Viruses

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Open AccessArticle

A Phylogeographic Investigation of African Monkeypox

by Yoshinori Nakazawa, Matthew R. Mauldin, Ginny L. Emerson, Mary G. Reynolds, R. Ryan Lash, Jinxin Gao, Hui Zhao, Yu Li, Jean-Jacques Muyembe, Placide Mbala Kingebeni, Okito Wemakoy, Jean Malekani, Kevin L. Karem, Inger K. Damon and Darin S. Carroll

Viruses 2015, 7(4), 2168-2184; https://doi.org/10.3390/v7042168 - 22 Apr 2015

Cited by 86 | Viewed by 10945

Abstract

Monkeypox is a zoonotic disease caused by a virus member of the genus Orthopoxvirus and is endemic to Central and Western African countries. Previous work has identified two geographically disjuct clades of monkeypox virus based on the analysis of a few genomes coupled [...] Read more.

Monkeypox is a zoonotic disease caused by a virus member of the genus Orthopoxvirus and is endemic to Central and Western African countries. Previous work has identified two geographically disjuct clades of monkeypox virus based on the analysis of a few genomes coupled with epidemiological and clinical analyses; however, environmental and geographic causes of this differentiation have not been explored. Here, we expand previous phylogenetic studies by analyzing a larger set of monkeypox virus genomes originating throughout Sub-Saharan Africa to identify possible biogeographic barriers associated with genetic differentiation; and projected ecological niche models onto environmental conditions at three periods in the past to explore the potential role of climate oscillations in the evolution of the two primary clades. Analyses supported the separation of the Congo Basin and West Africa clades; the Congo Basin clade shows much shorter branches, which likely indicate a more recent diversification of isolates within this clade. The area between the Sanaga and Cross Rivers divides the two clades and the Dahomey Gap seems to have also served as a barrier within the West African clade. Contraction of areas with suitable environments for monkeypox virus during the Last Glacial Maximum, suggests that the Congo Basin clade of monkeypox virus experienced a severe bottleneck and has since expanded its geographic range. Full article

(This article belongs to the Special Issue Poxvirus Evolution)

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Open AccessArticle

BST2/Tetherin Inhibition of Alphavirus Exit

by Yaw Shin Ooi, Mathieu Dubé and Margaret Kielian

Viruses 2015, 7(4), 2147-2167; https://doi.org/10.3390/v7042147 - 22 Apr 2015

Cited by 32 | Viewed by 7384

Abstract

Alphaviruses such as chikungunya virus (CHIKV) and Semliki Forest virus (SFV) are small enveloped RNA viruses that bud from the plasma membrane. Tetherin/BST2 is an interferon-induced host membrane protein that inhibits the release of many enveloped viruses via direct tethering of budded particles [...] Read more.

Alphaviruses such as chikungunya virus (CHIKV) and Semliki Forest virus (SFV) are small enveloped RNA viruses that bud from the plasma membrane. Tetherin/BST2 is an interferon-induced host membrane protein that inhibits the release of many enveloped viruses via direct tethering of budded particles to the cell surface. Alphaviruses have highly organized structures and exclude host membrane proteins from the site of budding, suggesting that their release might be insensitive to tetherin inhibition. Here, we demonstrated that exogenously-expressed tetherin efficiently inhibited the release of SFV and CHIKV particles from host cells without affecting virus entry and infection. Alphavirus release was also inhibited by the endogenous levels of tetherin in HeLa cells. While rubella virus (RuV) and dengue virus (DENV) have structural similarities to alphaviruses, tetherin inhibited the release of RuV but not DENV. We found that two recently identified tetherin isoforms differing in length at the N-terminus exhibited distinct capabilities in restricting alphavirus release. SFV exit was efficiently inhibited by the long isoform but not the short isoform of tetherin, while both isoforms inhibited vesicular stomatitis virus exit. Thus, in spite of the organized structure of the virus particle, tetherin specifically blocks alphavirus release and shows an interesting isoform requirement. Full article

(This article belongs to the Section Animal Viruses)

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Open AccessArticle

Genome Variability and Gene Content in Chordopoxviruses: Dependence on Microsatellites

by Eneida L. Hatcher, Chunlin Wang and Elliot J. Lefkowitz

Viruses 2015, 7(4), 2126-2146; https://doi.org/10.3390/v7042126 - 22 Apr 2015

Cited by 18 | Viewed by 6646

Abstract

To investigate gene loss in poxviruses belonging to the Chordopoxvirinae subfamily, we assessed the gene content of representative members of the subfamily, and determined whether individual genes present in each genome were intact, truncated, or fragmented. When nonintact genes were identified, the early [...] Read more.

To investigate gene loss in poxviruses belonging to the Chordopoxvirinae subfamily, we assessed the gene content of representative members of the subfamily, and determined whether individual genes present in each genome were intact, truncated, or fragmented. When nonintact genes were identified, the early stop mutations (ESMs) leading to gene truncation or fragmentation were analyzed. Of all the ESMs present in these poxvirus genomes, over 65% co-localized with microsatellites—simple sequence nucleotide repeats. On average, microsatellites comprise 24% of the nucleotide sequence of these poxvirus genomes. These simple repeats have been shown to exhibit high rates of variation, and represent a target for poxvirus protein variation, gene truncation, and reductive evolution. Full article

(This article belongs to the Special Issue Poxvirus Evolution)

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Open AccessReview

Baculovirus-mediated Gene Delivery and RNAi Applications

by Kaisa-Emilia Makkonen, Kari Airenne and Seppo Ylä-Herttulala

Viruses 2015, 7(4), 2099-2125; https://doi.org/10.3390/v7042099 - 22 Apr 2015

Cited by 25 | Viewed by 7314

Abstract

Baculoviruses are widely encountered in nature and a great deal of data is available about their safety and biology. Recently, these versatile, insect-specific viruses have demonstrated their usefulness in various biotechnological applications including protein production and gene transfer. Multiple in vitro and in [...] Read more.

Baculoviruses are widely encountered in nature and a great deal of data is available about their safety and biology. Recently, these versatile, insect-specific viruses have demonstrated their usefulness in various biotechnological applications including protein production and gene transfer. Multiple in vitro and in vivo studies exist and support their use as gene delivery vehicles in vertebrate cells. Recently, baculoviruses have also demonstrated high potential in RNAi applications in which several advantages of the virus make it a promising tool for RNA gene transfer with high safety and wide tropism. Full article

(This article belongs to the Special Issue Gene Therapy with Emphasis on RNA Interference)

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Open AccessReview

Can Plant Viruses Cross the Kingdom Border and Be Pathogenic to Humans?

by Fanny Balique, Hervé Lecoq, Didier Raoult and Philippe Colson

Viruses 2015, 7(4), 2074-2098; https://doi.org/10.3390/v7042074 - 20 Apr 2015

Cited by 68 | Viewed by 17352

Abstract

Phytoviruses are highly prevalent in plants worldwide, including vegetables and fruits. Humans, and more generally animals, are exposed daily to these viruses, among which several are extremely stable. It is currently accepted that a strict separation exists between plant and vertebrate viruses regarding [...] Read more.

