We use a three-step bottom-up approach to link the single-molecule events that trigger gene activation to the biological output of the genetic circuit. In the first step, we monitor the conformational dynamics of promoter DNA upon binding of transcription factors.
Genomic and proteomic methods have afforded a wealth of genetic network architectures in systems biology. However, quantitative predictions of the dynamics of such networks are limited by our incomplete knowledge about noise in gene expression mechanisms. We use cutting-edge superresolution microscopy to unravel how gene expression noise triggers the spontaneous switch into a transient phenotype.
More than 80% of all eukaryotic transcription factors contain disordered regions and a significant fraction of them are longer than 50 amino acids. What functional advantage do these disordered regions have compared to ordered domains? How are their biophysical properties related to diseases?
Transiently populated states, i.e., high-energy states in protein folding or protein-DNA binding reactions could be easily missed even though they might be a key step in the reaction. Non-equilibrium experiments on single molecules using a microfluidic mixing device for single-molecule FRET-applications offer an elegant solution to this problem. In addition, in single-molecule live-cell imaging, cells can be directly grown on the microscope in microfluidic bioreactors, thus enabling experiments under fully controlled environmental conditions.
