":"Journal of Virology","volume":" ","pages":"e0144324"},"PeriodicalIF":4.0,"publicationDate":"2024-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142915234","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}