Synchronization of Degrade-and-Fire Oscillations in Synthetic Gene Circuits

This talk reviews our recent work on the synchronization of synthetic gene oscillators operating in the degrade-and-fire regime. Computational modeling and theoretical analysis show that the key mechanism of oscillations is a small delay in the negative feedback loop. In a strongly nonlinear regime, this time delay can lead to long-period oscillations in gene expression that can be characterized by ``degrade and fire'' dynamics. I will present experimental, analytical, and computational results for the intra-cellular as well as population-wide synchronization when oscillators are coupled either by common protease enzymes or by coupling the oscillators to a quorum sensing machinery that produces chemical inducers freely diffusing through cell membranes.