Levayer Lab

Just had wonderful 3 days of science and connection in Nîmes for our joint lab retreat with @leopoldlab.bsky.social , Laura Boulan lab and @argo-mkhrji.bsky.social. A lots of brainstorming on growth regulation, robustness, plasticity and the future of drosophila (with hopf bifurcations in between)

So the wing disc overgrowth phenotype after all may just a be an ECM phenotype 😱😱😱 (ok there is a bit of a stretch here...). Beautiful story !

Plasticity of ventricle position after heart looping in heterotaxy with right isomerism The left/right position of ventricles needs to be maintained after heart looping, an unexpected step affected in heterotaxy.

New publication | Science Advances www.science.org/doi/10.1126/...

Excited to announce the first @cshlnews.bsky.social meeting on Cell Modeling in Space and Time, June 2026 💫

meetings.cshl.edu/meetings.asp...

Bringing together experiments, computation and theory to explore dynamic, multi-scale cellular organization and function!

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Big thanks for the support of our institution @pasteur.fr @cnrsbiologie.bsky.social and funding agency @erc.europa.eu and @agencerecherche.bsky.social who made this work possible.

Overall, our main message is that there are different flavours of mechanical competition where either growth or interfacial tension can contribute to WT cell compaction and elimination with distinctive geometrical and cell death distribution features.

Checking more carefully MyoII and tension, we found that N-cad induction also triggers a downregulation of MyoII and tension in junctions "orthogonal" to the clone boundary (for reasons we don't quite understand yet). Putting this feature in the vertex model fully recapitulate the pattern of death

There was one little feature though that was not recapitulated in our model: cells in the first row near N-cad clone interface tend to be bigger and are not eliminated. How to explain this ?

Alternatively, ectopic expression of N-cad was sufficient to increase boundary tension and could trigger WT or N-cad cell elimination as long as they are located in concave boundary/pockets. Basically, who is eliminated is fully set by the geometry of the interface (if you are in minority you lose)

Can we now find experimental conditions reproducing "pure" growth-driven or interfacial tension driven elimination ? First, activation of Yki/Yap in clones was sufficient to recapitulate all the features of growth driven compaction (no impact of curvature, elongation of cells parallel to long axis)

While both conditions could lead to cell compaction and elimination, clear distinctive features emerge in term of distribution of cell death, relationship with boundary shape and orientation of WT cell in the patch (check the paper to get the list)

So...we have now two contributors to WT cell compaction : growth and interfacial tension. Could we extract distinctive features from these two modes of cell deformation ? Alexis started to explore conditions in vertex model either increasing interfacial tension (below) or by increasing growth.

In this framework, just like the interface between two fluids, the pressure should be proportional to the local curvature. This is exactly what Léo found: WT cells near concave interfaces are more compacted and more likely to be eliminated

By imaging conditions with large clone coverage, Léo realised that WT patches surrounded by Ras cells tend to round up and sort. This is driven by the increase of tension at the interface of the clone. Could this generate a local increase of pressure (similar to Laplace pressure) ?

To sum up in few words, previously we found that activation of Ras in clones leads to neighbouring cell compaction and elimination. While we assumed that growth was the main driver of compaction, it was not clear whether other features could contribute to cell elimination

Happy to share the last version of our story @currentbiology.bsky.social on the role of interfacial tension in mechanical cell competition led by @leovalon.bsky.social and Alexis Matamoro Vidal
www.sciencedirect.com/science/arti...

Pour chaque vie, la science agit. Le Pasteurdon, c’est maintenant ! Soutenez la recherche et celles et ceux qui la font avancer. Faites un don sur pasteurdon.fr

Pour chaque vie, la science agit.
Le Pasteurdon, c’est maintenant !
Soutenez la recherche et celles et ceux qui la font avancer ↘️ pasteurdon.fr
#Pasteurdon

Professor Jochen Guck, Director at the Max Planck Institute for the Science of Light (MPL), He headed the division “Cell Physics” at MPL and the Max-Planck-Zentrum für Physik und Medizin (MPZPM).

