Journal of Virology最新文献

{"title":"Pseudorabies virus DNA polymerase processivity factor pUL42 inhibits type I IFN production by negatively regulating cGAS-STING signaling pathway.","authors":"Guangqiang Ye, Jiaxiu Gao, Haoxuan Cao, Xiaohong Liu, Hongyang Liu, Shanghui Wang, Yunfei Liu, Longfei Han, Qiongqiong Zhou, Yandong Tang, Jin Tian, Liping Huang, Li Huang, Zhaoxia Zhang, Changjiang Weng","doi":"10.1128/jvi.01218-25","DOIUrl":"https://doi.org/10.1128/jvi.01218-25","url":null,"abstract":"<p><p>Pseudorabies (PR), caused by the PR virus (PRV), is an acute infectious disease in livestock and various wild animals. PRV has developed several immune evasion mechanisms to antagonize the host's antiviral immune response. However, the precise role of PRV-encoded proteins in regulating the cyclic GMP-AMP synthase (cGAS)-stimulator of interferon (IFN) gene (STING) signal for immune evasion remains unclear. In this study, we demonstrate that the PRV UL42 protein (pUL42) inhibited cGAS-mediated antiviral signaling by modulating cGAS recognition of dsDNA. Mechanistically, pUL42 interacts with the DNA-binding domain of cGAS, thereby inhibiting its recognition of double-stranded DNA, leading to the inhibition of its dimerization and oligomerization activation. Furthermore, knocking down the expression of the <i>Ul42</i> gene in the PRV genome diminishes the antagonistic effect on type I IFN production and inhibits PRV replication. Ultimately, we have established that pUL42 targets cGAS-mediated signaling, thereby inhibiting the production of type I IFN and facilitating viral replication. Overall, our findings suggest that PRV pUL42 functions as an antagonist to evade the host's antiviral response by targeting the cGAS-STING axis.</p><p><strong>Importance: </strong>Cyclic GMP-AMP synthase (cGAS)-stimulator of interferon gene (STING) axis is essential for host resistance to DNA virus infections by regulating type I interferon production. However, whether pseudorabies virus (PRV) antagonizes the cGAS-STING signaling pathway to immune evasion is not fully investigated. In this study, we clearly demonstrated that the PRV pUL42 protein inhibits the recognition of double-stranded DNA of cGAS, leading to inhibiting the oligomerization and activation of cGAS, thereby suppressing the cGAS-mediated host antiviral immune responses. Taken together, our results reveal a novel strategy employed by PRV to evade host defenses, which will provide theoretical support for the development of anti-PRV drugs for the prevention and control of PRV.</p>","PeriodicalId":17583,"journal":{"name":"Journal of Virology","volume":" ","pages":"e0121825"},"PeriodicalIF":3.8,"publicationDate":"2025-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145192025","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":"Identifying a novel region in the Tembusu virus NS5 protein antagonizing type I interferon signaling.","authors":"Ji Zhang, Yunhao Fan, Da An, Mingtian Mao, Zhanbao Guo, Jing Yang, Qiuyue Li, Siming Zhu, Guannan Li, Xin Chen, Zhengkui Zhou, Shuisheng Hou, Youxiang Diao, Yi Tang","doi":"10.1128/jvi.01310-25","DOIUrl":"https://doi.org/10.1128/jvi.01310-25","url":null,"abstract":"<p><p>Numerous species in the genus <i>Flavivirus</i> have been identified to pose serious threats to public health. Most of them have developed evasion strategies to counteract antiviral activity triggered by type I interferon (IFN-I), making prevention and control challenging. Our study reveals that Tembusu virus (TMUV), a <i>Flavivirus</i> that mainly causes severe disease in ducks, can inhibit IFN-I signaling via its NS5 protein, efficiently preventing the nuclear translocation of IFN-activated transcription factor STATs and significantly impairing transcriptional induction of IFN-stimulated genes. Interestingly, our research shows that 37-45 amino acid (aa) residues in the N-terminal region of TMUV-NS5 constitute a functional nuclear localization signal (<i>NLS</i>) that interacts with karyopherins, disrupting the nuclear transport system, in contrast to the classical <i>α/β NLS</i> found in most flaviviruses. Moreover, through in-depth analysis, we highlight that the nuclear trafficking competence of <i>NLS</i> is modulated by multiple determinants, such as the species and molecular size of cargo proteins, providing critical mechanistic insights into