Hox Genes and Neural Patterning in Drosophila

Hox genes encode conserved homeodomain transcription factors that possess significant developmental power in shaping animal morphology. Hox genes are also expressed in the nervous system of Drosophila and have a wide array of functions in the development of the peripheral and central nervous system (CNS). In the peripheral nervous system of Drosophila , Hox genes are required for sensory organ development as well as for proper formation of neuromuscular networks. During embryogenesis of the CNS, Hox genes are involved in the establishment of regional neuronal identity, in fate specification in different segments, in regionalized programmed cell death of postmitotic neurons, and in the control of neural proliferation. During postembryonic development of the CNS, Hox genes are involved in limiting the proliferative potential of neural progenitors in the abdominal segments by controlling the time of their apoptosis, and this process is tightly controlled by the Polycomb group of genes. Hox genes and their cofactors are also subject to cross-regulatory interactions in neural patterning. Many features of Hox gene expression and function in the nervous system of Drosophila can be found in vertebrates, suggesting a high degree of evolutionary conservation of Hox gene action in neural tissues.