A novel Drosophila paired-like homeobox gene related to Caenorhabditis elegans unc-4 is expressed in subsets of postmitotic neurons and epidermal cells

We have isolated a novel Drosophila paired-like homeobox gene, DPHD-1. The homeodomain of DPHD-1 showed 85% amino-acid identity with that of the C. elegans Unc-4 protein. Whole-mount in situ hybridization of embryos and third-instar larvae revealed that the DPHD-1 mRNA is specifically localized in subsets of postmitotic neurons in the central nervous system (CNS) and in the developing epidermis with a segmentally repeated pattern. Double staining with a posterior compartment marker, an anti-Engrailed antibody, showed that DPHD-1 expressing neurons in the CNS were present in the posterior compartment, whereas DPHD-1 expression in the epidermis was restricted to the anterior compartment in each segment. This temporal and spatial expression pattern suggests that DPHD-1 may play a role in determining the distinct cell types in each segment.