Phytoviruses are highly prevalent in plants worldwide, including vegetables and fruits. Humans, and more generally animals, are exposed daily to these viruses, among which several are extremely stable. It is currently accepted that a strict separation exists between plant and vertebrate viruses regarding their host range and pathogenicity, and plant viruses are believed to infect only plants. Accordingly, plant viruses are not considered to present potential pathogenicity to humans and other vertebrates. Notwithstanding these beliefs, there are many examples where phytoviruses circulate and propagate in insect vectors. Several issues are raised here that question if plant viruses might further cross the kingdom barrier to cause diseases in humans. Indeed, there is close relatedness between some plant and animal viruses, and almost identical gene repertoires. Moreover, plant viruses can be detected in non-human mammals and humans samples, and there are evidence of immune responses to plant viruses in invertebrates, non-human vertebrates and humans, and of the entry of plant viruses or their genomes into non-human mammal cells and bodies after experimental exposure. Overall, the question raised here is unresolved, and several data prompt the additional extensive study of the interactions between phytoviruses and non-human mammals and humans, and the potential of these viruses to cause diseases in humans. Full article

(This article belongs to the Section Viruses of Plants, Fungi and Protozoa)

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Open AccessArticle

Enhancement of Herpes Simplex Virus (HSV) Infection by Seminal Plasma and Semen Amyloids Implicates a New Target for the Prevention of HSV Infection

by Lilith Torres, Tatiana Ortiz and Qiyi Tang

Viruses 2015, 7(4), 2057-2073; https://doi.org/10.3390/v7042057 - 20 Apr 2015

Cited by 22 | Viewed by 8027

Abstract

Human herpesviruses cause different infectious diseases, resulting in world-wide health problems. Sexual transmission is a major route for the spread of both herpes simplex virus-1 (HSV-1) and -2. Semen plays an important role in carrying the viral particle that invades the vaginal or [...] Read more.

Human herpesviruses cause different infectious diseases, resulting in world-wide health problems. Sexual transmission is a major route for the spread of both herpes simplex virus-1 (HSV-1) and -2. Semen plays an important role in carrying the viral particle that invades the vaginal or rectal mucosa and, thereby, initiates viral replication. Previously, we demonstrated that the amyloid fibrils semenogelin (SEM) and semen-derived enhancer of viral infection (SEVI), and seminal plasma (SP) augment cytomegalovirus infection (Tang et al., J. Virol 2013). Whether SEM or SEVI amyloids or SP could also enhance other herpesvirus infections has not been examined. In this study, we found that the two amyloids as well as SP strongly enhance both HSV-1 and -2 infections in cell culture. Along with SP, SEM and SEVI amyloids enhanced viral entry and increased infection rates by more than 10-fold, as assessed by flow cytometry assay and fluorescence microscopy. Viral replication was increased by about 50- to 100-fold. Moreover, viral growth curve assays showed that SEM and SEVI amyloids, as well as SP, sped up the kinetics of HSV replication such that the virus reached its replicative peak more quickly. The interactions of SEM, SEVI, and SP with HSVs are direct. Furthermore, we discovered that the enhancing effects of SP, SEM, and SEVI can be significantly reduced by heparin, a sulfated polysaccharide with an anionic charge. It is probable that heparin abrogates said enhancing effects by interfering with the interaction of the viral particle and the amyloids, which interaction results in the binding of the viral particles and both SEM and SEVI. Full article

(This article belongs to the Section Animal Viruses)

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Open AccessArticle

Humanized-V_HH Transbodies that Inhibit HCV Protease and Replication

by Surasak Jittavisutthikul, Jeeraphong Thanongsaksrikul, Kanyarat Thueng-in, Monrat Chulanetra, Potjanee Srimanote, Watee Seesuay, Aijaz Ahmad Malik and Wanpen Chaicumpa

Viruses 2015, 7(4), 2030-2056; https://doi.org/10.3390/v7042030 - 20 Apr 2015

Cited by 33 | Viewed by 7539

Abstract

There is a need for safe and broadly effective anti-HCV agents that can cope with genetic multiplicity and mutations of the virus. In this study, humanized-camel V_HHs to genotype 3a HCV serine protease were produced and were linked molecularly to a [...] Read more.

There is a need for safe and broadly effective anti-HCV agents that can cope with genetic multiplicity and mutations of the virus. In this study, humanized-camel V_HHs to genotype 3a HCV serine protease were produced and were linked molecularly to a cell penetrating peptide, penetratin (PEN). Human hepatic (Huh7) cells transfected with the JFH-1 RNA of HCV genotype 2a and treated with the cell penetrable nanobodies (transbodies) had a marked reduction of the HCV RNA intracellularly and in their culture fluids, less HCV foci inside the cells and less amounts of HCV core antigen in culture supernatants compared with the infected cells cultured in the medium alone. The PEN-V_HH-treated-transfected cells also had up-regulation of the genes coding for the host innate immune response (TRIF, TRAF3, IRF3, IL-28B and IFN-β), indicating that the cell penetrable nanobodies rescued the host innate immune response from the HCV mediated-suppression. Computerized intermolecular docking revealed that the V_HHs bound to residues of the protease catalytic triad, oxyanion loop and/or the NS3 N-terminal portion important for non-covalent binding of the NS4A protease cofactor protein. The so-produced transbodies have high potential for testing further as a candidate for safe, broadly effective and virus mutation tolerable anti-HCV agents. Full article

(This article belongs to the Section Viral Immunology, Vaccines, and Antivirals)

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Open AccessArticle

Frequent Infection of Human Cancer Xenografts with Murine Endogenous Retroviruses in Vivo

by Asif Naseer, Anne Terry, Kathryn Gilroy, Anna Kilbey, Ciorsdaidh Watts, Nancy Mackay, Margaret Bell, Susan Mason, Karen Blyth, Ewan Cameron and James C. Neil

Viruses 2015, 7(4), 2014-2029; https://doi.org/10.3390/v7042014 - 17 Apr 2015

Cited by 9 | Viewed by 8305

Abstract

Infection of human cancer xenografts in mice with murine leukemia viruses (MLVs) is a long-standing observation, but the likelihood of infection in vivo and its biological consequences are poorly understood. We therefore conducted a prospective study in commonly used xenograft recipient strains. From [...] Read more.

