Characterisation of NF-kappa B complexes in Theileria parva-transformed T cells

Transformation of T cells by the intracellular parasite Theileria parva is accompanied by constitutive I-kappaB degradation and NF-kappaB activation, a process which is essential to prevent the spontaneous apoptosis of these parasite-transformed cells. NF-kappaB-mediated responses are regulated by s elective combinations of NF-kappaB proteins as homo- or heterodimers and by distinct kappaB motifs. We characterised the NF-kappaB complexes induced b y T. parva infection in TpM(803)T cells. By western blot, we demonstrated t hat all members of the NF-kappaB/Rel family of proteins translocate to the nucleus of infected cells. Using two different kappaB oligonucleotides (kap paB-1 and kappaB-2), both containing the decameric consensus kappaB motif(G GGACTTTCC), clearly distinct patterns of DNA binding activities could be de monstrated in electrophoretic mobility shift assays. Supershift analysis an d UV crosslinking assays showed that complexes binding to kappaB-1 consiste d of p50, p65 and RelB home and/or heterodimers. We could also detect an as sociation of ATF-2 and c-Fos with one of the complexes. The HIV-derived kap paB-2 oligo only bound p50 and p65. Additionally, several agents known to i nhibit a wide range of NF-kappaB activation pathways had no inhibitory effe ct on the activation of NF-kappaB DNA binding in TpM(803)T cells. (C) 2000 Editions scientifiques et medicales Elsevier SAS.