Jordan Xiao Rose Hills
Using Light to Control Embryonic Development
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.