The invertebrate odorant-binding protein LUSH is required for normal olfactory behavior in Drosophila

The invertebrate odorant-binding proteins consist of a large family of low- molecular-weight, highly divergent proteins expressed exclusively in the ch emosensory sensilla of insects. Each member of this family studied to date is secreted into the sensillum lymph of a small subset of sensilla by non-n euronal support cells. These expression patterns suggests an odor-specific function for these proteins as opposed to a general role in sensillum biolo gy. Consistent with this notion, mutants defective for LUSH, a Drosophila m ember of this family, have odor-specific defects in olfactory behavior. The Drosophila genome contains at least 32 members of this gene family, rivali ng the number of odorant receptors in this species. The relationship betwee n these two protein families and how they act to determine odor specificity of olfactory neurons will be the topic of future studies.