Tissue-specific DNase I-hypersensitive sites and hypomethylation in the chicken cardiac myosin light chain gene (L2-A).

As an approach to determine DNA elements involved in tissue-specific gene expression, the functional promoter of the cardiac myosin light chain gene (MLC 2-A) was identified. Chromatin structure of the MLC 2-A gene was examined for tissue specific DNase I-hypersensitive and hypomethylated sites. Heart specific DNase I-hypersensitive sites were detected in the promoter region of the gene as well as in flanking DNA sequences upstream and downstream of the gene. In expressing heart nuclei a region located about 1.5 kilobase pairs upstream of the transcription start site was found to contain both a hypersensitive and an undermethylated site. These structural chromatin changes of the MLC 2-A gene may be related to the expression of the gene.