Molecular-genetic mechanisms regulating tissue-specific expression of the drosophila estS gene

A study was made of the Drosophila melanogaster est6 and D, virilis estS genes for tissue-specific esterase, and their expression at various stages of development was characterized. The former has one promoter and is expressed in the seminal ducts, whereas the latter has two promoters and is expressed in the seminal bulbs. In transgenic D. melanogaster, estS was expressed in the seminal bulbs, as observed in the donor. A region adjacent to the structural gene proved responsible for its expression in the seminal bulbs. Transgenic D. melanogaster lines were also obtained with constructs containing various fragments of the estS regulatory region and the lacZ reporter gene. Histochemical analysis with X-Gal staining allowed identification of a region that inhibits estS expression in all organs other than seminal bulbs. An esterase S homolog was found in a marine mollusk.