Abstract
Background - Myocardin (Myocd) is a strong coactivator that binds the serum response factor (SRF) transcription factor over CArG elements embedded within smooth muscle cell (SMC) and cardiac muscle cyto-contractile genes. Here, we sought to ascertain whether Myocd-mediated gene expression confers a structural and physiological cardiac or SMC phenotype. Methods and Results - Adenoviral-mediated expression of Myocd in the BC3H1 cell line induces cardiac and SMC genes while suppressing both skeletal muscle markers and cell growth. Immunofluorescence microscopy shows that SRF and a SMC-like cyto-contractile apparatus are elevated with Myocd overexpression. A short hairpin RNA to Srf impairs BC3H1 cyto-architecture; however, cotransduction with Myocd results in complete restoration of the cyto-architecture. Electron microscopic studies demonstrate a SMC ultrastructural phenotype with no evidence for cardiac sarcomerogenesis. Biochemical and time-lapsed videomicroscopy assays reveal clear evidence for Myocd-induced SMC-like contraction. Conclusion - Myocd is sufficient for the establishment of a SMC-like contractile phenotype.
Original language | English (US) |
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Pages (from-to) | 1505-1510 |
Number of pages | 6 |
Journal | Arteriosclerosis, thrombosis, and vascular biology |
Volume | 28 |
Issue number | 8 |
DOIs | |
State | Published - Aug 2008 |
Externally published | Yes |
Keywords
- Contraction
- Knockdown
- Myocardin
- Serum response factor
- Smooth muscle
ASJC Scopus subject areas
- Cardiology and Cardiovascular Medicine