Mechanical control of morphogenesis robustness

Epithelial sheets undergo highly reproducible remodeling to shape organs. This stereotyped morphogenesis depends on a well-defined sequence of events starting with the regionalized expression of developmental patterning genes that trigger downstream mechanical forces to drive tissue remodeling at a pre-defined position. Mechanical forces can refine this genetic information by a feedback loop, however the direct implication of mechanical forces in morphogenesis robustness has never been reported. Here, we show that a bias in force propagation ensures stereotyped morphogenesis in a mechanically noisy environment. We found that knockdown of the Arp2/3 complex member Arpc5 specifically affects fold directionality without altering the developmental or the force patterns. By combining in silico modeling, biophysical and ad hoc genetic tools, our data reveal that Myosin II planar polarity favors long-range transmission of forces and avoid force scattering, thus ensuring folding robustness by isolating the fold domain from surrounding mechanical perturbations.