Biological Basis of Behavior

Sai working at a lab bench




Professor of Neuroscience

Project Summary

I worked on my project in a laboratory run by Dr. Jonathan Raper in the Neuroscience Department in the Perelman School of Medicine. This project dealt with olfactory axon guidance, essentially, the tracing the development of axons and the organization of the nervous system in the olfactory bulb of larval zebrafish.

Olfactory sensory neurons are guided from the olfactory epithelium to their final destinations in the olfactory bulb via crucial interactions between guidance receptors and ligands. These interactions could be either attractive or repulsive. Here, I assess the roles of two such ligands, netrin1a and netrin1b, in olfactory guidance in zebrafish embryos. netrin1a and netrin1b loss of function mutants were generated and their effects were determined for the fluorescently labeled olfactory sensory neuron subpopulations expressing OR111-7:IRES:Gal4. These axons normally project to the CZ protoglomerulus in three-day old zebrafish olfactory bulb. We show that loss of ntn1a results in mistreating to the DZ protoglomerulus. ntn1b mutants show misprojections to the MG protoglomerulus as well as increased ectopic errors. ntn1a and ntn1b double mutants also show significant misprojections to the DZ, but this was not significantly higher than either of the single mutants. Our results suggest parallel pathways triggered by ntn1a and ntn1b in mediating axon targeting to the CZ.

By working on this project I learned many techniques such as sterile cell culture, drug treatment of live embryos, and staining procedures to olfactory guidance and image them using confocal microscopy techniques. In addition, I also extensively learned biochemical methods such as polymerase chain reaction, CRISPR cloning methods and gel electrophoresis methods. Finally, I was able to increase my understanding of cloning procedures and plasmid purification.