Robustness of anisotropic tissue deformation during animal development – RobustTissue

Anisotropic tissue deformation is a key process during animal development. However, the general robustness of such developmental processes is in stark contrast to a known instability of the homogeneously deforming state of active anisotropic materials. Within this project, we ask how active anisotropic deformation of biological tissues can be robust, despite active matter instabilities.

My team and I will study two hypotheses of how anisotropic tissue deformation might be stabilized during development:
(H1) through large-scale protein concentration gradients,
(H2) though externally applied forces.

We will test these hypotheses pursuing two objectives:
Objective 1 - Theory: We will theoretically study continuum models and cell-based tissue models that incorporate tissue flows together with a scalar field representing the protein concentration, a polar field representing cell polarity, and a nematic field representing cell shapes. We will establish general criteria for the robustness of the homogeneously deforming state.
Objective 2 - Experimental system: We will collaborate with the biology group of Thomas Lecuit, who will provide us with experimental image data on the deformation of the germ band tissue during fruit fly embryogenesis. We will analyze these image data to extract the relevant protein concentration, cell polarity, cell shape, and tissue flow data, and fit these data to our continuum model. Based on this approach, we will test our hypotheses by examining data from experimental perturbations of the protein concentration field (H1) and of externally applied forces (H2).

In this project, we address a fundamental open question at the interface between active matter physics and developmental biology. To achieve this, we will also develop new theoretical concepts to examine how scalar and polar fields interact with the cellular material structure.