title: Human T-cell leukemia virus type 1 Tax protein induces the expression of STAT1 and STAT5 genes in T-cells.
abstract: Human T-cell leukemia virus type 1 (HTLV-1) Tax transforms normal T-cells in the presence of interleukin (IL)-2 in vitro. STAT is a family of transcription factors that play a pivotal role in cytokine-induced functions of a various type of cells. We investigated the involvement of STATs in the transformation of T-cells by HTLV-1. HTLV-1-transformed T-cell lines expressed higher amounts of STAT1, STAT3 and STAT5 RNA and proteins than virus-negative T cells. The expression of STAT1 and STAT5 in a human T-cell line was induced by Tax. IL-2 induced the DNA binding activity of STAT3 and STAT5 of a HTLV-1-transformed cell line and then stimulated its proliferation. In contrast, IL-2 did neither in a cell line lacking STAT3 and STAT5. The expression of STAT1, STAT3 and STAT5 mRNAs were also induced by a T-cell mitogen in normal human peripheral blood mononuclear cells. Our results suggest that the induction of STAT1 and STAT5 by Tax enhances cytokine-induced functions of virus-infected T-cells, hence the induction may play a role in IL-2-dependent transformation steps of T-cells by HTLV-1.
authors.affiliation: Department of Microbiology, Tokyo Medical and Dental University, Japan.
authors.forename: N
authors.initials: N
authors.lastname: Nakamura
authors.forename: M
authors.initials: M
authors.lastname: Fujii
authors.forename: T
authors.initials: T
authors.lastname: Tsukahara
authors.forename: M
authors.initials: M
authors.lastname: Arai
authors.forename: T
authors.initials: T
authors.lastname: Ohashi
authors.forename: H
authors.initials: H
authors.lastname: Wakao
authors.forename: M
authors.initials: M
authors.lastname: Kannagi
authors.forename: N
authors.initials: N
authors.lastname: Yamamoto
mesh_terms: D002472:Cell Transformation, Viral; D004268:DNA-Binding Proteins / Q000235:genetics*; D015967:Gene Expression Regulation, Viral / Q000502:physiology*; D016356:Gene Products, tax / Q000502:physiology*; D015368:Human T-lymphotropic virus 1; D006801:Humans; D007376:Interleukin-2 / Q000494:pharmacology; D007963:Leukocytes, Mononuclear / Q000378:metabolism; D008894:Milk Proteins; D008934:Mitogens / Q000494:pharmacology; D050794:STAT1 Transcription Factor; D050799:STAT5 Transcription Factor; D015398:Signal Transduction / Q000502:physiology*; D013601:T-Lymphocytes / Q000378:metabolism*; D015534:Trans-Activators / Q000235:genetics*
chemical_list: D004268:DNA-Binding Proteins; D016356:Gene Products, tax; D007376:Interleukin-2; D008894:Milk Proteins; D008934:Mitogens; D050794:STAT1 Transcription Factor; C494079:STAT1 protein, human; D050799:STAT5 Transcription Factor; D015534:Trans-Activators