Journal of Virology最新文献

{"title":"Characterization of SARS-CoV-2 intrahost genetic evolution in vaccinated and non-vaccinated patients from the Kenyan population.","authors":"Doreen Lugano, Kennedy Mwangi, Bernard Mware, Gilbert Kibet, Shebbar Osiany, Edward Kiritu, Paul Dobi, Collins Muli, Regina Njeru, Tulio de Oliveira, M Kariuki Njenga, Andrew Routh, Samuel O Oyola","doi":"10.1128/jvi.00482-25","DOIUrl":"https://doi.org/10.1128/jvi.00482-25","url":null,"abstract":"<p><p>Vaccination is a key control measure of coronavirus disease 2019 by preventing severe effects of disease outcomes, reducing hospitalization rates and death, and increasing immunity. However, vaccination can affect the evolution and adaptation of SARS-CoV-2 largely through vaccine-induced immune pressure. Here, we investigated intrahost recombination and single nucleotide variations (iSNVs) on the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) genome in non-vaccinated and vaccinated sequences from the Kenyan population to profile intrahost viral genetic evolution and adaptations driven by vaccine-induced immune pressure. We identified recombination hotspots in the S, N, and ORF1a/b genes and showed the genetic evolution landscape of SARS-CoV-2 by comparing within- and inter-wave recombination events from the beginning of the pandemic (June 2020 to December 2022) in Kenya. We further reveal differential expression of recombinant RNA species between vaccinated and non-vaccinated individuals and perform an in-depth analysis of iSNVs to identify and characterize the functional properties of non-synonymous mutations found in ORF-1 a/b, S, and N genes. Lastly, we detected a minority variant in non-vaccinated patients in Kenya, with an immune escape mutation S255F of the spike gene, and showed differential recombinant RNA species. Overall, this work identified unique <i>in vivo</i> mutations and intrahost recombination patterns in SARS-CoV-2, which could have significant implications for virus evolution, virulence, and immune escape.IMPORTANCEThe impact of vaccination on severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) genetic diversity in Kenya and much of Africa remains unknown. This can be attributed to lower sequencing rates; however, this information is relevant to improvement in vaccine and antiviral research. In this study, we investigated how vaccination and SARS-CoV-2 transmission waves affect intrahost non-homologous recombination and single nucleotide variations (iSNVs). We identified unique <i>in vivo</i> mutations and intrahost recombination patterns in SARS-CoV-2, which could have significant implications for virus evolution, virulence, and immune escape. We also demonstrate a methodology for studying genetic changes in a pathogen by a simultaneous analysis of both intrahost single nucleotide variations and recombination events. The study reveals the diversity of SARS-CoV-2 in Kenya and highlights the need for sustained genomic surveillance in Kenya and Africa to better understand how the virus evolves. Such surveillance ensures detection of drifts in evolution, allowing information for updates in vaccines, policy making, and containment of future variants of SARS-CoV-2.</p>","PeriodicalId":17583,"journal":{"name":"Journal of Virology","volume":" ","pages":"e0048225"},"PeriodicalIF":4.0,"publicationDate":"2025-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144024410","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":"A BSL-2 chimeric system designed to screen SARS-CoV-2 E protein ion channel inhibitors.","authors":"Vashi Negi, Richard J Kuhn","doi":"10.1128/jvi.02252-24","DOIUrl":"https://doi.org/10.1128/jvi.02252-24","url":null,"abstract":"<p><p>A major hindrance to the identification of new drug targets and the large-scale testing of new or existing compound libraries against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is that research on the virus is restricted to biosafety level 3 (BSL-3) laboratories. In such cases, BSL-2 surrogate systems or chimeric and attenuated versions of the virus are developed for safer, faster, and cheaper examination of the stages of the virus life cycle and specific drug targets. In this study, we describe a BSL-2 chimeric viral system utilizing a Sindbis virus background as a tool to study one such target, the SARS-CoV-2 Envelope (E) protein channel activity. This protein is fully conserved between SARS-CoV and SARS-CoV-2 variants of concern (VOCs), except for a threonine to isoleucine mutation in