Semliki forest virus core protein fragmentation: Its possible role in nucleocapsid disassembly

1993 ◽  
Vol 13 (6) ◽  
pp. 333-347 ◽  
Author(s):  
Andreas Schlegel ◽  
Johann Schaller ◽  
Pia Jentsch ◽  
Christoph Kempf
Keyword(s):  
Capsid Protein ◽  
Semliki Forest Virus ◽  
Core Protein ◽  
Gradient Centrifugation ◽  
Biological Significance ◽  
Acidic Ph ◽  
Virus Particles ◽  
Virus Core ◽  
Core Proteins ◽  
Protein Fragmentation

Semliki Forest virus (SFV) envelope proteins function as proton pores under mildly acidic conditions and translocate protons across the viral membrane [Schlegel, A., Omar, A., Jentsch, P., Morell, A. and Kemp, F. C. (1991) Biosci. Rep. 11, 243–255]. As a consequence, during uptake of SFV by cells via receptor-mediated endocytosis the nucleocapsid is supposed to be exposed to protons. In this paper the effects of mildly acidic pH on SFV nucleocapsids were examined. A partial proteolytic fragmentation of core proteins was observed when nucleocapsids were exposed to mildly acidic pH. A similar proteolytic event was detected when intact SFV virions were exposed to identical conditions. Protease protection assays with exogenous bromelain provided evidence that the capsid protein degradation was due to an endogenous proteolytic activity and not to a proteolytic contamination. Detergent solubilization of virus particles containing degraded nucleocapsids followed by sucrose gradient centrifugation led to a separation of capsid protein fragments and remaining nucleocapsids. These data are discussed in terms of a putative biological significance, namely that the core protein fragmentation may play a role in nucleocapsid disassembly.

Structure of Semliki Forest virus core protein

1997 ◽  
Vol 27 (3) ◽  
pp. 345-359 ◽  
Author(s):  
Hok-Kin Choi ◽  
Guoguang Lu ◽  
Sukyeong Lee ◽  
Gerd Wengler ◽  
Michael G. Rossmann
Keyword(s):  
Semliki Forest Virus ◽  
Core Protein ◽  
Virus Core

scholarly journals B23/nucleophosmin is involved in regulation of adenovirus chromatin structure at late infection stages, but not in virus replication and transcription

2012 ◽  
Vol 93 (6) ◽  
pp. 1328-1338 ◽  
Author(s):  
Mohammad Abdus Samad ◽  
Tetsuro Komatsu ◽  
Mitsuru Okuwaki ◽  
Kyosuke Nagata
Keyword(s):  
Chromatin Immunoprecipitation ◽  
Infectious Virus ◽  
Core Protein ◽  
Virus Genome ◽  
Virus Particles ◽  
Core Proteins ◽  
Stimulatory Factor ◽  
Interfering Rna

B23/nucleophosmin has been identified in vitro as a stimulatory factor for replication of adenovirus DNA complexed with viral basic core proteins. In the present study, the in vivo function of B23 in the adenovirus life cycle was studied. It was found that both the expression of a decoy mutant derived from adenovirus core protein V that tightly associates with B23 and small interfering RNA-mediated depletion of B23 impeded the production of progeny virions. However, B23 depletion did not significantly affect the replication and transcription of the virus genome. Chromatin immunoprecipitation analyses revealed that B23 depletion significantly increased the association of viral DNA with viral core proteins and cellular histones. These results suggest that B23 is involved in the regulation of association and/or dissociation of core proteins and cellular histones with the virus genome. In addition, these results suggest that proper viral chromatin assembly, regulated in part by B23, is crucial for the maturation of infectious virus particles.

scholarly journals Comparative Antigenicity and Immunogenicity of Hepadnavirus Core Proteins

2005 ◽  
Vol 79 (21) ◽  
pp. 13641-13655 ◽  
Author(s):  
Jean-Noel Billaud ◽  
Darrell Peterson ◽  
Florian Schödel ◽  
Antony Chen ◽  
Matti Sallberg ◽  
...  
Keyword(s):  
T Cell ◽  
B Cell ◽  
Vaccine Development ◽  
Core Protein ◽  
Mhc Genes ◽  
Virus Core ◽  
Core Proteins ◽  
Particulate Antigen ◽  
Mhc Haplotype ◽  
Vaccine Carrier

ABSTRACT The hepatitis B virus core protein (HBcAg) is a uniquely immunogenic particulate antigen and as such has been used as a vaccine carrier platform. The use of other hepadnavirus core proteins as vaccine carriers has not been explored. To determine whether the rodent hepadnavirus core proteins derived from the woodchuck (WHcAg), ground squirrel (GScAg), and arctic squirrel (AScAg) viruses possess immunogen characteristics similar to those of HBcAg, comparative antigenicity and immunogenicity studies were performed. The results indicate that (i) the rodent core proteins are equal in immunogenicity to or more immunogenic than HBcAg at the B-cell and T-cell levels; (ii) major histocompatibility complex (MHC) genes influence the immune response to the rodent core proteins (however, nonresponder haplotypes were not identified); (iii) WHcAg can behave as a T-cell-independent antigen in athymic mice; (iv) the rodent core proteins are not significantly cross-reactive with the HBcAg at the antibody level (however, the nonparticulate “eAgs” do appear to be cross-reactive); (v) the rodent core proteins are only partially cross-reactive with HBcAg at the CD4+ T-cell level, depending on MHC haplotype; and (vi) the rodent core proteins are competent to function as vaccine carrier platforms for heterologous, B-cell epitopes. These results have implications for the selection of an optimal hepadnavirus core protein for vaccine design, especially in view of the “preexisting” immunity problem that is inherent in the use of HBcAg for human vaccine development.

