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.