Grass carp reovirus VP56 and VP35 induce formation of viral inclusion bodies for replication.

Viral inclusion bodies (VIBs) are subcellular structures required for efficient viral replication. How type II grass carp reovirus (GCRV-II), the mainly prevalent strain, forms VIBs is unknown. In this study, we found that GCRV-II infection induced punctate VIBs in grass carp ovary (GCO) cells and that non-structural protein 38 (NS38) functioned as a participant in VIB formation. Furthermore, VP56 and VP35 induced VIBs and recruited other viral proteins via the N-terminal of VP56 and the middle domain of VP35. Additionally, we found that the newly synthesized viral RNAs co-localized with VP56 and VP35 in VIBs during infection. Taken together, VP56 and VP35 induce VIB formation and recruit other viral proteins and viral RNAs to the VIBs for viral replication, which helps identify new targets for developing anti-GCRV-II drugs to disrupt viral replication.

Antimicrobial Protein LECT2-b Helps Maintain Gut Microbiota Homeostasis via Selectively Targeting Certain Pathogenic Bacteria.

Antimicrobial peptides/proteins (AMPs) constitute a critical component of gut immunity in animals, protecting the gut from pathogenic bacteria. However, the interactions between AMPs and gut microbiota remain elusive. In this study, we show that leukocyte-derived chemotaxin-2 (LECT2)-b, a recently discovered AMP, helps maintain gut homeostasis in grass carp (Ctenopharyngodon idella), one of the major farmed fish species globally, by directly regulating the gut microbiota. Knockdown of LECT2-b resulted in dysregulation of the gut microbiota. Specifically, LECT2-b deficiency led to the dominance of Proteobacteria, consisting of proinflammatory bacterial species, over Firmicutes, which includes anti-inflammatory bacteria. In addition, the opportunistic pathogenic bacteria genus Aeromonas became the dominant genus replacing the probiotic bacteria Lactobacillus and Bacillus. Further analysis revealed that this effect was due to the direct and selective inhibition of certain pathogenic bacterial species by LECT2-b. Moreover, LECT2-b knockdown promoted biofilm formation by gut microbiota, resulting in tissue damage and inflammation. Importantly, LECT2-b treatment alleviated the negative effects induced by LECT2-b knockdown. These findings highlight the crucial role of LECT2-b in maintaining the gut microbiota homeostasis and mucosal health. Overall, our study provides important data for understanding the roles of AMPs in the regulation of gut homeostasis in animals.

Snakehead vesiculovirus hijacks SH3RF1 for replication via mediating K63-linked ubiquitination at K264 of the phosphoprotein.

Snakehead vesiculovirus (SHVV) is a type of rhabdovirus that causes serious economic losses in snakehead fish culture in China. However, no specific antiviral drugs or vaccines are currently available for SHVV infection. In this study, 4D label-free ubiquitome analysis of SHVV-infected cells revealed dozens of ubiquitinated sites on the five SHVV proteins. We focused on investigating the ubiquitination of phosphoprotein (P), a viral polymerase co-factor involved in viral replication. SHVV-P was proved to be ubiquitinated via K63-linked ubiquitination at lysine 264 (K264). Overexpression of wild-type P, but not its K264R mutant, facilitated SHVV replication, indicating that K264 ubiquitination of the P protein is critical for SHVV replication. RNAi screening of 26 cellular E3 ubiquitin ligases identified five pro-viral factors for SHVV replication, including macrophage erythroblast attacher (MAEA), TNF receptor-associated factor 7 (TRAF7), and SH3 domain-containing ring finger protein 1 (SH3RF1), which interacted with and mediated ubiquitination of SHVV P. TRAF7 and SH3RF1, but not MAEA, mediated K63-linked ubiquitination of SHVV P, while only SH3RF1 mediated K264 ubiquitination of SHVV P. Besides, overexpression of SH3RF1 promoted SHVV replication and maintained the stability of SHVV P. In summary, SH3RF1 mediated K63-linked ubiquitination of SHVV P at K264 to facilitate SHVV replication, providing targets for developing anti-SHVV drugs and live-attenuated SHVV vaccines. Our study provides novel insights into the role of P protein in the replication of single-stranded, negative-sense RNA viruses.