the differential subcellular localization of <i>Flavivirus</i> NS5. Altogether, our findings contribute to a better understanding of how TMUV-NS5 inhibits IFN-I signaling and offer novel perspectives on the evasion of the innate immune responses by <i>Flavivirus</i>.IMPORTANCERecent studies have demonstrated that various flaviviruses can inhibit the innate type I interferon (IFN-I) response. Similarly, Tembusu virus (TMUV), a highly epidemic <i>Flavivirus</i> among ducks, has been reported to inhibit IFN-I induction. In the present study, we confirm that TMUV is also an antagonist of IFN-I signaling, and its NS5 plays a key role. However, different from <i>α/β</i> nuclear localization signal (<i>NLS</i>) in most flaviviruses, 37-45 amino acid region in N-terminus of TMUV-NS5 has been identified as a crucial area for interaction with KPNAs, thus inhibiting nuclear transport of STATs. In addition, we further discovered that the nuclear localization activity of <i>NLS</i> is regulated by multiple factors, such as different sizes and types of the cargos, thereby leading to the distinct subcellular distribution of <i>Flavivirus</i> NS5.</p>","PeriodicalId":17583,"journal":{"name":"Journal of Virology","volume":" ","pages":"e0131025"},"PeriodicalIF":3.8,"publicationDate":"2025-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145192076","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":"Developing an eVLP mRNA vaccine for respiratory syncytial virus with enhanced pre-fusion targeting humoral responses.","authors":"Lei Sun, Mengting Huang, Simin Feng, Wei Zhang, Yun Quan, Ruyi Chen, Yupeng Yang, Haidong Xu, Wansheng Li, Qianyu Pan, Xinwen Chen, Danyang Zhang, Bin Yuan, Jincun Zhao, Zhongfang Wang, Jinzhong Lin, Wei Peng, Martin Ludlow, Qiong Zhang","doi":"10.1128/jvi.01209-25","DOIUrl":"https://doi.org/10.1128/jvi.01209-25","url":null,"abstract":"<p><p>Respiratory syncytial virus (RSV) is a leading cause of lower respiratory tract disease (LRTD) in infants, the elderly, and immunocompromised individuals. In this study, we leveraged the innovative EABR (ESCRT- and ALIX-binding region) vaccine technology to develop a pre-fusion (Pre-F)-based RSV mRNA vaccine (Pre-F-EABR) that encodes self-assembling enveloped virus-like particles (eVLPs). <i>In vitro</i> expression of Pre-F-EABR mRNA manifested pronounced Pre-F protein expression, particularly on cell membranes and in cell culture supernatant, compared to classical Pre-F and Pre-F-Ferritin nanoparticle (Pre-F-Fe) mRNAs, suggesting efficient eVLP self-assembly. Immunization of mice with lipid nanoparticle-encapsulated, nucleoside-modified mRNAs (mRNA-LNPs) demonstrated that the Pre-F-EABR vaccine elicited enhanced neutralizing activities and more robust cellular immunity when compared to Pre-F or Pre-F-Fe mRNA vaccines. Notably, the Pre-F-EABR mRNA vaccine induced a significantly higher level of protective pre-fusion-specific antibodies in contrast to post-fusion-targeting antibodies, dramatically reducing pulmonary viral load following RSV challenge in vaccinated mice. Furthermore, the Pre-F-EABR mRNA vaccine demonstrated significantly improved efficacy against the contemporary clinical ON1 and BA9 isolates. Overall, these findings demonstrate that the Pre-F-EABR mRNA vaccine induces more robust immune responses, highlighting its potential in preventing RSV infection in vulnerable populations.</p><p><strong>Importance: </strong>Respiratory syncytial virus (RSV) is a major cause of lower respiratory tract disease in infants, the elderly, and immunocompromised individuals. It is well-established that enhancing the neutralizing antibody levels and Th1-biased cellular immune responses can potentially improve the efficacy and safety of RSV vaccines. In this study, we developed an RSV pre-fusion protein-based mRNA vaccine that encodes self-assembling enveloped virus-like particles. Mice immunized with this vaccine showed significantly enhanced pre-fusion protein-targeted humoral responses and improved protection against RSV infection compared to the conventional RSV mRNA vaccine. Additionally, this vaccine demonstrated a considerably stronger neutralizing ability against contemporary clinical RSV isolates and induced more robust Th1-biased cellular immune responses, suggesting its potential as a promising RSV vaccine candidate.