Cooperative reliable response from sloppy gene-expression dynamics

¹ School of Interdisciplinary Mathematical Sciences, Meiji University - 4-21-1 Nakano, Nakano-ku, Tokyo 164-8525, Japan
² Research Center for Complex Systems Biology, Universal Biology Institute, University of Tokyo 3-8-1 Komaba, Tokyo 153-8902, Japan

Received: 6 August 2018
Accepted: 7 November 2018

Abstract

Gene expression dynamics satisfying given input-output relationships were investigated by evolving the networks for an optimal response. We found three types of networks and corresponding dynamics, depending on the sensitivity of the gene expression dynamics: direct response with straight paths, amplified response by a feed-forward network, and cooperative response with a complex network. When the sensitivity of each gene's response is low and expression dynamics is sloppy, the last type is selected, in which many genes respond collectively to inputs, with local-excitation and global-inhibition structures. Robustness to noise is also demonstrated. The result provides an insight into how a reliable response is achieved with unreliable units, and on why complex networks are adopted in cells.