Mechanical induction and competence in epithelial morphogenesis.

Identifying the mechanisms that govern the precise sequence of tissue deformations and flows during development is a major topic in developmental biology. Recent studies have explored how the deformation or the flow of a tissue region can be induced by the activity of a neighboring region through mechanical coupling. Such a coupling process is akin to chemical induction, whereby differentiation in a region of competent cells is stimulated by a neighboring region through chemical induction: we therefore propose to name this phenomenon 'mechanical induction'. Focusing on examples of mechanically induced epithelial flow or planar deformation in vivo, this review aims at discussing the processes driving mechanical induction and the competence factors modulating the induced morphogenesis, in order to highlight the importance of integrating tissue and inter-tissue scales to understand morphogenesis.