Search results for "viral entry"

Cytoplasmic Parvovirus Capsids Recruit Importin Beta for Nuclear Delivery

2019

Parvoviruses are an important platform for gene and cancer therapy. Their cell entry and the following steps, including nuclear import, are inefficient, limiting their use in therapeutic applications. Two models exist on parvoviral nuclear entry: the classical import of the viral capsid using nuclear transport receptors of the importin (karyopherin) family or the direct attachment of the capsid to the nuclear pore complex leading to the local disintegration of the nuclear envelope. Here, by laser scanning confocal microscopy and in situ proximity ligation analyses combined with coimmunoprecipitation, we show that infection requires importin β-mediated access to the nuclear pore complex and …

Virus-receptor interactions of coxsackie B viruses and their putative influence on cardiotropism

2003

Specific virus-receptor interactions are important determinants in the pathogenesis of viral infections, influencing the location and initiation of primary infection as well as the viral spread to other target organs in the postviremic phase. Coxsackieviruses of group B (CVB) specifically interact with at least two receptor proteins, the coxsackievirus-adenovirus receptor (CAR) and the decay-accelerating factor (DAF), and cause a broad spectrum of diseases, including acute and chronic myocarditis. In the human heart, CAR is predominantly expressed in intercalated discs, regions of utmost importance for the functional integrity of the heart. Since DAF is abundantly expressed in epithelial an…

Non-redundant and redundant roles of cytomegalovirus gH/gL complexes in host organ entry and intra-tissue spread

2015

Herpesviruses form different gH/gL virion envelope glycoprotein complexes that serve as entry complexes for mediating viral cell-type tropism in vitro; their roles in vivo, however, remained speculative and can be addressed experimentally only in animal models. For murine cytomegalovirus two alternative gH/gL complexes, gH/gL/gO and gH/gL/MCK-2, have been identified. A limitation of studies on viral tropism in vivo has been the difficulty in distinguishing between infection initiation by viral entry into first-hit target cells and subsequent cell-to-cell spread within tissues. As a new strategy to dissect these two events, we used a gO-transcomplemented ΔgO mutant for providing the gH/gL/gO…

2014

Human papillomaviruses (HPV) are non-enveloped DNA tumor viruses that infect skin and mucosa. The most oncogenic subtype, HPV16, causes various types of cancer, including cervical, anal, and head and neck cancers. During the multistep process of infection, numerous host proteins are required for the delivery of virus genetic information into the nucleus of target cells. Over the last two decades, many host-cell proteins such as heparan sulfate proteoglycans, integrins, growth factor receptors, actin and the tetraspanin CD151 have been described to be involved in the process of infectious entry of HPV16. Tetraspanins have the ability to organize membrane microdomains and to directly influenc…

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…

Single-Cell Analysis of RNA Virus Infection Identifies Multiple Genetically Diverse Viral Genomes within Single Infectious Units

2015

Summary Genetic diversity enables a virus to colonize novel hosts, evade immunity, and evolve drug resistance. However, viral diversity is typically assessed at the population level. Given the existence of cell-to-cell variation, it is critical to understand viral genetic structure at the single-cell level. By combining single-cell isolation with ultra-deep sequencing, we characterized the genetic structure and diversity of a RNA virus shortly after single-cell bottlenecks. Full-length sequences from 881 viral plaques derived from 90 individual cells reveal that sequence variants pre-existing in different viral genomes can be co-transmitted within the same infectious unit to individual cell…

Viral Entry and Receptors

2007

Towards therapeutic gene delivery to human cancer cells : targeting and entry of baculovirus

2008

Geeniterapia on yksi tulevaisuuden hoitomuodoista taistelussa syöpää vastaan. Virukset ovat evoluution myötä kehittyneet tehokkaiksi geeninsiirtäjiksi ja ovat nykyään käytetyimpiä geeninsiirtovektoreita. Yksi geenihoitojen yleistymisen esteistä on kuitenkin ollut virusvektoreiden puutteellinen kohdennus haluttuun kudokseen. Kohdentaminen on erityisen tärkeää syövän hoidossa, jotta hoito vaikuttaisi pääasiassa pahanlaatuisiin soluihin.Mäkelä kehitti tutkimuksessaan syöpäsoluihin kohdentuvia bakulovirusperäisiä geeninsiirtovektoreita. Hän tutki myös viruksen sisäänmenomekanismeja ja kulkeutumista kohdesoluissa.- Hyönteisiä infektoiva bakulovirus on luontaisesti vaaraton ihmisille. Se on helpo…

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, …

Clathrin-independent entry of baculovirus triggers uptake of E. coli in non-phagocytic human cells

2008

The prototype baculovirus, Autographa californica multiple nucleopolyhedrovirus, an insect pathogen, holds great potential as a gene therapy vector. To develop transductional targeting and gene delivery by baculovirus, we focused on characterizing the nature and regulation of its uptake in human cancer cells. Baculovirus entered the cells along fluid-phase markers from the raft areas into smooth-surfaced vesicles devoid of clathrin. Notably, regulators associated with macropinocytosis, namely EIPA, Pak1, Rab34, and Rac1, had no significant effect on viral transduction, and the virus did not induce fluid-phase uptake. The internalization and nuclear uptake was, however, affected by mutants o…