Virology (Virology)

Publications in this journal

• Article: The HPV16 oncogenes cause aberrant stem cell mobilization.

  Stella Michael, Paul F Lambert, Katerina Strati
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  ABSTRACT: Human Papilloma Virus related epithelial cancers have been speculated to derive from virus-infected tissue stem cells. Stem cells also are thought to provide a reservoir of latently infected cells that can persist for long periods. In this study we have examined the effects of HPV16 E6 and E7 oncogenes on multipotent epithelial stem cells, using in vivo systems. Our results show that expression of HPV16 oncogenes reduces the number of bulge label-retaining cells within hair follicles at telogen suggesting aberrant mobilization, a result supported by increased mobilization upon acute anagen induction. Importantly the loss of relative quiescence, a hallmark feature of stem cells, occurs in the absence of a reduction in other stem cell markers. This points to an atypical stem cell compartment in the context of E6 and E7 expression. We hypothesize that this aberrant compartment may have important roles in the viral life cycle and/or ensuing carcinogenesis.
  Virology 05/2013;
• Article: Porcine reproductive and respiratory syndrome virus activates inflammasomes of porcine alveolar macrophages via its small envelope protein E.

  Kao Zhang, Qiang Hou, Zhenyu Zhong, Xiujin Li, Huihui Chen, Wenyan Li, Jiexia Wen, Liyue Wang, Weiquan Liu, Fei Zhong
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  ABSTRACT: Porcine reproductive and respiratory syndrome virus (PRRSV) infection results in extensive tissue inflammation and damage, which are believed to be responsible for increased susceptibility to secondary infection and even for death. However, its pathogenic mechanisms are not fully understood. To explore the mechanism underlying the PRRSV-induced tissue inflammation and damage, we investigated whether PRRSV activates porcine alveolar macrophage (PAM) inflammasomes which mediate por-IL-1β maturation/release and subsequently induce tissue inflammation and injury. Our results showed that PRRSV and its small envelope protein E significantly increased IL-1β release from LPS-primed PAMs; however, only PRRSV not protein E significantly increased IL-1β release from no-LPS-primed PAMs, which indicates PRRSV can activate inflammasomes of PAMs by its encoded protein E. These results provide a molecular basis for the pathogenic mechanism of PRRSV on inducing extensive tissue inflammation and damage, and suggest that the inflammasome may provide a potential therapeutic target for PRRS prevention and treatment.
  Virology 05/2013;
• Article: Identification of adenovirus-encoded small RNAs by deep RNA sequencing.

  Hongxing Zhao, Maoshan Chen, Ulf Pettersson
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  ABSTRACT: Using deep RNA sequencing, we have studied the expression of adenovirus-encoded small RNAs at different times after infection. Nineteen small RNAs which comprised more than 1% of the total pool of small RNAs at least one time point were identified. These small RNAs were between 25 and 35 nucleotides long and mapped in the region of the VA RNAI and RNAII genes. However, the overlap was incomplete and some contained a few extra nucleotides at the 3' end. This finding together with the observation that some of the small RNAs were detected before VA RNA expression had started might indicate that they are derived from other precursors than VA RNAI and II. Interestingly, the small RNAs displayed different expression profiles during the course of the infection suggesting that they have different functions. An effort was made to identify their mRNA targets by using computer prediction and deep cDNA sequencing. The most significant targets for the earliest small RNAs were genes involved in signaling pathways.
  Virology 05/2013;
• Article: Histamine enhances HIV-1-induced modulation of dendritic cells to skew naïve T cell differentiation toward regulatory T cells.

  Rong-Rong Zhai, Ai-Ping Jiang, Hai-Bo Wang, Li Ma, Xiao-Xin Ren, Jin-Feng Jiang, Li Wu, Ji-Fu Wei, Jian-Hua Wang
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  ABSTRACT: Altered cytokine profiles and imbalanced frequencies of CD4(+) T helper cell subsets are thought to be linked with HIV-1/AIDS pathogenesis, but the causes need to be further clarified. Histamine, a biogenic amine with many functions, shows enhancement in HIV-1 infected individuals, which are considered to link with disease progression, but is poorly understood. This study investigated histamine-assisted HIV-1 modulation of dendritic cell (DC) functions. Histamine and HIV-1 showed a synergistic role in induction of interleukin-10; histamine inhibited HIV-1-induced IL-12 production from MDDCs (monocyte-derived DCs); notably, histamine augmented HIV-1-induced MDDC functional polarization and skewed naïve T cell differentiation toward regulatory T cells (Tregs). The results indicate the novel role of histamine in HIV-1-induced DC functional regulation, which promoted Treg cell differentiation and up-regulated immunosuppressive factors. These findings help to bridge the correlation between elevated histamine and increased Treg cell frequency in HIV-1 infected individuals, and add to our understanding of HIV-1-induced immunosuppression.
  Virology 05/2013;
• Article: Mapping the telomere integrated genome of human herpesvirus 6A and 6B.

