Florian Roisné-Hamelin's Avatar

Florian Roisné-Hamelin

@roisnehamelinf

Molecular biologist moving to biochemistry Admirer of Cryo-EM Interested in a lot of things including SMC proteins, telomeres and DNA repair machines

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11.09.2023
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Latest posts by Florian Roisné-Hamelin @roisnehamelinf

Delighted to see our last work published, showing that Wadjet-I SMC hinges allow the selective bypass of obstacles on DNA!
At the @gruberlab.bsky.social, with @drhonsworth.bsky.social and @taschner.bsky.social, and with James & @dnatopologylab.bsky.social

25.11.2025 17:44 👍 6 🔁 0 💬 0 📌 0

Happy that the final version of our Lamassu work @yli18smc.bsky.social is now out:

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

Thanks again to our awesome collaborators @mblokesch.bsky.social and David and co and Mark Szczelkun and @steven-shaw.bsky.social and the DCI Lausanne @fbm-unil.bsky.social

14.10.2025 09:28 👍 46 🔁 21 💬 3 📌 0

Very nice collaboration with the BSI platform at @igbmc.bsky.social. Streptavidin grids were instrumental to solve a rather drastic anisotropy problem!

14.10.2025 10:42 👍 2 🔁 0 💬 0 📌 0

Thank you Biswajit 😊

10.10.2025 14:18 👍 0 🔁 0 💬 0 📌 0

Many thanks to the reviewers for their thoughtful and constructive comments on our manuscript.

09.10.2025 14:57 👍 1 🔁 0 💬 0 📌 0

Delighted to announce our latest work on how Wadjet loads onto and establishes topological entrapment of plasmid DNA prior to initiating loop extrusion. At @gruberlab.bsky.social, Dubochet Center for Imaging and BSI @igbmc.bsky.social

www.cell.com/molecular-ce...

09.10.2025 14:55 👍 22 🔁 7 💬 1 📌 0

Our Wadjet-II paper by @roisnehamelinf.bsky.social is out in polished form: www.cell.com/structure/fu...

With a great preview by @kevincorbett.bsky.social & @amardeeep.bsky.social highlighting the potential of Wadjets:

Wadjet—Keeping a watchful eye on circular DNA.

www.cell.com/structure/fu...

05.09.2025 06:29 👍 48 🔁 19 💬 1 📌 1
Preview
Telomeres stall DNA loop extrusion by condensin Analikwu et al. show that dense linear arrays of the telomeric protein Rap1 on DNA block DNA loop extrusion by condensin. Rap1-induced stalling depends on array length and protein density and leads to a local chromatin decompaction during anaphase, revealing how protein arrays can regulate SMC-driven genome organization.

Telomeres stall DNA loop extrusion by condensin

02.07.2025 19:50 👍 8 🔁 7 💬 0 📌 0

This reveals parallels with DNA end protection in eukaryotes and highlights the challenges of having linear chromosomes as well as functional repair of DNA double strand break.

www.biorxiv.org/cgi/content/...

16.06.2025 07:06 👍 11 🔁 5 💬 0 📌 0
DMF: Tenure Track Assistant Professor towards Associate Professor in Molecular Microbiology - Site des postulations FBM

New tenure track assistant professor position in molecular microbiology in our department @dmf-unil.bsky.social @unil.bsky.social! We are casting a wide net for an experimental molecular microbiologist. Apply here: wwwfbm.unil.ch/releve/appli...

10.06.2025 13:53 👍 112 🔁 162 💬 0 📌 8

Fantastic teamwork with @drhonsworth.bsky.social, @taschner.bsky.social, in the @gruberlab.bsky.social with James at @dnatopologylab.bsky.social

18.03.2025 08:15 👍 2 🔁 1 💬 0 📌 0

Happy to share our latest work. Wadjet-I SMC hinges are gates allowing selective bypass of obstacles connected through ssDNA BUT are dispensable for extrusion of naked DNA.

