ACETYLCHOLINE-RECEPTORS OF THE DROSOPHILA BRAIN - A 900 BP PROMOTER FRAGMENT CONTAINS THE ESSENTIAL INFORMATION FOR SPECIFIC EXPRESSION OF THE ARD GENE IN-VIVO

The ard gene encodes a beta-subunit of Drosophila nicotinic acetylchol ine receptors specifically expressed in a subset of neurons. To identi fy the cis-regulatory region responsible for this cell-specific expres sion, various 5' fragments of the and gene were fused to a lacZ report er gene and introduced into the Drosophila genome. A DNA fragment span ning similar to 760 bp upstream and similar to 140 bp downstream of a cluster of putative transcription start sites produced a pattern of be ta-galactosidase activity that resembles the distribution of ARD trans cripts. Both in embryos and adults the levels of lacZ RNA were similar to those of endogenous ARD transcripts, suggesting that the 900 bp fr agment harbors ail essential elements for proper expression of the ard gene.