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Uribe FR, González VPI, Kalergis AM, Soto JA, Bohmwald K. Understanding the Neurotrophic Virus Mechanisms and Their Potential Effect on Systemic Lupus Erythematosus Development. Brain Sci 2024; 14:59. [PMID: 38248274 PMCID: PMC10813552 DOI: 10.3390/brainsci14010059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2023] [Revised: 12/24/2023] [Accepted: 01/03/2024] [Indexed: 01/23/2024] Open
Abstract
Central nervous system (CNS) pathologies are a public health concern, with viral infections one of their principal causes. These viruses are known as neurotropic pathogens, characterized by their ability to infiltrate the CNS and thus interact with various cell populations, inducing several diseases. The immune response elicited by neurotropic viruses in the CNS is commanded mainly by microglia, which, together with other local cells, can secrete inflammatory cytokines to fight the infection. The most relevant neurotropic viruses are adenovirus (AdV), cytomegalovirus (CMV), enterovirus (EV), Epstein-Barr Virus (EBV), herpes simplex virus type 1 (HSV-1), and herpes simplex virus type 2 (HSV-2), lymphocytic choriomeningitis virus (LCMV), and the newly discovered SARS-CoV-2. Several studies have associated a viral infection with systemic lupus erythematosus (SLE) and neuropsychiatric lupus (NPSLE) manifestations. This article will review the knowledge about viral infections, CNS pathologies, and the immune response against them. Also, it allows us to understand the relevance of the different viral proteins in developing neuronal pathologies, SLE and NPSLE.
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Affiliation(s)
- Felipe R. Uribe
- Millennium Institute on Immunology and Immunotherapy, Laboratorio de Inmunología Traslacional, Departamento de Ciencias Biológicas, Facultad de Ciencias de la Vida, Universidad Andrés Bello, Santiago 8370146, Chile; (F.R.U.); (V.P.I.G.)
| | - Valentina P. I. González
- Millennium Institute on Immunology and Immunotherapy, Laboratorio de Inmunología Traslacional, Departamento de Ciencias Biológicas, Facultad de Ciencias de la Vida, Universidad Andrés Bello, Santiago 8370146, Chile; (F.R.U.); (V.P.I.G.)
| | - Alexis M. Kalergis
- Millennium Institute on Immunology and Immunotherapy, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago 8330025, Chile;
- Departamento de Endocrinología, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago 8331150, Chile
| | - Jorge A. Soto
- Millennium Institute on Immunology and Immunotherapy, Laboratorio de Inmunología Traslacional, Departamento de Ciencias Biológicas, Facultad de Ciencias de la Vida, Universidad Andrés Bello, Santiago 8370146, Chile; (F.R.U.); (V.P.I.G.)
| | - Karen Bohmwald
- Instituto de Ciencias Biomédicas, Facultad de Ciencias de la Salud, Universidad Autónoma, Santiago 8910060, Chile
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Abstract
A critical step in the life cycle of a virus is spread to a new target cell, which generally involves the release of new viral particles from the infected cell which can then initiate infection in the next target cell. While cell-free viral particles released into the extracellular environment are necessary for long distance spread, there are disadvantages to this mechanism. These include the presence of immune system components, the low success rate of infection by single particles, and the relative fragility of viral particles in the environment. Several mechanisms of direct cell-to-cell spread have been reported for animal viruses which would avoid the issues associated with cell-free particles. A number of viruses can utilize several different mechanisms of direct cell-to-cell spread, but our understanding of the differential usage by these pathogens is modest. Although the mechanisms of cell-to-cell spread differ among viruses, there is a common exploitation of key pathways and components of the cellular cytoskeleton. Remarkably, some of the viral mechanisms of cell-to-cell spread are surprisingly similar to those used by bacteria. Here we summarize the current knowledge of the conventional and non-conventional mechanisms of viral spread, the common methods used to detect viral spread, and the impact that these mechanisms can have on viral pathogenesis.
