Induction of nuclear NF-κB DNA binding activity after exposure of lymphoid cells to soluble Tax1 protein

P. F. Lindholm, S. J. Marriott, S. D. Gitlin, C. A. Bohan, J. N. Brady

Research output: Contribution to journalArticlepeer-review

81 Scopus citations

Abstract

We demonstrate that purified HTLV-I Tax1 protein can be taken up by 70Z/3 lymphoid cells and localized in both the nuclear and cytoplasmic compartments. Introduction of the Tax1 protein into the growth medium of 70Z/3 cells resulted in the rapid and transient induction of NF-κB binding activity in the nuclear fraction. Tax1 activation of NF-κB was not sensitive to either staurosporin or prolonged stimulation with the phorbol ester 12-O-tetradecanoylphorbol-13-acetate, suggesting that Tax1-dependent NF-κB activation did not require the protein kinase C pathway. Purified Tax1 did not directly increase NF-κB binding activity in 70Z/3 cytoplasmic extracts, suggesting that NF-κB induction may require cellular factors. Western blot and competitive radioimmunoassays demonstrated that Tax1 protein was present in the tissue culture media of HTLV-I-transformed cell lines. These results show that extracellular Tax1 may regulate cellular gene expression in noninfected cells.

Original languageEnglish (US)
Pages (from-to)1034-1043
Number of pages10
JournalNew Biologist
Volume2
Issue number11
StatePublished - Dec 1 1990

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)

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