We have isolated and characterized the human gene (COX7AH) for the contractile muscle isoform of cytochrome c oxidase (COX) subunit VIIa. This subunit is one of the 10 nuclear encoded subunits of the 13-subunit holoenzyme that carries out the terminal step in the electron transport chain. Using transient transfection assays, we have located a 5'-flanking region sufficient to direct high level, skeletal myotube-specific reporter gene expression. This 792 bp basal promoter, which contains the single transcription start but no canonical TATA or CCAAT boxes, contains one MEF2 site, three E boxes, and an Sp1 site that show binding to their cognate factors, and are all required for full expression. Mutation and transactivation analysis suggest that there is functional interaction between these binding sites.