CREB-1alpha is recruited to and mediates upregulation of the cytochrome c promoter during enhanced mitochondrial biogenesis accompanying skeletal muscle differentiation.
Mol Cell Biol
; 28(7): 2446-59, 2008 Apr.
Article
en En
| MEDLINE
| ID: mdl-18227154
To further understand pathways coordinating the expression of nuclear genes encoding mitochondrial proteins, we studied mitochondrial biogenesis during differentiation of myoblasts to myotubes. This energy-demanding process was accompanied by a fivefold increase of ATP turnover, covered by an eightfold increase of mitochondrial activity. While no change in mitochondrial DNA copy number was observed, mRNAs as well as proteins for nucleus-encoded cytochrome c, cytochrome c oxidase subunit IV, and mitochondrial transcription factor A (TFAM) increased, together with total cellular RNA and protein levels. Detailed analysis of the cytochrome c promoter by luciferase reporter, binding affinity, and electrophoretic mobility shift assays as well as mutagenesis studies revealed a critical role for cyclic AMP responsive element binding protein 1 (CREB-1) for promoter activation. Expression of two CREB-1 isoforms was observed by using specific antibodies and quantitative reverse transcription-PCR, and a shift from phosphorylated CREB-1Delta in myoblasts to phosphorylated CREB-1alpha protein in myotubes was shown, while mRNA ratios remained unchanged. Chromatin immunoprecipitation assays confirmed preferential binding of CREB-1alpha in situ to the cytochrome c promoter in myotubes. Overexpression of constitutively active and dominant-negative forms supported the key role of CREB-1 in regulating the expression of genes encoding mitochondrial proteins during myogenesis and probably also in other situations of enhanced mitochondrial biogenesis.
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Proteína de Unión a Elemento de Respuesta al AMP Cíclico
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Fibras Musculares Esqueléticas
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Regulación del Desarrollo de la Expresión Génica
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Desarrollo de Músculos
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Mioblastos
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Citocromos c
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Mitocondrias Musculares
Límite:
Animals
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Humans
Idioma:
En
Revista:
Mol Cell Biol
Año:
2008
Tipo del documento:
Article
País de afiliación:
Alemania
Pais de publicación:
Estados Unidos