The Physical Basis of Coordinated Tissue Spreading in Zebrafish Gastrulation

Publication date: Available online 16 February 2017
Source:Developmental Cell
Author(s): Hitoshi Morita, Silvia Grigolon, Martin Bock, S.F. Gabriel Krens, Guillaume Salbreux, Carl-Philipp Heisenberg
Embryo morphogenesis relies on highly coordinated movements of different tissues. However, remarkably little is known about how tissues coordinate their movements to shape the embryo. In zebrafish embryogenesis, coordinated tissue movements first become apparent during "doming," when the blastoderm begins to spread over the yolk sac, a process involving coordinated epithelial surface cell layer expansion and mesenchymal deep cell intercalations. Here, we find that active surface cell expansion represents the key process coordinating tissue movements during doming. By using a combination of theory and experiments, we show that epithelial surface cells not only trigger blastoderm expansion by reducing tissue surface tension, but also drive blastoderm thinning by inducing tissue contraction through radial deep cell intercalations. Thus, coordinated tissue expansion and thinning during doming relies on surface cells simultaneously controlling tissue surface tension and radial tissue contraction.

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Teaser

Morita et al. combine computational modeling and experiments to show that at zebrafish gastrulation onset, epithelial surface cells coordinate blastoderm thinning and expansion for its spread over the yolk cell. Active surface cell expansion simultaneously triggers tissue expansion by reducing tissue surface tension and tissue thinning by inducing deep cell radial intercalations.


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