  Jesse H Arbuckle, Shara N Pantry, Maria M Medveczky, Joshua Prichett, Kristin S Loomis, Dharam Ablashi, Peter G Medveczky
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  ABSTRACT: Human herpesvirus 6B (HHV-6B) is the causative agent of roseola infantum. HHV-6A and 6B can reactivate in immunosuppressed individuals and are linked with severe inflammatory response, organ rejection and central nervous system diseases. About 0.85% of the US and UK population carries an integrated HHV-6 genome in all nucleated cells through germline transmission. We have previously reported that the HHV-6A genome integrated in telomeres of patients suffering from neurological dysfunction and also in telomeres of tissue culture cells. We now report that HHV-6B also integrates in telomeres during latency. Detailed mapping of the integrated viral genomes demonstrates that a single HHV-6 genome integrates and telomere repeats join the left end of the integrated viral genome. When HEK-293 cells carrying integrated HHV-6A were exposed to the histone deacetylase inhibitor Trichostatin A, circularization and/or formation of concatamers were detected and this assay could be used to distinguish between lytic replication and latency.
  Virology 05/2013;
• Article: Lentivirus restriction by diverse primate APOBEC3A proteins.

  Kimberly Schmitt, Kejun Guo, Miki Katuwal, Darayu Wilson, Courtney Prochnow, Ronda Bransteitter, Xiaojiang S Chen, Mario L Santiago, Edward B Stephens
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  ABSTRACT: Rhesus macaque APOBEC3A (rhA3A) is capable of restricting both simian-human immunodeficiency virus (SHIVΔvif) and human immunodeficiency virus (HIV-1Δvif) to a greater extent than hA3A. We constructed chimeric A3A proteins to define the domains required for differential lentivirus restriction. Substitution of amino acids 25-33 from rhA3A into hA3A was sufficient to restrict HIVΔvif to levels similar to rhA3A restriction of SHIVΔvif. We tested if differential lentivirus restriction is conserved between A3A from Old World monkey and hominid lineages. A3A from African green monkey restricted SHIVΔvif but not HIV-1Δvif and colobus monkey A3A restricted both wild type and SHIVΔvif and HIV-1Δvif. In contrast, the gibbon ape A3A restricted neither SHIVΔvif nor HIV-1Δvif. Restriction of SHIVΔvif and HIV-1Δvif by New World monkey A3A proteins was not conserved as the A3A from the squirrel monkey but not the northern owl monkey restricted SHIVΔvif. Finally, the colobus A3A protein appears to restrict by a novel post-entry mechanism.
  Virology 05/2013;
• Article: Small RNA populations for two unrelated viruses exhibit different biases in strand polarity and proximity to terminal sequences in the insect host Homalodisca vitripennis.

  Raja Sekhar Nandety, Viacheslav Y Fofanov, Heather Koshinsky, Drake C Stenger, Bryce W Falk
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  ABSTRACT: Next generation sequence analyses were used to assess virus-derived small RNA (vsRNA) profiles for Homalodisca coagulata virus-1 (HoCV-1), family Dicistroviridae, and Homalodisca vitripennis reovirus (HoVRV), family Reoviridae, from virus-infected H. vitripennis, the glassy-winged sharpshooter. The vsRNA reads were mapped against the monopartite genome of HoCV-1 and all 12 genome segments of HoVRV, and 21nt vsRNAs were most common. However, strikingly contrasting patterns for the HoCV-1 and HoVRV genomic RNAs were observed. The majority of HoCV-1 vsRNAs mapped to the genomic positive-strand RNA and, although minor hotspots were observed, vsRNAs mapped across the entire genomic RNA. In contrast, HoVRV vsRNAs mapped to both positive and negative-sense strands for all genome segments, but different genomic segments showed distinct hotspots. The HoVRV vsRNAs were more common for 5' and 3' regions of HoVRV regions of all segments. These data suggest that taxonomically different viruses in the same host offer different targets for RNA-antiviral defense.
  Virology 05/2013;
• Article: O-GlcNAc modification of the coat protein of the potyvirus Plum pox virus enhances viral infection.

