Project description:Orthopoxviruses are large DNA viruses which can cause disease in numerous host species. Even though the eradication of variola virus - the causative agent of human smallpox – succeeded, with the end of vaccinations several other orthopoxviruses emerged as potential threat to human health. For instance, animal-borne monkeypox virus, cowpox virus and closely related vaccinia virus are all capable of establishing zoonotic infections in humans. The disease caused by each virus differs in terms of expression and severity, but we still know little about the reasons for these different phenotypes. They may be explained by the unique repertoire of host cell modulating factors encoded by each virus. In this study, we aimed at characterizing the specific modulation of the host cells gene expression profile by orthopoxvirus infection. In our study we analyzed changes in host cell gene expression of HeLa cells after infection with cowpox virus, monkeypox virus or vaccinia virus and compared these to each other and to the gene expression profile of non-infected cells using Agilent Whole Genome Microarray technology. We could identify major differences in viral modulation of host cell immune response genes, especially an induction of genes involved in leukocyte migration and Toll-like receptor signalling in cowpox and monkeypox virus infected cells. This was not observed following vaccinia virus infection. If these differences contribute to the different clinical manifestation of cowpox, monkeypox and vaccinia virus infections in certain host species remains to be elucidated.
Project description:Orthopoxviruses are large DNA viruses which can cause disease in numerous host species. Even though the eradication of variola virus - the causative agent of human smallpox M-bM-^@M-^S succeeded, with the end of vaccinations several other orthopoxviruses emerged as potential threat to human health. For instance, animal-borne monkeypox virus, cowpox virus and closely related vaccinia virus are all capable of establishing zoonotic infections in humans. The disease caused by each virus differs in terms of expression and severity, but we still know little about the reasons for these different phenotypes. They may be explained by the unique repertoire of host cell modulating factors encoded by each virus. In this study, we aimed at characterizing the specific modulation of the host cells gene expression profile by orthopoxvirus infection. In our study we analyzed changes in host cell gene expression of HeLa cells after infection with cowpox virus, monkeypox virus or vaccinia virus and compared these to each other and to the gene expression profile of non-infected cells using Agilent Whole Genome Microarray technology. We could identify major differences in viral modulation of host cell immune response genes, especially an induction of genes involved in leukocyte migration and Toll-like receptor signalling in cowpox and monkeypox virus infected cells. This was not observed following vaccinia virus infection. If these differences contribute to the different clinical manifestation of cowpox, monkeypox and vaccinia virus infections in certain host species remains to be elucidated. We analyzed the gene expression profile of HeLa cells wich were either mock-infected or infected with Vaccinia virus strain IHD-W, Cowpox virus strain Brighton Red or Monkeypox virus strain MSF#6 at a multiplicity of infection of 5. Experiments were performed in duplicate. At 6 h post infection total RNA was isolated from infected cells and used for microarray analysis.
Project description:<p>Tick-borne encephalitis virus is an enveloped, pathogenic, RNA virus in the family Flaviviridae, genus Flavivirus. Viral particles are formed when the nucleocapsid, consisting of an RNA genome and multiple copies of the capsid protein, buds through the endoplasmic reticulum membrane and acquires the viral envelope and the associated proteins. The coordination of the nucleocapsid components to the sites of assembly and budding are poorly understood. Here, we investigate nucleocapsid assembly by characterizing the interactions of the wild-type and truncated capsid proteins with membranes by using biophysical methods and model membrane systems. We show that capsid protein initially binds membranes via electrostatic interactions with negatively-charged lipids which is followed by membrane insertion. Additionally, we show that membrane-bound capsid protein can recruit viral genomic RNA. We confirm the biological relevance of the biophysical findings by using mass spectrometry to show that purified virions contain negatively-charged lipids. Our results suggest that nucleocapsid assembly is coordinated by negatively-charged membrane patches on the endoplasmic reticulum and that the capsid protein mediates direct contacts between the nucleocapsid and the membrane.</p>