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Gastrulation is an essential process in the early embryonic development of all higher animals. During gastrulation, the three embryonic germ layers, the ectoderm, mesoderm and endoderm, form and move to their correct positions in the developing embryo. This process requires the integration of cell division, differentiation and movement of thousands of cells. These cell behaviours are coordinated through shortand long-range signalling and must involve feedback to execute gastrulation in a reproducible and robust manner. Mechanosensitive signalling pathways and processes are being uncovered, revealing that shortand long-range mechanical stresses integrate cell behaviours at the tissue and organism scale. Because the interactions between cell behaviours, signalling and feedback are complex, combining experimental and modelling approaches is necessary to elucidate the regulatory mechanisms that drive development. We highlight how recent experimental and theoretical studies provided key insights into mechanical feedback that coordinates relevant cell behaviours at the organism scale during gastrulation. We outline advances in modelling the mechanochemical processes controlling primitive streak formation in the early avian embryo and discuss future developments.
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Control of tissue flows and embryo geometry in avian gastrulation
Abstract Embryonic tissues undergo coordinated flows during avian gastrulation to establish the body plan. Here, we elucidate how the interplay between embryonic and extraembryonic tissues affects the chick embryo’s size and shape. These two distinct geometric changes are each associated with dynamic curves across which trajectories separate (kinematic repellers). Through physical modeling and experimental manipulations of both embryonic and extraembryonic tissues, we selectively eliminate either or both repellers in model and experiments, revealing their mechanistic origins. We find that embryo size is affected by the competition between extraembryonic epiboly and embryonic myosin-driven contraction—which persists when mesoderm induction is blocked. Instead, the characteristic shape change from circular to pear-shaped arises from myosin-driven cell intercalations in the mesendoderm, irrespective of epiboly. These findings elucidate modular mechanisms controlling avian gastrulation flows and provide a mechanistic basis for the independent control of embryo size and shape during development.
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- Award ID(s):
- 2413073
- PAR ID:
- 10597896
- Publisher / Repository:
- Nature Publishing Group
- Date Published:
- Journal Name:
- Nature Communications
- Volume:
- 16
- Issue:
- 1
- ISSN:
- 2041-1723
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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