Two closely linked Drosophila POU domain genes are expressed in neuroblasts and sensory elements.

We have characterized two Drosophila POU genes designated dPOU-19 and dPOU-28. These genes are transcribed as 3.1- and 2.2-kilobase mRNAs, respectively, which accumulate maximally during the first 12 hr of embryogenesis. The mRNAs encode 601- and 475-amino acid deduced proteins; their POU domains are most related to those of the human OCT1 and OCT2. Both genes give similar nervous system expression patterns and map to an indistinguishable site at 33F on the cytological map. Transcription of the genes is first observed in the cellular blastoderm. In the course of embryonic development, expression is observed in the neuroectoderm, with subsets of neuroblasts in the procephalic and germband central nervous system as well as a subset of peripheral nervous system elements. The expression patterns of the two POU genes suggest a possible functional role for these putative transcription factors in neurogenesis and neurospecification.