</p>","PeriodicalId":17583,"journal":{"name":"Journal of Virology","volume":" ","pages":"e0120925"},"PeriodicalIF":3.8,"publicationDate":"2025-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145191985","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":"Primary envelopment of Kaposi's sarcoma-associated herpesvirus at the nucleoplasmic reticulum.","authors":"Alexa Wilson, Neale D Ridgway, Craig McCormick","doi":"10.1128/jvi.00588-25","DOIUrl":"https://doi.org/10.1128/jvi.00588-25","url":null,"abstract":"<p><p>Herpesvirus egress begins with primary envelopment of newly assembled capsids at the inner nuclear membrane (INM). Primary envelopment has been observed at the peripheral INM as well as nuclear infoldings. Nuclear infoldings from invaginations of the INM are Type-I nucleoplasmic reticulum (NR), whereas infoldings of both INM and outer nuclear membrane (ONM) are Type-II NR. Here, we report that Kaposi's sarcoma-associated herpesvirus (KSHV) reactivation from latency and lytic cycle progression correlates with increases in both types of NR, but primary envelopment is restricted to peripheral INM and Type-I NR. These Type-I NR structures co-localized with puncta containing CTP:phosphocholine cytidylyltransferase (CCTα), the enzyme that catalyzes the rate-limiting step in phosphatidylcholine (PtdCho) synthesis that drives the <i>de novo</i> membrane biogenesis and membrane curvature required for NR expansion; CCTα recruitment may provide sufficient Type-I NR to facilitate nuclear egress. Despite the concurrent expansion of Type-II NR, primary envelopment involves a mechanism that specifically targets capsids to Type-I NR. Building upon our observation of capsids lacking envelopes in complex higher-order Type-I NR structures, we used polar lipid dyes, CLICK-labeled fluorescent viral genomes, and fluorescent KSHV capsids to track the fate of NR-associated capsids via live cell microscopy. These studies provide evidence for trafficking of NR-associated capsids toward the nuclear periphery and cytoplasm. Taken together, these findings suggest that nuclear egress occurs not only at the nuclear periphery but also at the Type-I NR.</p><p><strong>Importance: </strong>Herpesvirus capsids assemble in the cell nucleus but are too large to exit via nuclear pores. Instead, they bud into the inner nuclear membrane to acquire a provisional lipid envelope that is shed through fusion with the outer nuclear membrane, delivering the capsid to the cytoplasm for subsequent steps in assembly and egress. These nuclear membranes are dynamic, with the ability to fold into invaginations that access the nuclear interior. Here, we demonstrate that during Kaposi's sarcoma-associated herpesvirus (KSHV) replication, nuclear membrane infolding increases, coinciding with recruitment of a host enzyme required for PtdCho synthesis at these sites. We observed accumulation of KSHV capsids at infoldings of the inner nuclear membrane and tracked the association and trafficking of fluorescent viral particles through these structures by live cell microscopy. This complements a more well-established mechanism of KSHV egress at the nuclear periphery and suggests versatility in nuclear egress mechanisms.</p>","PeriodicalId":17583,"journal":{"name":"Journal of Virology","volume":" ","pages":"e0058825"},"PeriodicalIF":3.8,"publicationDate":"2025-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145199997","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":"Discontinuous template switching generates coronavirus subgenomic RNAs from the 3' viral genome end by 5' to 3' transcription.","authors":"Ayslan Castro Brant, Zhe Hu, Angelika Zelma Chen, Vladimir Majerciak, Jonathan Yewdell, Zhi-Ming Zheng","doi":"10.1128/jvi.01438-25","DOIUrl":"https://doi.org/10.1128/jvi.01438-25","url":null,"abstract":"<p><p>In coronavirus (CoV)-infected cells, several structural and accessory proteins are synthesized from subgenome RNAs (sgRNA) containing a common genomic 5'-leader followed by a given open reading frame (ORF). We report that the abundance of these sgRNAs varies with distance from the 3'-end of the genome. Thus, there are more sgRNAs encoding nucleocapsid (N) than spike (S), presumably the results from discontinuous 5'-3' transcription template switch mediated by the viral replication and transcription complex (RTC). We optimized the circular polymerase