Self-organized tissue mechanics underlie embryonic regulation.

Early amniote development is highly self-organized, capable of adapting to interference through local and long-range cell-cell interactions. This process, called embryonic regulation, has been well illustrated in experiments on avian embryos, in which subdividing the epiblast disk into different parts not only redirects cell fates to eventually form a complete and well-proportioned embryo at its original location, but also leads to the self-organization of additional, fully formed embryos in the other separated parts. The cellular interactions underlying embryonic self-organization are widely believed to be mediated by molecular signals, yet the identity of such signals is unclear.

Homeotic compartment curvature and tension control spatiotemporal folding dynamics.

Shape is a conspicuous and fundamental property of biological systems entailing the function of organs and tissues. While much emphasis has been put on how tissue tension and mechanical properties drive shape changes, whether and how a given tissue geometry influences subsequent morphogenesis remains poorly characterized. Here, we explored how curvature, a key descriptor of tissue geometry, impinges on the dynamics of epithelial tissue invagination.

Topography-induced large-scale antiparallel collective migration in vascular endothelium.

Collective migration of vascular endothelial cells is central for embryonic development, angiogenesis, and wound closure. Although physical confinement of cell assemblies has been shown to elicit specific patterns of collective movement in various cell types, endothelial migration in vivo often occurs without confinement. Here we show that unconfined endothelial cell monolayers on microgroove substrates that mimic the anisotropic organization of the extracellular matrix exhibit a specific type of collective movement that takes the form of a periodic pattern of antiparallel cell streams.

Multi-view confocal microscopy enables multiple organ and whole organism live-imaging.

Understanding how development is coordinated in multiple tissues and gives rise to fully functional organs or whole organisms necessitates microscopy tools. Over the last decade numerous advances have been made in live-imaging, enabling high resolution imaging of whole organisms at cellular resolution. Yet, these advances mainly rely on mounting the specimen in agarose or aqueous solutions, precluding imaging of organisms whose oxygen uptake depends on ventilation.

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'.