title: Expression of the ligand-binding nicotinic acetylcholine receptor subunit D alpha 2 in the Drosophila central nervous system.
abstract: The D alpha 2 gene encodes a ligand-binding subunit of nicotinic acetylcholine receptors (nAChRs) from Drosophila melanogaster. We have studied the distribution of D alpha 2 transcripts and protein by in situ hybridization and immunohistochemistry, respectively, as well as the regulation of D alpha 2 gene expression in vivo using D alpha 2 promoter fragments fused to the Escherichia coli lacZ gene. Transcripts and protein from the D alpha 2 gene were detected exclusively in the central nervous system. Both in late embryos and adults D alpha 2-like immunoreactivity is widely but not uniformly distributed in the synaptic neuropil, suggesting that the D alpha 2 protein is a subunit of a synaptic nicotinic receptor. Its distribution resembles that of ALS and ARD proteins, two other nAChR subunits of the fly. Five different D alpha 2-lacZ fusion gene constructs were introduced into the Drosophila genome by P-element-mediated gene transfer to identity functional elements of the D alpha 2 promoter. All constructs produce a basic lacZ expression pattern that is compatible with the distribution of D alpha 2 transcripts and protein. A 880 bp upstream fragment harbors the cis elements for the expression of a weak but specific basic D alpha 2 pattern. The next 350 bp further upstream significantly enhance beta-galactosidase expression without influencing the pattern of expression. Between 1.7 and 7.3 kb upstream of the transcription start site one or more elements that are required for D alpha 2 expression in optic lobe tangential cells are located.
authors.affiliation: Center for Molecular Neurobiology, University of Hamburg, Germany.
authors.forename: P E
authors.initials: PE
authors.lastname: Jonas
authors.forename: B
authors.initials: B
authors.lastname: Phannavong
authors.forename: R
authors.initials: R
authors.lastname: Schuster
authors.forename: C
authors.initials: C
authors.lastname: Schröder
authors.forename: E D
authors.initials: ED
authors.lastname: Gundelfinger
mesh_terms: D000818:Animals; D001483:Base Sequence; D001923:Brain Chemistry; D002490:Central Nervous System / Q000166:cytology; D004330:Drosophila / Q000737:chemistry / Q000196:embryology / Q000235:genetics*; D018507:Gene Expression Regulation, Developmental; D017403:In Situ Hybridization; D007438:Introns; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic / Q000235:genetics*; D011978:Receptors, Nicotinic / Q000032:analysis / Q000737:chemistry / Q000235:genetics / Q000648:ultrastructure*; D001616:beta-Galactosidase / Q000032:analysis*
chemical_list: D011978:Receptors, Nicotinic; D001616:beta-Galactosidase