INFLUENCE OF DROSOPHILA VENTRAL EPIDERMAL DEVELOPMENT BY THE CNS MIDLINE CELLS AND SPITZ CLASS GENES

The ventral epidermis of Drosophila melanogaster is derived from longi tudinal rows of ectodermal precursor cells that divide and expand to f orm the ventral embryonic surface. The spitz class genes are required for the proper formation of the larval ventral cuticle. Using a group of enhancer trap lines that stain subsets of epidermal cells, it is sh own here that spitz. class gene function is necessary for ventral epid ermal development and gene expression. Analysis of single-minded mutan t embryos implies that ventral epidermal cell fate is influenced by th e CNS midline cells.