Coordinate positioning of MEF2 and myogenin binding sites

The MEF2 and MyoD families of transcriptional regulatory factors both play central roles in the terminal differentiation of skeletal muscle. Further, binding sites for the two families often occur nearby, and there have been a number of indications that members of the two families may bind coordinately. The present study provides evidence that known binding sites for the two occur with precise geometric restrictions related to the DNA helical repeat unit, that pairs of putative sites following these restrictions are indicative of skeletal muscle-specific transcriptional regulatory regions, and that the geometric relationship can help provide a consistent interpretation for data that has until now been difficult to explain.