From Growth Cone to Synapse at Drosophila Retinal Axon Terminals

Harvard University, Cambridge MA

Investigators

Abstract

The brain underlies the ability to perceive, process and retain information and to formulate novel outputs and behaviors. How neuronal circuits of the brain develop is of considerable interest and importance. During the development of the nervous system, the axon's growing tip, the growth cone, steers the axon over long distances to form the basic outlines of a neural circuit. A next essential step is for the axon terminus to make a transition from a growth cone suited for navigation to a synaptic terminal designed for neuron to neuron signaling in a neural circuit. Little is known about this step in development. In the developing visual system of the fruitfully, Drosophila melanogaster, the axon termini of photoreceptor neurons switch from growth cones to synaptic terminals. An essential signal for this switch appears to be provided by local glial cells that the growth cones first interact with when arriving in the brain. This signal turns on the expression of a protein that controls that activity of the photoreceptor synapse in neuron-to-neuron communication. A goal of this proposal is to understand the mechanism of this novel control of synaptic protein expression by glial cells, and more broadly, the mechanisms by which glia control the transition of a growth cone to a synaptic terminal. This work will increase our understanding of the development of neural circuits and the regulation of their activity. This project will be performed as a collaborative effort between the laboratory and a local high school science class. The laboratory will build on existing high school science outreach programs to establish a collaborative relationship. Through lectures, group meetings, workshops and summer internships, students will be directly involved in the progress of the research project. This will be a most effective way to translate scientific research at the university level into broader science literacy, and an understanding of science in terms of method and career.