the Omicron variant, making the E ion channel domain an attractive antiviral target for combination therapy. Using a BSL-2-chimeric system, we have been able to show similar inhibition profiles using channel inhibitors as previously reported for E-channel inhibition in authentic SARS-CoV-2. This system has the potential to allow faster initial screening of E-channel inhibitors and can be useful in developing broad-spectrum antivirals against viral channel proteins.IMPORTANCEDespite its importance in viral infections, no antivirals exist against the ion channel activity of the SARS-CoV-2 Envelope (E) protein. The E protein is highly conserved among SARS-CoV-2 variants, making it an attractive target for antiviral therapies. Research on SARS-CoV-2 is restricted to BSL-3 laboratories, creating a bottleneck for screening potential antiviral compounds. This study presents a BSL-2 chimeric system using a Sindbis virus background to study the ion channel activity of the E protein. This novel BSL-2 system bypasses this limitation, offering a safer and faster approach for the initial screening of ion channel inhibitors. By replicating the channel inhibition profiles of authentic SARS-CoV-2 in a more accessible system, this research paves the way for the development of broad-spectrum antivirals against viral channel proteins, potentially expediting the discovery of life-saving treatments for COVID-19 and other viral diseases.</p>","PeriodicalId":17583,"journal":{"name":"Journal of Virology","volume":" ","pages":"e0225224"},"PeriodicalIF":4.0,"publicationDate":"2025-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144027082","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":"Dendritic cell expression of MyD88 is required for rotavirus-induced B cell activation.","authors":"Sarah E Blutt, Amber D Miller, Margaret E Conner","doi":"10.1128/jvi.00653-25","DOIUrl":"https://doi.org/10.1128/jvi.00653-25","url":null,"abstract":"<p><p>Intestinal IgA, produced by local intestinal B cells, is thought to play a major role in protection against intestinal infections. Rotavirus, a well-characterized intestinal virus, induces a rapid viral-specific intestinal IgA response that occurs in the absence of T cells. Previous work has indicated that dendritic cells facilitate the early IgA response to rotavirus. To determine whether the early Peyer's patch B cell activation associated with rotavirus infection in mice requires dendritic cells, we depleted dendritic cells and assessed B cell activation. Depletion of CD11c⁺ cells <i>in vivo</i> prior to infection resulted in a complete abrogation of Peyer's patch B cell activation. With the use of <i>in vitro</i> cell-based assays, CD11c⁺, but not T or CD11b⁺ cells, was shown to be essential for rotavirus-induced activation of B cells. Investigation of several pathways of B cell activation revealed that dendritic cell expression of MyD88 and signaling through the type I interferon receptor were critical for the ability of the virus to induce B cell activation. These findings indicate that CD11c⁺ dendritic cells can modulate B cell responses to viruses through toll-like receptor and type I interferon signaling pathways.IMPORTANCEDendritic cells are key mediators of immune responses in the intestine. They can capture and process rotavirus antigens and present these antigens to B cells, which produce critical IgA antibody that is essential for clearance of rotavirus infection and protection from reinfection. In the work presented here, we demonstrate that dendritic cell expression of MyD88, a key component of pattern recognition pathways, and not classical IgA pathway molecules such as BAFF and APRIL, is critical for the ability of the dendritic cell to induce the activation of B cells. Our findings emphasize the important role that dendritic cells play in initiating and regulating immune responses including T cell-independent B cell activation. A consideration of the role of dendritic cells in B cell activation and antibody production is an important feature in the development of therapeutic and preventive modalities to combat intestinal viral infections.