Involvement of Oct-1 in the regulation of CDKN1A in response to clinically relevant doses of ionizing radiation.
Biochim Biophys Acta
; 1789(3): 225-31, 2009 Mar.
Article
em En
| MEDLINE
| ID: mdl-19118657
ABSTRACT
CDKN1A is a cyclin-dependent kinase inhibitor that plays a critical role in cell cycle checkpoint regulation. It is transcriptionally induced by TP53 (p53) following exposure to ionizing radiation (IR). Induction of CDKN1A after irradiation is closely related to IR-sensitivity of tumor cells, but the underlying mechanisms remain obscure because conventional reporter gene systems respond poorly to IR unless hyperlethal doses are used. Here, we performed a promoter analysis of the CDKN1A gene following irradiation with clinically relevant doses of IR using the adeno-associated virus-mediated reporter system which we have recently shown to be highly responsive to IR. We demonstrate that there are regulatory elements at -1.1 kb, -1.4 kb, and -1.8 kb, and deletion of these elements attenuate induction of the CDKN1A gene promoter in response to 0.2-2.0 Gy of IR. EMSA and ChIP assays showed that Oct-1 binds constitutively to the elements at -1.1 kb and -1.8 kb. Functional involvement of Oct-1 was confirmed by RNA interference targeting the Oct-1 gene, which suppressed both the basal and IR-inducible components of the CDKN1A expression. Thus, our results reveal that Oct-1 is crucial to the TP53-mediated regulation of the CDKN1A gene promoter following exposure to clinically relevant doses of IR.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Dependovirus
/
Inibidor de Quinase Dependente de Ciclina p21
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Fator 1 de Transcrição de Octâmero
Limite:
Female
/
Humans
Idioma:
En
Revista:
Biochim Biophys Acta
Ano de publicação:
2009
Tipo de documento:
Article