Both vertebrates and insects utilize their olfactory systems to interact with their complex environments, by recognizing a large number of structurally diverse odorants. Odor coding in Drosophila depends on the faithful and precise regulation of olfactory receptors, and therefore likely depends on those transcription factors that act on olfactory receptor genes. The olfactory mutant acj6, a POD family transcription factor mutant, has a role in regulating a subset of olfactory receptors in the palp and antenna. pdm3 (POU domain motif 3) is a novel Drosophila POU gene identified in the lab, and we have found that is expressed in olfactory neurons and brain, therefore may be involved in regulating olfactory receptors. I propose an examination of the role that this gene plays in odor receptor gene choice, using olfactory receptor expression and electrophysiological analyses on the pdm3 mutant. In addition, I will focus on whether Pdm3 regulates olfactory receptors directly. [unreadable] [unreadable] [unreadable]