Muscle-specific gene expression controlled by a regulatory element lacking a MyoD1-binding site.

Muscle-specific expression of the gene encoding the delta subunit of the acetylcholine receptor is controlled by a 54-base-pair region that does not contain a binding site for MyoD1, a protein involved in activation of the myogenic program. A MyoD1-binding site is present in the proximal promoter region of the gene encoding the delta-subunit, but is neither sufficient nor necessary for muscle-specific expression in transfected muscle cells.