</p>","PeriodicalId":17583,"journal":{"name":"Journal of Virology","volume":" ","pages":"e0065325"},"PeriodicalIF":4.0,"publicationDate":"2025-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144002454","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":"Spike proteins of coronaviruses activate mast cells for degranulation via stimulating Src/PI3K/AKT/Ca²⁺ intracellular signaling cascade.","authors":"Shuang Zhang, Chu-Lan Xu, Jingjing Wang, Xiaoli Xiong, Jian-Hua Wang","doi":"10.1128/jvi.00078-25","DOIUrl":"https://doi.org/10.1128/jvi.00078-25","url":null,"abstract":"<p><p>Mast cells (MCs) are strategically located at the interface between host and environment. The non-allergic functions of MCs in immunosurveillance against pathogens have been recently underscored. However, the activation of MCs by pathogens may beneficially or detrimentally regulate immune inflammation to combat or promote pathogen invasion. We and others have conclusively demonstrated that MCs serve as a crucial mediator in the induction of hyperinflammation initiated by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), leading to substantial tissue damage across multiple organs in murine and nonhuman primate models. Whereas the precise mechanism underlying virus-induced MC activation and degranulation remains largely elusive, our previous findings have indicated that the binding of the Spike proteins to cellular receptors is sufficient to elicit MC activation for rapid degranulation. This study aims to corroborate the ubiquity of coronavirus-induced MC degranulation and elucidate the intracellular signaling pathways that mediate the activation of MCs upon Spike protein binding to the cellular receptors. Our transcriptome analysis revealed MC activation upon the stimulations with a range of Spike/RBD proteins and viral particles of coronavirus. Notably, the interaction between these Spike/RBD proteins and cellular receptors triggered the activation of src kinase, a member of Src Family Kinases (SFKs). This activation, in turn, stimulated the PI3K/AKT signaling pathway, resulting in an accumulation of intracellular calcium ions. These calcium ions subsequently facilitated microtubule-dependent granule transport, ultimately promoting MC degranulation. In summary, this study elucidates the mechanism underlying virus-triggered activation of MCs and has the potential to aid in the development of MC-targeted antiviral therapeutic strategies.</p><p><strong>Importance: </strong>The activation and degranulation of mast cells (MCs), triggered by a variety of viruses, are intricately linked to viral pathogenesis. However, the precise mechanism underlying virus-induced MC degranulation remains largely unknown. In this study, we demonstrate the ubiquity of coronavirus-induced MC degranulation and investigate the intracellular signaling pathways that mediate this process. We reveal that the binding of Spike proteins and cellular receptors is sufficient to elicit MC activation for rapid degranulation. This binding triggers the activation of src kinase and the downstream PI3K/AKT cellular signaling pathway, resulting in an accumulation of intracellular calcium ions. These calcium ions subsequently facilitate microtubule-dependent granule transport, ultimately promoting MC degranulation. This study elucidates the mechanism underlying virus-triggered activation of MCs and has the potential to aid in the development of MC-targeted antiviral therapeutic strategies.</p>","PeriodicalId":17583,"journal":{"name":"Journal of Virology","volume":" ","pages":"e0007825"},"PeriodicalIF":4.0,"publicationDate":"2025-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144021168","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":"Novel murine model of human astrovirus infection reveals cardiovascular tropism<b> </b>.","authors":"Macee C Owen, Yuefang Zhou, Holly Dudley, Taylor Feehley, Ashley Hahn, Christine C Yokoyama, Margaret L Axelrod, Chieh-Yu Lin, David Wang, Andrew B Janowski","doi":"10.1128/jvi.00240-25","DOIUrl":"https://doi.org/10.1128/jvi.00240-25","url":null,"abstract":"<p><p>Astroviruses are a common cause of gastrointestinal disease in humans and have been linked to fatal cases of encephalitis. A major barrier to the study of human-infecting astroviruses is the lack of an <i>in vivo</i> model as previous attempts failed to identify a host that supports viral replication. We describe a novel murine model of infection using astrovirus VA1/HMO-C (VA1), an astrovirus with high seroprevalence in humans. VA1 is cardiotropic, and viral RNA levels peak in the heart tissue 7 days post-inoculation in multiple different murine genetic backgrounds. Infectious VA1 particles could be recovered from heart tissue 3 and 5 days post-inoculation. Viral capsid was detected intracellularly in the heart tissue by immunostaining, and viral RNA was detected in cardiac