Transrepression of lck gene expression by human T-cell leukemia virus type 1-encoded p40tax.
J Virol
; 71(3): 1975-83, 1997 Mar.
Article
em En
| MEDLINE
| ID: mdl-9032329
ABSTRACT
To understand the mechanism of p56lck protein downregulation observed in human T cells infected by human T-cell leukemia virus type 1 (HTLV-1), we have investigated the ability of the 3' end of the HTLV-1 genome as well as that of the tax and rex genes to modulate p56lck protein expression and p56lck mRNA synthesis. By using Jurkat T cells stably transfected with constructs that expressed either the 3' end of the HTLV-1 genome (JK C11-pMTEX), the tax gene (JK52-Tax) or the rex gene (JK9-Rex), we found that the expression of p40tax (Tax) was sufficient to modulate p56lck protein expression. Similarly, we found that the expression of the mRNA which encoded p56lck was repressed in Jurkat T cells which expressed Tax. This downregulation was shown to be proportional to the amount of tax mRNA found in the transfected cells, as evidenced by experiments that used cells (JPX-9) stably transfected with a tax gene driven by a cadmium-inducible promoter. Furthermore, cadmium induction of Tax in JPX-9 cells transiently transfected with a construct containing the chloramphenicol acetyltransferase (CAT) gene under control of the lck distal promoter (lck DP-CAT) resulted in the downregulation of CAT gene expression. In contrast, cadmium induction of Tax in JPX-9 cells transiently transfected with a CAT construct driven by a lck DP with a deletion extending from position -259 to -253 (a sequence corresponding to a putative E-Box) did not modulate CAT gene expression, suggesting that the effect of Tax on p56lck is mediated through an E-Box binding protein.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Proteínas Repressoras
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Vírus Linfotrópico T Tipo 1 Humano
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Regulação Viral da Expressão Gênica
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Proteínas Oncogênicas Virais
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Produtos do Gene rex
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Produtos do Gene tax
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Quinases da Família src
Limite:
Humans
Idioma:
En
Revista:
J Virol
Ano de publicação:
1997
Tipo de documento:
Article