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Affiliation(s)
- Nicolas Cifuentes-Munoz
- Instituto de Ciencias Biomédicas, Facultad de Ciencias de la Salud, Universidad Autónoma de Chile, San Miguel, Santiago, Chile
| | - Farah El Najjar
- Department of Molecular and Cellular Biochemistry, University of Kentucky College of Medicine, Lexington, KY, United States
| | - Rebecca Ellis Dutch
- Department of Molecular and Cellular Biochemistry, University of Kentucky College of Medicine, Lexington, KY, United States.
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Fabianova A, Barathova M, Csaderova L, Simko V, Zatovicova M, Labudova M, Pastorek J. Hypoxic marker CA IX and adhesion mediator β-catenin are downregulated by lymphocytic choriomeningitis virus persistent infection. Oncotarget 2018; 9:12879-12893. [PMID: 29560117 PMCID: PMC5849181 DOI: 10.18632/oncotarget.24387] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Accepted: 01/25/2018] [Indexed: 11/25/2022] Open
Abstract
Renal cell carcinoma is one of the most frequent cancer diseases with high resistance to radio- and chemotherapy. Mutation of VHL gene is frequent in these tumors leading to simulation of hypoxic conditions. Lymphocytic choriomeningitis virus, belonging to RNA viruses, is a neglected human pathogen and teratogen. We have found that infection of renal cell carcinoma cells by lymphocytic choriomeningitis virus strain MX causes a decrease of carbonic anhydrase IX protein and RNA level. Lower expression of carbonic anhydrase IX on the cell surface provides less target for carbonic anhydrase IX-targeted immunotherapy. What more, reduced levels of adhesion mediating protein β-catenin as well as E-cadherin, as a consequence of infection, suggest a possible increase in metastatic potential of cells infected by lymphocytic choriomeningitis virus strain MX. These results might help elucidate differences in patients susceptibility to immunotherapy directed against carbonic anhydrase IX or in developing new therapeutical strategies. Our data indicate that presence of infection can significantly affect patient response to cancer therapy.
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Affiliation(s)
- Andrea Fabianova
- Institute of Virology, Biomedical Research Center, Slovak Academy of Sciences, Bratislava 845 05, Slovak Republic
| | - Monika Barathova
- Institute of Virology, Biomedical Research Center, Slovak Academy of Sciences, Bratislava 845 05, Slovak Republic
| | - Lucia Csaderova
- Institute of Virology, Biomedical Research Center, Slovak Academy of Sciences, Bratislava 845 05, Slovak Republic
| | - Veronika Simko
- Institute of Virology, Biomedical Research Center, Slovak Academy of Sciences, Bratislava 845 05, Slovak Republic
| | - Miriam Zatovicova
- Institute of Virology, Biomedical Research Center, Slovak Academy of Sciences, Bratislava 845 05, Slovak Republic
| | - Martina Labudova
- Institute of Virology, Biomedical Research Center, Slovak Academy of Sciences, Bratislava 845 05, Slovak Republic
| | - Jaromir Pastorek
- Institute of Virology, Biomedical Research Center, Slovak Academy of Sciences, Bratislava 845 05, Slovak Republic.,Department of Chemistry, Faculty of Natural Sciences, University of SS. Cyril and Methodius, Trnava 917 01, Slovak Republic
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A Map of the Arenavirus Nucleoprotein-Host Protein Interactome Reveals that Junín Virus Selectively Impairs the Antiviral Activity of Double-Stranded RNA-Activated Protein Kinase (PKR). J Virol 2017; 91:JVI.00763-17. [PMID: 28539447 DOI: 10.1128/jvi.00763-17] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Accepted: 05/12/2017] [Indexed: 11/20/2022] Open
Abstract
