Adaptive improvisation in gene regulatory networks

Naama Brenner, Chemical Engineering & Network Biology Research Lab, Technion, Haifa, Israel




The capacity of cells and organisms to respond in a repeatable manner to challenging conditions is limited by the finite repertoire of such available responses. Beyond this capacity, novel and unforeseen challenges may elicit exploratory dynamics, improvisational in nature, which could in principle answer to a much broader array of conditions. However little is known about the underlying mechanisms of such exploration and its ability to converge to a new cell state.

I will present experiments on yeast cells showing that, following genetic rewiring perturbations, regulatory networks are driven into exploratory dynamics, resulting in relaxation to adapted states. Inspired by these experiments we construct and study a model of a gene regulatory network driven by the environment, which converges to new adapted stable states by purely stochastic exploration. Such convergence is not guaranteed in a high-dimensional space, and indeed is not universal. We find conditions on network structure that facilitate convergence; surprisingly these conditions are satisfied by real genetic networks. These results demonstrate how cells can harness their improvisational capacity to form adaptive response to challenge.