  José de Jesús Pérez, Namrata D Udeshi, Jeffrey Shabanowitz, Sergio Ciordia, Silvia Juárez, Cheryl L Scott, Neil E Olszewski, Donald F Hunt, Juan Antonio García
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  ABSTRACT: O-GlcNAcylation is a dynamic protein modification which has been studied mainly in metazoans. We reported previously that an Arabidopsis thaliana O-GlcNAc transferase modifies at least two threonine residues of the Plum pox virus (PPV) capsid protein (CP). Now, six additional residues were shown to be involved in O-GlcNAc modification of PPV CP. CP O-GlcNAcylation was abolished in the PPV CP7-T/A mutant, in which seven threonines were mutated. PPV CP7-T/A infected Nicotiana clevelandii, Nicotiana benthamiana, and Prunus persica without noticeable defects. However, defects in infection of A. thaliana were readily apparent. In mixed infections of wild-type arabidopsis, the CP7-T/A mutant was outcompeted by wild-type virus. These results indicate that CP O-GlcNAcylation has a major role in the infection process. O-GlcNAc modification may have a role in virion assembly and/or stability as the CP of PPV CP7-T/A was more sensitive to protease digestion than that of the wild-type virus.
  Virology 04/2013;
• Article: Negatively charged residues in the endodomain are critical for specific assembly of spike protein into murine coronavirus.

  Qianqian Yao, Paul S Masters, Rong Ye
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  ABSTRACT: Coronavirus spike (S) protein assembles into virions via its carboxy-terminus, which is composed of a transmembrane domain and an endodomain. Here, the carboxy-terminal charge-rich motif in the endodomain was verified to be critical for the specificity of S assembly into mouse hepatitis virus (MHV). Recombinant MHVs exhibited a range of abilities to accommodate the homologous S endodomains from the betacoronaviruses bovine coronavirus and human SARS-associated coronavirus, the alphacoronavirus porcine transmissible gastroenteritis virus (TGEV), and the gammacoronavirus avian infectious bronchitis virus respectively. Interestingly, in TGEV endodomain chimeras the reverting mutations resulted in stronger S incorporation into virions, and a net gain of negatively charged residues in the charge-rich motif accounted for the improvement. Additionally, MHV S assembly could also be rescued by the acidic carboxy-terminal domain of the nucleocapsid protein. These results indicate an important role for negatively charged endodomain residues in the incorporation of MHV S protein into assembled virions.
  Virology 04/2013;
• Article: Intranasal vaccination with H5, H7 and H9 hemagglutinins co-localized in a virus-like particle protects ferrets from multiple avian influenza viruses.

  Irina Tretyakova, Melissa B Pearce, Ruth Florese, Terrence M Tumpey, Peter Pushko
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  ABSTRACT: Avian influenza H5, H7 and H9 viruses top the World Health Organization's (WHO) list of subtypes with the greatest pandemic potential. Here we describe a recombinant virus-like particle (VLP) that co-localizes hemagglutinin (HA) proteins derived from H5N1, H7N2, and H9N2 viruses as an experimental vaccine against these viruses. A baculovirus vector was configured to co-express the H5, H7, and H9 genes from A/Viet Nam/1203/2004 (H5N1), A/New York/107/2003 (H7N2) and A/Hong Kong/33982/2009 (H9N2) viruses, respectively, as well as neuraminidase (NA) and matrix (M1) genes from A/Puerto Rico/8/1934 (H1N1) virus. Co-expression of these genes in Sf9 cells resulted in production of triple-subtype VLPs containing HA molecules derived from the three influenza viruses. The triple-subtype VLPs exhibited hemagglutination and neuraminidase activities and morphologically resembled influenza virions. Intranasal vaccination of ferrets with the VLPs resulted in induction of serum antibody responses and efficient protection against experimental challenges with H5N1, H7N2, and H9N2 viruses.
  Virology 04/2013;
• Article: Reconstituted plant viral capsids can release genes to mammalian cells.

