Puralpha and Purbeta collaborate with Sp3 to negatively regulate beta-myosin heavy chain gene expression during skeletal muscle inactivity.
Mol Cell Biol
; 27(4): 1531-43, 2007 Feb.
Article
em En
| MEDLINE
| ID: mdl-17145772
ABSTRACT
Adult skeletal muscle retains the capability of transcriptional reprogramming. This attribute is readily observable in the non-weight-bearing (NWB) soleus muscle, which undergoes a slow-to-fast fiber type transition concurrent with decreased beta-myosin heavy chain (betaMyHC) gene expression. Our previous work showed that Sp3 contributes to decreased betaMyHC gene expression under NWB conditions. In this study, we demonstrate that physical and functional interactions between Sp3, Puralpha, and Purbeta proteins mediate repression of betaMyHC expression under NWB conditions. Binding of Puralpha or Purbeta to the single-stranded betaMyHC distal negative regulatory element-sense strand (dbetaNRE-S) element is markedly increased under NWB conditions. Ectopic expression of Puralpha and Purbeta decreased betaMyHC reporter gene expression, while mutation of the dbetaNRE-S element increased expression in C2C12 myotubes. The dbetaNRE-S element conferred Pur-dependent decreased expression on a minimal thymidine kinase promoter. Short interfering RNA sequences specific for Sp3 or for Puralpha and Purbeta decreased endogenous Sp3 and Pur protein levels and increased betaMyHC reporter gene expression in C2C12 myotubes. Immunoprecipitation assays revealed an association between endogenous Puralpha, Purbeta, and Sp3, while chromatin immunoprecipitation assays demonstrated Puralpha, Purbeta, and Sp3 binding to the betaMyHC proximal promoter region harboring the dbetaNRE-S and C-rich elements in vivo. These data demonstrate that Pur proteins collaborate with Sp3 to regulate a transcriptional program that enables muscle cells to remodel their phenotype.
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Regulação para Baixo
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Músculo Esquelético
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Cadeias Pesadas de Miosina
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Proteínas de Ligação a DNA
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Fator de Transcrição Sp3
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Proteínas do Tecido Nervoso
Limite:
Animals
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Humans
Idioma:
En
Ano de publicação:
2007
Tipo de documento:
Article