Infection of human cancer xenografts in mice with murine leukemia viruses (MLVs) is a long-standing observation, but the likelihood of infection in vivo and its biological consequences are poorly understood. We therefore conducted a prospective study in commonly used xenograft recipient strains. From BALB/c nude mice engrafted with MCF7 human mammary carcinoma cells, we isolated a virus that was virtually identical to Bxv1, a locus encoding replication-competent xenotropic MLV (XMLV). XMLV was detected in 9/17 (53%) independently isolated explants. XMLV was not found in primary leukemias or in THP1 leukemia cells grown in Bxv1-negative NSG (NOD/SCID/γCnull) mice, although MCF7 explants harbored replication-defective MLV proviruses. To assess the significance of infection for xenograft behavior in vivo, we examined changes in growth and global transcription in MCF7 and the highly susceptible Raji Burkitt lymphoma cell line chronically infected with XMLV. Raji cells showed a stronger transcriptional response that included up-regulation of chemokines and effectors of innate antiviral immunity. In conclusion, the risk of de novo XMLV infection of xenografts is high in Bxv1 positive mice, while infection can have positive or negative effects on xenograft growth potential with significant consequences for interpretation of many xenograft studies. Full article

(This article belongs to the Special Issue Endogenous Viruses)

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Open AccessCommunication

Serological Evidence of Hantavirus Infection in Apparently Healthy People from Rural and Slum Communities in Southern Chile

by Claudia Muñoz-Zanzi, Farides Saavedra, Carola Otth, Ljubica Domancich, Melissa Hott and Paula Padula

Viruses 2015, 7(4), 2006-2013; https://doi.org/10.3390/v7042006 - 17 Apr 2015

Cited by 13 | Viewed by 5757

Abstract

Hantavirus disease in America has been recognizable because of its rapid progression in clinical cases, occurrence in previously healthy young adults, and high case fatality rate. Hantavirus disease has been proposed now to define the diversity of clinical manifestations. Since 1995, a total [...] Read more.

Hantavirus disease in America has been recognizable because of its rapid progression in clinical cases, occurrence in previously healthy young adults, and high case fatality rate. Hantavirus disease has been proposed now to define the diversity of clinical manifestations. Since 1995, a total of 902 cases of hantavirus pulmonary syndrome have been reported in Chile, caused by Andes virus (ANDV), with overall fatality of 32%. This report describes the sero-epidemiology of hantavirus in apparently healthy people in rural and urban slum communities from southern Chile. Ten of 934 samples yielded a positive result resulting in a seroprevalence of 1.07% (95% confidence intervals: 0.05%–2.0%). A higher proportion of positive samples was found among individuals from rural villages (1.3%) and slums (1.5%) compared with farms (0.5%). Seropositivity was associated with age (p = 0.011), low education level (p = 0.006) and occupations linked to the household (homemaker, retired, or student) (p = 0.016). No evidence of infection was found in 38 sigmodontinae rodents trapped in the peri-domestic environment. Our findings highlight that exposure risk was associated with less documented risk factors, such as women in slum and rural villages, and the occurrence of infection that may have presented as flu-like illness that did not require medical attention or was misdiagnosed. Full article

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Open AccessArticle

A Piscine Birnavirus Induces Inhibition of Protein Synthesis in CHSE-214 Cells Primarily through the Induction of eIF2α Phosphorylation

by Amr A.A. Gamil, Stephen Mutoloki and Øystein Evensen

Viruses 2015, 7(4), 1987-2005; https://doi.org/10.3390/v7041987 - 15 Apr 2015

Cited by 14 | Viewed by 7856

Abstract

Inhibition of protein synthesis represents one of the antiviral mechanisms employed by cells and it is also used by viruses for their own propagation. To what extent members of the Birnaviridae family employ such strategies is not well understood. Here we use a [...] Read more.

Inhibition of protein synthesis represents one of the antiviral mechanisms employed by cells and it is also used by viruses for their own propagation. To what extent members of the Birnaviridae family employ such strategies is not well understood. Here we use a type-strain of the Aquabirnavirus, infectious pancreatic necrosis virus (IPNV), to investigate this phenomenon in vitro. CHSE-214 cells were infected with IPNV and at 3, 12, 24, and 48 hours post infection (hpi) before the cells were harvested and labeled with S³⁵ methionine to assess protein synthesis. eIF2α phosphorylation was examined by Western blot while RT-qPCR was used to assess virus replication and the expression levels of IFN-α, Mx1 and PKR. Cellular responses to IPNV infection were assessed by DNA laddering, Caspase-3 assays and flow cytometry. The results show that the onset and kinetics of eIF2α phosphorylation was similar to that of protein synthesis inhibition as shown by metabolic labeling. Increased virus replication and virus protein formation was observed by 12 hpi, peaking at 24 hpi. Apoptosis was induced in a small fraction (1−2%) of IPNV-infected CHSE cells from 24 hpi while necrotic/late apoptotic cells increased from 10% by 24 hpi to 59% at 48 hpi, as shown by flow cytometry. These results were in accordance with a small decline in cell viability by 24hpi, dropping below 50% by 48 hpi. IPNV induced IFN-α mRNA upregulation by 24 hpi while no change was observed in the expression of Mx1 and PKR mRNA. Collectively, these findings show that IPNV induces inhibition of protein synthesis in CHSE cells through phosphorylation of eIF2α with minimal involvement of apoptosis. The anticipation is that protein inhibition is used by the virus to evade the host innate antiviral responses. Full article

(This article belongs to the Section Animal Viruses)

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Open AccessArticle

Evaluating Environmental Persistence and Disinfection of the Ebola Virus Makona Variant

by Bradley W. M. Cook, Todd A. Cutts, Aidan M. Nikiforuk, Philip Guillaume Poliquin, Deborah A. Court, James E. Strong and Steven S. Theriault

Viruses 2015, 7(4), 1975-1986; https://doi.org/10.3390/v7041975 - 14 Apr 2015

Cited by 51 | Viewed by 11838

Abstract

Background: The current disease outbreak caused by the Ebola virus Makona variant (EBOV/Mak) has led to unprecedented morbidity and lethality given its geographic reach and sustained transmission. Sodium hypochlorite and ethanol are well-accepted decontamination agents, however little published evidence supports the selection of [...] Read more.

Background: The current disease outbreak caused by the Ebola virus Makona variant (EBOV/Mak) has led to unprecedented morbidity and lethality given its geographic reach and sustained transmission. Sodium hypochlorite and ethanol are well-accepted decontamination agents, however little published evidence supports the selection of appropriate concentrations and contact times. The present study addresses the environmental robustness of EBOV/Mak and evaluates the effectiveness of sodium hypochlorite and ethanol as disinfectants. Methods: EBOV/Mak was suspended in a simulated organic soil load and dried onto surfaces. Viability was measured at 1 hour, 24 hours, 72 hours, and 192 hours. For the evaluation of disinfectants, EBOV/Mak in a simulated organic soil was dried onto stainless steel carriers and disinfected with 0.01% (v/v), 0.1% (v/v), 0.5% (v/v) and 1% (v/v) sodium hypochlorite solutions or 67% (v/v) ethanol at contact times of 1, 5 or 10 minutes. Results: EBOV/Mak persisted longer on steel and plastic surfaces (192 hours) than cotton (<24 hours). Dilute sodium hypochlorite (0.01% and 0.1%) showed little antiviral action, whereas 0.5% and 1% sodium hypochlorite solutions demonstrated recoverable virus at one minute but sterilized surfaces in five minutes. Disinfection with 67% ethanol did not fully clear infectious virions from 3/9 carriers at 1 minute but sterilized all carriers at 5 and 10 minutes. Conclusions: Sodium hypochlorite and ethanol effectively decontaminate EBOV/Mak suspended in a simulated organic load; however, selection of concentration and contact time proves critical. Full article

(This article belongs to the Collection Advances in Ebolavirus, Marburgvirus, and Cuevavirus Research)

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Open AccessArticle

Gene Acquisition Convergence between Entomopoxviruses and Baculoviruses

by Julien Thézé, Jun Takatsuka, Madoka Nakai, Basil Arif and Elisabeth A. Herniou

Viruses 2015, 7(4), 1960-1974; https://doi.org/10.3390/v7041960 - 13 Apr 2015

Cited by 42 | Viewed by 7653

Abstract

Organisms from diverse phylogenetic origins can thrive within the same ecological niches. They might be induced to evolve convergent adaptations in response to a similar landscape of selective pressures. Their genomes should bear the signature of this process. The study of unrelated virus [...] Read more.