Arenaviruses are enveloped negative-strand RNA viruses that cause significant human disease. These viruses encode only four proteins to accomplish the viral life cycle, so each arenavirus protein likely plays unappreciated accessory roles during infection. Here we used immunoprecipitation and mass spectrometry to identify human proteins that interact with the nucleoproteins (NPs) of the Old World arenavirus lymphocytic choriomeningitis virus (LCMV) and the New World arenavirus Junín virus (JUNV) strain Candid #1. Bioinformatic analysis of the identified protein partners of NP revealed that host translation appears to be a key biological process engaged during infection. In particular, NP associates with the double-stranded RNA (dsRNA)-activated protein kinase (PKR), a well-characterized antiviral protein that inhibits cap-dependent protein translation initiation via phosphorylation of eIF2α. JUNV infection leads to increased expression of PKR as well as its redistribution to viral replication and transcription factories. Further, phosphorylation of PKR, which is a prerequisite for its ability to phosphorylate eIF2α, is readily induced by JUNV. However, JUNV prevents this pool of activated PKR from phosphorylating eIF2α, even following exposure to the synthetic dsRNA poly(I·C), a potent PKR agonist. This blockade of PKR function is highly specific, as LCMV is unable to similarly inhibit eIF2α phosphorylation. JUNV's ability to antagonize the antiviral activity of PKR appears to be complete, as silencing of PKR expression has no impact on viral propagation. In summary, we provide a detailed map of the host machinery engaged by arenavirus NPs and identify an antiviral pathway that is subverted by JUNV.IMPORTANCE Arenaviruses are important human pathogens for which FDA-approved vaccines do not exist and effective antiviral therapeutics are needed. Design of antiviral treatment options and elucidation of the mechanistic basis of disease pathogenesis will depend on an increased basic understanding of these viruses and, in particular, their interactions with the host cell machinery. Identifying host proteins critical for the viral life cycle and/or pathogenesis represents a useful strategy to uncover new drug targets. This study reveals, for the first time, the extensive human protein interactome of arenavirus nucleoproteins and uncovers a potent antiviral host protein that is neutralized during Junín virus infection. In so doing, it shows further insight into the interplay between the virus and the host innate immune response and provides an important data set for the field.
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Vidotto A, Morais ATS, Ribeiro MR, Pacca CC, Terzian ACB, Gil LHVG, Mohana-Borges R, Gallay P, Nogueira ML. Systems Biology Reveals NS4B-Cyclophilin A Interaction: A New Target to Inhibit YFV Replication. J Proteome Res 2017; 16:1542-1555. [PMID: 28317380 DOI: 10.1021/acs.jproteome.6b00933] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Yellow fever virus (YFV) replication is highly dependent on host cell factors. YFV NS4B is reported to be involved in viral replication and immune evasion. Here interactions between NS4B and human proteins were determined using a GST pull-down assay and analyzed using 1-DE and LC-MS/MS. We present a total of 207 proteins confirmed using Scaffold 3 Software. Cyclophilin A (CypA), a protein that has been shown to be necessary for the positive regulation of flavivirus replication, was identified as a possible NS4B partner. 59 proteins were found to be significantly increased when compared with a negative control, and CypA exhibited the greatest difference, with a 22-fold change. Fisher's exact test was significant for 58 proteins, and the p value of CypA was the most significant (0.000000019). The Ingenuity Systems software identified 16 pathways, and this analysis indicated sirolimus, an mTOR pathway inhibitor, as a potential inhibitor of CypA. Immunofluorescence and viral plaque assays showed a significant reduction in YFV replication using sirolimus and cyclosporine A (CsA) as inhibitors. Furthermore, YFV replication was strongly inhibited in cells treated with both inhibitors using reporter BHK-21-rep-YFV17D-LucNeoIres cells. Taken together, these data suggest that CypA-NS4B interaction regulates YFV replication. Finally, we present the first evidence that YFV inhibition may depend on NS4B-CypA interaction.
