Search results for "Virus Internalization"
showing 10 items of 37 documents
Protoparvovirus Knocking at the Nuclear Door
2017
Protoparvoviruses target the nucleus due to their dependence on the cellular reproduction machinery during the replication and expression of their single-stranded DNA genome. In recent years, our understanding of the multistep process of the capsid nuclear import has improved, and led to the discovery of unique viral nuclear entry strategies. Preceded by endosomal transport, endosomal escape and microtubule-mediated movement to the vicinity of the nuclear envelope, the protoparvoviruses interact with the nuclear pore complexes. The capsids are transported actively across the nuclear pore complexes using nuclear import receptors. The nuclear import is sometimes accompanied by structural chan…
A Bimolecular Multicellular Complementation System for the Detection of Syncytium Formation: A New Methodology for the Identification of Nipah Virus …
2019
Fusion of viral and cellular membranes is a key step during the viral life cycle. Enveloped viruses trigger this process by means of specialized viral proteins expressed on their surface, the so-called viral fusion proteins. There are multiple assays to analyze the viral entry including those that focus on the cell-cell fusion induced by some viral proteins. These methods often rely on the identification of multinucleated cells (syncytium) as a result of cell membrane fusions. In this manuscript, we describe a novel methodology for the study of cell-cell fusion. Our approach, named Bimolecular Multicellular Complementation (BiMuC), provides an adjustable platform to qualitatively and quanti…
Focus on clinical practice: angiotensin-converting enzyme 2 and corona virus disease 2019: pathophysiology and clinical implications.
2020
: ACE2 receptor has a broad expression pattern in the cellular membrane and provides a protective action against the development of cardiovascular diseases. Recently, this enzyme has become of extreme interest during the pandemic infection of COVID-19 (coronavirus disease 2019). This virus invades alveolar epithelium and cardiomyocytes using ACE2 as a transmembrane receptor. ACE2 is a counter-regulatory peptide that degrades Ang II into Ang 1-7, thereby attenuating the biological effects of the AT1 receptor. The binding between the spike protein of COVID-19 and the enzyme is crucial for the virus to enter the target cells, but whether an increase in ACE2 activity could facilitate the infect…
Duck Hepatitis B Virus Requires Cholesterol for Endosomal Escape during Virus Entry
2008
ABSTRACT The identity and functionality of biological membranes are determined by cooperative interaction between their lipid and protein constituents. Cholesterol is an important structural lipid that modulates fluidity of biological membranes favoring the formation of detergent-resistant microdomains. In the present study, we evaluated the functional role of cholesterol and lipid rafts for entry of hepatitis B viruses into hepatocytes. We show that the duck hepatitis B virus (DHBV) attaches predominantly to detergent-soluble domains on the plasma membrane. Cholesterol depletion from host membranes and thus disruption of rafts does not affect DHBV infection. In contrast, depletion of chole…
Enhancing the multiplication of nucleopolyhedrovirus in vitro by manipulation of the pH
2009
Insect nucleopolyhedroviruses (NPVs) are studied widely as agents for biological control, as expression vectors for the production of heterologous proteins, and as transduction vectors for gene therapy applications. Most of these applications rely on the existence of cell lines that allow in vitro multiplication of the virus. The influence of pH in the medium culture on the multiplication of SeMNPV, HearSNPV and AcMNPV in different cell culture lines was investigated. The study showed a strong influence of the medium pH on the virus multiplication with the best results at pH 6.5, about half pH unit above the pH of insect culture media used most commonly. Additional experiments using a recom…
Reply to "Heparan Sulfate in Baculovirus Binding and Entry of Mammalian Cells"
2014
(1), we investigated the interaction ofbaculovirus and mammalian cell surface heparan sulfate pro-teoglycans (HSPG). The data show that baculovirus requiresHSPG sulfation, particularly N- and 6-O-sulfation, to bind andtransduce mammalian cells. We also show that baculovirus asso-ciates specifically with syndecan-1 (SDC-1) but not with othersyndecans or glypicans.As discussed in the article, HS has previously been shown to beinvolved in glycoprotein 64 (gp64)-mediated baculovirus bindingonto mammalian cells. Heparin and heparinase I and II treatmentof cells have also been shown to prevent the virus binding (2, 3).The role of HS in baculovirus entry was further studied in ourarticle (1). Bindi…
Morphological characterization of baculovirus Autographa californica multiple nucleopolyhedrovirus
2009
The budded form of baculovirus Autographa californica multiple nucleopolyhedrovirus is used widely in biotechnological applications. In this study, we observed the morphology of baculovirus in nanometer scale by atomic force microscopy. Additionally, the correlation between transduction efficiency and virus stock storage time was evaluated. By atomic force microscopy, asymmetrical baculovirus particles with enlarged head regions were detected. Observed virus stocks contained variable-length particles, 256 ± 40 nm, along with disintegrated particles and/or cellular components. Long-term storage of stocks led to virus aggregation and decreased cellular entry and transgene expression in mammal…
Echovirus 1 Entry into Polarized Caco-2 Cells Depends on Dynamin, Cholesterol, and Cellular Factors Associated with Macropinocytosis
2013
ABSTRACT Enteroviruses invade their hosts by crossing the intestinal epithelium. We have examined the mechanism by which echovirus 1 (EV1) enters polarized intestinal epithelial cells (Caco-2). Virus binds to VLA-2 on the apical cell surface and moves rapidly to early endosomes. Using inhibitory drugs, dominant negative mutants, and small interfering RNAs (siRNAs) to block specific endocytic pathways, we found that virus entry requires dynamin GTPase and membrane cholesterol but is independent of both clathrin- and caveolin-mediated endocytosis. Instead, infection requires factors commonly associated with macropinocytosis, including amiloride-sensitive Na + /H + exchange, protein kinase C, …
Coxsackievirus A9 Infects Cells via Nonacidic Multivesicular Bodies
2014
ABSTRACT Coxsackievirus A9 (CVA9) is a member of the human enterovirus B species in the Enterovirus genus of the family Picornaviridae . According to earlier studies, CVA9 binds to αVβ3 and αVβ6 integrins on the cell surface and utilizes β2-microglobulin, dynamin, and Arf6 for internalization. However, the structures utilized by the virus for internalization and uncoating are less well understood. We show here, based on electron microscopy, that CVA9 is found in multivesicular structures 2 h postinfection (p.i.). A neutral red labeling assay revealed that uncoating occurs mainly around 2 h p.i., while double-stranded RNA is found in the cytoplasm after 3 h p.i. The biogenesis of multivesicu…
Early entry events in Echovirus 30 infection
2020
Echovirus 30 (E30), a member of the enterovirus B species, is a major cause of viral meningitis, targeting children and adults alike. While it is a frequently isolated enterovirus and the cause of several outbreaks all over the world, surprisingly little is known regarding its entry and replication strategy within cells. In this study, we used E30 strain Bastianni (E30B) generated from an infectious cDNA clone in order to study early entry events during infection in human RD cells. E30B required the newly discovered Fc echovirus receptor (FcRn) for successful infection, but not the coxsackievirus and adenovirus receptor (CAR) or decay-accelerating factor (DAF), although an interaction with …