Organisms from diverse phylogenetic origins can thrive within the same ecological niches. They might be induced to evolve convergent adaptations in response to a similar landscape of selective pressures. Their genomes should bear the signature of this process. The study of unrelated virus lineages infecting the same host panels guarantees a clear identification of phyletically independent convergent adaptation. Here, we investigate the evolutionary history of genes in the accessory genome shared by unrelated insect large dsDNA viruses: the entomopoxviruses (EPVs, Poxviridae) and the baculoviruses (BVs). EPVs and BVs have overlapping ecological niches and have independently evolved similar infection processes. They are, in theory, subjected to the same selective pressures from their host’s immune responses. Their accessory genomes might, therefore, bear analogous genomic signatures of convergent adaption and could point out key genomic mechanisms of adaptation hitherto undetected in viruses. We uncovered 32 homologous, yet independent acquisitions of genes originating from insect hosts, different eukaryotes, bacteria and viruses. We showed different evolutionary levels of gene acquisition convergence in these viruses, underlining a continuous evolutionary process. We found both recent and ancient gene acquisitions possibly involved to the adaptation to both specific and distantly related hosts. Multidirectional and multipartite gene exchange networks appear to constantly drive exogenous gene assimilations, bringing key adaptive innovations and shaping the life histories of large DNA viruses. This evolutionary process might lead to genome level adaptive convergence. Full article

(This article belongs to the Special Issue Poxvirus Evolution)

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Open AccessReview

Insect-Specific Flaviviruses: A Systematic Review of Their Discovery, Host Range, Mode of Transmission, Superinfection Exclusion Potential and Genomic Organization

by Bradley J. Blitvich and Andrew E. Firth

Viruses 2015, 7(4), 1927-1959; https://doi.org/10.3390/v7041927 - 10 Apr 2015

Cited by 241 | Viewed by 17785

Abstract

There has been a dramatic increase in the number of insect-specific flaviviruses (ISFs) discovered in the last decade. Historically, these viruses have generated limited interest due to their inability to infect vertebrate cells. This viewpoint has changed in recent years because some ISFs [...] Read more.

There has been a dramatic increase in the number of insect-specific flaviviruses (ISFs) discovered in the last decade. Historically, these viruses have generated limited interest due to their inability to infect vertebrate cells. This viewpoint has changed in recent years because some ISFs have been shown to enhance or suppress the replication of medically important flaviviruses in co-infected mosquito cells. Additionally, comparative studies between ISFs and medically important flaviviruses can provide a unique perspective as to why some flaviviruses possess the ability to infect and cause devastating disease in humans while others do not. ISFs have been isolated exclusively from mosquitoes in nature but the detection of ISF-like sequences in sandflies and chironomids indicates that they may also infect other dipterans. ISFs can be divided into two distinct phylogenetic groups. The first group currently consists of approximately 12 viruses and includes cell fusing agent virus, Kamiti River virus and Culex flavivirus. These viruses are phylogenetically distinct from all other known flaviviruses. The second group, which is apparently not monophyletic, currently consists of nine viruses and includes Chaoyang virus, Nounané virus and Lammi virus. These viruses phylogenetically affiliate with mosquito/vertebrate flaviviruses despite their apparent insect-restricted phenotype. This article provides a review of the discovery, host range, mode of transmission, superinfection exclusion ability and genomic organization of ISFs. This article also attempts to clarify the ISF nomenclature because some of these viruses have been assigned more than one name due to their simultaneous discoveries by independent research groups. Full article

(This article belongs to the Section Invertebrate Viruses)

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Open AccessArticle

Archaeal Viruses Multiply: Temporal Screening in a Solar Saltern

by Nina S. Atanasova, Tatiana A. Demina, Andrius Buivydas, Dennis H. Bamford and Hanna M. Oksanen

Viruses 2015, 7(4), 1902-1926; https://doi.org/10.3390/v7041902 - 10 Apr 2015

Cited by 30 | Viewed by 7929

Abstract

Hypersaline environments around the world are dominated by archaea and their viruses. To date, very little is known about these viruses and their interaction with the host strains when compared to bacterial and eukaryotic viruses. We performed the first culture-dependent temporal screening of [...] Read more.

Hypersaline environments around the world are dominated by archaea and their viruses. To date, very little is known about these viruses and their interaction with the host strains when compared to bacterial and eukaryotic viruses. We performed the first culture-dependent temporal screening of haloarchaeal viruses and their hosts in the saltern of Samut Sakhon, Thailand, during two subsequent years (2009, 2010). Altogether we obtained 36 haloarchaeal virus isolates and 36 archaeal strains, significantly increasing the number of known archaeal virus isolates. Interestingly, the morphological distribution of our temporal isolates (head-tailed, pleomorphic, and icosahedral membrane-containing viruses) was similar to the outcome of our previous spatial survey supporting the observations of a global resemblance of halophilic microorganisms and their viruses. Myoviruses represented the most abundant virus morphotype with strikingly broad host ranges. The other viral morphotypes (siphoviruses, as well as pleomorphic and icosahedral internal membrane-containing viruses) were more host-specific. We also identified a group of Halorubrum strains highly susceptible to numerous different viruses (up to 26). This high virus sensitivity, the abundance of broad host range viruses, and the maintenance of infectivity over a period of one year suggest constant interplay of halophilic microorganisms and their viruses within an extreme environment. Full article

(This article belongs to the Section Bacterial Viruses)

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Open AccessReview

The Role of Merkel Cell Polyomavirus and Other Human Polyomaviruses in Emerging Hallmarks of Cancer

by Ugo Moens, Kashif Rasheed, Ibrahim Abdulsalam and Baldur Sveinbjørnsson

Viruses 2015, 7(4), 1871-1901; https://doi.org/10.3390/v7041871 - 10 Apr 2015

Cited by 41 | Viewed by 9968

Abstract

Polyomaviruses are non-enveloped, dsDNA viruses that are common in mammals, including humans. All polyomaviruses encode the large T-antigen and small t-antigen proteins that share conserved functional domains, comprising binding motifs for the tumor suppressors pRb and p53, and for protein phosphatase 2A, respectively. [...] Read more.

