Segregation of cardiac and skeletal muscle-specific regulatory elements of the beta-myosin heavy chain gene.
AUTOR(ES)
Rindt, H
RESUMO
The beta-myosin heavy chain (beta-MyHC) gene is expressed in cardiac and slow skeletal muscles. To examine the regulatory sequences that are required for the gene's expression in the two compartments in vivo, we analyzed the expression pattern of a transgene consisting of the beta-MyHC gene 5' upstream region linked to the chloramphenicol acetyltransferase reporter gene. By using 5600 bp of 5' upstream region, the transgene was expressed at high levels in the slow skeletal muscles. Decreased levels of thyroid hormone led to the up-regulation of the transgene in both cardiac and skeletal muscles, mimicking the behavior of the endogenous beta-MyHC gene. After deleting the distal 5000 bp, the level of reporter gene expression was strongly reduced. However, decreased levels of thyroid hormone led to an 80-fold skeletal muscle-specific increase in transgene expression, even upon the ablation of a conserved cis-regulatory element termed MCAT, which under normal (euthyroid) conditions abolishes muscle-specific expression. In contrast, cardiac-specific induction was not detected with the deletion construct. These observations indicate that the cardiac and skeletal muscle regulatory elements can be functionally segregated on the beta-MyHC gene promoter.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=42555Documentos Relacionados
- cis-acting elements responsible for muscle-specific expression of the myosin heavy chain beta gene.
- Complete sequence and organization of the human cardiac beta-myosin heavy chain gene.
- Transcription factor GATA-4 regulates cardiac muscle-specific expression of the alpha-myosin heavy-chain gene.
- Both muscle-specific and ubiquitous nuclear factors are required for muscle-specific expression of the myosin heavy-chain beta gene in cultured cells.
- Cardiac alpha- and beta-myosin heavy chain genes are organized in tandem.