scholarly journals Lack of expression of hepatitis C virus core protein in human monocyte-erived dendritic cells using recombinant semliki forest virus

2019 ◽  
Vol 24 (3) ◽  
pp. 493-502
Author(s):  
Maria-Cristina Navas ◽  
Françoise Stoll-Keller ◽  
Jovan Pavlovic
Keyword(s):  
Dendritic Cells ◽  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Viral Vectors ◽  
Semliki Forest Virus ◽  
Core Protein ◽  
Human Monocyte ◽  
Host Immune System ◽  
Virus Core ◽  
Hcv Core Protein

Hepatitis C Virus belongs to the Flaviviridae family.  One proposed mechanism of HCV persistence in the ability to infect hematopoietic cells, including Dendritic cells (DCs). HCV infection of DCs could impair their functions that represent one of the mechanisms, thus hampering viral clearance by the host immune system. Among HCV-encoded proteins, the highly conserved Core protein has been suggested to be responsible for the immunomodulatory properties of this Hepacivirus. Recombinant viral vectors expressing the HCV Core protein and allowing its transduction and therefore the expression of the protein into DCs could be useful tools for the analysis of the properties of the Core protein. Vaccinia Virus and retrovirus have been used to transduce human DCs. Likewise, gene transfer into DCs using Semliki Forest Virus has been reported. This study aimed to express the HCV Core protein in human monocyte-derived DCs using an SFV vector, in which the subgenomic RNA encoding the structural proteins was replaced by the HCV Core sequence and then analyze the effects of its expression on DCs functions.

Purification and structure of Semliki Forest virus isolated from mouse brain

1968 ◽  
Vol 14 (2) ◽  
pp. 153-159 ◽  
Author(s):  
P. Faulkner ◽  
S. M. McGee-Russell
Keyword(s):  
Semliki Forest Virus ◽  
Gradient Centrifugation ◽  
Sedimentation Coefficient ◽  
Cesium Chloride ◽  
Equilibrium Density ◽  
Thin Sections ◽  
Virus Particles ◽  
Fundamental Symmetry ◽  
The Core ◽  
Intact Virus

Semliki Forest virus from brains of infected suckling mouse was separated by cesium chloride equilibrium density gradient centrifugation into two fractions, both able to agglutinate red blood cells of goose. The heavy fraction (HF density 1.24) had more infectivity, had a sedimentation coefficient of 285 S, and contained intact virus particles, diameter about 75 mμ. The light fraction (LF density 1.205) of equivalent HA (hemagglutinating activity), had less than 1% of the infectivity of the HF and did not contain intact virus particles. It consisted of "empty" virus particles and fragments of the fragile envelope material. The complete virus particle consists of an envelope of complex character surrounding a well-defined core. Shadow-cast preparations of HF show pointed and truncated shadows which suggest cubical symmetry, and the core of full particles, in thin sections, shows an angular, often pentagonal or hexagonal configuration. This suggests that the cubical symmetry of the full particle depends upon the fundamental symmetry of the core, which appears to be icosahedral.

scholarly journals The Wild-Type Hepatitis C Virus Core Inhibits Initiation of Antigen-Specific T- and B-Cell Immune Responses in BALB/c Mice

2010 ◽  
Vol 17 (7) ◽  
pp. 1139-1147 ◽  
Author(s):  
Wenbo Zhu ◽  
Yanzi Chang ◽  
Chunchen Wu ◽  
Qingxia Han ◽  
Rongjuan Pei ◽  
...  
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Immune Responses ◽  
Core Protein ◽  
Repeated Administration ◽  
Wild Type ◽  
Virus Core ◽  
Hcv Core Protein ◽  
Core Proteins ◽  
Potential Applications

ABSTRACT In this study, the effects of wild-type and deletion mutant hepatitis C virus (HCV) core proteins on the induction of immune responses in BALB/c mice were assessed. p2HA-C145-S23, encoding a core protein with the C-terminal 46 amino acids truncated, significantly produced stronger antibody and cellular responses than p2HA-C191-S23. The induction of immune responses by p2HA-C145-S23 was dose dependent. However, increasing the doses or repeated administration did not enhance immune responses by the wild-type core protein. In addition, p2HA-C191-S23 was apparently able to interfere with the priming of specific immune responses by p2HA-C145-S23 when the two were coadministered. These results demonstrated that the wild-type HCV core protein itself could inhibit the priming of immune responses in the course of a DNA vaccination, whereas the truncated HCV core protein could provide potential applications for the development of DNA- and peptide-based HCV vaccines.

Uranyl Acetate and Rotary Shadowing to Increase the Contrast of Small Aggregated Virus Particles

1969 ◽  
Vol 27 ◽  
pp. 424-425
Author(s):  
Lee F. Ellis ◽  
Richard M. Van Frank ◽  
Walter J. Kleinschmidt
Keyword(s):  
Electron Microscopy ◽  
Tissue Culture ◽  
Density Gradient ◽  
Density Gradient Centrifugation ◽  
Gradient Centrifugation ◽  
Uranyl Acetate ◽  
Interferon Inducer ◽  
Virus Particles ◽  
Staining Methods ◽  
Rotary Shadowing

The extract from Penicillum stoliniferum, known as statolon, has been purified by density gradient centrifugation. These centrifuge fractions contained virus particles that are an interferon inducer in mice or in tissue culture. Highly purified preparations of these particles are difficult to enumerate by electron microscopy because of aggregation. Therefore a study of staining methods was undertaken.

Biosynthesis and biochemical properties of the hepatitis C virus core protein.

1994 ◽  
Vol 68 (6) ◽  
pp. 3631-3641 ◽  
Author(s):  
E Santolini ◽  
G Migliaccio ◽  
N La Monica
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Core Protein ◽  
Biochemical Properties ◽  
Virus Core
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