Cyno-EBV, a cynomolgus monkey EBV-like virus, and its latent membrane protein 1 oncogene.
|Title:||Cyno-EBV, a cynomolgus monkey EBV-like virus, and its latent membrane protein 1 oncogene.|
|Abstract:||Epstein-Barr virus (EBV) and its oncogene, the latent membrane protein 1 (LMP1), are associated with many human malignancies. Likewise, EBV-like viruses have been associated with lymphomas in immunosuppressed cynomolgus monkeys. This study characterizes the biology of Cyno-EBV, a cynomolgus monkey EBV-like virus, including the structural proteins, antigenic relatedness to EBV and molecular and functional analysis of its LMP1 homologue. Cyno-EBV infection is ubiquitous in its host species. In vitro , Cyno-EBV immortalized cynomolgus monkey but not human B cells. The electrophoretic profile of Cyno-EBV structural proteins was almost identical to that of EBV proteins, and cynomolgus monkey and human sera showed reciprocal reactivities for several of these proteins, including the EBV receptor binding protein gp350. The coding region of the Cyno-EBV LMP1 gene was cloned and expressed. The sequence predicted a 588 amino acid (a.a.) protein with a 19 a.a. N-terminus, 6 transmembrane domains and a carboxy tail of 404 a.a. containing a 8-histidine cluster used as a natural protein tag in expression studies. Western blot analysis revealed a major polypeptide of 110 kDa. Cyno-EBV LMP1 contained series of repeats that shared no homology with other LMP1s. However, a proline-rich sequence GPXXPX6 found within the 11 a.a.-repeats of EBV LMP1 was conserved in a non-repeat region of Cyno-EBV LMP1 and contained two Janus kinase (JAK) binding motifs PXXPXP. Cyno-EBV LMP1 harbored 4 motifs PXQXT/S, predicted to interact with TRAFs, adapter proteins of the tumor necrosis factor receptor signaling pathway, which lead to activation of the nuclear factor kappaB (NFkappaB). Cyno-EBV LMP1 shared the same ability as EBV LMP1 to induce a NFkappaB driven reporter gene. An apparent increased toxicity of Cyno-EBV LMP1 for rodent Rat-1 cells impeded the establishment of LMP1 expressing cell lines whereas a reduced toxicity was observed for transiently expressing 293 cells when compared to EBV LMP1. Cyno-EBV is structurally and antigenically closely related to EBV. Cyno-EBV LMP1 harbored several features and motifs found in EBV LMP1. New conserved sequences were reported including a histidine cluster and a proline-rich sequence encompassing two Janus kinase binding motifs. The increased numbers of TRAF motifs found in Cyno-EBV LMP1 did not result in increased ability to activate NFkappaB in 293 cells and as for EBV LMP1, the protein appeared to have specific cell type toxicity.|
|Collection||Thèses, 1910 - 2010 // Theses, 1910 - 2010|