Forces driving epithelial spreading in zebrafish gastrulation.
Contractile actomyosin rings drive various fundamental morphogenetic processes ranging from cytokinesis to wound healing. Actomyosin rings are generally thought to function by circumferential contraction. Here, we show that the spreading of the enveloping cell layer (EVL) over the yolk cell during zebrafish gastrulation is driven by a contractile actomyosin ring. In contrast to previous suggestions, we find that this ring functions not only by circumferential contraction but also by a flow-friction mechanism. This generates a pulling force through resistance against retrograde actomyosin flow. EVL spreading proceeds normally in situations where circumferential contraction is unproductive, indicating that the flow-friction mechanism is sufficient. Thus, actomyosin rings can function in epithelial morphogenesis through a combination of cable-constriction and flow-friction mechanisms.
Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, 01307 Dresden, Germany.
Martin
M
Behrndt
Guillaume
G
Salbreux
Pedro
P
Campinho
Robert
R
Hauschild
Felix
F
Oswald
Julia
J
Roensch
Stephan W
SW
Grill
Carl-Philipp
CP
Heisenberg
D000205:Actomyosin / Q000502:physiology*; D000818:Animals; D003250:Constriction; D004847:Epithelial Cells / Q000166:cytology / Q000502:physiology*; D017276:Friction; D054262:Gastrulation; D015017:Yolk Sac / Q000166:cytology*; D015027:Zebrafish / Q000196:embryology*
D000205:Actomyosin