  Odisse Azizgolshani, Rees F Garmann, Ruben Cadena-Nava, Charles M Knobler, William M Gelbart
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  ABSTRACT: The nucleocapsids of many plant viruses are significantly more robust and protective of their RNA contents than those of enveloped animal viruses. In particular, the capsid protein (CP) of the plant virus Cowpea Chlorotic Mottle Virus (CCMV) is of special interest because it has been shown to spontaneously package, with high efficiency, a large range of lengths and sequences of single-stranded RNA molecules. In this work we demonstrate that hybrid virus-like particles, assembled in vitro from CCMV CP and a heterologous RNA derived from a mammalian virus (Sindbis), are capable of releasing their RNA in the cytoplasm of mammalian cells. This result establishes the first step in the use of plant viral capsids as vectors for gene delivery and expression in mammalian cells. Furthermore, the CCMV capsid protects the packaged RNA against nuclease degradation and serves as a robust external scaffold with many possibilities for further functionalization and cell targeting.
  Virology 04/2013;
• Article: Genomic analysis of vaccinia virus strain TianTan provides new insights into the evolution and evolutionary relationships between Orthopoxviruses.

  Li Qin, Min Liang, David H Evans
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  ABSTRACT: Vaccinia virus (VACV) strain TianTan was used for much of China's modern history to vaccinate against smallpox, however the only genome sequence contains errors. We have sequenced additional examples of TianTan to obtain a better picture of this important virus. We detected two different subclones. One (TP03) encodes large deletions in the terminal repeats that extend into both VEGF genes and create a small plaque variant. The second clone (TP05) encodes a nearly intact complement of genes in the terminal repeats, except for an insertion of sequences resembling the telomeric 69bp repeats. The TP05 genome spans 196,260bp and encodes 219 genes. The revised sequence documents the integrity of all the genes in the conserved virus core. Phylogenetic methods show that TianTan belongs to a unique clade of VACV, but probably also share a common origin with strains belonging to the Copenhagen/Lister lineage and distinct from the Wyeth/Dryvax lineage.
  Virology 04/2013;
• Article: Ophioviruses CPsV and MiLBVV movement protein is encoded in RNA 2 and interacts with the coat protein.

  Gabriel Robles Luna, Eduardo José Peña, María Belén Borniego, Manfred Heinlein, Maria Laura Garcia
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  ABSTRACT: Citrus psorosis virus (CPsV) and Mirafiori lettuce big-vein virus (MiLBVV), members of the Ophioviridae family, have segmented negative-sense single-stranded RNA genomes. To date no reports have described how ophioviruses spread within host plants and/or the proteins involved in this process. Here we show that the 54K protein of CPsV is encoded by RNA 2 and describe its subcellular distribution. Upon transient expression in Nicotiana benthamiana epidermal cells the 54K protein, and also its 54K counterpart protein of MiLBVV, localize to plasmodesmata and enhance GFP cell-to-cell diffusion between cells. Both proteins, but not the coat proteins (CP) of the respective viruses, functionally trans-complement cell-to-cell movement-defective Potato virus X (PVX) and Tobacco mosaic virus (TMV) mutants. The 54K and 54K proteins interact with the virus-specific CP in the cytoplasm, suggesting a potential role of CP in ophiovirus movement. This is the first study characterizing the movement proteins (MP) of ophioviruses.
  Virology 04/2013;
• Article: ORF50-dependent and ORF50-independent activation of the ORF45 gene of Kaposi's sarcoma-associated herpesvirus.

  Pey-Jium Chang, Shie-Shan Wang, Li-Yu Chen, Chien-Hui Hung, Hsiao-Yun Huang, Ying-Ju Shih, Ju-Bei Yen, Jieh-Yuan Liou, Lee-Wen Chen
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  ABSTRACT: The ORF45 gene of Kaposi's sarcoma-associated herpesvirus (KSHV) encodes a multifunctional tegument protein. Here, we characterize the transcriptional control of the ORF45 gene and show that its promoter can be activated by ORF50 protein, a latent-lytic switch transactivator. The ORF45 promoter can also be induced by sodium butyrate (SB), a histone deacetylase inhibitor, in the absence of ORF50 protein. Although SB induces the ORF45 gene independently of ORF50, its full activation may require the presence of ORF50. Deletion and point mutation analyses revealed that two RBP-Jκ-binding sites in the ORF45 promoter confer the ORF50 responsiveness, whereas NF-Y and Sp1-binding sites mediate the response to SB. Direct binding of NF-Y, Sp1, or RBP-Jκ protein to the ORF45 promoter is required for the promoter activation induced by SB or by ORF50. In conclusion, our study demonstrates both ORF50-dependent and ORF50-independent transcriptional mechanisms operated on the activation of the ORF45 gene.
  Virology 04/2013;
• Article: Susceptibility and adaptation to human TRIM5α alleles at positive selected sites in HIV-1 capsid.

