Florian Roisné-Hamelin
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Florian Roisné-Hamelin
@roisnehamelinf.bsky.social
460 followers 120 following 7 posts
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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Florian Roisné-Hamelin @roisnehamelinf.bsky.social · Oct 9
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...
Reposted by Florian Roisné-Hamelin
gruberlab.bsky.social
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
gruberlab.bsky.social Stephan Gruber @gruberlab.bsky.social · Mar 16
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.
Alt : Structure of the apo Lamassu protein complex. Schematic model of the active LmuA tetramer nuclease (top right). Lamassu icon (top left).
October 14, 2025 at 9:28 AM
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...
October 9, 2025 at 2:55 PM
Reposted by Florian Roisné-Hamelin
gruberlab.bsky.social
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...
September 5, 2025 at 6:29 AM
Reposted by Florian Roisné-Hamelin
cp-cellreports.bsky.social
Telomeres stall DNA loop extrusion by condensin
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.
dlvr.it
July 2, 2025 at 7:50 PM
Reposted by Florian Roisné-Hamelin
gruberlab.bsky.social
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/...
www.biorxiv.org
June 16, 2025 at 7:06 AM
Reposted by Florian Roisné-Hamelin
veeninglab.com
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...
DMF: Tenure Track Assistant Professor towards Associate Professor in Molecular Microbiology - Site des postulations FBM
wwwfbm.unil.ch
June 10, 2025 at 1:53 PM
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...
March 18, 2025 at 8:14 AM
Reposted by Florian Roisné-Hamelin
biorxiv-molbio.bsky.social
The SMC Hinge is a Selective Gate for Obstacle Bypass https://www.biorxiv.org/content/10.1101/2025.03.17.643644v1
March 18, 2025 at 5:20 AM
Reposted by Florian Roisné-Hamelin
cootymccootface.bsky.social
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
Screenshot of 2d ligand environment view, 1x8b 4dfr, 2vtq, 2p4y
March 17, 2025 at 7:48 PM
Reposted by Florian Roisné-Hamelin
gruberlab.bsky.social
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.
Alt : Structure of the apo Lamassu protein complex. Schematic model of the active LmuA tetramer nuclease (top right). Lamassu icon (top left).
March 16, 2025 at 9:15 AM
Reposted by Florian Roisné-Hamelin
gruberlab.bsky.social
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.
Side view of the structure of a monomer of type II Wadjet.
March 11, 2025 at 9:22 AM
Reposted by Florian Roisné-Hamelin
biorxiv-microbiol.bsky.social
Structure of a Type II SMC Wadjet Complex from Neobacillus vireti https://www.biorxiv.org/content/10.1101/2025.03.10.642339v1
March 11, 2025 at 8:17 AM
Reposted by Florian Roisné-Hamelin
fbm-unil.bsky.social
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
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...
www.unil.ch
March 4, 2025 at 10:59 AM
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...
gruberlab.bsky.social Stephan Gruber @gruberlab.bsky.social · Feb 2
Our new work on the Wadjet (JET) anti-plasmid defence system is out:

authors.elsevier.com/a/1iXM53vVUP...

Showing structures of SMC complexes on extruded DNA (first time?)

and blockage (!) of DNA extrusion by obstacles on DNA

and more...
February 2, 2024 at 6:50 PM
Reposted by Florian Roisné-Hamelin
gruberlab.bsky.social
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
Structures of JetABCD complex on kinked plasmid DNA.
November 4, 2023 at 7:39 AM