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Affiliation(s)
- Alessandra Vidotto
- Laboratório de Virologia, Faculdade de Medicina de José do Rio Preto , São José do Rio Preto, São Paulo 15090-000, Brazil
| | - Ana T S Morais
- Laboratório de Virologia, Faculdade de Medicina de José do Rio Preto , São José do Rio Preto, São Paulo 15090-000, Brazil
| | - Milene R Ribeiro
- Laboratório de Virologia, Faculdade de Medicina de José do Rio Preto , São José do Rio Preto, São Paulo 15090-000, Brazil
| | - Carolina C Pacca
- Laboratório de Virologia, Faculdade de Medicina de José do Rio Preto , São José do Rio Preto, São Paulo 15090-000, Brazil
| | - Ana C B Terzian
- Laboratório de Virologia, Faculdade de Medicina de José do Rio Preto , São José do Rio Preto, São Paulo 15090-000, Brazil
| | - Laura H V G Gil
- Departamento de Virologia, Centro de Pesquisa Aggeu Magalhães , Fundação Oswaldo Cruz (FIOCRUZ) - Recife, Pernambuco 50740-465, Brazil
| | - Ronaldo Mohana-Borges
- Laboratório de Genômica Estrutural, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro - UFRJ , Rio de Janeiro RJ 21941-902, Brazil
| | - Philippe Gallay
- Department of Immunology & Microbial Science, The Scripps Research Institute - La Jolla , San Diego, California 92037, United States
| | - Mauricio L Nogueira
- Laboratório de Virologia, Faculdade de Medicina de José do Rio Preto , São José do Rio Preto, São Paulo 15090-000, Brazil
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Han M, Fan L, Qin Z, Lavingia B, Stastny P. Alleles of keratin 1 in families and populations. Hum Immunol 2013; 74:1453-8. [DOI: 10.1016/j.humimm.2013.05.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2013] [Revised: 05/02/2013] [Accepted: 05/15/2013] [Indexed: 11/16/2022]
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Zhu C, Bai Y, Liu Q, Li D, Hong J, Yang Z, Cui L, Hua X, Yuan C. Depolymerization of cytokeratin intermediate filaments facilitates intracellular infection of HeLa cells by Bartonella henselae. J Infect Dis 2013; 207:1397-405. [PMID: 23359593 DOI: 10.1093/infdis/jit040] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Bartonella henselae is capable of invading epithelial and endothelial cells by modulating the function of actin-dependent cytoskeleton proteins. Although understanding of the pathogenesis has been increased by the development of an in vitro infection model involving endothelial cells, little is known about the mechanism of interaction between B. henselae and epithelial cells. This study aims to identify the binding candidates of B. henselae in epithelial cells and explores their effect on B. henselae infection. Pull-down assays and mass spectrometry analysis confirmed that some of the binding proteins (keratin 14, keratin 6, and F-actin) are cytoskeleton associated. B. henselae infection significantly induces the expression of the cytokeratin genes. Chemical disruption of the keratin network by using ethylene glycol tetraacetic acid promotes the intracellular persistence of B. henselae in HeLa cells. However, cytochalasin B and phalloidin treatment inhibits B. henselae invasion. Immunofluorescent staining demonstrates that B. henselae infection induces an F-actin-dependent rearrangement of the cytoskeleton. However, we demonstrated via immunofluorescent staining and whole-mount cell electron microscopy that keratin intermediate filaments are depolymerized by B. henselae. The results indicate that B. henselae achieves an intracellular persistence in epithelial cells through the depolymerization of cytokeratin intermediate filaments that are protective against B. henselae invasion.
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Affiliation(s)
- Caixia Zhu
- School of Agriculture and Biology, Shanghai Jiaotong University, Beijing, People's Republic of China
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Droniou-Bonzom ME, Cannon PM. A systems biology starter kit for arenaviruses. Viruses 2012; 4:3625-46. [PMID: 23342371 PMCID: PMC3528283 DOI: 10.3390/v4123625] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2012] [Revised: 11/28/2012] [Accepted: 12/05/2012] [Indexed: 12/05/2022] Open
Abstract
Systems biology approaches in virology aim to integrate viral and host biological networks, and thus model the infection process. The growing availability of high-throughput “-omics” techniques and datasets, as well as the ever-increasing sophistication of in silico modeling tools, has resulted in a corresponding rise in the complexity of the analyses that can be performed. The present study seeks to review and organize published evidence regarding virus-host interactions for the arenaviruses, from alterations in the host proteome during infection, to reported protein-protein interactions. In this way, we hope to provide an overview of the interplay between arenaviruses and the host cell, and lay the foundations for complementing current arenavirus research with a systems-level approach.
