Yohanns Bellaïche

Polarity, division and morphogenesis

Yohanns Bellaïche Epithelia, cytoskeleton, biophysics, forces

Development & Epigenesis

Stem cells and Life time potential

Shape is a conspicuous and fundamental property of living multicellular organisms. Questions related to embryo shape or morphogenesis have naturally haunted developmental biologists for decades. Recent advances have highlighted that the understanding of the morphogenesis of proliferative tissue will require (i) the dissection of how subcellular cytoskeleton dynamics controls cellular processes such as cell division orientation and adherens junction formation; (ii) the study of the interplay between biochemical and mechanical processes regulating collective cell behaviours and thus tissue movements. In addition, whole tissue imaging has revealed that distinct local cell dynamics account for tissue shape regulation. Yet, it remains poorly explored how gene expression patterns specify distinct local cell dynamics within a proliferative epithelium.

To decipher the mechanisms of Drosophila epithelial tissue morphogenesis, we are using a series of complementary, state of the art methods (quantitative measurement of cell and tissue morphogenesis, mechanical stress inference, opto-genetics, computer simulation and advanced statistics) in order to:

1. Dissect the molecular and mechanical mechanisms regulating cytoskeleton and cell dynamics by focusing on mitotic spindle orientation and de novo adherens junction formation during cell division.

2. Link cytoskeleton organization, cell dynamics and mechanics to the regulation of large-scale tissue deformation.

3. Analyze how combinatory gene expression patterns can account for distinct cell dynamics observed in the different regions of a tissue.

4. Define the mechanisms coordinating tissue growth and morphogenesis during development and repair.

By exploring the mechanisms of tissue morphogenesis at different time-scales and length-scales, as well as by focusing both on its genetic and mechanical regulation, these complementary aims should advance the understanding of morphogenesis in animals.

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FIgure 1. Proliferation in the epithelium of the dorsal thorax (Bosveled et al., Science 2012).

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Figure 2. Cytokinesis of an epithelial cell (Herszterg et al., Dev Cell 2013).

 

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