Defining smooth muscle cells and smooth muscle injury
J. Clin. Invest. William M. Mahoney, et al. 115:221 doi:10.1172/JCI24272 [Go to this article.]

Figure 1
Regulation of CArG-specific SMC genes. (A) CArG box elements in the SM α-actin promoter. The SM α-actin promoter contains 2 consensus CArG boxes [CC(A/T)₆GG]. However, the wild-type sequences are degenerate relative to the canonical sequence first identified in c-fos (CCATATTAGG). The positions of the specific nucleotide modulations are noted by underline. The other CArG-regulated SMC genes also contain multiple and degenerate CArG box elements. The number of consensus CArG boxes as well as their specific sequences varies from gene to gene. In addition, there are a number of SMC genes that do not contain CArG sequences, which suggests yet another mechanism for controlling gene expression in a gene- and stimulus-specific manner. (B) Molecular control of CArG-specific SMC genes. CArG boxes are bound by SRF. This protein-DNA complex is further regulated through interactions between SRF and specialized cofactors, including myocardin. Ultimately, CArG-specific SMC gene expression is controlled through these macromolecular complexes, which allows the SMC to respond to various stimuli, including injury.