9870396 TAYLOR Sexual development in the fruitfly, Drosophila melanogaster, is governed by a cascade of sex-determination genes. This cascade branches into three output pathways controlling mating behavior and the formation of the relevant sex-specific neurons in males and females. Each of the output branches is headed by a separate regulatory gene, "fruitless" (fru), "dissatisfaction" (dsf) or "doublesex" (dsx), which control distinct aspects of the sex-specific behavioral repertoire. fru controls all, or virtually all, aspects of male reproductive behaviors and the formation of a male-specific motorneuron that induces a sex-specific muscle, the Muscle of Lawrence (MOL). The sex-specific transcripts of the fru gene are expressed in a tiny fraction of neurons in the central nervous systems (about 0.5% of 100,000 neurons). The working model of fru action is that the fru-expressing neurons form dedicated neural circuits that direct other neurons to produce male-specific behaviors such as courtship song and copulation. The aim of this research is to characterize the role of the fru gene in specifying the male-specific motorneuron that innervates the MOL. In males, this neuron induces the formation of the male-specific MOL muscle, whereas in fru mutants, the motorneuron makes incorrect synapses and the male-specific characteristics of the MOL is not induced. This POWRE award will allow Dr. Taylor to spend a year on sabbatical in the laboratory of Dr. Michael Bate at the University of Cambridge. She plans to investigate sex-specific differences in the physiology of the synapse between the MOL motorneuron and its target muscle in males versus the homologous synapse in females. A second goal of the project is to determine whether specific electrical activity in the motorneuron is required to induce the MOL. This project is particularly suitable for a POWRE award because Dr. Taylor will learn insect neurophysiology at one of the best laboratories for such studies. The introduction of this new approach and technical expertise will allow her to make scientific contributions to a wider audience than previously, which should, in turn, make her laboratory more visible and attractive to graduate students and postdoctoral researchers at a crucial point in her career.