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

18.03.2025 08:14 👍 3 🔁 2 💬 1 📌 0

The SMC Hinge is a Selective Gate for Obstacle Bypass https://www.biorxiv.org/content/10.1101/2025.03.17.643644v1

18.03.2025 05:20 👍 6 🔁 6 💬 0 📌 0
Screenshot of 2d ligand environment view, 1x8b 4dfr, 2vtq, 2p4y

Screenshot of 2d ligand environment view, 1x8b 4dfr, 2vtq, 2p4y

Coot 1.1.14 has been released!

Coming to homebrew and flatpak soon!

- Clark & Labute comes to Coot 1, Moorhen & chapi!
(svg, 2D ligand environment view)
- Solid Symmetry (symmetry that you can see!)
- PAE plot for AlphaFold models
#coot
#molmatinf

17.03.2025 19:50 👍 27 🔁 10 💬 0 📌 0
Alt : Structure of the apo Lamassu protein complex. Schematic model of the active LmuA tetramer nuclease (top right). Lamassu icon (top left).

Alt : Structure of the apo Lamassu protein complex. Schematic model of the active LmuA tetramer nuclease (top right). Lamassu icon (top left).

Glad to share the work of @yli18smc.bsky.social and co on Lamassu, a bacterial defense system related to Rad50/Mre11 (RM). While RM carefully trims DNA ends for repair, Lamassu chops up the host chromosome. Our study reveals how it is regulated to minimize damage, activating only during infection.

16.03.2025 09:15 👍 63 🔁 31 💬 4 📌 3
Side view of the structure of a monomer of type II Wadjet.

Side view of the structure of a monomer of type II Wadjet.

Happy to share the beautiful structure of a Wadjet SMC complex by @roisnehamelinf.bsky.social, with support from the DCI and @drhonsworth.bsky.social ! This is a type II Wadjet with unique characteristics including a tandem KITE subunit, distinct coiled coil architecture and a deviant hinge.

11.03.2025 09:22 👍 95 🔁 33 💬 1 📌 2

Structure of a Type II SMC Wadjet Complex from Neobacillus vireti https://www.biorxiv.org/content/10.1101/2025.03.10.642339v1

11.03.2025 08:17 👍 0 🔁 2 💬 0 📌 1
Preview
Soutien aux projets en cryo-microscopie électronique: découvrez les 4 récipiendaires de la FBM Pour cette toute première mise au concours en cryo-microscopie électronique, la Commission de la Recherche de la FBM a retenu 4 projets innovants qui seront menés au sein des Départements de microbiol...

Soutien aux projets en cryo-microscopie électronique: découvrez les 4 récipiendaires @fbm-unil.bsky.social
➡️ www.unil.ch/news/1740986...

👏 Félicitations à Paula Navarro, Cyrielle Hou, Violeta Block, Florian Roisné-Hamelin 👏

@unil.bsky.social @dmf-unil.bsky.social @dib-unil.bsky.social

04.03.2025 10:59 👍 6 🔁 2 💬 1 📌 0

Pleased to announce the publication of our latest work on how Wadjet senses DNA circularity prior to cleavage. Collaborative effort with @drhonsworth.bsky.social at @gruberlab.bsky.social & Dubochet Center for Imaging. Deep thanks to our advisors and reviewers.

authors.elsevier.com/c/1iXM53vVUP...

02.02.2024 18:50 👍 4 🔁 0 💬 0 📌 0
Structures of JetABCD complex on kinked plasmid DNA.

Structures of JetABCD complex on kinked plasmid DNA.

First preprint 📢 on bsky: New work on the Wadjet defence system by @roisnehamelinf.bsky.social & @drhonsworth.bsky.social revealing beautiful & exciting structures of JET on plasmid DNA. With loop extrusion, obstacles, DNA bending, kinking, cleavage 🦠🧫 🧪
t.co/RaO7IO3zDk 
With help from @DCI_Lausanne

04.11.2023 07:39 👍 42 🔁 22 💬 1 📌 4