Viruses

484 KiB

Open AccessReview

Small Ruminant Lentiviruses: Genetic Variability, Tropism and Diagnosis

by Hugo Ramírez, Ramsés Reina, Beatriz Amorena, Damián De Andrés and Humberto A. Martínez

Viruses 2013, 5(4), 1175-1207; https://doi.org/10.3390/v5041175 - 23 Apr 2013

Cited by 93 | Viewed by 7211

Small ruminant lentiviruses (SRLV) cause a multisystemic chronic disease affecting animal production and welfare. SRLV infections are spread across the world with the exception of Iceland. Success in controlling SRLV spread depends largely on the use of appropriate diagnostic tools, but the existence [...] Read more.

Small ruminant lentiviruses (SRLV) cause a multisystemic chronic disease affecting animal production and welfare. SRLV infections are spread across the world with the exception of Iceland. Success in controlling SRLV spread depends largely on the use of appropriate diagnostic tools, but the existence of a high genetic/antigenic variability among these viruses, the fluctuant levels of antibody against them and the low viral loads found in infected individuals hamper the diagnostic efficacy. SRLV have a marked in vivo tropism towards the monocyte/macrophage lineage and attempts have been made to identify the genome regions involved in tropism, with two main candidates, the LTR and env gene, since LTR contains primer binding sites for viral replication and the env-encoded protein (SU ENV), which mediates the binding of the virus to the host’s cell and has hypervariable regions to escape the humoral immune response. Once inside the host cell, innate immunity may interfere with SRLV replication, but the virus develops counteraction mechanisms to escape, multiply and survive, creating a quasi-species and undergoing compartmentalization events. So far, the mechanisms of organ tropism involved in the development of different disease forms (neurological, arthritic, pulmonary and mammary) are unknown, but different alternatives are proposed. This is an overview of the current state of knowledge on SRLV genetic variability and its implications in tropism as well as in the development of alternative diagnostic assays. Full article

(This article belongs to the Special Issue Small Ruminant Lentiviruses)

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Open AccessArticle

Characterization of Clade 2.3.2.1 H5N1 Highly Pathogenic Avian Influenza Viruses Isolated from Wild Birds (Mandarin Duck and Eurasian Eagle Owl) in 2010 in Korea

by Jun-Gu Choi, Hyun-Mi Kang, Woo-Jin Jeon, Kang-Seuk Choi, Kwang-Il Kim, Byung Min Song, Hee-Soo Lee, Jae-Hong Kim and Youn-Jeong Lee

Viruses 2013, 5(4), 1153-1174; https://doi.org/10.3390/v5041153 - 23 Apr 2013

Cited by 30 | Viewed by 8811

Abstract

Starting in late November 2010, the H5N1 highly pathogenic avian influenza (HPAI) virus was isolated from many types of wild ducks and raptors and was subsequently isolated from poultry in Korea. We assessed the genetic and pathogenic properties of the HPAI viruses isolated [...] Read more.

Starting in late November 2010, the H5N1 highly pathogenic avian influenza (HPAI) virus was isolated from many types of wild ducks and raptors and was subsequently isolated from poultry in Korea. We assessed the genetic and pathogenic properties of the HPAI viruses isolated from a fecal sample from a mandarin duck and a dead Eurasian eagle owl, the most affected wild bird species during the 2010/2011 HPAI outbreak in Korea. These viruses have similar genetic backgrounds and exhibited the highest genetic similarity with recent Eurasian clade 2.3.2.1 HPAI viruses. In animal inoculation experiments, regardless of their originating hosts, the two Korean isolates produced highly pathogenic characteristics in chickens, ducks and mice without pre-adaptation. These results raise concerns about veterinary and public health. Surveillance of wild birds could provide a good early warning signal for possible HPAI infection in poultry as well as in humans. Full article

(This article belongs to the Special Issue H5N1 Influenza Virus)

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467 KiB

Open AccessArticle

Induced Degradation of Tat by Nucleocapsid (NC) via the Proteasome Pathway and Its Effect on HIV Transcription

by Hye-Won Hong, Seong-Wook Lee and Heejoon Myung

Viruses 2013, 5(4), 1143-1152; https://doi.org/10.3390/v5041143 - 23 Apr 2013

Cited by 14 | Viewed by 6694

Abstract

Human Immunodeficiency Virus type 1 (HIV-1) is a retrovirus that causes acquired immunodeficiency syndrome (AIDS). HIV-1 Tat protein upregulates transcriptional transactivation. The nucleocapsid protein NC of HIV-1 is a component of virion and plays a key role in genome packaging. Herein, we have [...] Read more.

