Identification of motifs that are conserved in twelve Drosophila species and regulate midline glia versus neuron expression

Functional complexity of the central nervous system is reflected by the large number and diversity of genes expressed in its many different cell types. Understanding the control of gene expression within cells of the central nervous system will help reveal how various neurons and glia develop and function. Midline cells of Drosophila differentiate into glial cells and several types of neurons, and also serve as a signaling center for surrounding tissues. Here, we examine regulation of the midline gene, wrapper, required for both neuron-glia interactions and viability of midline glia. We identify a region upstream of wrapper required for its midline expression pattern that is highly conserved (87%) between twelve Drosophila species. Site-directed mutagenesis identifies five motifs necessary for midline glial expression: a motif that restricts expression to midline glia and excludes it from midline neurons, a Single-minded/Tango binding site, and three additional, uncharacterized motifs. The results suggest short, highly conserved genomic sequences flanking Drosophila midline genes are indicative of functional regulatory regions and that small changes within these sequences can alter the expression pattern of a gene.

Key Words: genomes, glia, midline, neurons, transcription

Online ISS 1091-6490
Copyright 2008 by the Genetics Society of America
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