Polyomaviruses are non-enveloped, dsDNA viruses that are common in mammals, including humans. All polyomaviruses encode the large T-antigen and small t-antigen proteins that share conserved functional domains, comprising binding motifs for the tumor suppressors pRb and p53, and for protein phosphatase 2A, respectively. At present, 13 different human polyomaviruses are known, and for some of them their large T-antigen and small t-antigen have been shown to possess oncogenic properties in cell culture and animal models, while similar functions are assumed for the large T- and small t-antigen of other human polyomaviruses. However, so far the Merkel cell polyomavirus seems to be the only human polyomavirus associated with cancer. The large T- and small t-antigen exert their tumorigenic effects through classical hallmarks of cancer: inhibiting tumor suppressors, activating tumor promoters, preventing apoptosis, inducing angiogenesis and stimulating metastasis. This review elaborates on the putative roles of human polyomaviruses in some of the emerging hallmarks of cancer. The reciprocal interactions between human polyomaviruses and the immune system response are discussed, a plausible role of polyomavirus-encoded and polyomavirus-induced microRNA in cancer is described, and the effect of polyomaviruses on energy homeostasis and exosomes is explored. Therapeutic strategies against these emerging hallmarks of cancer are also suggested. Full article

(This article belongs to the Special Issue Tumour Viruses)

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Open AccessReview

A Current Overview of the Papaya meleira virus, an Unusual Plant Virus

by Paolla M. V. Abreu, Tathiana F. S. Antunes, Anuar Magaña-Álvarez, Daisy Pérez-Brito, Raúl Tapia-Tussell, José A. Ventura, Antonio A. R. Fernandes and Patricia M. B. Fernandes

Viruses 2015, 7(4), 1853-1870; https://doi.org/10.3390/v7041853 - 8 Apr 2015

Cited by 32 | Viewed by 13621

Abstract

Papaya meleira virus (PMeV) is the causal agent of papaya sticky disease, which is characterized by a spontaneous exudation of fluid and aqueous latex from the papaya fruit and leaves. The latex oxidizes after atmospheric exposure, resulting in a sticky feature on the [...] Read more.

Papaya meleira virus (PMeV) is the causal agent of papaya sticky disease, which is characterized by a spontaneous exudation of fluid and aqueous latex from the papaya fruit and leaves. The latex oxidizes after atmospheric exposure, resulting in a sticky feature on the fruit from which the name of the disease originates. PMeV is an isometric virus particle with a double-stranded RNA (dsRNA) genome of approximately 12 Kb. Unusual for a plant virus, PMeV particles are localized on and linked to the polymers present in the latex. The ability of the PMeV to inhabit such a hostile environment demonstrates an intriguing interaction of the virus with the papaya. A hypersensitivity response is triggered against PMeV infection, and there is a reduction in the proteolytic activity of papaya latex during sticky disease. In papaya leaf tissues, stress responsive proteins, mostly calreticulin and proteasome-related proteins, are up regulated and proteins related to metabolism are down-regulated. Additionally, PMeV modifies the transcription of several miRNAs involved in the modulation of genes related to the ubiquitin-proteasome system. Until now, no PMeV resistant papaya genotype has been identified and roguing is the only viral control strategy available. However, a single inoculation of papaya plants with PMeV dsRNA delayed the progress of viral infection. Full article

(This article belongs to the Section Viruses of Plants, Fungi and Protozoa)

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Open AccessArticle

In Ovo Delivery of CpG DNA Reduces Avian Infectious Laryngotracheitis Virus Induced Mortality and Morbidity

by Simrika Thapa, Mohamed Sarjoon Abdul Cader, Kalamathy Murugananthan, Eva Nagy, Shayan Sharif, Markus Czub and Mohamed Faizal Abdul-Careem

Viruses 2015, 7(4), 1832-1852; https://doi.org/10.3390/v7041832 - 8 Apr 2015

Cited by 29 | Viewed by 6829

Abstract

Endosomal toll-like receptor-21 and -9 sense CpG DNA activating production of pro-inflammatory mediators with antimicrobial effects. Here, we investigated the induction of antiviral response of in ovo delivered CpG DNA against infectious laryngotracheitis virus (ILTV) infection. We found that in ovo delivered CpG [...] Read more.

Endosomal toll-like receptor-21 and -9 sense CpG DNA activating production of pro-inflammatory mediators with antimicrobial effects. Here, we investigated the induction of antiviral response of in ovo delivered CpG DNA against infectious laryngotracheitis virus (ILTV) infection. We found that in ovo delivered CpG DNA significantly reduces ILTV infection pre-hatch correlating with the expression of IL-1β and increase of macrophages in lungs. As assessed in vitro, CpG DNA stimulated avian macrophages could be a potential source of IL-1β and other pro-inflammatory mediators. Since we also found that in ovo CpG DNA delivery maintains increased macrophages in the lungs post-hatch, we infected the chickens on the day of hatch with ILTV. We found that in ovo delivered CpG DNA significantly reduces mortality and morbidity resulting from ILTV infection encountered post-hatch. Thus, CpG DNA can be a candidate innate immune stimulant worthy of further investigation for the control of ILTV infection in chickens. Full article

(This article belongs to the Section Viral Immunology, Vaccines, and Antivirals)

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Open AccessCommunication

Analysis of HDAC6 and BAG3-Aggresome Pathways in African Swine Fever Viral Factory Formation

by Raquel Muñoz-Moreno, Lucía Barrado-Gil, Inmaculada Galindo and Covadonga Alonso

Viruses 2015, 7(4), 1823-1831; https://doi.org/10.3390/v7041823 - 8 Apr 2015

Cited by 15 | Viewed by 7160

Abstract

African swine fever virus (ASFV) is a double-stranded DNA virus causing a hemorrhagic fever disease with high mortality rates and severe economic losses in pigs worldwide. ASFV replicates in perinuclear sites called viral factories (VFs) that are morphologically similar to cellular aggresomes. This [...] Read more.

