Quantitative Analysis of Cell Behaviours underlying Tissue Dynamics during Chick Embryo Gastrulation

Abstract

Gastrulation is an essential stage during the development of vertebrates that is characterised by the formation of a transient structure known as the primitive streak. Streak development relies on tightly controlled behaviour of tens of thousands of cells, leading to large scale tissue flows, that transport the mesoderm precursors into the midline of the epiblast.

Mechanics play an important role in early embryogenesis, driving cell shape change and regulation of biomechanical properties in tissues. In particular, the role of active myosin II cables to generate tension in cellular junctions has been linked to cell intercalations and axis elongation.

This thesis combines data from mechanical perturbation experiments, image analysis techniques, and computational modelling to investigate the role of mechanical properties in chick embryonic development.

Laser ablation experiments combined with the addition of myosin inhibitors show differences in regional levels of tension, which are strongly linked to the presences of myosin II cables. A high dependence of junctional recoil on biomechanical properties was highlighted by simulations using the vertex model, which highlights that an additional term for viscoelasticity is required to replicate empirical results. Finally, the response of myosin and actin dynamics to laser ablation is observed.

Together, these results offer insight into the spatial distribution of myosin II cables and their contribution to the mechanical regulation of morphogenesis in the chick.

Date of Award	2022
Original language	English
Awarding Institution	University of Dundee
Supervisor	Kees Weijer (Supervisor) & Rastko Sknepnek (Supervisor)