Abstract
Nuclear transcription extracts were prepared from embryos of Drosophila melanogaster to study the in vitro transcription of the tropomyosin genes. Several non-muscle gene promoters, including the non-muscle promoter of the Tropomyosin II gene, were shown to be efficiently transcribed in vitro. The Tropomyosin I gene and the muscle promoter of the Tropomyosin II gene, as well as two other contractile protein muscle genes, were not transcribed in vitro. The embryonic extract did, however, contain developmental-specific proteins that bound to the muscle enhancer regulatory region of the Tropomyosin I gene.