Biology subjects

Rouviere, C.

Publications and source records attributed to Rouviere, C..

4 recordsLinked to original sources

bioRxiv2025

Spatio-temporal control of nuclear mechanotransduction during EMT

During epithelial-to-mesenchymal transition (EMT), cells generate mechanical forces. How the nucleus reacts to these mechanical cues, ensuring a tight balance between mechano-protection and mechanotransduction, is a key yet unresolved question. Here we dissect the spatio-temporal control of nuclear mechanostransduction during EMT, using Drosophila mesoderm invagination as a model. We found that two conserved pro-EMT genes respond differently to compressive forces: while snail transcription remains unaffected, compression is sufficient to activate twist transcription within seconds. We further revealed a spatially patterned genome-wide transcriptional response to EMT forces, with an apical mechanoprotection contrasting with a permissive basal nuclear environment. The direct recording of nascent transcription in response to a controlled nuclear micromanipulation provides compelling evidence of nuclear heterogeneity in the transcriptional response to forces. Overall, these results reveal that EMT nuclei respond directly and rapidly to mechanical forces, in a spatially defined pattern.

cell biology↗

bioRxiv2024

Local activation of Cxcl12a signaling controls olfactory placode morphogenesis in zebrafish embryos

Morphogenesis and cell-type differentiation are highly coordinated in sensory organs to ensure their function. Morphogenesis of the olfactory epithelium (OE) in zebrafish provides a unique model to study this process as undifferentiated cells aligned around the anterior neural plate mature into clusters of early olfactory neurons across a short time scale. While the Cxcl12a/Cxcr4b signaling pathway drives this process, what constraints on pathway activation apply during morphogenesis are unclear. We developed a mathematical model recapitulating Cxcl12a-mediated OE morphogenesis. Restoring Cxcl12a expression in mutants for the ligand rescues correct morphogenesis both in silico and in vivo. However, where expression of the ligand is restored is crucial for rescue, a point not predicted by our model and suggesting an unexpected level of pathway activation control. Analysis of a Cxcr4b activation reporter supports this idea. We concluded that mosaic and heterochronic Cxcl12a activation along the anteroposterior axis sculpts the olfactory epithelium.

developmental biology↗

bioRxiv2024

Compressive stress drives morphogenetic apoptosis

Tissues and organs are constantly submitted to physical stress, including compression, stretching, shear stress. The impact of compression due to overcrowding on cell extrusion has been the focus of recent studies. However, how tissue compression impact cell death in the context of morphogenesis is mostly unexplored. Here, we showed that a natural compression is exerted on the Drosophila developing leg by the surrounding tissue (or envelope) that is required for correct leg morphogenesis. In this tissue, apoptosis, preferentially localized in the future fold region, contributes to drive tissue folding through the generation of a pulling force on the apical surface. However, only a subset of these cells are dying within the expression domain of proapoptotic genes and how this precise pattern of cell death is established is totally unknown. We found that the natural compression exerted by the envelope contributes to the regulation of apoptosis, revealing that compression constitutes an integral part of apoptosis regulation during leg morphogenesis. We further reveal that compression drives a significant increase in lateral tension and favors apoptosis through the mechanosensor Piezo. Finally, perturbing cell cortex anchoring or membrane stiffness prove sufficient to block this process. Altogether, these results open new perspectives in term of mechanotransduction during morphogenesis.

developmental biology↗

bioRxiv2020

Super-resolved live-cell imaging using Random Illumination Microscopy

Super-resolution fluorescence microscopy has been instrumental to progress in biology. Yet, the photo-induced toxicity, the loss of resolution into scattering samples or the complexity of the experimental setups curtail its general use for functional cell imaging. Here, we describe a new technology for tissue imaging reaching a 114nm/8Hz resolution at 30 {micro}m depth. Random Illumination Microscopy (RIM) consists in shining the sample with uncontrolled speckles and extracting a high-fidelity super-resolved image from the variance of the data using a reconstruction scheme accounting for the spatial correlation of the illuminations. Super-resolution unaffected by optical aberrations, undetectable phototoxicity, fast image acquisition rate and ease of use, altogether, make RIM ideally suited for functional live cell imaging in situ. RIM ability to image molecular and cellular processes in three dimensions and at high resolution is demonstrated in a wide range of biological situations such as the motion of Myosin II minifilaments in Drosophila.

bioengineering↗