Human Immunodeficiency Virus type 1 (HIV-1) is a retrovirus that causes acquired immunodeficiency syndrome (AIDS). HIV-1 Tat protein upregulates transcriptional transactivation. The nucleocapsid protein NC of HIV-1 is a component of virion and plays a key role in genome packaging. Herein, we have demonstrated the interaction between NC and Tat by means of a yeast two-hybrid assay, GST pull-down analysis, co-immunoprecipitation and subcellular colocalization analysis. We observed that the level of Tat was significantly reduced in the presence of NC. But NC did not affect mRNA expression level of Tat. The level of Tat in the presence of NC was increased by treating cells with a proteasome inhibitor, MG132. The ubiquitination state of Tat was not seen to increase in the presence of NC, suggesting the proteasomal degradation was independent of ubiquitination. Lowered level of Tat in the presence of NC led to a decrease in Tat-mediated transcriptional transactivation. Full article

(This article belongs to the Special Issue HIV Latency)

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417 KiB

Open AccessArticle

Generation and Characterization of a Novel Recombinant Antibody against LMP1-TES1 of Epstein-Barr Virus Isolated by Phage Display

by Dawei Zhang, Yuan Mao, Qing Cao, Lin Xiong, Juan Wen, Renjie Chen and Jin Zhu

Viruses 2013, 5(4), 1131-1142; https://doi.org/10.3390/v5041131 - 22 Apr 2013

Cited by 14 | Viewed by 8036

Abstract

Latent Membrane Protein 1 (LMP1) is a primary target for controlling tumorigenesis in Epstein-Barr virus related malignancies; in this study, we aimed to develop a specific antibody against the TES1 domain of the oncogenic LMP1. We screened a full human naïve Fab phage [...] Read more.

Latent Membrane Protein 1 (LMP1) is a primary target for controlling tumorigenesis in Epstein-Barr virus related malignancies; in this study, we aimed to develop a specific antibody against the TES1 domain of the oncogenic LMP1. We screened a full human naïve Fab phage library against TES1 peptide, which consisted of C terminal-activating regions proximal 44 amino acids. After three rounds of panning, enrichment and testing by phage ELISA and further analyzed by DNA sequencing, we selected a phage clone with the highest affinity to LMP1-TES1 and designated it as htesFab. The positive clone was expressed in Escherichia coli and the purified htesFab was characterized for its binding specificity and affinity to LMP1. ELISA, immunofluorescence and FACS analysis confirmed that htesFab could recognize LMP1 TES1 both in vitro and in LMP1 expressing HNE2-LMP1 cells. Furthermore, MTT assay showed that htesFab inhibited the proliferation of HNE2-LMP1 cells in a dose-dependent manner. In summary, this study reported the isolation and characterization of human Fab, which specifically targets the C terminal region/TES1 of LMP1, and has potential to be developed as novel tool for the diagnosis and therapy of Epstein-Barr virus related carcinoma Full article

(This article belongs to the Special Issue Phage Display in Virus Research)

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718 KiB

Open AccessArticle

Induction of Partial Protection against Foot and Mouth Disease Virus in Guinea Pigs by Neutralization with the Integrin β6-1 Subunit

by Yan Zhang, Yingjun Sun, Fan Yang, Jianhong Guo, Jijun He, Qiong Wu, Weijun Cao, Lv Lv, Haixue Zheng and Zhidong Zhang

Viruses 2013, 5(4), 1114-1130; https://doi.org/10.3390/v5041114 - 19 Apr 2013

Cited by 9 | Viewed by 8635

Abstract

The mechanism by which the foot-and-mouth disease virus (FMDV) initiates infection of cells is thought to involve the attachment of the viral capsid to host integrins on the surface of target cells. However, the role of integrins in FMDV infection still needs to [...] Read more.