myocytes, endocardium, and endothelial cells based on fluorescent <i>in situ</i> hybridization and confocal microscopy. Histologically, we identified inflammatory infiltrates consistent with myocarditis in some mice, with viral RNA colocalizing with the infiltrates. These foci contained CD3 +T cells and CD68 +macrophages. Viral RNA levels increased by >10 fold in the heart tissue or serum samples from Rag1 or Stat1 knockout mice, demonstrating the role of both adaptive and innate immunity in the response to VA1 infection. Based on the <i>in vivo</i> tropisms, we tested cardiac-derived primary cells and determined that VA1 can replicate in primary human cardiac endothelial cells, suggesting a novel cardiovascular tropism in human cells. This novel <i>in vivo</i> model of a human-infecting astrovirus enables further characterization of the host immune response and reveals a new cardiovascular tropism of astroviruses.</p><p><strong>Importance: </strong>Astroviruses routinely cause infections in humans; however, few methods were available to study these viruses. Here, we describe the first animal system to study human-infecting astroviruses by using mice. We demonstrate that mice are susceptible to astrovirus VA1, a strain that commonly infects humans and has been linked to fatal brain infections. The virus infects the heart tissue and is associated with inflammation. When mice with impaired immune systems were infected with VA1, they were found to have higher amounts of the virus in their hearts and blood. We found that VA1 can infect cells from human blood vessels of the heart, which is associated with human health. This model will enable us to better understand how astroviruses cause disease and how the immune system responds to infection. Our findings also suggest that astroviruses could be linked to cardiovascular diseases, including in humans.</p>","PeriodicalId":17583,"journal":{"name":"Journal of Virology","volume":" ","pages":"e0024025"},"PeriodicalIF":4.0,"publicationDate":"2025-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144032890","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":"dNTP depletion and beyond: the multifaceted nature of SAMHD1-mediated viral restriction.","authors":"Pak-Hin Hinson Cheung, Hua Yang, Li Wu","doi":"10.1128/jvi.00302-25","DOIUrl":"https://doi.org/10.1128/jvi.00302-25","url":null,"abstract":"<p><p>SAMHD1 is a dNTPase of mammalian cells. In 2011, SAMHD1 was found to be a host restriction factor against retroviruses through dNTP reduction. Recent research provides evidence that the antiviral mechanisms of SAMHD1 cannot be explained solely by its dNTPase activity. Instead, the versatility of SAMHD1-mediated restriction of various viruses suggests that its antiviral mechanisms extend beyond dNTP depletion. This explains the multifaceted and broad restriction functions of SAMHD1 that play a significant role in innate antiviral immunity.</p>","PeriodicalId":17583,"journal":{"name":"Journal of Virology","volume":" ","pages":"e0030225"},"PeriodicalIF":4.0,"publicationDate":"2025-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144017305","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":"Ubiquitin-dependent proteasomal degradation of small hepatitis B virus surface antigen mediated by TRIM21 and antagonized by OTUD4.","authors":"Shuxiang Wu, Zhihan Chen, Zhengqian Zhang, Jing Xu, Hang Li, Mengxian Lin, Wenjie Xie, Yan Chen, Xinjian Lin, Xu Lin","doi":"10.1128/jvi.02309-24","DOIUrl":"https://doi.org/10.1128/jvi.02309-24","url":null,"abstract":"<p><p>The small hepatitis B surface antigen (SHBs) is the most abundant hepatitis B virus (HBV) protein in individuals infected with HBV, and clearance of HBV surface antigen, which is primarily composed of SHBs, is considered a surrogate biomarker for achieving a functional cure of chronic HBV. Understanding SHBs degradation is crucial for its elimination and targeted eradication strategies. This study demonstrates that SHBs undergoes degradation via a ubiquitin/proteasome pathway, primarily through K48-linked ubiquitination, with K122 as the critical ubiquitination site. Utilizing immunoprecipitation and mass spectrometry, we identified TRIM21 (an E3 ubiquitin ligase) and OTUD4 (a deubiquitinase) as key regulators of SHBs. We verified the direct interaction between SHBs and TRIM21's coiled-coil domain, as well as the N-terminal amino acids 1-180 of OTUD4, using coimmunoprecipitation and glutathione S-transferase (GST) pull-down assays in both <i>in vivo</i> and <i>in vitro</i> settings. TRIM21 was observed to reduce SHBs stability and abundance by promoting its polyubiquitination, whereas OTUD4 acted to negate the effects of TRIM21-induced polyubiquitination, thereby stabilizing and increasing the levels of SHBs. Notably, TRIM21-mediated degradation of SHBs substantially impaired subviral particle and virion production and its biological activities such as migratory and angiogenic capabilities, opposite to the effect produced by the introduction of OTUD4. These findings suggest that TRIM21 and OTUD4 modulate SHBs protein stability and function through a ubiquitination-dependent proteasomal pathway, offering new insights into clearing SHBs and intervening in the progression of HBV-related liver diseases.IMPORTANCEThe small hepatitis B surface antigen (SHBs) is a key structural component of the hepatitis B virus (HBV) virion and subviral particles and is the most abundant HBV protein in individuals with chronic infection. Gaining a better understanding of its degradation pathways may help inform strategies to reduce SHBs levels and potentially support the design of targeted therapies. However, the specific mechanisms and processes involved in the degradation of SHBs remain largely unexplored. This study reveals that SHBs is degraded via the ubiquitin/proteasome pathway, specifically through K48-linked ubiquitination at the K122 site. TRIM21 promotes SHBs degradation by enhancing its polyubiquitination, while OTUD4 stabilizes SHBs by counteracting TRIM21's effects. TRIM21 reduces SHBs stability, subviral particle and virion production, and its related biological activities, whereas OTUD4 stabilizes SHBs, promoting its accumulation. These findings highlight the roles of TRIM21 and OTUD4 in regulating SHBs stability and function, offering new insights into potential interventions for HBV-related liver diseases.</p>","PeriodicalId":17583,"journal":{"name":"Journal of Virology","volume":" ","pages":"e0230924"},"PeriodicalIF":4.0,"publicationDate":"2025-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143971012","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":"Twelfth scientific biennial meeting of the Australasian Virology Society: AVS12 2024.","authors":"Ebony A Monson, Robson K Loterio, Justin A Roby, Anurag Adhikari, Rowena A Bull, Jill M Carr, Demetra S M Chatzileontiadou, Colin X Cheng, Fasséli Coulibaly, Samantha K Davis, Joshua M Deerain, Mark W Douglas, Heidi E Drummer, Nicholas S Eyre, Wesley Freppel, Anjali Gowripalan, Emma J Grant, Stephanie Gras, Jenna J Guthmiller, Lara J Herrero, Eva Hesping, Bethany A Horsburgh, Jennifer L Hyde, Marios Koutsakos, Jason M Mackenzie, Jackie E Mahar, Laura C McCoullough, Christopher L D McMillan, Naphak Modhiran, Rhys H Parry, Damian F J Purcell, Daniel J Rawle, Andrii Slonchak, Peter G Speck, Gilda Tachedjian, Thomas Tu, Gregory W Moseley, Johanna E Fraser, Michelle D Tate","doi":"10.1128/jvi.02255-24","DOIUrl":"https://doi.org/10.1128/jvi.02255-24","url":null,"abstract":"<p><p>The Australasian Virology Society (AVS) holds premier biennial virology meetings that foster multidisciplinary research and collaboration and promote equity and inclusion of early-career researchers. The 12th AVS meeting (AVS12), convened by M. Tate, J. Fraser, and G. Moseley, was held from 2 to 5 December 2024 on Dja Dja Wurrung country at the RACV Goldfields Resort in Creswick, Victoria, Australia. In this report, we give a brief overview of the history of AVS and outline the current and developing priorities for the society. We provide a summary of the insightful panel discussions held to address career development and Indigenous virology, highlight the presentations given by international plenary speakers Joe Grove and Chantal Abergel, and celebrate the recipients of the numerous awards.</p>","PeriodicalId":17583,"journal":{"name":"Journal of Virology","volume":" ","pages":"e0225524"},"PeriodicalIF":4.0,"publicationDate":"2025-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143971200","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":"Syntaxin-6 restricts SARS-CoV-2 infection by facilitating virus trafficking to autophagosomes.","authors":"Hao Sun, Qi Yang, Yecheng Zhang, Saisai Cui, Zhe Zhou, Peilu Zhang, Lijia Jia, Mingxia Zhang, Yun Wang, Xinwen Chen, Rongjuan Pei","doi":"10.1128/jvi.00002-25","DOIUrl":"https://doi.org/10.1128/jvi.00002-25","url":null,"abstract":"<p><p>Despite the diminishing global impact of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus