The varicella-zoster virus ORF47 kinase interferes with host innate immune response by inhibiting the activation of IRF3.
Vandevenne, Patricia ; Lebrun, Marielle ; et al
in PLoS ONE (2011), 9(2),
The innate immune response constitutes the first line of host defence that limits viral spread and plays an important role in the activation of adaptive immune response. Viral components are recognized by ... [more ▼]
The innate immune response constitutes the first line of host defence that limits viral spread and plays an important role in the activation of adaptive immune response. Viral components are recognized by specific host pathogen recognition receptors triggering the activation of IRF3. IRF3, along with NF-kappaB, is a key regulator of IFN-beta expression. Until now, the role of IRF3 in the activation of the innate immune response during Varicella-Zoster Virus (VZV) infection has been poorly studied. In this work, we demonstrated for the first time that VZV rapidly induces an atypical phosphorylation of IRF3 that is inhibitory since it prevents subsequent IRF3 homodimerization and induction of target genes. Using a mutant virus unable to express the viral kinase ORF47p, we demonstrated that (i) IRF3 slower-migrating form disappears; (ii) IRF3 is phosphorylated on serine 396 again and recovers the ability to form homodimers; (iii) amounts of IRF3 target genes such as IFN-beta and ISG15 mRNA are greater than in cells infected with the wild-type virus; and (iv) IRF3 physically interacts with ORF47p. These data led us to hypothesize that the viral kinase ORF47p is involved in the atypical phosphorylation of IRF3 during VZV infection, which prevents its homodimerization and subsequent induction of target genes such as IFN-beta and ISG15. [less ▲]Detailed reference viewed: 44 (7 ULg)
Varicella-Zoster Virus interferes with the innate immune resposne by interfering with both NF-KB and IRF-3 singaling pathways
Vandevenne, Patricia ; ; Bontems, Sébastien et al
Conference (2010, May)Detailed reference viewed: 81 (13 ULg)
Innate immune response and viral interference strategies developed by Human Herpeviruses
Vandevenne, Patricia ; Sadzot-Delvaux, Catherine ; Piette, Jacques
in Biochemical Pharmacology (2010), 80Detailed reference viewed: 33 (3 ULg)
Varicella-Zoster Virus IE4 Protein Interacts with SR Proteins and Exports mRNAs through the TAP/NXF1 Pathway.
Ote, Isabelle ; Vandevenne, Patricia ; Bontems, Sébastien et al
in PLoS ONE (2009), 4(11), 7882
Available data suggest that the Varicella-Zoster virus (VZV) IE4 protein acts as an important regulator on VZV and cellular genes expression and could exert its functions at post-transcriptional level ... [more ▼]
Available data suggest that the Varicella-Zoster virus (VZV) IE4 protein acts as an important regulator on VZV and cellular genes expression and could exert its functions at post-transcriptional level. However, the molecular mechanisms supported by this protein are not yet fully characterized. In the present study, we have attempted to clarify this IE4-mediated gene regulation and identify some cellular partners of IE4. By yeast two-hybrid and immunoprecipitation analysis, we showed that IE4 interacts with three shuttling SR proteins, namely ASF/SF2, 9G8 and SRp20. We positioned the binding domain in the IE4 RbRc region and we showed that these interactions are not bridged by RNA. We demonstrated also that IE4 strongly interacts with the main SR protein kinase, SRPK1, and is phosphorylated in in vitro kinase assay on residue Ser-136 contained in the Rb domain. By Northwestern analysis, we showed that IE4 is able to bind RNA through its arginine-rich region and in immunoprecipitation experiments the presence of RNA stabilizes complexes containing IE4 and the cellular export factors TAP/NXF1 and Aly/REF since the interactions are RNase-sensitive. Finally, we determined that IE4 influences the export of reporter mRNAs and clearly showed, by TAP/NXF1 knockdown, that VZV infection requires the TAP/NXF1 export pathway to express some viral transcripts. We thus highlighted a new example of viral mRNA export factor and proposed a model of IE4-mediated viral mRNAs export. [less ▲]Detailed reference viewed: 72 (21 ULg)
Varicella-zoster virus modulates NF-kappaB recruitment on selected cellular promoters.
El Mjiyad, Nadia ; Bontems, Sébastien ; Gloire, Geoffrey et al
in Journal of Virology (2007), 81(23), 13092-104
Intercellular adhesion molecule 1 (ICAM-1) expression is down-regulated in the center of cutaneous varicella lesions despite the expression of proinflammatory cytokines such as gamma interferon and tumor ... [more ▼]
Intercellular adhesion molecule 1 (ICAM-1) expression is down-regulated in the center of cutaneous varicella lesions despite the expression of proinflammatory cytokines such as gamma interferon and tumor necrosis factor alpha (TNF-alpha). To study the molecular basis of this down-regulation, the ICAM-1 induction of TNF-alpha was analyzed in varicella-zoster virus (VZV)-infected melanoma cells (MeWo), leading to the following observations: (i) VZV inhibits the stimulation of icam-1 mRNA synthesis; (ii) despite VZV-induced nuclear translocation of p65, p52, and c-Rel, p50 does not translocate in response to TNF-alpha; (iii) the nuclear p65 present in VZV-infected cells is no longer associated with p50 and is unable to bind the proximal NF-kappaB site of the icam-1 promoter, despite an increased acetylation and accessibility of the promoter in response to TNF-alpha; and (iv) VZV induces the nuclear accumulation of the NF-kappaB inhibitor p100. VZV also inhibits icam-1 stimulation of TNF-alpha by strongly reducing NF-kappaB nuclear translocation in MRC5 fibroblasts. Taken together, these data show that VZV interferes with several aspects of the immune response by inhibiting NF-kappaB binding and the expression of target genes. Targeting NF-kappaB activation, which plays a central role in innate and adaptive immune responses, leads to obvious advantages for the virus, particularly in melanocytes, which are a site of viral replication in the skin. [less ▲]Detailed reference viewed: 98 (19 ULg)
Caractérisation de la réponse immunitaire unnée au virus de la varicelle et du zona (VZV): implication du Toll-like récepteur 3
Vandevenne, Patricia ; ; et al
Poster (2007)Detailed reference viewed: 25 (4 ULg)