Propagating gene expression fronts in a one-dimensional coupled system of artificial cells

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Abstract

Living systems employ front propagation and spatiotemporal patterns encoded in biochemical reactions for communication, self-organization and computation1,2,3,4. Emulating such dynamics in minimal systems is important for understanding physical principles in living cells5,6,7,8 and in vitro9,10,11,12,13,14. Here, we report a one-dimensional array of DNA compartments in a silicon chip as a coupled system of artificial cells, offering the means to implement reaction–diffusion dynamics by integrated genetic circuits and chip geometry. Using a bistable circuit we programmed a front of protein synthesis propagating in the array as a cascade of signal amplification and short-range diffusion. The front velocity is maximal at a saddle-node bifurcation from a bistable regime with travelling fronts to a monostable regime that is spatially homogeneous. Near the bifurcation the system exhibits large variability between compartments, providing a possible mechanism for population diversity. This demonstrates that on-chip integrated gene circuits are dynamical systems driving spatiotemporal patterns, cellular variability and symmetry breaking.

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Figure 1: Travelling gene expression front in an array of coupled DNA compartments.
Figure 2: Propagation dynamics regulated by gene circuit.
Figure 3: Emergent fluctuations in single compartments near the transition.

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Acknowledgements

We thank S. S. Daube for helpful discussions. V.N. thanks J. Garamella, R. Marshall and M. Rustad for technical help. This work was supported by: the Israel Science Foundation, the Minerva Foundation, and the Volkswagen Foundation (R.H.B.-Z.); the US–Israel Binational Science Foundation (R.H.B.-Z. and V.N.).

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All authors contributed to all aspects of this work.

Correspondence to Roy H. Bar-Ziv.

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Tayar, A., Karzbrun, E., Noireaux, V. et al. Propagating gene expression fronts in a one-dimensional coupled system of artificial cells. Nature Phys 11, 1037–1041 (2015) doi:10.1038/nphys3469

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