Using Light to Control Embryonic Development

Summer 2017

Jordan Xiao : Physics

Mentor: Hernan Garcia

At the level of transcription, gene expression is controlled by activator and repressor proteins (transcription factors) which bind to DNA in concentration-dependent manners. Current models in biophysics depict transcriptional regulation as an input-output function where the output rate of mRNA synthesis depends on the concentrations of input transcription factors. Our project seeks to evaluate and improve these quantitative models by developing optogenetic techniques to systematically perturb the natural system, in this case the common fruit fly embryo. We fuse a special light-sensitive protein to maternal transcription factors, then use different laser channels in a confocal fluorescence microscope to control the nuclear concentration of transcription factors while simultaneously measuring rates of mRNA synthesis with high spatiotemporal resolution. This technology opens the door to uncovering whether current models provide a sufficient basis for a quantitative description of developmental programs, or whether our fundamental assumptions need to be revisited both experimentally and theoretically.

I would like to express my greatest thanks to the Rose Hills Foundation for making this summer research experience possible. As my first in-depth exposure to scientific research, it has provided an invaluable reality check for me on the nature of scientific research. The long hours and countless failures are all made worth it when one's cumulative hard work, coupled with a little luck, finally yield results that bring us closer to expanding the limits of human knowledge, even if just a tiny bit. As such, this past summer has reaffirmed my desire to attend graduate school after earning my bachelor's degree and given me a much-appreciated confidence boost, since I now believe I have what it takes to succeed in this line of work. None of this would have been possible without the Foundation's generous financial support, so I'm forever grateful for having been afforded this opportunity.