Open AccessHRC Is a Direct Transcriptional Target of MEF2 during Cardiac, Skeletal, and Arterial Smooth Muscle Development In Vivo
Author(s) -
Joshua P. Anderson,
Evdokia Dodou,
Analeah B. Heidt,
Sarah J. De Val,
Eric J. Jaehnig,
Stephanie Greene,
Eric N. Olson,
Brian L. Black
Publication year - 2004
Publication title -
molecular and cellular biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.14
H-Index - 327
eISSN - 1067-8824
pISSN - 0270-7306
DOI - 10.1128/mcb.24.9.3757-3768.2004
Subject(s) - mef2 , biology , enhancer , skeletal muscle , myocyte , microbiology and biotechnology , regulatory sequence , cardiac muscle , regulation of gene expression , gene expression , gene , transcriptional regulation , enhancer rnas , transcription factor , serum response factor , genetics , anatomy
The HRC gene encodes the histidine-rich calcium-binding protein, which is found in the lumen of the junctional sarcoplasmic reticulum (SR) of cardiac and skeletal muscle and within calciosomes of arterial smooth muscle. The expression of HRC in cardiac, skeletal, and smooth muscle raises the possibility of a common transcriptional mechanism governing its expression in all three muscle cell types. In this study, we identified a transcriptional enhancer from the HRC gene that is sufficient to direct the expression of lacZ in the expression pattern of endogenous HRC in transgenic mice. The HRC enhancer contains a small, highly conserved sequence that is required for expression in all three muscle lineages. Within this conserved region is a consensus site for myocyte enhancer factor 2 (MEF2) proteins that we show is bound efficiently by MEF2 and is required for transgene expression in all three muscle lineages in vivo. Furthermore, the entire HRC enhancer sequence lacks any discernible CArG motifs, the binding site for serum response factor (SRF), and we show that the enhancer is not activated by SRF. Thus, these studies identify the HRC enhancer as the first MEF2-dependent, CArG-independent transcriptional target in smooth muscle and represent the first analysis of the transcriptional regulation of an SR gene in vivo.