Sources of Variability in a Synthetic Gene Oscillator
A. Circuit diagram of the oscillator. Transcription of araC and lacI is driven by identical copies of the Plac/ara-1 promoter, which is up-regulated by AraC in the presence of arabinose and repressed by LacI in the absence of isopropyl-β-D-1-thiogalactopyranoside (IPTG). B. Typical lineage fluorescence trajectory of the oscillator. Black bars at the top of the panel represent the number of cell divisions in each frame. Insets show representative images of some of the cells within the microfluidic trap (see Methods). C. Histogram of all recorded oscillation periods for traces shown in (B). The average period was 41 min, with coefficient of variation 0.11. D. Corresponding histogram of peak amplitudes. The mean peak amplitude was 317 (AU), with coefficient of variation 0.47.