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Comparative analysis of HTLV-1 and HTLV-2 post-translational modifications of Tax proteins in relation to their intracellular localization and activation of gene expression

The functional analysis of regulatory proteins Tax-1 and Tax-2 can provide useful information to further understand the difference in pathogenicity between HTLV-1 and HTLV-2.

Tax-1 molecules phosphorylated at serine residues 300 and 301, ubiquitinated or sumoylated at lysine residues 280 and 284 and acetylated at lysine 346 have been identified. These modifications control Tax-1 intracellular localization, the formation of Tax-1 nuclear bodies and sequential steps in Tax-1-mediated activation of the NF-κB pathway, a critical event thought to be involved in HTLV-1 transforming capacity [1].

By comparing internally tagged Tax-1 and Tax-2B, we demonstrated that Tax-2B activates gene expression via the NF-κB pathway, is present in nuclear bodies and in the cytoplasm and is modified by ubiquitination and sumoylation similarly to its homologue Tax-1 [2].

In the present study, we constructed a series of Tax-2B mutants with substitutions of specific lysine residues by arginines. The post-translational modifications, subcellular localization and capacity to activate gene expression of these Tax-2B mutants will be compared to those obtained for the corresponding mutants of Tax-1.


  1. 1.

    Lamsoul I, Lodewick J, Lebrun S, Brasseur R, Burny A, Gaynor RB, Bex F: Exclusive ubiquitination and sumoylation on overlapping lysine residues mediate NF-kappaB activation by the human T-cell leukemia virus tax oncoprotein. Mol Cell Biol. 2005, 25: 10391-10406. 10.1128/MCB.25.23.10391-10406.2005.

  2. 2.

    Turci M, Lodewick J, Righi P, Polania A, Romanelli MG, Bex F, Bertazzoni U: HTLV-2B Tax oncoprotein is modified by ubiquitination and sumoylation and displays intracellular localization similar to its homologue HTLV-1 Tax. Virology. 2009

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Correspondence to Marco Turci.

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Open Access This article is published under license to BioMed Central Ltd. This is an Open Access article is distributed under the terms of the Creative Commons Attribution 2.0 International License (, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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  • Serine
  • Lysine
  • Comparative Analysis
  • Arginine
  • Functional Analysis