extension reaction (CPER) methodology to generate infectious double-stranded circular cDNA (ds-circDNA) containing the mNeonGreen (NG) reporter in accessory ORFs of human CoVs OC43 and SARS-CoV-2. In each CoV, we found that levels of sgRNAs and NG expression increased with 3' proximal genomic NG location. By reinfection of HCT-8 cells with the same MOI 0.01, however, we found that the slow-growing OC43 NG-ns2 virions exhibited equal infectivity and productivity as the fast-growing OC43 NG-ns12.9 virions. Introduction of point-mutations into the mapped TRS_B motif for synthesis of the OC43 ns12.9 and M sgRNAs led to disrupt TRS_B-TRS_L cross-interactions and block production of the corresponding sgRNAs and infectious virions. Together, our data indicate that, by using an optimized CPER approach for positional NG insertions, we demonstrated the progressional reduction of the RTC-mediated template switch (read-through individual TRS_B) efficiency in production of the corresponding sgRNAs in an order from the 3' viral genome end.IMPORTANCEThe mechanism for sgRNA synthesis in the coronavirus life cycle is poorly understood. The current model suggests discontinuous template-switch transcription mediated by viral replication and transcription complex (RTC) for synthesis of individual sgRNAs to translate corresponding structural and accessory proteins but lacks experimental data support. This report provides the first experimental evidence that, in both hCoV-OC43 and SARS-CoV-2, viral RTC synthesizes its sgRNAs by long-range base-pairing between a distal transcription regulatory body sequence (TRS_B) upstream of each structural/accessory ORF and the transcription regulatory leader sequence (TRS_L) from the viral genome 5'-UTR, leading to the production of viral sgRNAs in abundance order from the viral genome 3' -end, with more N sgRNAs but less S sgRNAs. Our data support a \"first-come, first-serving\" model in TRS_B-TRS_L cross-interaction and read-through TRS_B process to mediate discontinuous transcription switch in coronavirus sgRNA synthesis in a 5'-3' transcription direction from the 3' viral genome during coronavirus infection.</p>","PeriodicalId":17583,"journal":{"name":"Journal of Virology","volume":" ","pages":"e0143825"},"PeriodicalIF":3.8,"publicationDate":"2025-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145137966","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":"HCC-derived SNU cell lines as model systems to study HBV life cycle.","authors":"Igor Zaiets, Oleksandra Chazova, Sumedha Gunewardena, Severin O Gudima","doi":"10.1128/jvi.01144-25","DOIUrl":"https://doi.org/10.1128/jvi.01144-25","url":null,"abstract":"<p><p>Human SNU cell lines, derived from hepatocellular carcinomas associated with chronic hepatitis B virus (HBV) infection, were examined. The analysis of intracellular RNA and DNA markers of HBV replication and examination of HBV RNA readss coverage of selected regions on HBV-related RNAs and polyadenylation positions within HBV sequence using RNA-sequencing suggested the absence of HBV replication in SNU-423, SNU-368, SNU-398, SNU-182, SNU-449, SNU-475, SNU-354, SNU-739, and SNU-387 cells, while SNU-761 and SNU-886 still could maintain residual HBV replication. The undetectable intracellular HBV core antigen (HBcAg) and absence of significant levels of secreted core-associated and virion-associated HBV DNA confirmed the absence or profound suppression of HBV replication in parental SNU cell lines. Various 5'-human-HBV-3' and 5'-HBV-human-3' RNAs transcribed from integrated HBV DNA were found in most of the SNU cell lines. The 5'-HBV-human-3' junctions suggested that several SNU cell lines could generate 5'-HBV-human-3' RNAs encoding HBV envelope proteins. The known and novel spliced HBV RNAs were detected in SNU-886, SNU-739, SNU-387, SNU-761, and SNU-354 cells. At least some of them were generated independently of HBV replication. None of the SNU cell lines supported efficient HBV replication after transfection with the vector that initiates efficient HBV replication in Huh7 cells. This was reflected by three distinct accumulation patterns of HBV replication markers, undetectable intracellular HBcAg, and by the lack of considerable levels of secreted core-bound and virion-associated HBV DNA. Overall, SNU cell lines represent valuable model systems for