The Effects of the Al and Zr Contents on the Microstructure Evolution of Light-Weight AlxNbTiVZry High Entropy Alloy.

To investigate the comprehensive effects of the Al and Zr element contents on the microstructure evolution of the AlNbTiVZr series light-weight refractory high entropy alloys (HEAs), five samples were studied. Samples with different compositions were designated Al1.5NbTiVZr, Al1.5NbTiVZr0.5, AlNbTiVZr, AlNbTiVZr0.5, and Al0.5NbTiVZr0.5. The results demonstrated that the actual density of the studied HEA samples ranged from 5.291 to 5.826 g·cm-3. The microstructure of these HEAs contains a solid solution phase with a BCC structure and a Laves phase. The Laves phase was further identified as the ZrAlV intermetallic compound by TEM observations. The microstructure of the AlNbTiVZr series HEAs was affected by both the Al and Zr element contents, whereas the Zr element showed a more dominant effect due to Zr atoms occupying the core position of the ZrAlV Laves phase (C14 structure). Therefore, the as-cast Al0.5NbTiVZr0.5 sample exhibits the best room temperature compression property with a compression strength (σp) of 1783 MPa and an engineering strain of 28.8% due to having the lowest ZrAlV intermetallic compound area fraction (0.7%), as characterized by the EBSD technique.

An Atlas of Grass Carp IgM+ B Cells in Homeostasis and Bacterial Infection Helps to Reveal the Unique Heterogeneity of B Cells in Early Vertebrates.

Teleost B cells are primitive lymphocytes with both innate and adaptive immune functions. However, the heterogeneity and differentiation trajectory of teleost B cells remain largely unknown. In this study, the landscape of grass carp IgM+ (gcIgM+) B cells was revealed by single-cell RNA sequencing. The results showed that gcIgM+ B cells mainly comprise six populations: (im)mature B cells, innate B cells, proliferating B cells, plasma cells, CD22+ cells, and CD34+ cells, among which innate B cells and proliferating B cells were uncommon B cell subsets with, to our knowledge, new characteristics. Remarkably, three functional IgMs were discovered in grass carp, and a significant percentage of gcIgM+ B cells, especially plasma cells, expressed multiple Igµ genes (Igµ1, Igµ2, and/or Igµ3). More importantly, through single-cell sorting combined with Sanger sequencing, we found that distinct VHDJH recombination patterns of Igµ genes were present in single IgM+ B cells, indicating that individual teleost B cells might produce multiple Abs by coexpressing rearranged IgM subclass genes. Moreover, the percentage of IgM1highIgM2highIgM3high plasma cells increased significantly after bacterial infection, suggesting that individual plasma cells might tend to produce multiple IgMs to resist the infection in teleost fish. In summary, to our knowledge, this study not only helps to uncover the unique heterogeneity of B cells in early vertebrates but also provided significant new evidence supporting the recently proposed "one cell-multiple Abs" paradigm, challenging the classical rule of "one cell-one Ab."

Characterization and application of a lytic jumbo phage ZPAH34 against multidrug-resistant Aeromonas hydrophila.

