POX-NEURO IS REQUIRED FOR DEVELOPMENT OF CHEMOSENSORY BRISTLES IN DROSOPHILA

The gene pox-neuro (poxn), which encodes a possible transcriptional re gulator including a paired domain, specifies the differences between m onoinnervated and polyinnervated sensory organs in the embryo. A detai led analysis of this gene, and in particular, an analysis of its funct ion in the adult sensory organs, has so far been hampered by the unava ilability of loss-of-function mutations. Here, we report the isolation of loss-of-function mutations of poxn and show that the chemosensory bristles are transformed into mechanosensory bristles in mutant flies. The external morphology of putative chemosensory bristles, number of innervating neurons, and cell division pattern are all affected in the mutants, showing that poxn is strictly required for development of th e adult chemosensory bristles. In addition, the formation of some prec ursor cells is suppressed in the mutants, suggesting that poxn is also required for formation of the precursors of chemosensory bristles. (C ) 1997 John Wiley & Sons, Inc.