With deep sadness, we share that Prof. Jochen Guck, Director at the Max Planck Institute for the Science of Light passed away on October 3. His visionary work bridged physics and medicine. We have lost a brilliant scientist and dear friend.

mpl.mpg.de/news/article...
@fau.de

📸 Stephan Spangenberg

New preprint from the lab! We discovered a transient fluidization in the basal region of human forebrains by tracking microdroplets in cerebral organoids.This “basal fluidization”, absent in gorilla and mouse, may contribute to greater surface expansion in human forebrains
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doi.org/10.1101/2025...

Cell-type-specific nucleotide sharing through gap junctions impacts sensitivity to replication stress in Drosophila Boumard et al. demonstrate gap-junction-dependent tissue-scale nucleotide sharing, which impacts cellular sensitivity to perturbation of nucleotide homeostasis and replication stress. Drosophila wing ...

The PhD work of @bboumard.bsky.social officially out in print! Happy to share this issue with our downstairs colleagues in the BDD @frelab.bsky.social @robinjournot.bsky.social

www.cell.com/developmenta...

Research engineer in Bioimage Analysis for the researchers of the inIdEx FORMULA Hi all We are looking for a bioimage analysis to work in an image analysis core facility in beautiful Paris. Can I ask you to share this opportunity with your networks? The position is in the Instit...

Job alert!

We are looking for a bioimage analysis to work in an image analysis core facility in beautiful Paris. Can I ask you to share this opportunity with your networks?

See also on the forum:
forum.image.sc/t/research-e...

Great combo of nice basic science and very timely topic ! Will read the preprint for sure.

🧵1/14 Preprint thread! Can we predict a cell’s fate based on its dynamics? 🔮 Our new study unveils a framework for watching development unfold in real-time, revealing how a cell's shape and movement encode info about its future fate. 🔬📄 Preprint: tinyurl.com/4shf8v4x

How is developmental speed regulated ? 🪰

Happy to share my PhD story from Schweisguth Lab @devstempasteur.bsky.social. Here we show that cellular NAD+ availability and redox constrain developmental speed in the fly eye.

www.biorxiv.org/content/10.1...

A big thanks to everyone involved!

⌛1 month left to apply – 2025 PPU call for candidates

We invite you to discover 4 Develpmental & Stem Cell Biology projects and 3 Immunology projects👇

🕰️Application deadline: October 20, 2025
📍Program starts: October 2026

Discover all the projects (50+) & apply: www.pasteur.fr/en/education...

Signaling-dependent refinement of cell fate choice during tissue remodeling in Drosophila pupal wings Herszterg et al. show that during morphogenesis of the Drosophila pupal wing, a wave of Notch signaling activity updates cell fates to ensure robust and precise patterning of wing veins.

We only had a very minor contribution to this story with Alexis, but definitly worth a reading for those interested by patterning, precision and refinment. Nice combining of quantitative live imaging, modeling and optogenetics to dissect vein patterning dynamics
www.cell.com/developmenta...

Computational image analyst (m/f/d) The Max Planck Institute for Molecular Biomedicine in Münster, Germany, has an opening for a

My lab @mpi-muenster.bsky.social is looking for a computational biologist with a passion for imaging and spatial biology. A staff scientist position with long-term perspective! Apply and spread the word 🙏 jobs.mpi-muenster.mpg.de/jobposting/0...

🚨 The International Developmental Mechanics Zoom Seminar Series is back on Sept 25!
🎤 We have an exciting line-up of speakers this fall. See the image below for details
🌐 Website: sites.google.com/view/devmech...
📝 Interested in presenting? Sign up here: tinyurl.com/2munv5bv

A though provocative idea potentially connecting cell metabolic state and sensitivity to mechanical stress (and thus potentially relevant for cell competition)

Energy deficiency selects crowded live epithelial cells for extrusion - Nature Crowded epithelial cells with the least energy and membrane potential are selected for extrusion.

Epithelial crowding drives membrane depolarisation by ENaC/Na+ entry which triggers rapid volume loss, piezo activation and live cell extrusion. Importantly, low intracellular ATP primes cells for live extrusion by preventing the restoring of mb polarisation.

www.nature.com/articles/s41...