Monday  |  Salon 8  |  04:10 PM–04:30 PM

#15749, Signatures of Cell Packings and Myosin Network Architecture Reveal Transitions in Embryonic Tissue Mechanics

The ability for epithelial tissues to remodel and flow during development is essential to generating functional tissue structure. Coordinated cellular movements allow collections of cells to rearrange positions in the tissue so that the tissue can remodel and flow as a fluid-like material to generate complex structures during development. Drosophila body axis elongation is a dramatic example of a rapid tissue flow that drives embryo morphogenesis. This convergent and extension process doubles the length of the germband epithelial tissue in 30 minutes and is driven by local cell rearrangements that require anisotropic myosin II activity. Recent work from our group and others has revealed that the germband tissue becomes more fluid-like just at the onset of body axis elongation, which is likely to help accommodate rapid cell rearrangements and tissue flow. However, it is not understood how molecular composition and cell packings in the tissue control this transition in mechanical behavior and influence the likelihood for a cell rearrangement to occur at a particular location and time. Here, we develop a framework for analyzing local cell packings and myosin network architecture in the embryonic epithelium as a foundation for linking tissue mechanics to underlying spatiotemporal patterns of protein activity and gene expression patterns in developing embryos. We find key signatures in cell packing disorder and myosin network connectivity that correspond to distinct steps in the transition from solid to fluid-like tissue behavior, revealing molecular and mechanical mechanisms that control tissue flow during morphogenesis.

Christian Cupo   Columbia University
Cole Allan   Columbia University
Karen Kasza   Columbia University