MUSASHI, A NEURAL RNA-BINDING PROTEIN REQUIRED FOR DROSOPHILA ADULT EXTERNAL SENSORY ORGAN DEVELOPMENT

A family of neural RNA-binding proteins has recently been described in both vertebrates and invertebrates. We have identified a new member o f this family, the Drosophila musashi (msi) locus, which is required f or development of adult external sensory organs (sensilla). In contras t with wild-type sensilla, which contain two outer support cells, the msi mutation typically results in the appearance of extra outer suppor t cells. The msi putative RNA-binding protein is localized to the nucl eus and appears to be expressed in all cells in each sensillum and pre dominantly in neurons during embryogenesis. We propose that the msi pr otein regulates sensillum development by controlling the expression of target genes at the posttranscriptional level.