Aeromonas hydrophila is an emerging foodborne pathogen causing human gastroenteritis. Aeromonas species isolated from food such as seafood presented multidrug-resistance (MDR), raising serious concerns regarding food safety and public health. The use of phages to infect bacteria is a defense against drug-resistant pathogens. In this study, phage ZPAH34 isolated from the lake sample exerted lytic activity against MDR A. hydrophila strain ZYAH75 and inhibited the biofilm on different food-contacting surfaces. ZPAH34 has a large dsDNA genome of 234 kb which belongs to a novel jumbo phage. However, its particle size is the smallest of known jumbo phages so far. Based on phylogenetic analysis, ZPAH34 was used to establish a new genus Chaoshanvirus. Biological characterization revealed that ZPAH34 exhibited wide environmental tolerance, and a high rapid adsorb and reproductive capacity. Food biocontrol experiments demonstrated that ZPAH34 reduces the viable count of A. hydrophila on fish fillets (2.31 log) and lettuce (3.28 log) with potential bactericidal effects. This study isolated and characterized jumbo phage ZPAH34 not only enriched the understanding of phage biological entity diversity and evolution because of its minimal virion size with large genome but also was the first usage of jumbo phage in food safety to eliminate A. hydrophila.

Correction: An aquatic virus exploits the IL6-STAT3-HSP90 signaling axis to promote viral entry.

[This corrects the article DOI: 10.1371/journal.ppat.1011320.].

p38MAPK- and GSK3-Mediated Phosphorylation of Snakehead Vesiculovirus Phosphoprotein at Threonine 160 Facilitates Viral Replication.

Phosphoprotein (P), co-factor of the polymerase (large protein, L) of single-stranded negative-sense RNA viruses, is phosphorylated during viral infection and its phosphorylation has been reported to play important roles in viral replication. However, the function of P phosphorylation in viral replication is still far from clear. Snakehead vesiculovirus (SHVV) is a kind of fish rhabdovirus that has caused serious economic losses in snakehead fish culture in China without any effective preventive or therapeutical measures currently. In this study, 4D label-free phosphoproteomics sequencing of SHVV-infected cells identified five phosphorylated sites on SHVV P, among which threonine 160 (T160) was proved to be phosphorylated. Overexpression of wild-type P, but not P-T160A or P-T160E mutant, promoted SHVV replication, suggesting that the T160 phosphorylation on the P protein is critical for SHVV replication. Moreover, we found that T160A or T160E mutation on SHVV P had no effect on the interactions of P-nucleoprotein (N), P-P, or P-L. Further study revealed that p38 mitogen-activated protein kinase (p38MAPK) and glycogen synthase kinase 3 (GSK3) interacted with SHVV P and mediated the T160 phosphorylation. Besides, overexpression of p38MAPK or GSK3 facilitated, while knockdown or activity inhibition of p38MAPK or GSK3 suppressed, SHVV replication. Overall, p38MAPK- and GSK3-mediated phosphorylation of the P protein at T160 is required for SHVV replication, which provided targets for designing anti-SHVV drugs and developing live-attenuated SHVV vaccines. Our study helps understand the role of P phosphorylation in the replication of single-stranded negative-sense RNA viruses. IMPORTANCE Phosphorylation of viral proteins plays important roles in viral replication. Currently, the role of phosphorylation of phosphoprotein (P) in the replication of single-stranded negative-sense RNA viruses is far from clear. Identification of the phosphorylated sites on viral P protein and the related host kinases is helpful for developing live-attenuated vaccines and designing antiviral drugs. This study focused on identifying the phosphorylated sites on P protein of a fish rhabdovirus SHVV, determining the related host kinases, and revealing the effects of the phosphorylated sites and kinases on SHVV replication. We found that SHVV P was phosphorylated at T160, which was mediated by the kinases p38MAPK and GSK3 to promote SHVV replication. This study is the first time to study the role of P phosphorylation in fish rhabdovirus replication.

An Aquareovirus Exploits Membrane-Anchored HSP70 To Promote Viral Entry.

