An Act88F promoter drives expression of the Mhc embryonic body wall muscle isoform S1 domain (cDNA sequence encoding exons 2, 3a, 4, 5, 6, 7a, 8, 9b, 10, 11c and part of exon 12) attached to the Mhc indirect flight muscle rod region (genomic fragment encoding from the ApaI site in 12 through exon 19). The protein is tagged at the N-terminal end with Tag:polyHis and with the Tag:CS(TEVp) cleavage site.