Polarity and Morphogenesis

Group leader

The understanding of the mechanisms, which orchestrate tissue and organ formation and which control their architecture maintenance, is a fundamental question in biology. Tissue formation and associated homeostasis are coordinated through cellular processes that include cell polarity, cell adhesion and motility. The understanding of these processes is also essential to better understand the molecular mechanisms controlling the development of pathologies such as cancer.

Our research team aims to elucidate the molecular mechanisms that control cell polarity and tissue morphogenesis in relation with the cytoskeleton and in particular with the microtubule network. To do so we are using Drosophila development as model system and we focus our research especially on two axes.

  1. At a cellular level, by exploring cytoskeleton requirement for the oocyte polarity establishment during oogenesis. We are investigating the molecular mechanisms involved in protein and mRNA asymmetric transport and those required for the asymmetric positioning of the nucleus.
  2. At a tissue level, by studying cytoskeleton requirement in tissue morphogenesis. We are looking for the molecular processes controlling collective cell migration required for the establishment of the reparatory system during embryogenesis.

We are using both conventional and innovative methodologies by combining genetic, biophysics and cell biology technics. Furthermore, live imaging associated with advanced light microscopy and electron microscopy are the core our experiments.

Nuclear migration in the Drosophila oocyte  

Membrane organisation in the Drosophila oocyte

Collective migration of tracheal
cells in the Drosophila embryo

The research topics of the team:

* Identification of mechanisms controlling the asymmetric positioning of the nucleus in the oocyte.

* Identification and characterisation of the different microtubule networks required for the oocyte polarisation.

* Relationship between the lipid domains connected to phosphatidylinositol(4,5) biphosphate and the polarity proteins in the intracellular organisation and the polarized transport.

* Characterisation of the cytoskeleton requirement, microtubules and actin, in the collective cell migration process controlling the formation of the tracheal branches in the embryo.

Keywords: Cell polarity, morphogenesis, microtubules, asymmetric transport, phospholipids, PAR protein complexes

The research topics of the team:

* Identification of mechanisms controlling the asymmetric positioning of the nucleus in the oocyte.

* Identification and characterisation of the different microtubule networks required for the oocyte polarisation.

* Relationship between the lipid domains connected to phosphatidylinositol(4,5) biphosphate and the polarity proteins in the intracellular organisation and the polarized transport.

* Characterisation of the cytoskeleton requirement, microtubules and actin, in the collective cell migration process controlling the formation of the tracheal branches in the embryo.

Keywords: Cell polarity, morphogenesis, microtubules, asymmetric transport, phospholipids, PAR protein complexes

Selection of publications

Bernard F, Lepesant JA, Guichet A. Nucleus positioning within Drosophila egg chamber. Semin Cell Dev Biol. S1084-9521(17) (2017).
Abstract

Tissot N, Lepesant J-A, Bernard F, Legent K, Bosveld F, Martin C, Orestis F, Bellaïche Y, Coppey M, Guichet A. Complementary molecular cues ensure a robust microtubule-dependent nuclear positioning in the Drosophila oocyte. Nature Communication 8:15168 (2017).
Abstract

Jouette J, Claret S, Guichet A. Phosphoinositides and cell polarity in the Drosophila egg chamber. Results and Problems in Cell Differentiation 63:169-187 (2017).
Abstract

Le Droguen PM, Claret S, Guichet A, Brodu V. Microtubule-dependent apical restriction of recycling endosomes sustains adherens junctions during morphogenesis of the Drosophila tracheal system. Development. 142(2) (2015).
Abstract

Claret S, Jouette J, Benoit B, Legent K, Guichet A. 
PI(4,5)P2, maintained by the PIP5K Skittles, controls apical membrane size by tethering PAR-3 in Drosophila epithelial cells. Current Biology. 24(10) (2014).
Abstract

Baffet A, Benoit B, Januschke J, Audo J, Gourhand V, Roth S, Guichet A. 
Drosophila Tubulin Binding Cofactors B is required for microtubule network formation and for cell polarity.  Molecular Biology of the Cell. 23(18) (2012).
Abstract

Brodu V, Baffet A, Le Droguen PM, Casanova J, Guichet A. 
A developmentally regulated two-step process generates a non-centrosomal microtubule network in Drosophila tracheal cells. Developmental Cell. 18(5) (2010).
Abstract

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