detailed analysis of integrant-transcribed HBV RNAs, spliced HBV RNAs, and mechanisms of suppression of HBV genome replication.IMPORTANCESNU cell lines without ongoing hepatitis B virus (HBV) genome replication are invaluable experimental systems that allow detailed study of the biogenesis and properties of integrant-transcribed 5'-human-HBV-3' and 5'-HBV-human-3' RNAs and mechanisms generating spliced HBV-related RNA species independently of concomitant viral replication. Three unique patterns of intracellular accumulation of HBV replication markers were observed in SNU cell lines transfected with the vector that initiates efficient HBV genome replication in Huh7 cells: (i) very low levels of pre-genomic RNA (pgRNA), total HBV RNA, replication-derived RNAs (rd-RNAs), covalently closed circular DNA (cccDNA), and core-associated HBV DNA; (ii) moderate pgRNA, high total HBV RNA, rd-RNAs, and cccDNA, but very low core-associated HBV DNA; and (iii) very low pgRNA, total HBV RNA, rd-RNAs, and core-associated HBV DNA, but moderate/high cccDNA likely reflect three natural host-mediated mechanisms suppressing HBV replication, the analysis of which should advance our understanding of HBV-host interactions and could be informative for the search for novel anti-HBV interventions.</p>","PeriodicalId":17583,"journal":{"name":"Journal of Virology","volume":" ","pages":"e0114425"},"PeriodicalIF":3.8,"publicationDate":"2025-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145137992","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":"Comparison of the biological properties of bat-derived filovirus envelope glycoproteins.","authors":"Francois Edidi-Atani, Yannick Munyeku Bazitama, Hiroko Miyamoto, Akina Mori-Kajihara, Hayato Sugiura, Manabu Igarashi, Jean Jacques Muyembe-Tamfum, Steve Ahuka-Mundeke, Ayato Takada","doi":"10.1128/jvi.01018-25","DOIUrl":"https://doi.org/10.1128/jvi.01018-25","url":null,"abstract":"<p><p>Although some filoviruses, such as Ebola virus (EBOV) and Marburg virus (MARV), are highly pathogenic in humans, novel filoviruses, including Lloviu virus (LLOV), Bombali virus (BOMV), Mengla virus (MLAV), and Dehong virus (DEHV), whose biological properties are poorly understood, have been found in bats. In this study, we characterized the envelope glycoproteins (GPs) of these bat-derived filoviruses (BatFiloVs). We first confirmed that virus-like particles consisting of their GPs, nucleoproteins, and matrix proteins were filamentous. Interestingly, although BatFiloVs were serologically distinct, some previously established monoclonal antibodies (MAbs) (e.g., 6D6) successfully neutralized vesicular stomatitis Indiana viruses pseudotyped with LLOV, BOMV, or DEHV GPs. The pseudotyped viruses bearing BatFiloV GPs utilized human TIM-1 and C-type lectins for entry into cells, although the efficiency tended to be lower than for EBOV and/or MARV GP-pseudotyped viruses. These viruses broadly infected cultured cells derived from various animal species, including humans and bats. However, viruses pseudotyped with DEHV and MARV GPs failed to infect the Yaeyama flying fox cell line, whereas the other pseudotyped viruses infected this cell line. Interestingly, the virus bearing BOMV GP showed the greatest ability to infect cell lines derived from Angolan free-tailed bats, the only known host species of BOMV. We identified unique amino acid residues at the interface between GP and its receptor (i.e., Niemann-Pick C1), which might explain these differences. Our results suggest that the biological properties of filovirus GPs are generally consistent with their phylogenetic relationship and that BatFiloVs may have differential pathogenicity and host range restriction.IMPORTANCEFiloviruses, such as EBOV and MARV, are known to cause severe hemorrhagic fever in humans and nonhuman primates. With the recent advancements in next-generation sequencing, novel filoviruses have been detected in bats. However, their pathogenicity and host tropism remain largely unknown. Here, we focus on the filovirus spike protein GP, which plays a crucial role in the viral lifecycle, and discuss the biological properties of BatFiloVs. We studied the primary structures of GPs, virus particle morphology, antigenic differences of GPs, neutralizing capacities of anti-EBOV and -MARV GP MAbs, usage of some attachment factors during the entry into cells, and GP-mediated cellular tropism. The present study provides fundamental information for understanding the BatFiloV ecology, host ranges, and potential risks as zoonotic pathogens for humans. This knowledge will guide public health interventions to prevent virus spillovers and the development of surveillance strategies and specific countermeasures.