The 5'-flanking region of the human smooth muscle cell calponin gene contains a cis-acting domain for interaction with a methylated DNA-binding transcription repressor.

The human smooth muscle cell (SMC) calponin gene, which is composed of seven exons and six introns, spanning an approximately 11.2 kilobase (kb) genomic DNA, has been isolated and characterized by sequence analysis. As determined by primer extension mapping and rapid amplification of mRNA transcripts, a major transcription start site of the calponin gene is located at 101 base-pairs (bp) upstream of the ATG start codon. A striking feature of the 5'-flanking, 5'-untranslated, and amino-terminal protein coding regions is the presence of an Alu repetitive sequence and a stretch of DNA sequence identified using a methyl CpG-binding protein affinity column [Cross, S.H., Charlton, J.A., Nan, X., and Bird, A.P. (1994) Nature Genet, 6,236-244]. The results of this study provide a new insight into the molecular mechanism underlying regulation of SMC-lineage specific gene expression.