Genetic control of macrochaetae development in Drosophila melanogaster

The Drosophila head and body have a regular species-specific pattern of strictly defined number of external sensory organs-macrochaetae (large bristles). The pattern constancy and relatively simple organization of each bristle organ composed of only four specialized cells makes macrochaetae a convenient model to study the developmental patterns of spatial structures with a fixed number of elements in specific positions as well as the mechanisms of cell differentiation. The experimental data on the major genes and their products controlling three stages of macrochaetae development-the emergence of proneural clusters in the imaginal disc ectoderm, the precursor cell determination in the proneural clusters, and the specialization of cells of the definitive sensory organ-were reviewed. The role of the achaete-scute gene complex, EGFR and Notch signaling, and selector genes in these processes was considered. Analysis of published data allowed us to propose an integrated diagram of the system controlling macrochaetae development in D. melanogaster.