African swine fever virus (ASFV) is a double-stranded DNA virus causing a hemorrhagic fever disease with high mortality rates and severe economic losses in pigs worldwide. ASFV replicates in perinuclear sites called viral factories (VFs) that are morphologically similar to cellular aggresomes. This fact raises the possibility that both VFs and aggresomes may be the same structure. However, little is known about the process involved in the formation of these viral replication platforms. In order to expand our knowledge on the assembly of ASFV replication sites, we have analyzed the involvement of both canonical aggresome pathways in the formation of ASFV VFs: HDAC6 and BAG3. HDAC6 interacts with a component of the dynein motor complex (dynactin/p150^Glued) and ubiquitinated proteins, transporting them to the microtubule-organizing center (MTOC) and leading to aggresome formation, while BAG3 is mediating the recruitment of non-ubiquitinated proteins through a similar mechanism. Tubacin-mediated HDAC6 inhibition and silencing of BAG3 pathways, individually or simultaneously, did not prevent ASFV VF formation. These findings show that HDAC6 and Bag3 are not required for VFs formation suggesting that aggresomes and VFs are not the same structures. However, alternative unexplored pathways may be involved in the formation of aggresomes. Full article

(This article belongs to the Section Animal Viruses)

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Open AccessArticle

by Harald Eriksson, Barbara Maciejewska, Agnieszka Latka, Grazyna Majkowska-Skrobek, Marios Hellstrand, Öjar Melefors, Jin-Town Wang, Andrew M. Kropinski, Zuzanna Drulis-Kawa and Anders S. Nilsson

Viruses 2015, 7(4), 1804-1822; https://doi.org/10.3390/v7041804 - 7 Apr 2015

Cited by 35 | Viewed by 9896

Abstract

Klebsiella pneumoniae phages vB_KpnP_SU503 (SU503) and vB_KpnP_SU552A (SU552A) are virulent viruses belonging to the Autographivirinae subfamily of Podoviridae that infect and kill multi-resistant K. pneumoniae isolates. Phages SU503 and SU552A show high pairwise nucleotide identity to Klebsiella phages KP34 (NC_013649), F19 (NC_023567) and [...] Read more.

Klebsiella pneumoniae phages vB_KpnP_SU503 (SU503) and vB_KpnP_SU552A (SU552A) are virulent viruses belonging to the Autographivirinae subfamily of Podoviridae that infect and kill multi-resistant K. pneumoniae isolates. Phages SU503 and SU552A show high pairwise nucleotide identity to Klebsiella phages KP34 (NC_013649), F19 (NC_023567) and NTUH-K2044-K1-1 (NC_025418). Bioinformatic analysis of these phage genomes show high conservation of gene arrangement and gene content, conserved catalytically active residues of their RNA polymerase, a common and specific lysis cassette, and form a joint cluster in phylogenetic analysis of their conserved genes. Also, we have performed biological characterization of the burst size, latent period, host specificity (together with KP34 and NTUH-K2044-K1-1), morphology, and structural genes as well as sensitivity testing to various conditions. Based on the analyses of these phages, the creation of a new phage genus is suggested within the Autographivirinae, called “Kp34likevirus” after their type phage, KP34. This genus should encompass the recently genome sequenced Klebsiella phages KP34, SU503, SU552A, F19 and NTUH-K2044-K1-1. Full article

(This article belongs to the Special Issue 21st Evergreen International Phage Biology Meeting - Emerging Research)

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Open AccessReview

The Evolution of Poxvirus Vaccines

by Lucas Sánchez-Sampedro, Beatriz Perdiguero, Ernesto Mejías-Pérez, Juan García-Arriaza, Mauro Di Pilato and Mariano Esteban

Viruses 2015, 7(4), 1726-1803; https://doi.org/10.3390/v7041726 - 7 Apr 2015

Cited by 161 | Viewed by 15514

Abstract

After Edward Jenner established human vaccination over 200 years ago, attenuated poxviruses became key players to contain the deadliest virus of its own family: Variola virus (VARV), the causative agent of smallpox. Cowpox virus (CPXV) and horsepox virus (HSPV) were extensively used to [...] Read more.

After Edward Jenner established human vaccination over 200 years ago, attenuated poxviruses became key players to contain the deadliest virus of its own family: Variola virus (VARV), the causative agent of smallpox. Cowpox virus (CPXV) and horsepox virus (HSPV) were extensively used to this end, passaged in cattle and humans until the appearance of vaccinia virus (VACV), which was used in the final campaigns aimed to eradicate the disease, an endeavor that was accomplished by the World Health Organization (WHO) in 1980. Ever since, naturally evolved strains used for vaccination were introduced into research laboratories where VACV and other poxviruses with improved safety profiles were generated. Recombinant DNA technology along with the DNA genome features of this virus family allowed the generation of vaccines against heterologous diseases, and the specific insertion and deletion of poxvirus genes generated an even broader spectrum of modified viruses with new properties that increase their immunogenicity and safety profile as vaccine vectors. In this review, we highlight the evolution of poxvirus vaccines, from first generation to the current status, pointing out how different vaccines have emerged and approaches that are being followed up in the development of more rational vaccines against a wide range of diseases. Full article

(This article belongs to the Special Issue Poxvirus Evolution)

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Open AccessReview

Incorporation of Spike and Membrane Glycoproteins into Coronavirus Virions

by Makoto Ujike and Fumihiro Taguchi

Viruses 2015, 7(4), 1700-1725; https://doi.org/10.3390/v7041700 - 3 Apr 2015

Cited by 115 | Viewed by 14219

Abstract

The envelopes of coronaviruses (CoVs) contain primarily three proteins; the two major glycoproteins spike (S) and membrane (M), and envelope (E), a non-glycosylated protein. Unlike other enveloped viruses, CoVs bud and assemble at the endoplasmic reticulum (ER)-Golgi intermediate compartment (ERGIC). For efficient virion [...] Read more.

The envelopes of coronaviruses (CoVs) contain primarily three proteins; the two major glycoproteins spike (S) and membrane (M), and envelope (E), a non-glycosylated protein. Unlike other enveloped viruses, CoVs bud and assemble at the endoplasmic reticulum (ER)-Golgi intermediate compartment (ERGIC). For efficient virion assembly, these proteins must be targeted to the budding site and to interact with each other or the ribonucleoprotein. Thus, the efficient incorporation of viral envelope proteins into CoV virions depends on protein trafficking and protein–protein interactions near the ERGIC. The goal of this review is to summarize recent findings on the mechanism of incorporation of the M and S glycoproteins into the CoV virion, focusing on protein trafficking and protein–protein interactions. Full article

(This article belongs to the Special Issue Viral Glycoprotein Incorporation)

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Open AccessCommunication

Deep Sequencing Reveals the Complete Genome and Evidence for Transcriptional Activity of the First Virus-Like Sequences Identified in Aristotelia chilensis (Maqui Berry)

by Javier Villacreses, Marcelo Rojas-Herrera, Carolina Sánchez, Nicole Hewstone, Soledad F. Undurraga, Juan F. Alzate, Patricio Manque, Vinicius Maracaja-Coutinho and Victor Polanco

Viruses 2015, 7(4), 1685-1699; https://doi.org/10.3390/v7041685 - 3 Apr 2015

Cited by 7 | Viewed by 7644

Abstract

Here, we report the genome sequence and evidence for transcriptional activity of a virus-like element in the native Chilean berry tree Aristotelia chilensis. We propose to name the endogenous sequence as Aristotelia chilensis Virus 1 (AcV1). High-throughput sequencing of the genome of [...] Read more.

