Kate Wilson
The Effects of Protein Gradients on Neuronal Movement
Mentor:  Dr. Joshua Maurer, Chemistry Department, Washington University in St. Louis 

Our group is currently working on an accurate in vitro model of how retinal ganglion cells (optic neurons) cross-over in the brain to the lateral geniculate nucleus during development. As neurons move, they are attracted and repulsed by enzymes and proteins. The exact function of all these enzymes and proteins is not yet known. We are trying to replicate this process in vitro by using a Self-Assembled Monolayer (SAM). A SAM is a piece of metal (usually titanium dioxide or gold) with long molecules attached. These molecules can be photo-deprotected by a laser to reveal a very specific binding region. The laser can also be used to create gradients. After the molecules have been deprotected, proteins (we used proteins from Mus musculus) can be bound to the new sites. I focused on isolating and making the proteins Eph-A7, Ephrin-A5, and Ephrin-A2. After patterning the SAM with an assortment of protein gradients to replicate the brain environment during development, a neuron (we will use one from Rattus norvegicus) can be added and we can watch in real-time the movement of the neuron up and down the gradients to try to determine the function of all the enzymes and proteins on the SAM. We are still working on finding an appropriate molecule to use on the SAM and finalizing the vectors with the protein cDNA. Once everything is working we can observe the movements of the neuron and draw conclusions about the effects of protein gradients on neuronal movement.