The mechanism by which the foot-and-mouth disease virus (FMDV) initiates infection of cells is thought to involve the attachment of the viral capsid to host integrins on the surface of target cells. However, the role of integrins in FMDV infection still needs to be fully understood, although it has been demonstrated that integrin αvβ6 interferes with FMDV in vitro and results in neutralization of its infectivity. In the present study, we describe the cloning and sequencing of suckling mouse integrin β6 and the subsequent expression of two segments of integrin β6 extracellular domains: β6-1 (which contains the ligand-binding domain) and β6-2. Sequencing of the mouse integrin β6 subunit revealed close homology (~90%) with its human counterpart. When recombinant integrin extracellular domains β6-1 and β6-2 formulated with adjuvant were inoculated into guinea pigs, anti-integrin antibody expression was high before FMDV challenge. Interestingly, guinea pigs (50%) inoculated with integrin β6-1 were protected from FMDV infection; in contrast, none of the animals inoculated with integrin β6-2 were protected. This result indicates that an integrin blockade may be able to interfere with FMDV infection in vivo, which raises the possibility that targeting integrin in vivo may be the basis for a new strategy to control FMDV infection. Full article

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459 KiB

Open AccessReview

A Current Overview of Two Viroids That Infect Chrysanthemums: Chrysanthemum stunt viroid and Chrysanthemum chlorotic mottle viroid

by Won Kyong Cho, Yeonhwa Jo, Kyoung-Min Jo and Kook-Hyung Kim

Viruses 2013, 5(4), 1099-1113; https://doi.org/10.3390/v5041099 - 17 Apr 2013

Cited by 36 | Viewed by 10145

Abstract

The chrysanthemum (Dendranthema X grandiflorum) belongs to the family Asteraceae and it is one of the most popular flowers in the world. Viroids are the smallest known plant pathogens. They consist of a circular, single-stranded RNA, which does not encode a [...] Read more.

The chrysanthemum (Dendranthema X grandiflorum) belongs to the family Asteraceae and it is one of the most popular flowers in the world. Viroids are the smallest known plant pathogens. They consist of a circular, single-stranded RNA, which does not encode a protein. Chrysanthemums are a common host for two different viroids, the Chrysanthemum stunt viroid (CSVd) and the Chrysanthemum chlorotic mottle viroid (CChMVd). These viroids are quite different from each other in structure and function. Here, we reviewed research associated with CSVd and CChMVd that covered disease symptoms, identification, host range, nucleotide sequences, phylogenetic relationships, structures, replication mechanisms, symptom determinants, detection methods, viroid elimination, and development of viroid resistant chrysanthemums, among other studies. We propose that the chrysanthemum and these two viroids represent convenient genetic resources for host–viroid interaction studies. Full article

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

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815 KiB

Open AccessReview

Foamy Virus Budding and Release

by Sylvia Hütter, Irena Zurnic and Dirk Lindemann

Viruses 2013, 5(4), 1075-1098; https://doi.org/10.3390/v5041075 - 10 Apr 2013

Cited by 23 | Viewed by 13642

Abstract

Like all other viruses, a successful egress of functional particles from infected cells is a prerequisite for foamy virus (FV) spread within the host. The budding process of FVs involves steps, which are shared by other retroviruses, such as interaction of the capsid [...] Read more.

Like all other viruses, a successful egress of functional particles from infected cells is a prerequisite for foamy virus (FV) spread within the host. The budding process of FVs involves steps, which are shared by other retroviruses, such as interaction of the capsid protein with components of cellular vacuolar protein sorting (Vps) machinery via late domains identified in some FV capsid proteins. Additionally, there are features of the FV budding strategy quite unique to the spumaretroviruses. This includes secretion of non-infectious subviral particles and a strict dependence on capsid-glycoprotein interaction for release of infectious virions from the cells. Virus-like particle release is not possible since FV capsid proteins lack a membrane-targeting signal. It is noteworthy that in experimental systems, the important capsid-glycoprotein interaction could be bypassed by fusing heterologous membrane-targeting signals to the capsid protein, thus enabling glycoprotein-independent egress. Aside from that, other systems have been developed to enable envelopment of FV capsids by heterologous Env proteins. In this review article, we will summarize the current knowledge on FV budding, the viral components and their domains involved as well as alternative and artificial ways to promote budding of FV particle structures, a feature important for alteration of target tissue tropism of FV-based gene transfer systems. Full article

(This article belongs to the Special Issue Recent Progress in Foamy Virus (FV) Research)

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Open AccessReview

Early Events in Foamy Virus—Host Interaction and Intracellular Trafficking

by Ursula Berka, Martin Volker Hamann and Dirk Lindemann

Viruses 2013, 5(4), 1055-1074; https://doi.org/10.3390/v5041055 - 8 Apr 2013

Cited by 18 | Viewed by 9270

Abstract

Here we review viral and cellular requirements for entry and intracellular trafficking of foamy viruses (FVs) resulting in integration of viral sequences into the host cell genome. The virus encoded glycoprotein harbors all essential viral determinants, which are involved in absorption to the [...] Read more.

