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

Stephan Gruber@gruberlab.bsky.social · 8mo ago

The hinge bypass gate paper is finally out! doi.org/10.1038/s414... We show how loop-extruding SMC complexes can maintain DNA entrapment while bypassing obstacles on DNA — including transcription machinery & potentially other SMCs. A lucky convergence of 3 projects lead to the initial discovery!

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

Stephan Gruber@gruberlab.bsky.social · last yr.

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.

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...

Mechanism of DNA entrapment by a loop-extruding Wadjet SMC motor

Wadjet is an SMC-based prokaryotic defense system that eliminates plasmid DNA. Roisné-Hamelin et al. present structures capturing key steps of its DNA-loading mechanism. This work reveals how Wadjet t...

cell.com

Stephan Gruber@gruberlab.bsky.social · 10mo ago

How do SMC complexes load onto DNA to get ready for loop extrusion? @roisnehamelinf.bsky.social & co discovered that Wadjet, an SMC complex involved in bacterial DNA immunity, performs some impressive molecular gymnastics 🤸‍♂️🤸‍♂️🤸‍♂️. Check out the new paper: www.cell.com/molecular-ce...

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...

Structure of a type II SMC Wadjet complex from Neobacillus vireti

Wadjet are SMC-based prokaryotic defense systems that cleave plasmid DNA. Roisné-Hamelin et al. reconstitute a type II Wadjet and demonstrate that it exhibits substrate selection and cleavage properti...

cell.com

Stephan Gruber@gruberlab.bsky.social · last yr.

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.

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

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/...

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...

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...

The SMC Hinge is a Selective Gate for Obstacle Bypass

DNA loop-extruding SMC complexes play vital roles in genome maintenance and DNA immunity. However, the ability of these ring-shaped DNA motors to navigate large DNA-bound obstacles, such as DNA/RNA po...

biorxiv.org

Stephan Gruber@gruberlab.bsky.social · last yr.

Yet another preprint from the lab—this one is personal. During my PhD, I ended up working on the cohesin SMC hinge, showing its role in sister chromatid cohesion and proposing it as a DNA entry gate in the SMC ring. But the details have remained mysterious and controversial.

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

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

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.

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.

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

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...

unil.ch

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...

Stephan Gruber@gruberlab.bsky.social · 3y ago

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...

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