TEMPORAL AND SPATIAL EXPRESSION PATTERNS OF 2 G-PROTEIN COUPLED RECEPTORS IN DROSOPHILA-MELANOGASTER

Temporal and spatial expression patterns of a muscarinic acetylcholine receptor (Acr60C) and an octopamine/tyramine receptor (Octyr) were de termined in Drosophila melanogaster using quantitative Northern analys is and in situ hybridization to tissue sections. Expression of mRNA en coding both of these G-protein coupled receptors peaks initially in 18 to 21 hour embryos following the formation of the mature larval nervo us system. Levels of mRNA then decline during larval stages, rising to a second peak in 3 to 4-day-old pupae after a period of major nervous system reorganization. The muscarinic acetylcholine receptor mRNA is expressed throughout the cortical regions of the central nervous syste m in adults and embryos. Particularly high levels of expression of Acr 60C are observed in cell bodies adjacent to the antennal lobes, sugges ting a major role for this muscarinic receptor in the processing of ol factory information. In contrast, the octopamine/tyramine receptor mRN A is distributed diffusely throughout the adult brain, with patches of signal concentrated in the cortex of the dorsal protocerebrum near th e mushroom bodies. These patches may represent individual cells expres sing Octyr receptors.