Synthetic lateral inhibition governs cell-type bifurcation with robust ratios

Cell-type diversity in multicellular organisms is created through a series of binary cell fate decisions. Lateral inhibition controlled by Delta–Notch signalling is the core mechanism for the choice of alternative cell types by homogeneous neighbouring cells. Here, we show that cells engineered with a Delta–Notch-dependent lateral inhibition circuit spontaneously bifurcate into Delta-positive and Notch-active cell populations. The synthetic lateral inhibition circuit comprises transcriptional repression of Delta and intracellular feedback of Lunatic fringe (Lfng). The Lfng-feedback subcircuit, even alone, causes the autonomous cell-type bifurcation. Furthermore, the ratio of two cell populations bifurcated by lateral inhibition is reproducible and robust against perturbation. The cell-type ratio is adjustable by the architecture of the lateral inhibition circuit as well as the degree of cell–cell attachment. Thus, the minimum lateral inhibition mechanism between adjacent cells not only serves as a binary cell-type switch of individual cells but also governs the cell-type ratio at the cell-population level.