Here we review viral and cellular requirements for entry and intracellular trafficking of foamy viruses (FVs) resulting in integration of viral sequences into the host cell genome. The virus encoded glycoprotein harbors all essential viral determinants, which are involved in absorption to the host membrane and triggering the uptake of virus particles. However, only recently light was shed on some details of FV’s interaction with its host cell receptor(s). Latest studies indicate glycosaminoglycans of cellular proteoglycans, particularly heparan sulfate, to be of utmost importance. In a species-specific manner FVs encounter endogenous machineries of the target cell, which are in some cases exploited for fusion and further egress into the cytosol. Mostly triggered by pH-dependent endocytosis, viral and cellular membranes fuse and release naked FV capsids into the cytoplasm. Intact FV capsids are then shuttled along microtubules and are found to accumulate nearby the centrosome where they can remain in a latent state for extended time periods. Depending on the host cell cycle status, FV capsids finally disassemble and, by still poorly characterized mechanisms, the preintegration complex gets access to the host cell chromatin. Host cell mitosis finally allows for viral genome integration, ultimately starting a new round of viral replication. Full article

(This article belongs to the Special Issue Recent Progress in Foamy Virus (FV) Research)

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1142 KiB

Open AccessCommentary

Interpreting the Epstein-Barr Virus (EBV) Epigenome Using High-Throughput Data

by Aaron Arvey, Italo Tempera and Paul M. Lieberman

Viruses 2013, 5(4), 1042-1054; https://doi.org/10.3390/v5041042 - 2 Apr 2013

Cited by 46 | Viewed by 8677

Abstract

The Epstein-Barr virus (EBV) double-stranded DNA genome is subject to extensive epigenetic regulation. Large consortiums and individual labs have generated a vast number of genome-wide data sets on human lymphoblastoid and other cell lines latently infected with EBV. Analysis of these data sets [...] Read more.

The Epstein-Barr virus (EBV) double-stranded DNA genome is subject to extensive epigenetic regulation. Large consortiums and individual labs have generated a vast number of genome-wide data sets on human lymphoblastoid and other cell lines latently infected with EBV. Analysis of these data sets reveals important new information on the properties of the host and viral chromosome structure organization and epigenetic modifications. We discuss the mapping of these data sets and the subsequent insights into the chromatin structure and transcription factor binding patterns on latent EBV genomes. Colocalization of multiple histone modifications and transcription factors at regulatory loci are considered in the context of the biology and regulation of EBV. Full article

(This article belongs to the Special Issue Recent Progress in EBV Research)

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846 KiB

Open AccessReview

The Foamy Virus Gag Proteins: What Makes Them Different?

by Erik Müllers

Viruses 2013, 5(4), 1023-1041; https://doi.org/10.3390/v5041023 - 26 Mar 2013

Cited by 30 | Viewed by 8170

Abstract

Gag proteins play an important role in many stages of the retroviral replication cycle. They orchestrate viral assembly, interact with numerous host cell proteins, engage in regulation of viral gene expression, and provide the main driving force for virus intracellular trafficking and budding. [...] Read more.

Gag proteins play an important role in many stages of the retroviral replication cycle. They orchestrate viral assembly, interact with numerous host cell proteins, engage in regulation of viral gene expression, and provide the main driving force for virus intracellular trafficking and budding. Foamy Viruses (FV), also known as spumaviruses, display a number of unique features among retroviruses. Many of these features can be attributed to their Gag proteins. FV Gag proteins lack characteristic orthoretroviral domains like membrane-binding domains (M domains), the major homology region (MHR), and the hallmark Cys-His motifs. In contrast, they contain several distinct domains such as the essential Gag-Env interaction domain and the glycine and arginine rich boxes (GR boxes). Furthermore, FV Gag only undergoes limited maturation and follows an unusual pathway for nuclear translocation. This review summarizes the known FV Gag domains and motifs and their functions. In particular, it provides an overview of the unique structural and functional properties that distinguish FV Gag proteins from orthoretroviral Gag proteins. Full article

(This article belongs to the Special Issue Recent Progress in Foamy Virus (FV) Research)

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Viruses, Volume 5, Issue 4 (April 2013) – 10 articles , Pages 1023-1207

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