In the Green Lab, we analyse how cells build up tissues. We look at the molecules that give cells specific directions in three-dimensional space by controlling their fates, behaviours, spatial orientations, proportions and movements. We also investigate the movements themselves.
Morphogen action in periodic patterning: Individual secreted protein signals allow cells to organise themselves during embryonic development and the Green Lab is working to understand how the main theory of how this works – the Turing Reaction-Diffusion theory – actually acts in creating patterns in vivo.
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Scientists prove Turing's tiger stripe theory
Face morphogenesis: At the cell-to-tissue level, we are mapping how cell proliferation, movement and shape change build up tissues in the mammalian face, jaws and palate. Understanding how these processes combine to sculpt the complex structures will illuminate causes and potential routes for prevention or regenerative therapy in conditions such as cleft palate. They also serve as models for understanding morphogenesis of other structures throughout the body and animal kingdom.
Morphogenesis of placodal organs: Teeth, hair follicles, mammary ducts and numerous other organs require an initial invagination (bending or dimpling). We are analyzing the way in which cells achieve this morphogenetic motif to understand the fundamental forces that drive this basic process.
Cell polarity and signalling: At the molecules-to-cells level, we have focused on the polarity protein PAR-1, which controls cell division orientation, cell migration and the generation of new neurons in the early nervous system. We have identified molecules that PAR-1 acts on and signalling pathways involving the morphogen Wnt that modulate and are affected by cell polarity. We are investigating the way Wnt, PAR-1 and its targets affect the cellular reorganisation of axial cells using Xenopus as a model system.
IMAGE 1. Cells in an early frog embryo become aligned and move between one another, like two packs of cards being pushed together, to elongate the body axis. Green-stained cells among their red neighbours highlight the extreme shape variations
IMAGE 2: Building a rod: dissociated cells stick themselves together into a sphere, but if treated with a specific “morphogen” (a type of secreted protein found in embryos), they then elongate into a rod shape, in this case about half a millimetre long.
IMAGE 3: Directed cell division: when cells divide to make two daughter cells, the “spindle” structures that separate the chromosomes (red) can be oriented horizontally (left), obliquely (middle) or vertically (right), with PAR-1 driving the vertical, tissue-thickening mode.
Self-organisation of morphogenesis:
Much of embryonic development and normal injury repair and recovery requires cells to organise themselves locally and autonomously. The Green lab has developed a system of reaggregating dissociated embryonic Xenopus cells that self-organises spherical or rod shapes depending on conditions. This project aims to elucidate the signals and cell behaviours that execute this self-organisation as a model for tissue elongation more generally.
then rearrange the paragraphs in the following order:
1. Morphogenesis of placodal organs renamed as Epithelial bending and morphogenesis of placodal organs
2. Self-organisation of morphogenesis
3. Morphogen action in periodic patterning
4. Face morphogenesis
5. Cell polarity and signalling