Gene circuit designs for noisy excitable dynamics

Certain cellular processes take the form of activity pulses that can be interpreted in terms of noise-driven excitable dynamics. Here we present an overview of different gene circuit architectures that exhibit excitable pulses of protein expression, when subject to molecular noise. Different types of excitable dynamics can occur depending on the bifurcation structure leading to the specific excitable phase-space topology. The bifurcation structure is not, however, linked to a particular circuit architecture. Thus a given gene circuit design can sustain different classes of excitable dynamics depending on the system parameters.

► Gene circuits may exhibit two types of excitability, with distinct frequency behavior.
► The different frequency behaviors are associated with distinct bifurcations.
► The two excitability types respond differently to noise.
► Excitability types are not linked to any particular gene circuit architecture.