Project 18

Exploring the intracellular pathways of neurons responding to combinations of extracellular cues.

Neurons must respond to many different guidance cues in order to form appropriate topographic connections. The best characterised of the repulsive cues in the visual system is the EphA/ephrin-A receptor ligand pair, whereas the neurotrophin BDNF is an attractive guidance cue. Each of these guidance cues in isolation operates via similar and reasonably well characterized intracellular signalling pathways. However it is currently unknown how these extracellular signals interact and what signalling pathways are activated in response to these interactions. In this project we will follow the growth and branching of purified retinal ganglion cells in culture, using live imaging and time lapse photography. Growth of neurons from wild type or knockout (ephrin-A2 and/or ephrin-A5) mice will be modified by treatment with recombinant BDNF and/or ephrin-A2 or ephrin-A5 in clusters and expression of Ephs and ephrins will be monitored immunohistochemically. Specific intracellular signalling pathways will then be activated or inhibited using pharmacological agents.