Regulation of cyclooxygenase-2 expression by the translational silencer TIA-1.
J Exp Med
; 198(3): 475-81, 2003 Aug 04.
Article
em En
| MEDLINE
| ID: mdl-12885872
ABSTRACT
The cyclooxygenase-2 (COX-2) enzyme catalyzes the rate-limiting step of prostaglandin formation in inflammatory states, and COX-2 overexpression plays a key role in carcinogenesis. To understand the mechanisms regulating COX-2 expression, we examined its posttranscriptional regulation mediated through the AU-rich element (ARE) within the COX-2 mRNA 3'-untranslated region (3'UTR). RNA binding studies, performed to identify ARE-binding regulatory factors, demonstrated binding of the translational repressor protein TIA-1 to COX-2 mRNA. The significance of TIA-1-mediated regulation of COX-2 expression was observed in TIA-1 null fibroblasts that produced significantly more COX-2 protein than wild-type fibroblasts. However, TIA-1 deficiency did not alter COX-2 transcription or mRNA turnover. Colon cancer cells demonstrated to overexpress COX-2 through increased polysome association with COX-2 mRNA also showed defective TIA-1 binding both in vitro and in vivo. These findings implicate that TIA-1 functions as a translational silencer of COX-2 expression and support the hypothesis that dysregulated RNA-binding of TIA-1 promotes COX-2 expression in neoplasia.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Biossíntese de Proteínas
/
Proteínas
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Regulação Enzimológica da Expressão Gênica
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Processamento Pós-Transcricional do RNA
/
Proteínas de Ligação a RNA
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Prostaglandina-Endoperóxido Sintases
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Isoenzimas
/
Proteínas de Membrana
Tipo de estudo:
Prognostic_studies
Limite:
Animals
/
Humans
Idioma:
En
Revista:
J Exp Med
Ano de publicação:
2003
Tipo de documento:
Article
País de afiliação:
Estados Unidos