Here, we report the genome sequence and evidence for transcriptional activity of a virus-like element in the native Chilean berry tree Aristotelia chilensis. We propose to name the endogenous sequence as Aristotelia chilensis Virus 1 (AcV1). High-throughput sequencing of the genome of this tree uncovered an endogenous viral element, with a size of 7122 bp, corresponding to the complete genome of AcV1. Its sequence contains three open reading frames (ORFs): ORFs 1 and 2 shares 66%–73% amino acid similarity with members of the Caulimoviridae virus family, especially the Petunia vein clearing virus (PVCV), Petuvirus genus. ORF1 encodes a movement protein (MP); ORF2 a Reverse Transcriptase (RT) and a Ribonuclease H (RNase H) domain; and ORF3 showed no amino acid sequence similarity with any other known virus proteins. Analogous to other known endogenous pararetrovirus sequences (EPRVs), AcV1 is integrated in the genome of Maqui Berry and showed low viral transcriptional activity, which was detected by deep sequencing technology (DNA and RNA-seq). Phylogenetic analysis of AcV1 and other pararetroviruses revealed a closer resemblance with Petuvirus. Overall, our data suggests that AcV1 could be a new member of Caulimoviridae family, genus Petuvirus, and the first evidence of this kind of virus in a fruit plant. Full article

(This article belongs to the Section Viruses of Plants, Fungi and Protozoa)

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Open AccessArticle

Human Pirh2 is A Novel Inhibitor of Prototype Foamy Virus Replication

by Lanlan Dong, Qingqing Cheng, Zhihao Wang, Peipei Yuan, Zhi Li, Yan Sun, Song Han, Jun Yin, Biwen Peng, Xiaohua He and Wanhong Liu

Viruses 2015, 7(4), 1668-1684; https://doi.org/10.3390/v7041668 - 2 Apr 2015

Cited by 21 | Viewed by 5913

Abstract

Prototype foamy virus (PFV) is a member of the unconventional and nonpathogenic retroviruses. PFV causes lifelong chronic infections, which are partially attributable to a number of host cell factors that restrict viral replication. Herein, we identified human p53-induced RING-H2 protein (Pirh2) as a [...] Read more.

Prototype foamy virus (PFV) is a member of the unconventional and nonpathogenic retroviruses. PFV causes lifelong chronic infections, which are partially attributable to a number of host cell factors that restrict viral replication. Herein, we identified human p53-induced RING-H2 protein (Pirh2) as a novel inhibitor of prototype foamy virus. Overexpression of Pirh2 decreased the replication of PFV, whereas knockdown of Pirh2 with specific siRNA increased PFV replication. Dual-luciferase assays and coimmunoprecipitation demonstrated that Pirh2 negatively influences the Tas-dependent transcriptional activation of the PFV long terminal repeat (LTR) and internal promoter (IP) by interacting with the transactivator Tas and down-regulating its expression. In addition, the viral inhibitory function of Pirh2 is N-terminal and RING domain dependent. Together, these results indicated that Pirh2 suppresses PFV replication by negatively impacting its transactivator Tas and the transcription of two viral promoters, which may contribute to the latency of PFV infection. Full article

(This article belongs to the Section Animal Viruses)

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Open AccessAddendum

Addendum: Kaźmierczak, Z.; Górski, A.; Dąbrowska, K. Facing Antibiotic Resistance: Staphylococcus aureus Phages as a Medical Tool. Viruses 2014, 6, 2551-2570.

by Zuzanna Kaźmierczak, Andrzej Górski and Krystyna Dąbrowska

Viruses 2015, 7(4), 1667; https://doi.org/10.3390/v7041667 - 31 Mar 2015

Cited by 5 | Viewed by 4079

Abstract

The authors would like to add the following Acknowledgements section: “Acknowledgements This work was funded by the National Science Centre in Poland grant UMO-2012/05/E/NZ6/03314.” [...] Full article

(This article belongs to the Section Bacterial Viruses)

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Open AccessConference Report

Tenth International Foamy Virus Conference 2014–Achievements and Perspectives

by Magdalena Materniak, Piotr Kubiś, Marzena Rola–Łuszczak, Arifa S. Khan, Florence Buseyne, Dirk Lindemann, Martin Löchelt and Jacek Kuźmak

Viruses 2015, 7(4), 1651-1666; https://doi.org/10.3390/v7041651 - 31 Mar 2015

Cited by 5 | Viewed by 6286

Abstract

For the past two decades, scientists from around the world, working on different aspects of foamy virus (FV) research, have gathered in different research institutions almost every two years to present their recent results in formal talks, to discuss their ongoing studies informally, [...] Read more.

For the past two decades, scientists from around the world, working on different aspects of foamy virus (FV) research, have gathered in different research institutions almost every two years to present their recent results in formal talks, to discuss their ongoing studies informally, and to initiate fruitful collaborations. In this report we review the 2014 anniversary conference to share the meeting summary with the virology community and hope to arouse interest by other researchers to join this exciting field. The topics covered included epidemiology, virus molecular biology, and immunology of FV infection in non-human primates, cattle, and humans with zoonotic FV infections, as well as recent findings on endogenous FVs. Several topics focused on virus replication and interactions between viral and cellular proteins. Use of FV in biomedical research was highlighted with presentations on using FV vectors for gene therapy and FV proteins as scaffold for vaccine antigen presentation. On behalf of the FV community, this report also includes a short tribute to commemorate Prof. Axel Rethwilm, one of the leading experts in the field of retrovirology and foamy viruses, who passed away 29 July 2014. Full article

(This article belongs to the Section Animal Viruses)

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Open AccessCommunication

Presence of Poly(A) Tails at the 3'-Termini of Some mRNAs of a Double-Stranded RNA Virus, Southern Rice Black-Streaked Dwarf Virus

by Ming He, Ziqiong Jiang, Shuo Li and Peng He

Viruses 2015, 7(4), 1642-1650; https://doi.org/10.3390/v7041642 - 31 Mar 2015

Cited by 7 | Viewed by 11352

Abstract

Southern rice black-streaked dwarf virus (SRBSDV), a new member of the genus Fijivirus, is a double-stranded RNA virus known to lack poly(A) tails. We now showed that some of SRBSDV mRNAs were indeed polyadenylated at the 3' terminus in plant hosts, and [...] Read more.

Southern rice black-streaked dwarf virus (SRBSDV), a new member of the genus Fijivirus, is a double-stranded RNA virus known to lack poly(A) tails. We now showed that some of SRBSDV mRNAs were indeed polyadenylated at the 3' terminus in plant hosts, and investigated the nature of 3' poly(A) tails. The non-abundant presence of SRBSDV mRNAs bearing polyadenylate tails suggested that these viral RNA were subjected to polyadenylation-stimulated degradation. The discovery of poly(A) tails in different families of viruses implies potentially a wide occurrence of the polyadenylation-assisted RNA degradation in viruses. Full article

(This article belongs to the Section Viruses of Plants, Fungi and Protozoa)

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Open AccessArticle

Glycosylation of KSHV Encoded vGPCR Functions in Its Signaling and Tumorigenicity

by Hui Wu, Liqun Liu, Jun Xiao, Mengdie Chi, Yixiao Qu and Hao Feng

Viruses 2015, 7(4), 1627-1641; https://doi.org/10.3390/v7041627 - 31 Mar 2015

Cited by 12 | Viewed by 6264

Abstract

Kaposi’s sarcoma-associated herpesvirus (KSHV) is a tumor virus and the etiologic agent of Kaposi’s Sarcoma (KS). KSHV G protein-coupled receptor (vGPCR) is an oncogene that is implicated in malignancies associated with KHSV infection. In this study, we show that vGPCR undergoes extensive [...] Read more.

