The structure of rat muscle-specific enolase (ββ enolase) gene was determined. It comprises 12 exons of various lengths (59–223 bp) spanning about 6 kbp and its exon-intron organization is similar to that of neuron-specific enolase (γγ enolase) gene. A transcriptional start site was identified by a combination of S1 nuclease mapping and primer extension analyses. In the 5'-flanking region we found a TATA-box-like sequence and several MyoD-binding motifs. The in vitro cell free transcription of the truncated genomic DNA fragment using HeLa cell extract showed that the transcription start site has been correctly identified and the promoter sequences work well.
