Tax oncoprotein trans-represses endogenous B-myb promoter activity in human T cells.
AIDS Res Hum Retroviruses
; 16(16): 1629-32, 2000 Nov 01.
Article
en En
| MEDLINE
| ID: mdl-11080802
The B-myb gene was identified on the basis of its homology with the protooncogene c-myb, homolog of the avian myeloblastosis virus (AMV) and avian leukemia virus (E26) transforming genes. Several studies using antisense constructs or antisense oligonucleotides as well as overexpression experiments suggest that B-Myb plays an important role in the transition from G(1) to S phase of the cell cycle and that B-Myb expression is cell cycle regulated. We have previously demonstrated that the human T cell lymphotropic virus type 1 (HTLV1) trans-activator Tax is able to repress transcription from c-myb promoter reporter constructs as well as from the endogenous c-myb promoter in human T cells and that this effect is mediated through inhibition of the c-Myb trans-activating functions. Here we report that both HTLV-1 as well as HTLV-2 Tax proteins inhibit c-Myb trans-activation in mouse embryo fibroblasts (MEFs). In addition to c-Myb, B-Myb expression is also markedly downregulated in HTLV-1-transformed cells at both RNA and protein levels. Furthermore, by using a Jurkat T cell line stably transfected with a tax gene driven by a cadmium-inducible promoter (JPX9), we were able to demonstrate that Tax directly represses the endogenous B-myb promoter in T cells. Because c-Myb and B-Myb have been involved in cell cycle progression, our results suggest that Tax, by repressing both c-Myb and B-Myb endogenous promoters, may bypass their requirement for cell cycle progression in HTLV-1-transformed T cells.
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Linfocitos T
/
Virus Linfotrópico T Tipo 1 Humano
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Virus Linfotrópico T Tipo 2 Humano
/
Activación Transcripcional
/
Transactivadores
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Productos del Gen tax
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Proteínas de Ciclo Celular
/
Proteínas de Unión al ADN
Tipo de estudio:
Prognostic_studies
Límite:
Animals
/
Humans
Idioma:
En
Revista:
AIDS Res Hum Retroviruses
Asunto de la revista:
SINDROME DA IMUNODEFICIENCIA ADQUIRIDA (AIDS)
Año:
2000
Tipo del documento:
Article
País de afiliación:
Estados Unidos
Pais de publicación:
Estados Unidos