Our research scientist Núria Ros-Rocher won the 1st prize @zeiss-microscopy.bsky.social microscopy contest with this beautiful choano colony www.zeiss.fr/microscopie/... 🥳
C. flexa might not yet be a genetic model, but it is now at least a calendar model, which counts for something. I think.
Why does life explore so few of the forms it could possibly take? Using fractal descriptors, this #scienceadvances paper shows that Earth’s biosphere clusters around simple shapes, reflecting deep evolutionary constraints. @artemyte.bsky.social @manlius.bsky.social www.science.org/doi/pdf/10.1...
Nature research paper: Genetic switch between unicellularity and multicellularity in marine yeasts
go.nature.com/4poZ9HP
Our transgenic quail line enables visualization of diverse cellular dynamics. We are delighted to collaborate with anyone interested in using this model. Please feel free to contact us (@jeromegros.bsky.social). Let’s cheer on the epithelial morphogenesis and gastrulation community together!
I thank my PhD supervisor, Jérôme, and all my labmates. I am sincerely grateful to the PPU PhD program (@pasteuredu.bsky.social), Sorbonne Université (@sorbonne-universite.fr), Institut Pasteur (@pasteur.fr), CNRS (@cnrs.fr), and the FRM Fin-de-thèse fellowship (@frm-officiel.bsky.social)! (10/n)
In summary, we characterized actomyosin dynamics during PS formation and cell ingression in avian embryos and showed that epithelial remodeling was largely associated with junctional myosin contractility, in cooperation with medioapical actomyosin activity. (9/n)
Additionally, we observe apoptotic extrusions, whose dynamics contrast with ingression in the PS. Dying cells show strong accumulation of myosin, forming a medioapical “plaque.” This plaque rapidly contracts the apical surface area within ~5 min. This mechanism depends on cleaved caspases. (8/n)
Early “isolated ingression” was proposed as a first step in gastrulation. With long-term, wide-field imaging, we found that this event is slower and ends prior to PS formation. Lineage tracing shows that it is “polyingression,” contributing to PGCs & hypoblast formation, not gastrulation. (7/n)
Interestingly, during the contraction of this “junctional belt,” we observe intense medioapical myosin activity, suggesting that medioapical and junctional pools cooperate during cell ingression within the PS. (6/n)
How cells then ingress within the avian PS remained unclear. Here, we observe that junctional myosin accumulation appears to form a “junctional belt” that steadily constricts, driving apical constriction and, ultimately, ingression within ~20 min, without an obvious ratchet mechanism. (5/n)
During PS formation, myosin accumulates at apical junctions in a polarized manner to drive convergence & extension (C&E) within the PS. Fast, high-resolution imaging reveals that medioapical myosin appears to be recruited to support junctional contractility during C&E, thereby forming the PS. (4/n)
Using live imaging of gastrulating embryos, we observed medioapical, pulsatile actomyosin contractions at the apical surface of epiblast cells, similar to those in other epithelial models (e.g., the Drosophila ectoderm). (3/n)
To characterize these dynamics, we generated a new transgenic quail line expressing fluorescent reporters for the myosin regulatory light chain (MYL9) and F-actin (LifeAct). In both the epiblast and the PS, the reporters are strongly enriched at epithelial junctions. (2/n)
The avian epiblast is a ~3 mm monolayer disc of ~50k columnar epithelial cells. During gastrulation, it shows large-scale, actomyosin-driven epithelial remodeling as the primitive streak (PS) extends and germ layers form via cell ingression. However, the underlying cell dynamics was unclear. (1/n)
I’m pleased to share our latest preprint (my first as 1st-author) from Jérôme Gros’ group (@jeromegros.bsky.social), now on bioRxiv. It reports actin and myosin dynamics during epithelial remodeling in avian gastrulation. (doi: doi.org/10.64898/202...)
Image of cell junction puncta from https://www.molbiolcell.org/doi/full/10.1091/mbc.E23-03-0077
To build the body plan of an animal, cells must adhere to one another via cell-cell junctions. We now know these assemble as punctate protein complexes containing thousands of proteins, but how this occurs remains mysterious. 1/n 🧪
www.molbiolcell.org/doi/full/10....
Join us next week for the second Eastern VGZT of the season! 🤩
🗓️ Wednesday, December 10th
⏰ 9:00 UTC / 9:00 GMT / 10:00 CET / 14:30 IST / 18:00 JST / 20:00 AEDT
Our speakers are:
👉 Guojun Sheng
👉 Jennifer Zenker
See you there! ✨
Register now for the EMBO Workshop "Limb development and regeneration: Quantitative, ecological, and diversification studies" in #Tokyo, Japan, 23–27 March 2026.
Abstract submission/Registration deadline:
12/15 December 2025
https://meetings.embo.org/event/26-limb-dev
#EMBOLimbDev #EMBOevents 🧪
Interested in polarity and mechanics during epithelial morphogenesis? Considering joining us! Students to be hired initially as Research Associates. Postdocs encouraged to obtain fellowship, and we help/train you to do that. Apply to tinyurl.com/y6x489t5. Deadline Dec 15.
Please repost!
Want to know why #microtubules should be depolymerised before #cyokinesis is completed.
#mitosis #cellbiology #midbody
Check out our new study in @jcellsci.bsky.social @bric-cdfd.bsky.social
doi.org/10.1242/jcs....
Amazing day at #GastrulationReloaded with thought provoking science and jaw dropping methods.
Also, for no reason at all, re-posting this open Collection: www.nature.com/collections/...
Don’t sweat the deadline, we’ll extend it and I’ll add relevant papers that come to me @natcomms.nature.com
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...
New publication | Science Advances www.science.org/doi/10.1126/...
Fantastic work from Xi and Qi-long! Chicken ES cells will take classic chicken embryology to a new level.
Our calcium paper is out in PLOS Biology!
Check it out! #Calcium #Embryo #Development
Latest from ours: www.cell.com/cell-reports...
This is two stories in one: a case study/cautionary tale on developing genetic tools in new organisms, and the first hint at a gene regulatory network for choanoflagellate multicellular development (which turn out to involve a Hippo/YAP/ECM loop!) A 🧵
⏳ Still time to register + submit your poster abstract
🗓️ Deadline: Sept 19!
Pasteur-Paris University International Doctoral Programme, The call for enrollment of students in October 2026 will be open from September 1st to October 20th, 2025
🎓 Applications for Institut Pasteur's PhD programs open Sept 1-Oct 20, 2025 for October 2026 entry.
Apply to up to 4 projects across 6 programs: PPU, PPU-IMAGINE @institutimagine.bsky.social, PPU-@ox.ac.uk, PPU-EID @upcite.bsky.social & more 🧬
Register now ✍️ www.pasteur.fr/en/education...
🚨 theory/math devbio preprint alert!!! 🚨
Led by my v. talented PhD student, Daniel Muzatko, we’ve found some rather general and intriguing constraints on reaction-diffusion systems that allow them to self-organize developmental patterns:
www.biorxiv.org/content/10.1...
🔈 We’re excited to welcome Jérôme Gros @jeromegros.bsky.social as an invited speaker at #ICDB2025!
Jérôme's stunning in vivo imaging reveals the cellular mechanics driving vertebrate morphogenesis. 🎥🐣🧪
