Thesis defense: Zoé Bomsel
Monday, December 8 2025 2 pm - INRAE, Versailles
Regulation of pre-mitotic microtubule arrays in plants : characterization of interphasic TRM proteins
Cell division and elongation are the driving forces of development and morphogenesis in organisms. In addition to their plasma membranes, plant cells have semi-rigid pectocellulosic cell walls involved in cell elongation processes, among other functions. These walls bind neighbouring cells to each other, and prevent any cell migration. Positioning of the plane of cell division, separating daughter cells during cytokinesis at the end of mitosis by the formation of a new cell wall, is therefore a crucial factor in the development, morphogenesis and organization of plant tissues.
The plane of cell division is regulated at several scales by geometrical, physical and biomolecular factors. In plants, this division plane is determined before mitosis, and prefigured at the G2/M phase transition, by the preprophase band (PPB) of microtubules. However, recent studies have shown that the positioning of the division plane of the cell is relatively independent from PPB formation. The regulatory pathways determining the plane of cell division in plants remain largely unknown.
This thesis therefore aims to explore interphasic mechanisms that may be responsible for the regulation of the plane of cell division upstream of PPB formation, through the study of TRM proteins of the TTP complex in Arabidopsis thaliana. The TTP complex, composed of TON1 (TONNEAU1), TON1-Recruiting Motif (TRM) proteins, and a PP2A phosphatase, is involved in the regulation of cortical microtubule arrays, and is regulated at the transcriptional and post-translational levels. The diversity of TRM sequences and expression patterns within the 34-member multigenic family of A. thaliana suggests an important functional diversity of the TTP complex in the regulation of microtubule arrays, at different stages of the cell cycle, and in different developmental contexts.
Director: David Bouchez, "Spatial Control of Cell Division" SPACE team, INRAE, IJPB, Versailles
Co-supervision: Magalie Uyttewaal, "Spatial Control of Cell Division" SPACE team, INRAE, IJPB, Versailles
Jury members
> Nathalie Gonzalez (Rapportrice) - INRAE, BFP, FDFE, Villenave d'Ornonhttps://www.cnrs.fr/en
> Benoît Landrein (Rapporteur) - CNRS, ENS Lyon, RDP, Seed mechanism group
> Marianne Delarue (Examinatrice) - IPS2, Université Paris-Saclay, Gif-sur-Yvette
> Stéphanie Drevensek (Examinatrice) - École polytechnique, Palaiseau
Cell division and elongation are the driving forces of development and morphogenesis in organisms. In addition to their plasma membranes, plant cells have semi-rigid pectocellulosic cell walls involved in cell elongation processes, among other functions. These walls bind neighbouring cells to each other, and prevent any cell migration. Positioning of the plane of cell division, separating daughter cells during cytokinesis at the end of mitosis by the formation of a new cell wall, is therefore a crucial factor in the development, morphogenesis and organization of plant tissues.
The plane of cell division is regulated at several scales by geometrical, physical and biomolecular factors. In plants, this division plane is determined before mitosis, and prefigured at the G2/M phase transition, by the preprophase band (PPB) of microtubules. However, recent studies have shown that the positioning of the division plane of the cell is relatively independent from PPB formation. The regulatory pathways determining the plane of cell division in plants remain largely unknown.
This thesis therefore aims to explore interphasic mechanisms that may be responsible for the regulation of the plane of cell division upstream of PPB formation, through the study of TRM proteins of the TTP complex in Arabidopsis thaliana. The TTP complex, composed of TON1 (TONNEAU1), TON1-Recruiting Motif (TRM) proteins, and a PP2A phosphatase, is involved in the regulation of cortical microtubule arrays, and is regulated at the transcriptional and post-translational levels. The diversity of TRM sequences and expression patterns within the 34-member multigenic family of A. thaliana suggests an important functional diversity of the TTP complex in the regulation of microtubule arrays, at different stages of the cell cycle, and in different developmental contexts.
Director: David Bouchez, "Spatial Control of Cell Division" SPACE team, INRAE, IJPB, Versailles
Co-supervision: Magalie Uyttewaal, "Spatial Control of Cell Division" SPACE team, INRAE, IJPB, Versailles
Jury members
> Nathalie Gonzalez (Rapportrice) - INRAE, BFP, FDFE, Villenave d'Ornonhttps://www.cnrs.fr/en
> Benoît Landrein (Rapporteur) - CNRS, ENS Lyon, RDP, Seed mechanism group
> Marianne Delarue (Examinatrice) - IPS2, Université Paris-Saclay, Gif-sur-Yvette
> Stéphanie Drevensek (Examinatrice) - École polytechnique, Palaiseau
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