Temperature dependency of viral diseases in ectotherms has been an important scientific issue for decades, while the molecular mechanism behind this phenomenon remains largely mysterious. In this study, deploying infection with grass carp reovirus (GCRV), a double-stranded RNA aquareovirus, as a model system, we demonstrated that the cross talk between HSP70 and outer capsid protein VP7 of GCRV determines temperature-dependent viral entry. Multitranscriptomic analysis identified HSP70 as a key player in the temperature-dependent pathogenesis of GCRV infection. Further biochemical, small interfering RNA (siRNA) knockdown, pharmacological inhibition, and microscopic approaches revealed that the primary plasma membrane-anchored HSP70 interacts with VP7 to facilitate viral entry during the early phase of GCRV infection. Moreover, VP7 functions as a key coordinator protein to interact with multiple housekeeping proteins and regulate receptor gene expression, concomitantly facilitating viral entry. This work illuminates a previously unidentified immune evasion mechanism by which an aquatic virus hijacks heat shock response-related proteins to enhance viral entry, pinpointing targeted preventives and therapeutics for aquatic viral diseases. IMPORTANCE The seasonality of viral diseases in ectotherms is a prevailing phenomenon in the aquatic environment, which causes huge economic losses every year worldwide and hinders sustainable development of the aquaculture industry. Nevertheless, our understanding of the molecular mechanism of how temperature determines the pathogenesis of aquatic viruses remains largely unexplored. In this study, by deploying grass carp reovirus (GCRV) infection as a model system, we demonstrated that temperature-dependent, primarily membrane-localized HSP70 interacts with major outer capsid protein VP7 of GCRV to bridge the virus-host interaction, reshape the host's behaviors, and concomitantly facilitate viral entry. Our work unveils a central role of HSP70 in the temperature-dependent pathogenesis of aquatic viruses and provides a theoretical basis for the formulation of prevention and control strategies for aquatic viral diseases.

An aquatic virus exploits the IL6-STAT3-HSP90 signaling axis to promote viral entry.

Viral seasonality in the aquaculture industry is an important scientific issue for decades. While the molecular mechanisms underpinning the temperature-dependent pathogenesis of aquatic viral diseases remain largely unknown. Here we report that temperature-dependent activation of IL6-STAT3 signaling was exploited by grass carp reovirus (GCRV) to promote viral entry via increasing the expression of heat shock protein 90 (HSP90). Deploying GCRV infection as a model system, we discovered that GCRV induces the IL6-STAT3-HSP90 signaling activation to achieve temperature-dependent viral entry. Further biochemical and microscopic analyses revealed that the major capsid protein VP7 of GCRV interacted with HSP90 and relevant membrane-associated proteins to boost viral entry. Accordingly, exogenous expression of either IL6, HSP90, or VP7 in cells increased GCRV entry in a dose-dependent manner. Interestingly, other viruses (e.g., koi herpesvirus, Rhabdovirus carpio, Chinese giant salamander iridovirus) infecting ectothermic vertebrates have evolved a similar mechanism to promote their infection. This work delineates a molecular mechanism by which an aquatic viral pathogen exploits the host temperature-related immune response to promote its entry and replication, instructing us on new ways to develop targeted preventives and therapeutics for aquaculture viral diseases.

hnRNPA1 impedes snakehead vesiculovirus replication via competitively disrupting viral phosphoprotein-nucleoprotein interaction and degrading viral phosphoprotein.

Heterogeneous nuclear ribonucleoprotein A1 (hnRNPA1) plays an important role in regulating the replication of many viruses. However, it remains elusive whether and how hnRNPA1 regulates fish virus replication. In this study, the effects of twelve hnRNPs on the replication of snakehead vesiculovirus (SHVV) were screened. Three hnRNPs, one of which was hnRNPA1, were identified as anti-SHVV factors. Further verification showed that knockdown of hnRNPA1 promoted, while overexpression of hnRNPA1 inhibited, SHVV replication. SHVV infection reduced the expression level of hnRNPA1 and induced the nucleocytoplasmic shuttling of hnRNPA1. Besides, we found that hnRNPA1 interacted with the viral phosphoprotein (P) via its glycine-rich domain, but not with the viral nucleoprotein (N) or large protein (L). The hnRNPA1-P interaction competitively disrupted the viral P-N interaction. Moreover, we found that overexpression of hnRNPA1 enhanced the polyubiquitination of the P protein and degraded it through proteasomal and lysosomal pathways. This study will help understanding the function of hnRNPA1 in the replication of single-stranded negative-sense RNA viruses and providing a novel antiviral target against fish rhabdoviruses.

