Patterning the Drosophila adult musculature: A role for neuron-founder cell interactions PI: Joyce Fernandes
The fruit fly Drosophila melanogaster has been used as a model organism for over a century. An attractive feature of Drosophila is that it has two distinct life forms, the larva, and the adult, each with a distinct repertoire of behaviors. Many tissues that are generated in the embryonic stage are restructured during the four-day period of metamorphosis to give rise to more complex structures of the adult. An interesting question relates to the repertoire of genes that control adult development. Are embryonic genes redeployed? Are similar developmental pathways utilized to generate adult tissues?
Development of the adult musculature has not been studied as extensively as the embryonic/larval stages. The adult muscles are responsible for specific functions in the fly such as flight, jump, and reproduction. This proposal addresses a unique situation that is encountered during adult muscle development- the role of motor neurons in patterning development of their post-synaptic muscle targets. Dr. Fernandes' previous studies have suggested that the neuron-muscle interaction is a means to control target size, which is in accordance with general principles of nervous system development where matching of pre- and post-synaptic targets is important for function.
Her recent studies have suggested that this nerve-dependent patterning may involve specialized founder cells that through their expression of Dumbfounded, a protein of the Immunoglobulin superfamily, organize muscle precursors to aggregate and form muscle fibers. Studies described in this proposal will investigate cellular and molecular mechanisms that underlie neuron- founder cell interactions, to understand their role in adult muscle patterning. As founder cells engage in myogenesis, they will be examined using time-lapse imaging and fluorescent immunolabeling. The founder cells will be disrupted by targeting specific transgenes, and their behavior will be examined under conditions of experimental denervation. These studies will allow her to test hypotheses relating to neuronal control of muscle size and muscle patterning and will set the stage for ongoing and future studies on understanding signaling pathways that are activated as a result of neuron-founder cell communication.
In addition to contributing scientific knowledge to the area of muscle patterning mechanisms, the proposed research program contains components that integrate research and science education activities of all personnel involved- undergraduates, graduate students, post-doctoral fellow and PI. In addition to training science majors, research opportunities will be made available to Life Science education majors, and a high-school science teacher to develop research based instructional units that meet state and national science standards.
