Lethal cutaneous disease in transgenic mice conditionally expressing type I human T cell leukemia virus Tax

J Biol Chem. 2005 Oct 21;280(42):35713-22. doi: 10.1074/jbc.M504848200. Epub 2005 Aug 16.


Type I human T cell leukemia virus (HTLV-I) is etiologically linked with adult T cell leukemia, an aggressive and usually fatal expansion of activated CD4+ T lymphocytes that frequently traffic to skin. T cell transformation induced by HTLV-I involves the action of the 40-kDa viral Tax transactivator protein. Tax both stimulates the HTLV-I long terminal repeat and deregulates the expression of select cellular genes by altering the activity of specific host transcription factors, including cyclic AMP-responsive element-binding protein (CREB)/activating transcription factor, NF-kappaB/Rel, and serum response factor. To study initiating events involved in HTLV-I Tax-induced T cell transformation, we generated "Tet-off" transgenic mice conditionally expressing in a lymphocyte-restricted manner (EmuSR alpha promoter-enhancer) either wild-type Tax or mutant forms of Tax that selectively compromise the NF-kappaB (M22) or CREB/activating transcription factor (M47) activation pathways. Wild-type Tax and M47 Tax-expressing mice, but not M22-Tax expressing mice, developed progressive alopecia, hyperkeratosis, and skin lesions containing profuse activated CD4 T cell infiltrates with evidence of deregulated inflammatory cytokine production. In addition, these animals displayed systemic lymphadenopathy and splenomegaly. These findings suggest that Tax-mediated activation of NF-kappaB plays a key role in the development of this aggressive skin disease that shares several features in common with the skin disease occurring during the preleukemic stage in HTLV-I-infected patients. Of note, this skin disease completely resolved when Tax transgene expression was suppressed by administration of doxycycline, emphasizing the key role played by this viral oncoprotein in the observed pathology.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Blotting, Western
  • CD4-Positive T-Lymphocytes / metabolism
  • Cyclic AMP Response Element-Binding Protein / metabolism
  • Cytokines / metabolism
  • DNA / chemistry
  • Flow Cytometry
  • Gene Products, tax / chemistry
  • Gene Products, tax / physiology*
  • Genotype
  • Humans
  • Immunohistochemistry
  • Inflammation
  • Keratinocytes / cytology
  • Keratinocytes / virology
  • Leukemia, T-Cell / metabolism*
  • Lymphocytes / virology
  • Mice
  • Mice, Transgenic
  • NF-kappa B / metabolism
  • Phenotype
  • Polymerase Chain Reaction
  • Promoter Regions, Genetic
  • RNA, Messenger / metabolism
  • Reverse Transcriptase Polymerase Chain Reaction
  • Ribonucleases / metabolism
  • Serum Response Factor / metabolism
  • Skin / metabolism
  • Skin / virology*
  • Time Factors
  • Up-Regulation


  • Cyclic AMP Response Element-Binding Protein
  • Cytokines
  • Gene Products, tax
  • NF-kappa B
  • RNA, Messenger
  • Serum Response Factor
  • DNA
  • Ribonucleases