Structure of the Spring Viraemia of Carp Virus Ribonucleoprotein Complex Reveals Its Assembly Mechanism and Application in Antiviral Drug Screening.

Spring viremia of carp virus (SVCV) is a highly pathogenic Vesiculovirus infecting the common carp, yet neither a vaccine nor effective therapies are available to treat spring viremia of carp (SVC). Like all negative-sense viruses, SVCV contains an RNA genome that is encapsidated by the nucleoprotein (N) in the form of a ribonucleoprotein (RNP) complex, which serves as the template for viral replication and transcription. Here, the three-dimensional (3D) structure of SVCV RNP was resolved through cryo-electron microscopy (cryo-EM) at a resolution of 3.7 Å. RNP assembly was stabilized by N and C loops; RNA was wrapped in the groove between the N and C lobes with 9 nt nucleotide per protomer. Combined with mutational analysis, our results elucidated the mechanism of RNP formation. The RNA binding groove of SVCV N was used as a target for drug virtual screening, and it was found suramin had a good antiviral effect. This study provided insights into RNP assembly, and anti-SVCV drug screening was performed on the basis of this structure, providing a theoretical basis and efficient drug screening method for the prevention and treatment of SVC. IMPORTANCE Aquaculture accounts for about 70% of global aquatic products, and viral diseases severely harm the development of aquaculture industry. Spring viremia of carp virus (SVCV) is the pathogen causing highly contagious spring viremia of carp (SVC) disease in cyprinids, especially common carp (Cyprinus carpio), yet neither a vaccine nor effective therapies are available to treat this disease. In this study, we have elucidated the mechanism of SVCV ribonucleoprotein complex (RNP) formation by resolving the 3D structure of SVCV RNP and screened antiviral drugs based on the structure. It is found that suramin could competitively bind to the RNA binding groove and has good antiviral effects both in vivo and in vitro. Our study provides a template for rational drug discovery efforts to treat and prevent SVCV infections.

Preparation of the monoclonal antibody against Nile tilapia Igλ and study on the Igλ+ B cell subset in Nile tilapia.

Immunoglobulins (Igs) are important effector molecules that mediate humoral immunity. A typical Ig consists of two heavy and two light chains. In teleosts, three Ig heavy chain isotypes (Igµ, Igδ and Igτ) and three Ig light chain isotypes (Igκ, Igλ and Igσ) have been identified. Compared to the heavy chains, teleost Ig light chains have been poorly studied due to the lack of antibodies. In this study, a mouse anti-Nile tilapia Igλ monoclonal antibody (mAb) was prepared, which could specifically recognize Igλ in serum and Igλ+ B cells in tissues. Further, the composition of IgM+ and Igλ+ B cell subsets was analyzed using this antibody and a mouse anti-tilapia IgM heavy chain mAb. The ratio of IgM+Igλ+ B cells to total IgM+ B cells in head kidney and peripheral blood was about 30%, while that in spleen was about 50%; the ratio of IgM-Igλ+ B cells to total Igλ+ B cells in head kidney and peripheral blood was about 45%, while that in spleen was about 25%. The IgM-Igλ+ B cells was speculated to be IgT+ B cells. Finally, we detected an increase in the level of specific antibodies against the surface antigen-Sip of Streptococcus agalactiae in serum after S. agalactiae infection, indicating that mouse anti-tilapia Igλ mAb can be used to detect the antibody level after immunization of Nile tilapia, which lays a foundation for the evaluation of immunization effect of tilapia vaccine.

Influence of Material Removal Strategy on Machining Deformation of Aluminum Plates with Asymmetric Residual Stresses.