continues to circulate and undergo mutations, posing ongoing challenges for public health. A comprehensive understanding of virus entry mechanisms is crucial for managing new epidemic strains. However, the cellular processes post-endocytosis remain largely unexplored. This study employs proximity labeling to examine proteins near ACE2 post-viral infection and identified syntaxin-6 (STX6) as a factor that inhibits SARS-CoV-2 infection by impeding the endocytic release of the virus. SARS-CoV-2 infection enhances early endosome recruitment of STX6. STX6 appears to hinder the maturation of viral particles-laden early endosomes into late endosomes, from which the virus could escape. Instead, it promotes the trafficking of the virus toward the autophagy-lysosomal degradation pathway. STX6 exhibits a broad-spectrum effect against various SARS-CoV-2 variants and several other viruses that enter via endocytosis. We report for the first time the function of STX6 as a restrictive factor in viral infection.IMPORTANCEVirus entry is the first step of the virus life cycle, and the exploitation of the endo-lysosome pathway for cellular entry by viruses has been well documented. Meanwhile, the intrinsic defense present within cells interferes with virus entry. We identified STX6 as a host restriction factor for viral entry by facilitating the virus trafficking to the autophagy-lysosomal degradation pathway. Notably, STX6 exhibits broad-spectrum antiviral activity against diverse severe acute respiratory syndrome coronavirus 2 variants and other viruses employing endocytosis for entry.</p>","PeriodicalId":17583,"journal":{"name":"Journal of Virology","volume":" ","pages":"e0000225"},"PeriodicalIF":4.0,"publicationDate":"2025-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144002600","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":"HIV-1 Nef activates proviral DNA transcription by recruiting Src kinase to phosphorylate host protein Nef-associated factor 1 to compromise its viral restrictive function.","authors":"Tian-Jiao Fan, Chengzuo Xie, Lisha Li, Xia Jin, Jie Cui, Jian-Hua Wang","doi":"10.1128/jvi.00280-25","DOIUrl":"https://doi.org/10.1128/jvi.00280-25","url":null,"abstract":"<p><p>HIV-1 accessory protein Nef is a multifunctional pathogenic factor that mediates immune evasion, enhances virion infectivity, antagonizes host restrictive factors, and promotes viral dissemination. However, the modulation of Nef on proviral DNA transcription of latently infected viruses is not well understood. In this study, we found that Nef activated HIV-1 proviral DNA transcription by recruiting Src Family Kinases (SFKs) member Src to stimulate the downstream PI3K/AKT/mTOCR1/CDK9 cellular pathway, and that Naf1 (Nef-associated factor 1), a host protein that is known to suppress HIV-1 transcription, was required for this function of Nef. This seemingly contradictory interplay between Nef and Naf1 was investigated. Naf1 was a repressor of the PI3K/AKT/mTOCR1/CDK9 cellular pathway, but in the presence of Nef, Naf1 was phosphorylated at the Tyrosine-552 by Nef-recruited Src, consequently converting its normal restrictive role to coordinate with Nef to activate proviral DNA transcription. These findings reveal a mechanism by which Nef activates HIV-1 proviral DNA transcription and discover the dual function of Naf1 protein in regulating HIV infection, depending on its phosphorylation status. This study reports a new interaction mode between host factors and viral proteins in regulating HIV-1 replication.</p><p><strong>Importance: </strong>HIV-1 accessory protein Nef is a multifunctional pathogenic factor; however, the modulation of Nef on proviral DNA transcription of latently infected virus is not well understood. This study demonstrates Nef's role in activating HIV-1 proviral DNA transcription and uncovers the underlying cellular mechanism. Nef recruits Src kinase to phosphorylate Naf1, and the phosphorylation of Naf1 converts its normal restrictive role to coordinate with Nef to activate proviral DNA transcription by stimulating the downstream PI3K/AKT/mTOCR1/CDK9 cellular pathway. These findings also report a new interaction mode between host factors and viral proteins in regulating HIV-1 replication.</p>","PeriodicalId":17583,"journal":{"name":"Journal of Virology","volume":" ","pages":"e0028025"},"PeriodicalIF":4.0,"publicationDate":"2025-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143999758","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}