Cell-Free Characterization of Coherent Feed-Forward Loop-Based Synthetic Genetic Circuits
Pascal A. Pieters, Bryan L. Nathalia, Ardjan J. van der Linden, Peng Yin, Jongmin Kim, Wilhelm T. S. Huck, Tom F. A. de Greef
Abstract
cell-free transcription-translation system and build larger composite feed-forward architectures. We employ microfluidic flow reactors to probe the response of the CFFL circuit using both persistent and short, noise-like inputs and analyze the influence of different circuit components on the steady-state and dynamics of the output. We demonstrate that our synthetic CFFL implementation can reliably repress background activity compared to a reference circuit, but displays low potential as a temporal filter, and validate these findings using a computational model. Our results offer practical insight into the putative noise-filtering behavior of CFFLs and show that this motif can be used to mitigate leakage and increase the fold-change of the output of synthetic genetic circuits.