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Affiliation(s)
- Magali E Droniou-Bonzom
- Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, 2011 Zonal Avenue, Los Angeles, CA 90033, USA.
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Korns Johnson D, Homann D. Accelerated and improved quantification of lymphocytic choriomeningitis virus (LCMV) titers by flow cytometry. PLoS One 2012; 7:e37337. [PMID: 22615984 PMCID: PMC3355137 DOI: 10.1371/journal.pone.0037337] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2012] [Accepted: 04/20/2012] [Indexed: 01/06/2023] Open
Abstract
Lymphocytic choriomeningitis virus (LCMV), a natural murine pathogen, is a member of the Arenavirus family, may cause atypical meningitis in humans, and has been utilized extensively as a model pathogen for the study of virus-induced disease and immune responses. Historically, viral titers have been quantified by a standard plaque assay, but for non-cytopathic viruses including LCMV this requires lengthy incubation, so results cannot be obtained rapidly. Additionally, due to specific technical constraints of the plaque assay including the visual detection format, it has an element of subjectivity along with limited sensitivity. In this study, we describe the development of a FACS-based assay that utilizes detection of LCMV nucleoprotein (NP) expression in infected cells to determine viral titers, and that exhibits several advantages over the standard plaque assay. We show that the LCMV-NP FACS assay is an objective and reproducible detection method that requires smaller sample volumes, exhibits a ∼20-fold increase in sensitivity to and produces results three times faster than the plaque assay. Importantly, when applied to models of acute and chronic LCMV infection, the LCMV-NP FACS assay revealed the presence of infectious virus in samples that were determined to be negative by plaque assay. Therefore, this technique represents an accelerated, enhanced and objective alternative method for detection of infectious LCMV that is amenable to adaptation for other viral infections as well as high throughput diagnostic platforms.
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Affiliation(s)
- Darlynn Korns Johnson
- Integrated Department of Immunology, University of Colorado Denver and National Jewish Health, Denver, Colorado, United States of America
- Department of Anesthesiology, University of Colorado Denver, Aurora, Colorado, United States of America
- * E-mail: (DKJ); (DH)
| | - Dirk Homann
- Integrated Department of Immunology, University of Colorado Denver and National Jewish Health, Denver, Colorado, United States of America
- Department of Anesthesiology, University of Colorado Denver, Aurora, Colorado, United States of America
- * E-mail: (DKJ); (DH)
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Hypoxia induces the gene expression and extracellular transmission of persistent lymphocytic choriomeningitis virus. J Virol 2011; 85:13069-76. [PMID: 21957293 DOI: 10.1128/jvi.00829-11] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The physiological context of virus-infected cells can markedly affect multiplication and spread of the virus progeny. During persistent infection, the virus exploits the host cell without disturbing its vital functions. However, microenvironmental hypoxia can uncouple this intimate relationship and escalate virus pathogenesis. Accumulating evidence suggests that hypoxia-inducible factor (HIF) modulates gene expression of the viruses that pass through a DNA stage, contain hypoxia-responsive promoter elements, and replicate in the nucleus. Here we show that hypoxia can influence the gene expression and transmission of the cytoplasmic RNA virus lymphocytic choriomeningitis virus (LCMV), which is a neglected human pathogen and teratogen. The MX strain of LCMV, which we used as a model, replicates in a persistent mode in human HeLa cells, fails to produce mature envelope glycoproteins, and spreads through cell-cell contacts in the absence of extracellular infectious virions. Both exposure of MX-infected HeLa cells to chronic hypoxia and gene transfer approaches led to increased virus RNA transcription and higher levels of the viral proteins via a HIF-dependent mechanism. Moreover, hypoxia enhanced the formation of infectious virions capable of transmitting LCMV by cell-free medium. This LCMV "reactivation" might have health-compromising consequences in hypoxia-associated situations, such as fetal development and ischemia-related pathologies.
