136 Oral - Patterning and Morphogenesis I
Saturday April 09, 8:00 AM - 8:15 AM

Authors:
Noah Mitchell ¹; Dillon Cislo ¹; Suraj Shankar ^1,2; Yuzheng Lin ¹; Boris Shraiman ¹; Sebastian Streichan ¹

Affiliations:
1) University of California Santa Barbara, Santa Barbara, CA; 2) Harvard University, Cambridge, MA

Keywords:
w. biomechanical forces; k. gut

During development, interacting tissue layers orchestrate complex shape changes to form visceral organs. Tracing the dynamics and mechanical interactions across tissue layers and across scales -- from cell to tissue, to entire organs -- remains an outstanding challenge. Here, we study the embryonic Drosophila midgut as a model visceral organ. Using light-sheet microscopy, genetics, computer vision, and tissue cartography, we reconstruct in toto the dynamics of individual tissue layers to map the time course of shape across scales. We identify the kinematic mechanism driving shape change by linking out-of-plane motion to active contraction patterns, revealing a convergent extension process in which cells deform as they flow into deepening folds. Optogenetic perturbations of muscle contractility reveal that muscle activity drives these contraction patterns and induces cell shape changes in the adjacent endoderm layer. This induction cascade relies on calcium pulses in the muscle, under the control of hox genes. Our study of multi-layer organogenesis reveals how genetic patterning in one layer triggers a dynamic molecular mechanism to control a physical process in the adjacent layer, orchestrating whole-organ shape change.