HTLV-I and HTLV-II tax trans-activate the human EGR-1 promoter through different cis-acting sequences.
The immediate-early response gene, EGR-1, encodes a zinc finger-containing transcription factor that is involved in growth and differentiation of a variety of cell types. EGR-1 is induced in normal T cells following mitogenic stimulation and has recently been shown to be constitutively expressed in human T-cell leukemia virus type I (HTLV-I)- and type II (HTLV-II)-transformed T-cell lines. The trans-activating protein of HTLV-I, Tax, has been demonstrated to trans-activate promoters of a number of cellular genes, some of which may be critical in regulating T-cell proliferation. In this study, we examine the effect of Tax on expression of EGR-1 in three T-cell lines and demonstrate that both HTLV-I and -II Tax are capable of trans-activating human EGR-1 recombinant promoter constructs. Interestingly, HTLV-I and -II Tax trans-activate the human EGR-1 promoter through different promoter regions in the Jurkat cell line, suggesting that HTLV-I and -II Tax may lead to constitutive expression of EGR-1 through different signaling pathways. Deregulated expression of EGR-1 may contribute to uncontrolled cell growth and transformation during early stages of T-cell activation in HTLV-I and -II-infected cells.
Department of Pediatrics, UCLA School of Medicine.
K M
KM
Sakamoto
S D
SD
Nimer
J D
JD
Rosenblatt
J C
JC
Gasson
D001483:Base Sequence; D002472:Cell Transformation, Viral; D004268:DNA-Binding Proteins / Q000235:genetics*; D006800:Deltaretrovirus Infections / Q000235:genetics; D051766:Early Growth Response Protein 1; D005786:Gene Expression Regulation; D016356:Gene Products, tax / Q000494:pharmacology*; D006801:Humans; D017874:Immediate-Early Proteins; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D014157:Transcription Factors / Q000235:genetics*; D015533:Transcriptional Activation; D016335:Zinc Fingers / Q000235:genetics*
D004268:DNA-Binding Proteins; C497325:EGR1 protein, human; D051766:Early Growth Response Protein 1; D016356:Gene Products, tax; D017874:Immediate-Early Proteins; D014157:Transcription Factors