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Herpesviruses and intermediate filaments: close encounters with the third type. Viruses 2011; 3:1015-40. [PMID: 21994768 PMCID: PMC3185793 DOI: 10.3390/v3071015] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2011] [Revised: 06/07/2011] [Accepted: 06/24/2011] [Indexed: 01/29/2023] Open
Abstract
Intermediate filaments (IF) are essential to maintain cellular and nuclear integrity and shape, to manage organelle distribution and motility, to control the trafficking and pH of intracellular vesicles, to prevent stress-induced cell death, and to support the correct distribution of specific proteins. Because of this, IF are likely to be targeted by a variety of pathogens, and may act in favor or against infection progress. As many IF functions remain to be identified, however, little is currently known about these interactions. Herpesviruses can infect a wide variety of cell types, and are thus bound to encounter the different types of IF expressed in each tissue. The analysis of these interrelationships can yield precious insights into how IF proteins work, and into how viruses have evolved to exploit these functions. These interactions, either known or potential, will be the focus of this review.
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Zhang C, Xue C, Li Y, Kong Q, Ren X, Li X, Shu D, Bi Y, Cao Y. Profiling of cellular proteins in porcine reproductive and respiratory syndrome virus virions by proteomics analysis. Virol J 2010; 7:242. [PMID: 20849641 PMCID: PMC2949843 DOI: 10.1186/1743-422x-7-242] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2010] [Accepted: 09/18/2010] [Indexed: 11/14/2022] Open
Abstract
Background Porcine reproductive and respiratory syndrome virus (PRRSV) is an enveloped virus, bearing severe economic consequences to the swine industry worldwide. Previous studies on enveloped viruses have shown that many incorporated cellular proteins associated with the virion's membranes that might play important roles in viral infectivity. In this study, we sought to proteomically profile the cellular proteins incorporated into or associated with the virions of a highly virulent PRRSV strain GDBY1, and to provide foundation for further investigations on the roles of incorporated/associated cellular proteins on PRRSV's infectivity. Results In our experiment, sixty one cellular proteins were identified in highly purified PRRSV virions by two-dimensional gel electrophoresis coupled with mass spectrometric approaches. The identified cellular proteins could be grouped into eight functional categories including cytoskeletal proteins, chaperones, macromolecular biosynthesis proteins, metabolism-associated proteins, calcium-dependent membrane-binding proteins and other functional proteins. Among the identified proteins, four have not yet been reported in other studied envelope viruses, namely, guanine nucleotide-binding proteins, tyrosine 3-monooxygenase/tryptophan 5-monooxygenase, peroxiredoxin 1 and galectin-1 protein. The presence of five selected cellular proteins (i.e., β-actin, Tubulin, Annexin A2, heat shock protein Hsp27, and calcium binding proteins S100) in the highly purified PRRSV virions was validated by Western blot and immunogold labeling assays. Conclusions Taken together, the present study has demonstrated the incorporation of cellular proteins in PRRSV virions, which provides valuable information for the further investigations for the effects of individual cellular proteins on the viral replication, assembly, and pathogenesis.
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Affiliation(s)
- Chengwen Zhang
- State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou 510006, China
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The anti-anti-sigma factor BldG is involved in activation of the stress response sigma factor σ(H) in Streptomyces coelicolor A3(2). J Bacteriol 2010; 192:5674-81. [PMID: 20817765 DOI: 10.1128/jb.00828-10] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The alternative stress response sigma factor σ(H) has a role in regulation of the osmotic stress response and in morphological differentiation in Streptomyces coelicolor A3(2). Its gene, sigH, is located in an operon with the gene that encodes its anti-sigma factor UshX (PrsH). However, no gene with similarity to an anti-anti-sigma factor which may have a role in σ(H) activation by a "partner-switching" mechanism is located in the operon. By using a combination of several approaches, including pull-down and bacterial two-hybrid assays and visualization of the complex by native polyacrylamide electrophoresis, we demonstrated a direct interaction between UshX and the pleiotropic sporulation-specific anti-anti-sigma factor BldG. Osmotic induction of transcription of the sigHp2 promoter that is specifically recognized by RNA polymerase containing σ(H) was absent in an S. coelicolor bldG mutant, indicating a role of BldG in σ(H) activation by a partner-switching-like mechanism.
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