</p>","PeriodicalId":17583,"journal":{"name":"Journal of Virology","volume":" ","pages":"e0101825"},"PeriodicalIF":3.8,"publicationDate":"2025-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145137904","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":"Respiratory syncytial virus phosphoprotein has NTPase and helicase-like activities.","authors":"Ting Shu, Xiaotong Wang, Yiyang Li, Jiaoling Su, Haiwu Zhou, Mengyu Hu, Puyu Yang, Chao Shan, Yang Qiu, Xi Zhou","doi":"10.1128/jvi.00996-25","DOIUrl":"https://doi.org/10.1128/jvi.00996-25","url":null,"abstract":"<p><p>Respiratory syncytial virus (RSV), a non-segmented, negative-sense RNA virus (NNSV) in the family Pneumoviridae, represents a significant global health burden causing severe lower respiratory tract infections in infants and immunocompromised adults. While RNA helicases are essential for viral replication through their RNA remodeling functions, the presence of such enzymatic activities in RSV remains unclear. Here, we reveal that the RSV phosphoprotein (P), despite lacking canonical helicase motifs, demonstrates nucleoside triphosphatase (NTPase) activity and directional 5'-to-3' RNA helix-unwinding capacity in an NTP-dependent manner. Through mutagenesis assays, we establish a functional coupling between NTP hydrolysis and helicase-like activity. Importantly, reverse genetics experiments, RSV minigenome, and antiviral-effect assays demonstrate the essentiality of RSV P's helicase-like activity for viral viability and replication. These findings identify P as an enzymatic component critical for RSV replication, providing new insights into the mechanisms of pneumovirus propagation.</p><p><strong>Importance: </strong>RNA helicases and helicase-like viral proteins are crucial for viral RNA replication and are prime targets for antiviral development. RSV infects nearly all children by age two, causing over 30 million acute lower respiratory infections, 3.6 million hospitalizations, and 100,000 deaths annually in children under five, while also posing a significant threat to immunocompromised adults and the elderly. In this study, we demonstrate for the first time that the RSV P has NTPase activity and unwinds RNA helices in an NTP-dependent manner. Mutagenesis and reverse genetics experiments confirm that these enzymatic activities are essential for RSV viability. These findings not only redefine RSV P as a multifunctional protein but also expand our understanding of the RSV replication machinery, highlighting the potential of targeting P for antiviral therapy.</p>","PeriodicalId":17583,"journal":{"name":"Journal of Virology","volume":" ","pages":"e0099625"},"PeriodicalIF":3.8,"publicationDate":"2025-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145137907","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 novel ZIKV-targeted scRNA-seq method for precise quantification of ZIKV RNA.","authors":"Yang Zhou, Libo Liu, Wei Yang, Yanhua Wu, Chongyao Zhong, Yuxuan Liu, Kunqi Lin, Dongying Fan, Yisong Wang, Peigang Wang, Jing An","doi":"10.1128/jvi.01114-25","DOIUrl":"https://doi.org/10.1128/jvi.01114-25","url":null,"abstract":"<p><p>Zika virus (ZIKV), transmitted by mosquitoes, poses a serious public health threat. Currently, precise quantitative diagnostic methods are lacking. Existing single-cell RNA-sequencing (scRNA-seq) techniques are challenged to detect ZIKV RNA due to its absence of a poly(A) tail, hindering the identification of infected cells. In this study, we developed a novel ZIKV-targeted scRNA-seq method that enables precise quantification of ZIKV RNA in individual cells. Immunocompetent suckling mice were intracerebrally infected with ZIKV to establish persistent infection in the brain. Samples were collected at 10-day post infection for ZIKV-targeted and 10× Genomics scRNA-seq analysis. Comparative analysis identified 17 distinct cell types in both ZIKV-infected and control suckling mouse brains, with significant changes in cell type distribution and