Regulation and composition of activator protein 1 (AP-1) transcription factors controlling collagenase and c-Jun promoter activities.
Biochem J
; 360(Pt 3): 599-607, 2001 Dec 15.
Article
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| MEDLINE
| ID: mdl-11736649
The activator protein 1 (AP-1) transcription factor is composed of heterodimers of the Fos/activating transcription factor (ATF) and Jun subfamilies of basic-region leucine-zipper (B-ZIP) proteins. In order to determine the identities of individual B-ZIP proteins in various AP-1 complexes we tested the effect of dominant-negative mutants to the B-ZIP proteins c-Fos, ATF2, ATF4 and CCAAT-enhancer-binding protein (C/EBP) on the activities of the collagenase and c-Jun promoters. These dominant-negative mutants inhibit DNA binding of wild-type B-ZIP proteins in a leucine-zipper-dependent fashion. Transcription of a collagenase promoter/reporter gene was induced in HepG2 hepatoma cells by expression of c-Fos and c-Jun, administration of PMA ("TPA") or by expression of a truncated form of MEK (mitogen-activated/extracellular-signal-regulated kinase kinase) kinase-1, MEKK1Delta. In all cases, the dominant-negative mutants A-Fos and A-ATF2 decreased collagenase promoter activity. However, A-ATF4 and A-C/EBP had no effect. A-Fos and A-ATF2 also reduced MEKK1Delta-induced stimulation of the c-Jun promoter. In contrast, constitutive c-Jun promoter activity was blocked solely by A-ATF2, strongly suggesting that ATF2 and/or an ATF2-dimerizing protein are of major importance for c-Jun transcription in unstimulated cells. These results demonstrate that AP-1 transcription factors of different compositions control c-jun gene transcription in resting or stimulated cells.
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Regulación Neoplásica de la Expresión Génica
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Regiones Promotoras Genéticas
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Proteínas Proto-Oncogénicas c-jun
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Colagenasas
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Factor de Transcripción AP-1
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Quinasa 1 de Quinasa de Quinasa MAP
Límite:
Humans
Idioma:
En
Revista:
Biochem J
Año:
2001
Tipo del documento:
Article
País de afiliación:
Alemania
Pais de publicación:
Reino Unido