In this work, we combine genetic perturbation, time-lapse imaging and quantitative image analysis to investigate how pulsatile actomyosin contractility drives cell oscillations, apical cell contraction and tissue closure during morphogenesis of the amnioserosa, the main force-generating tissue during the dorsal closure in Drosophila. We show that Myosin activity determines the oscillatory and contractile behaviour of amnioserosa cells. Reducing Myosin activity prevents cell shape oscillations and reduces cell contractility. By contrast, increasing Myosin activity increases the amplitude of cell shape oscillations and the time cells spend in the contracted phase relative to the expanded phase during an oscillatory cycle, promoting cell contractility and tissue closure. Furthermore, we show that in AS cells, Rok controls Myosin foci formation and Mbs regulates not only Myosin phosphorylation but also adhesion dynamics through control of Moesin phosphorylation, showing that Mbs coordinates actomyosin contractility with cell-cell adhesion during amnioserosa morphogenesis.
The authors declare no competing or financial interests.
N.G. conceived the project. J.D. and N.G. performed the experiments, analysed the data and discussed the results. N.G. wrote the paper.
This work was supported by grants from the Ministerio de Ciencia e Innovación (BFU-2011-25828 and ‘Ramón y Cajal’ fellowship award) and a European Commission Marie Curie Career Integration Grant (PCIG09-GA-2011-293479). J.D. is a recipient of a PhD FPI-fellowship (BES-2012-051839) from the Ministerio de Ciencia e Innovación.
Supplementary information available online at http://dev.biologists.org/lookup/doi/10.1242/dev.136127.supplemental
- Received February 3, 2016.
- Accepted October 27, 2016.