In this paper, the effects of material removal strategies and initial stress states on the machining deformation of aluminum alloy plates were investigated through a combination of finite element simulation and experiments. We developed different machining strategies described by Tm+Bn, which removal m mm materials form top and n mm materials from the bottom of the plate. The results demonstrate that the maximum deformation of structural components with the T10+B0 machining strategy could reach 1.94 mm, whereas with the T3+B7 machining strategy was only 0.065 mm, decreasing by more than 95%. The asymmetric initial stress state had a significant impact on the machining deformation of the thick plate. The machined deformation of thick plates increased with the increase in the initial stress state. The concavity of the thick plates changed with the T3+B7 machining strategy due to the asymmetry of the stress level. The deformation of frame parts was smaller when the frame opening was facing the high-stress level surface during machining than when it was facing the low-stress level. Moreover, the modeling results for the stress state and machining deformation were accurate and in good accordance with the experimental findings.

Comparative study on antibacterial characteristics of the multiple liver expressed antimicrobial peptides (LEAPs) in teleost fish.

Antimicrobial peptides are important components of the host innate immune system, forming the first line of defense against infectious microorganisms. Among them, liver-expressed antimicrobial peptides (LEAPs) are a family of antimicrobial peptides that widely exist in vertebrates. LEAPs include two types, named LEAP-1 and LEAP-2, and many teleost fish have two or more LEAP-2s. In this study, LEAP-2C from rainbow trout and grass carp were discovered, both of which are composed of 3 exons and 2 introns. The antibacterial functions of the multiple LEAPs were systematically compared in rainbow trout and grass carp. The gene expression pattern revealed that rainbow trout and grass carp LEAP-1, LEAP-2A, LEAP-2B and/or LEAP-2C were differentially expressed in various tissues/organs, mainly in liver. After bacterial infection, the expression levels of LEAP-1, LEAP-2A, LEAP-2B and/or LEAP-2C in the liver and gut of rainbow trout and grass carp increased to varying degrees. Moreover, the antibacterial assay and bacterial membrane permeability assay showed that rainbow trout and grass carp LEAP-1, LEAP-2A, LEAP-2B and LEAP-2C all have antibacterial activities against a variety of Gram-positive and Gram-negative bacteria with varying levels through membrane rupture. Furthermore, cell transfection assay showed that only rainbow trout LEAP-1, but not LEAP-2, can lead to the internalization of ferroportin, the only iron exporter on cell surface, indicating that only LEAP-1 possess iron metabolism regulation activity in teleost fish. Taken together, this study systematically compared the antibacterial function of LEAPs in teleost fish and the results suggest that multiple LEAPs can enhance the immunity of teleost fish through different expression patterns and different antibacterial activities to various bacteria.

Omics analysis of Mycobacterium tuberculosis isolates uncovers Rv3094c, an ethionamide metabolism-associated gene.

Global control of the tuberculosis epidemic is threatened by increasing prevalence of drug resistant M. tuberculosis isolates. Many genome-wide studies focus on SNP-associated drug resistance mechanisms, but drug resistance in 5-30% of M. tuberculosis isolates (varying with antibiotic) appears unrelated to reported SNPs, and alternative drug resistance mechanisms involving variation in gene/protein expression are not well-studied. Here, using an omics approach, we identify 388 genes with lineage-related differential expression and 68 candidate drug resistance-associated gene pairs/clusters in 11 M. tuberculosis isolates (variable lineage/drug resistance profiles). Structural, mutagenesis, biochemical and bioinformatic studies on Rv3094c from the Rv3093c-Rv3095 gene cluster, a gene cluster selected for further investigation as it contains a putative monooxygenase/repressor pair and is associated with ethionamide resistance, provide insights on its involvement in ethionamide sulfoxidation, the initial step in its activation. Analysis of the structure of Rv3094c and its complex with ethionamide and flavin mononucleotide, to the best of our knowledge the first structures of an enzyme involved in ethionamide activation, identify key residues in the flavin mononucleotide and ethionamide binding pockets of Rv3094c, and F221, a gate between flavin mononucleotide and ethionamide allowing their interaction to complete the sulfoxidation reaction. Our work broadens understanding of both lineage- and drug resistance-associated gene/protein expression perturbations and identifies another player in mycobacterial ethionamide metabolism.

