Planar polarized force propagation integrates cell behavior and tissue morphogenesis during convergent extension

Convergent extension (CE) is an evolutionarily conserved developmental process whereby polarized collective cell movements drive the elongation of tissues or organs, and defects in CE are associated with multiple human birth defects. Here, we combined embryology with cell biology and newly developed biomechanical tools to interrogate the link between cell behavior and tissue-scale CE. We found that unique patterns of polarized cortex tension are required to resolve individual cell intercalation events, and this in turn maintains normal cell packing configurations that favor the planar propagation of the cellular forces across the tissue, and thus normal CE. Our data suggest that planar polarized force propagation plays a critical role in the propagation of cell behaviors via cellular mechanoreciprocity, underpinning the propagation of tissue-scale CE.