  Nadia Rahm, David Gfeller, Joke Snoeck, Raquel Martinez, Paul J McLaren, Millán Ortiz, Angela Ciuffi, Amalio Telenti
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  ABSTRACT: Numerous in vitro studies attribute to human TRIM5α some modest anti-HIV-1 activity and human population studies suggest some differential effect of TRIM5α polymorphisms on disease progression. If the activity of TRIM5α were relevant in vivo, it could result in positive selection on the viral capsid. To address this issue, we identified 10 positively selected sites in HIV-1 capsid from multiple viral strains and generated 17 clade B viruses carrying a minor (i.e. low frequency) residue or an alanine at those positions. All recombinant viruses were susceptible to the modest effect of common human TRIM5α and allelic variants R136Q, and H419Y; H43Y and G249D TRIM5α were generally inactive. Increased sensitivity to TRIM5α was observed for some capsid variants, suggesting that minor residues are selected against in human populations. On the other hand, the modest potency of human TRIM5α does not translate in escape mutations in the viral capsid.
  Virology 04/2013;
• Article: Double-stranded RNA binding by the human cytomegalovirus PKR antagonist TRS1.

  Craig J Bierle, Kathryn M Semmens, Adam P Geballe
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  ABSTRACT: Protein Kinase R (PKR) inhibits translation initiation following double-stranded RNA (dsRNA) binding and thereby represses viral replication. Human cytomegalovirus (HCMV) encodes two noncanonical dsRNA binding proteins, IRS1 and TRS1, and the expression of at least one of these PKR antagonists is essential for HCMV replication. In this study, we investigated the role of dsRNA binding by TRS1 in PKR inhibition. We found that purified TRS1 binds specifically to dsRNA with an affinity lower than that of PKR. Point mutants in the TRS1 dsRNA binding domain that were deficient in rescuing the replication of vaccinia virus lacking its PKR antagonist E3L were unable to bind to dsRNA but retained the ability bind to PKR. Thus TRS1 binding to dsRNA and to PKR are separable. Overall, our results are most consistent with a model in which TRS1 binds simultaneously to both dsRNA and PKR to inhibit PKR activation.
  Virology 04/2013;
• Article: Therapeutic targeting of regulatory T cells enhances tumor-specific CD8+ T cell responses in Epstein-Barr virus associated nasopharyngeal carcinoma.

  Mark Fogg, John R Murphy, Jochen Lorch, Marshall Posner, Fred Wang
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  ABSTRACT: Epstein-Barr virus (EBV) is associated with multiple malignancies including nasopharyngeal carcinoma (NPC). In nasopharynx cancer, CD8+ T cells specific for EBV Nuclear Antigen-1 (EBNA-1) and Latent Membrane Protein 2 (LMP2) are important components of anti-tumor immunity since both are consistently expressed in NPC. We have previously shown that EBNA-1-specific CD8+ T cell responses were suppressed in NPC patients compared to healthy controls. We now find that CD8+ T cell responses specific for LMP2 are also abnormal in NPC patients, and both EBNA-1- and LMP2-specific responses are suppressed by regulatory T cells (Treg). EBNA-1 and LMP2-specific CD8+ T cell responses, as well as immune control of EBV-infected cells in vitro, could be restored by the depletion of Tregs and by use of a clinically approved drug targeting Tregs. Thus, in vivo modulation of Tregs may be an effective means of enhancing these anti-tumor immune responses in NPC patients.
  Virology 04/2013;
• Article: Role for subgenomic mRNA in host translation inhibition during Sindbis virus infection of mammalian cells.

  Rohini K Patel, Andrew J Burnham, Natasha N Gebhart, Kevin J Sokoloski, Richard W Hardy
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  ABSTRACT: Sindbis virus subgenomic mRNA is efficiently translated in infected vertebrate cells whereas host translation is shut-off. Deletions in the 5'UTR of the subgenomic mRNA were made to investigate its role in viral gene expression. Deletion of nucleotides 1-10 and 11-20 caused a small plaque phenotype, reduced levels of subgenomic mRNA and structural proteins, and increased expression of nonstructural proteins. Whereas deletion 1-10 virus inhibited cellular protein synthesis, deletion 11-20 did so inefficiently. A large plaque revertant of deletion 11-20, possessing a duplication of the subgenomic promoter region, produced subgenomic mRNA at WT levels and restored inhibition of host protein synthesis. Further analysis of the mutant and revertant 5'UTR sequences showed the ability to shut-off host cell translation correlated with the efficiency of translation of subgenomic mRNA. We propose that the translational efficiency and quantity of the subgenomic mRNA play a role in inhibition of host cell translation.
  Virology 04/2013;