DDX3X Is Hijacked by Snakehead Vesiculovirus Phosphoprotein To Facilitate Virus Replication via Stabilization of the Phosphoprotein.

Asp-Glu-Ala-Asp (DEAD) box helicase 3 X-linked (DDX3X) plays important regulatory roles in the replication of many viruses. However, the role of DDX3X in rhabdovirus replication has seldomly been investigated. In this study, snakehead vesiculovirus (SHVV), a kind of fish rhabdovirus, was used to study the role of DDX3X in rhabdovirus replication. DDX3X was identified as an interacting partner of SHVV phosphoprotein (P). The expression level of DDX3X was increased at an early stage of SHVV infection and then decreased to a normal level at a later infection stage. Overexpression of DDX3X promoted, while knockdown of DDX3X using specific small interfering RNAs (siRNAs) suppressed, SHVV replication, indicating that DDX3X was a proviral factor for SHVV replication. The N-terminal and core domains of DDX3X (DDX3X-N and DDX3X-Core) were determined to be the regions responsible for its interaction with SHVV P. Overexpression of DDX3X-Core suppressed SHVV replication by competitively disrupting the interaction between full-length DDX3X and SHVV P, suggesting that full-length DDX3X-P interaction was required for SHVV replication. Mechanistically, DDX3X-mediated promotion of SHVV replication was due not to inhibition of interferon expression but to maintenance of the stability of SHVV P to avoid autophagy-lysosome-dependent degradation. Collectively, our data suggest that DDX3X is hijacked by SHVV P to ensure effective replication of SHVV, which suggests an important anti-SHVV target. This study will help elucidate the role of DDX3X in regulating the replication of rhabdoviruses. IMPORTANCE Growing evidence has suggested that DDX3X plays important roles in virus replication. In one respect, DDX3X inhibits the replication of viruses, including hepatitis B virus, influenza A virus, Newcastle disease virus, duck Tembusu virus, and red-spotted grouper nervous necrosis virus. In another respect, DDX3X is required for the replication of viruses, including hepatitis C virus, Japanese encephalitis virus, West Nile virus, murine norovirus, herpes simplex virus, and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Because DDX3X has rarely been investigated in rhabdovirus replication, this study aimed at investigating the role of DDX3X in rhabdovirus replication by using the fish rhabdovirus SHVV as a model. We found that DDX3X was required for SHVV replication, with the mechanism that DDX3X interacts with and maintains the stability of SHVV phosphoprotein. Our data provide novel insights into the role of DDX3X in virus replication and will facilitate the design of antiviral drugs against rhabdovirus infection.

Single-cell transcriptome landscape and antigen receptor dynamic during SARS-CoV-2 vaccination.

Vaccination by inactivated vaccine is an effective strategy to prevent the COVID-19 pandemic. However, the detailed molecular immune response at single-cell level is poorly understood. In this study, we systematically delineated the landscape of the pre- and post-vaccination single-cell transcriptome, TCR (T cell antigen receptor) and BCR (B cell antigen receptor) expression profile of vaccinated candidates. The bulk TCR sequencing analysis of COVID-19 patients was also performed. Enrichment of a clonal CD8+ T cell cluster expressing specific TCR was identified in both vaccination candidates and COVID-19 patients. These clonal CD8+ T cells showed high expression of cytotoxicity, phagosome and antigen presentation related genes. The cell-cell interaction analysis revealed that monocytes and dendritic cells could interact with these cells and initiate phagocytosis via ICAM1-ITGAM and ITGB2 signaling. Together, our study systematically deciphered the detailed immunological response during SARS-CoV-2 vaccination and infection. It may facilitate understanding the immune response and the T-cell therapy against COVID-19.