MOLECULAR CHARACTERIZATION OF NEURALLY EXPRESSING GENES IN THE PARA SODIUM-CHANNEL GENE-CLUSTER OF DROSOPHILA

To elucidate the mechanisms regulating expression of para, which encod es the major class of sodium channels in the Drosophila nervous system , we have tried to locate upstream cis-acting regulatory elements by m apping the transcriptional start site and analyzing the region immedia tely upstream of para in region 14D of the polytene chromosomes. From these studies, we have discovered that the region contains a cluster o f neurally expressing genes. Here we report the molecular characteriza tion of the genomic organization of the 14D region and the genes withi n this region, which are: calnexin (Cnx), actin related protein 14D (A rp14D), calcineurin A 14D (CnnA14D), and chromosome associated protein (Cap). The tight clustering of these genes, their neuronal expression patterns, and their potential functions related to expression, modula tion, or regulation of sodium channels raise the possibility that thes e genes represent a functionally related group sharing some coordinate regulatory mechanism.