DROSOPHILA PHOTORECEPTOR AXON GUIDANCE AND TARGETING REQUIRES THE DREADLOCKS SH2 SH3 ADAPTER PROTEIN/

Mutations in the Drosophila gene dreadlocks (dock) disrupt photorecept or cell (R cell) axon guidance and targeting. Genetic mosaic analysis and cell-type-specific expression of dock transgenes demonstrate dock is required in R cells for proper innervation. Dock protein contains o ne SH2 and three SH3 domains, implicating it in tyrosine kinase signal ing, and is highly related to the human proto-oncogene Nck. Dock expre ssion is detected in R cell growth cones in the target region. We prop ose Dock transmits signals in the growth cone in response to guidance and targeting cues. These findings provide an important step for disse ction of signaling pathways regulating growth cone motility.