Transcriptional activator Tax of HTLV-1 binds to the NF-kappa B precursor p105.
Human T-cell leukemia virus type 1 (HTLV-1) induces adult T-cell leukemia and also a neurological disease, tropical spastic paraparesis. Tax protein (p40tax) of HTLV-1 activates in trans its own transcriptional enhancer in the long terminal repeat and also those in some cellular genes such as interleukin 2 receptor alpha, granulocyte-macrophage colony-stimulating factor, Fos, Jun and MHC class I. Thus, Tax has been proposed to play a critical role in the pathogenesis induced by HTLV-1 infection. Here, we report formation of a complex of Tax protein with the precursor protein p105 of the NF-kappa B p50 subunit. p105 was co-immunoprecipitated with Tax protein from cells infected with HTLV-1 from cells transfected with the Tax expression plasmid, but not from cells transfected with inactive mutants of Tax. Furthermore, a GST-p105 fusion protein produced in Escherichia coli bound to Tax protein. These results strongly suggest that the trans-activator Tax protein forms a complex with precursor NF-kappa B p105 and plays a role in trans-activation of transcriptional initiation.
Hirai
H
H
Department of Cellular and Molecular Biology, University of Tokyo, Japan.
Fujisawa
J
J
Suzuki
T
T
Ueda
K
K
Muramatsu
M
M
Tsuboi
A
A
Arai
N
N
Yoshida
M
M
D016356:Gene Products, tax / Q000378:metabolism*; D015368:Human T-lymphotropic virus 1 / Q000472:pathogenicity*; D006801:Humans; D016328:NF-kappa B / Q000378:metabolism*; D011498:Protein Precursors / Q000378:metabolism*; D015533:Transcriptional Activation
D016356:Gene Products, tax; D016328:NF-kappa B; D011498:Protein Precursors