proportion post-infection. The ZIKV-targeted scRNA-seq method suggested higher efficiency in capturing exogenous cells compared to the 10× Genomics scRNA-seq method. Both methods identified multiple endogenous and exogenous cell types susceptible to ZIKV, with peripheral blood-derived monocytes/macrophages (PBDMMs), neurons, and T cells as primary cell types expressing ZIKV RNA. IFA validated scRNA-seq findings, revealing that neurons and microglia could be infected by ZIKV, with significant reductions in their numbers post-infection. This study presents a novel ZIKV-targeted scRNA-seq that enables accurate quantification of ZIKV RNA within individual cells, identifies key susceptible cell types, and offers advantages in detecting exogenous cells, making it a scalable solution for providing valuable insights into therapeutic and vaccine development.</p><p><strong>Importance: </strong>This study marks the first use of a scRNA-seq method tailored for ZIKV, allowing accurate measurement of ZIKV RNA in individual cells and identification of critical susceptible cell types. A comparative analysis with the 10× Genomics scRNA-seq method highlighted the advantages of ZIKV-targeted scRNA-seq in terms of accuracy and practicality, particularly its superior ability to capture exogenous cells. Beyond ZIKV, this method also helps establish precise quantification of viral RNA at the single-cell level for other viruses by designing target-specific beads based on conserved regions of the viral genome. This advancement is set to greatly enhance studying pathogenesis of ZIKV infection and then significantly contribute to improve prevention and research in therapeutics and vaccines.</p>","PeriodicalId":17583,"journal":{"name":"Journal of Virology","volume":" ","pages":"e0111425"},"PeriodicalIF":3.8,"publicationDate":"2025-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145131150","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":"Variation in virion phosphatidylserine content drives differential GAS6 binding among closely related flaviviruses.","authors":"Lizhou Zhang, Byoung-Shik Shim, Claire Kitzmiller, Young-Chan Kwon, Audrey Stéphanie Richard, Michael Reynolds Farzan, Hyeryun Choe","doi":"10.1128/jvi.01111-25","DOIUrl":"https://doi.org/10.1128/jvi.01111-25","url":null,"abstract":"<p><p>Many enveloped viruses engage phosphatidylserine (PS) receptors to enter cells, a phenomenon known as \"apoptotic mimicry.\" We previously reported that Zika virus (ZIKV), but not closely related West Nile virus (WNV) or dengue virus (DENV), utilized AXL to infect cells because only ZIKV could bind the AXL ligand GAS6, a PS-binding protein. In this study, we investigated the mechanisms underlying the differential ability of these viruses to bind GAS6. Although immature virions expose larger patches of the viral membrane than do mature ones, our data show that virion maturity levels did not contribute to GAS6 binding. Surprisingly, while ZIKV contains PS comparable to cellular membranes, PS on WNV and DENV is markedly reduced. These findings explain why only ZIKV can bind GAS6 and provide insights into a novel mechanism by which closely related flaviviruses differentially utilize cellular entry factors.</p><p><strong>Importance: </strong>Among flaviviruses, Zika virus uniquely causes microcephaly and congenital defects. While no flavivirus-specific entry receptors have been identified, they commonly take advantage of phosphatidylserine (PS) receptors to enter cells. Our previous studies revealed that Zika virus uniquely utilizes AXL, found in immune-privileged sites, such as the brain and placenta, via binding to its ligand, GAS6. Our current study shows that despite being produced from the same cells, the Zika virus has substantially higher PS content than closely related dengue and West Nile viruses, which likely explains the Zika virus's unique ability to bind GAS6. These findings provide insight into how closely related flaviviruses can vary substantially in their use of cellular entry factors, potentially contributing to the distinct diseases they cause.</p>","PeriodicalId":17583,"journal":{"name":"Journal of Virology","volume":" ","pages":"e0111125"},"PeriodicalIF":3.8,"publicationDate":"2025-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145131254","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}