Virus assembly factories in a lipid world

2016 ◽  
Vol 18 ◽  
pp. 20-26 ◽  
Author(s):  
Isabel Fernández de Castro ◽  
Raquel Tenorio ◽  
Cristina Risco
Keyword(s):  
Author(s):  
W. Djaczenko ◽  
M. Müller ◽  
A. Benedetto ◽  
G. Carbone

A thickening of ER membranes in murine myeloma cells was attributed by de Harven to the assembly of intracisternal virus particles. We observed similar thickening of GER membranes in Friend leukemia cells (FLC) apparently associated with Friend leukemia virus (FLV) assembly. We reinvestigated the problem of GER involvement in FLV assembly using high pressure cryofixed FLC.FLC (745A clone growing in suspension and FF clone growing in monolayer) were immersed in Hexadecene (Fluka, Switzerland) and rapidly frozen in Balzers HPM 010 freezing machine working at 2200 bar. All cells were freeze substituted at -90°C in 2% OsO4 in absolute acetone. Serial sections cut to avoid misinterpretations due to the geometry of sections, were collected on carbon coated 100 mesh grids.


Vaccines ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 622
Author(s):  
Kassandra L. Carpio ◽  
Alan D. T. Barrett

The Flavivirus genus contains many important human pathogens, including dengue, Japanese encephalitis (JE), tick-borne encephalitis (TBE), West Nile (WN), yellow fever (YF) and Zika (ZIK) viruses. While there are effective vaccines for a few flavivirus diseases (JE, TBE and YF), the majority do not have vaccines, including WN and ZIK. The flavivirus nonstructural 1 (NS1) protein has an unusual structure–function because it is glycosylated and forms different structures to facilitate different roles intracellularly and extracellularly, including roles in the replication complex, assisting in virus assembly, and complement antagonism. It also plays a role in protective immunity through antibody-mediated cellular cytotoxicity, and anti-NS1 antibodies elicit passive protection in animal models against a virus challenge. Historically, NS1 has been used as a diagnostic marker for the flavivirus infection due to its complement fixing properties and specificity. Its role in disease pathogenesis, and the strong humoral immune response resulting from infection, makes NS1 an excellent target for inclusion in candidate flavivirus vaccines.


2021 ◽  
Vol 14 (7) ◽  
pp. 622
Author(s):  
Arne Krüger ◽  
Ana Paula de Jesus Santos ◽  
Vanessa de Sá ◽  
Henning Ulrich ◽  
Carsten Wrenger

Aptamers are single-stranded DNA or RNA molecules which are submitted to a process denominated SELEX. SELEX uses reiterative screening of a random oligonucleotide library to identify high-affinity binders to a chosen target, which may be a peptide, protein, or entire cells or viral particles. Aptamers can rival antibodies in target recognition, and benefit from their non-proteic nature, ease of modification, increased stability, and pharmacokinetic properties. This turns them into ideal candidates for diagnostic as well as therapeutic applications. Here, we review the recent accomplishments in the development of aptamers targeting emerging viral diseases, with emphasis on recent findings of aptamers binding to coronaviruses. We focus on aptamer development for diagnosis, including biosensors, in addition to aptamer modifications for stabilization in body fluids and tissue penetration. Such aptamers are aimed at in vivo diagnosis and treatment, such as quantification of viral load and blocking host cell invasion, virus assembly, or replication, respectively. Although there are currently no in vivo applications of aptamers in combating viral diseases, such strategies are promising for therapy development in the future.


2010 ◽  
Vol 9 (8) ◽  
pp. 1742-1751 ◽  
Author(s):  
Glen K. Shoemaker ◽  
Esther van Duijn ◽  
Sue E. Crawford ◽  
Charlotte Uetrecht ◽  
Marian Baclayon ◽  
...  

Viruses ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1517
Author(s):  
Rebecca S. Brown ◽  
Lisa Kim ◽  
Margaret Kielian

Alphaviruses are small enveloped viruses with positive-sense RNA genomes. During infection, the alphavirus capsid protein (Cp) selectively packages and assembles with the viral genomic RNA to form the nucleocapsid core, a process critical to the production of infectious virus. Prior studies of the alphavirus Semliki Forest virus (SFV) showed that packaging and assembly are promoted by Cp binding to multiple high affinity sites on the genomic RNA. Here, we developed an in vitro Cp binding assay based on fluorescently labeled RNA oligos. We used this assay to explore the RNA sequence and structure requirements for Cp binding to site #1, the top binding site identified on the genomic RNA during all stages of virus assembly. Our results identify a stem-loop structure that promotes specific binding of the SFV Cp to site #1 RNA. This structure is also recognized by the Cps of the related alphaviruses chikungunya virus and Ross River virus.


2007 ◽  
Vol 82 (5) ◽  
pp. 2120-2129 ◽  
Author(s):  
Pablo Gastaminza ◽  
Guofeng Cheng ◽  
Stefan Wieland ◽  
Jin Zhong ◽  
Wei Liao ◽  
...  

ABSTRACT Intracellular infectious hepatitis C virus (HCV) particles display a distinctly higher buoyant density than do secreted virus particles, suggesting that the characteristic low density of extracellular HCV particles is acquired during viral egress. We took advantage of this difference to examine the determinants of assembly, maturation, degradation, and egress of infectious HCV particles. The results demonstrate that HCV assembly and maturation occur in the endoplasmic reticulum (ER) and post-ER compartments, respectively, and that both depend on microsomal transfer protein and apolipoprotein B, in a manner that parallels the formation of very-low-density lipoproteins (VLDL). In addition, they illustrate that only low-density particles are efficiently secreted and that immature particles are actively degraded, in a proteasome-independent manner, in a post-ER compartment of the cell. These results suggest that by coopting the VLDL assembly, maturation, degradation, and secretory machinery of the cell, HCV acquires its hepatocyte tropism and, by mimicry, its tendency to persist.


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