Kaposi’s sarcoma-associated herpesvirus (KSHV) is a tumor virus and the etiologic agent of Kaposi’s Sarcoma (KS). KSHV G protein-coupled receptor (vGPCR) is an oncogene that is implicated in malignancies associated with KHSV infection. In this study, we show that vGPCR undergoes extensive N-linked glycosylation within the extracellular domains, specifically asparagines 18, 22, 31 and 202. An immunofluorescence assay demonstrates that N-linked glycosylation are necessary for vGPCR trafficking to the cellular membrane. Employing vGPCR mutants whose glycosylation sites were ablated, we show that these vGPCR mutants failed to activate downstream signaling in cultured cells and were severely impaired to induce tumor formation in the xenograph nude mouse model. These findings support the conclusion that glycosylation is critical for vGPCR tumorigenesis and imply that chemokine regulation at the plasma membrane is crucial for vGPCR mediated signaling. Full article

(This article belongs to the Special Issue Kaposi's Sarcoma-Associated Herpesvirus)

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Open AccessArticle

Apigenin Restricts FMDV Infection and Inhibits Viral IRES Driven Translational Activity

by Suhong Qian, Wenchun Fan, Ping Qian, Dong Zhang, Yurong Wei, Huanchun Chen and Xiangmin Li

Viruses 2015, 7(4), 1613-1626; https://doi.org/10.3390/v7041613 - 31 Mar 2015

Cited by 95 | Viewed by 9018

Abstract

Foot-and-mouth disease (FMD) is a highly contagious disease of domestic and wild ruminants that is caused by FMD virus (FMDV). FMD outbreaks have occurred in livestock-containing regions worldwide. Apigenin, which is a flavonoid naturally existing in plant, possesses various pharmacological effects, including anti-inflammatory, [...] Read more.

Foot-and-mouth disease (FMD) is a highly contagious disease of domestic and wild ruminants that is caused by FMD virus (FMDV). FMD outbreaks have occurred in livestock-containing regions worldwide. Apigenin, which is a flavonoid naturally existing in plant, possesses various pharmacological effects, including anti-inflammatory, anticancer, antioxidant and antiviral activities. Results show that apigenin can inhibit FMDV-mediated cytopathogenic effect and FMDV replication in vitro. Further studies demonstrate the following: (i) apigenin inhibits FMDV infection at the viral post-entry stage; (ii) apigenin does not exhibit direct extracellular virucidal activity; and (iii) apigenin interferes with the translational activity of FMDV driven by internal ribosome entry site. Studies on applying apigein in vivo are required for drug development and further identification of potential drug targets against FDMV infection. Full article

(This article belongs to the Section Viral Immunology, Vaccines, and Antivirals)

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Open AccessArticle

Development of a Recombination System for the Generation of Occlusion Positive Genetically Modified Anticarsia Gemmatalis Multiple Nucleopolyhedrovirus

by Santiago Haase, Christina B. McCarthy, M. Leticia Ferrelli, Matias L. Pidre, Alicia Sciocco-Cap and Victor Romanowski

Viruses 2015, 7(4), 1599-1612; https://doi.org/10.3390/v7041599 - 31 Mar 2015

Cited by 9 | Viewed by 6007

Abstract

Anticarsia gemmatalis is an important pest in legume crops in South America and it has been successfully controlled using Anticarsia gemmatalis Multiple Nucleopolyhedrovirus (AgMNPV) in subtropical climate zones. Nevertheless, in temperate climates its speed of kill is too slow. Taking this into account, [...] Read more.

Anticarsia gemmatalis is an important pest in legume crops in South America and it has been successfully controlled using Anticarsia gemmatalis Multiple Nucleopolyhedrovirus (AgMNPV) in subtropical climate zones. Nevertheless, in temperate climates its speed of kill is too slow. Taking this into account, genetic modification of AgMNPV could lead to improvements of its biopesticidal properties. Here we report the generation of a two-component system that allows the production of recombinant AgMNPV. This system is based on a parental AgMNPV in which the polyhedrin gene (polh) was replaced by a bacterial β-galactosidase (lacZ) gene flanked by two target sites for the homing endonuclease I-PpoI. Co-transfection of insect cells with linearized (I-PpoI-digested) parental genome and a transfer vector allowed the restitution of polh and the expression of a heterologous gene upon homologous recombination, with a low background of non-recombinant AgMNPV. The system was validated by constructing a recombinant occlusion-positive (polh⁺) AgMNPV expressing the green fluorescent protein gene (gfp). This recombinant virus infected larvae normally per os and led to the expression of GFP in cell culture as well as in A. gemmatalis larvae. These results demonstrate that the system is an efficient method for the generation of recombinant AgMNPV expressing heterologous genes, which can be used for manifold purposes, including biotechnological and pharmaceutical applications and the production of orally infectious recombinants with improved biopesticidal properties. Full article

(This article belongs to the Special Issue Insect Viruses and Their Use for Microbial Pest Control)

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Open AccessReview

Eradication of HIV-1 from the Macrophage Reservoir: An Uncertain Goal?

by Wasim Abbas, Muhammad Tariq, Mazhar Iqbal, Amit Kumar and Georges Herbein

Viruses 2015, 7(4), 1578-1598; https://doi.org/10.3390/v7041578 - 31 Mar 2015

Cited by 74 | Viewed by 12928

Abstract

Human immunodeficiency virus type 1 (HIV-1) establishes latency in resting memory CD4+ T cells and cells of myeloid lineage. In contrast to the T cells, cells of myeloid lineage are resistant to the HIV-1 induced cytopathic effect. Cells of myeloid lineage including macrophages [...] Read more.

Human immunodeficiency virus type 1 (HIV-1) establishes latency in resting memory CD4+ T cells and cells of myeloid lineage. In contrast to the T cells, cells of myeloid lineage are resistant to the HIV-1 induced cytopathic effect. Cells of myeloid lineage including macrophages are present in anatomical sanctuaries making them a difficult drug target. In addition, the long life span of macrophages as compared to the CD4+ T cells make them important viral reservoirs in infected individuals especially in the late stage of viral infection where CD4+ T cells are largely depleted. In the past decade, HIV-1 persistence in resting CD4+ T cells has gained considerable attention. It is currently believed that rebound viremia following cessation of combination anti-retroviral therapy (cART) originates from this source. However, the clinical relevance of this reservoir has been questioned. It is suggested that the resting CD4+ T cells are only one source of residual viremia and other viral reservoirs such as tissue macrophages should be seriously considered. In the present review we will discuss how macrophages contribute to the development of long-lived latent reservoirs and how macrophages can be used as a therapeutic target in eradicating latent reservoir. Full article

(This article belongs to the Section Animal Viruses)

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