Mitosis Lab

Human RPA is an essential telomerase processivity factor for maintaining telomeres Telomerase counteracts telomere shortening by repeatedly adding DNA repeats to chromosome ends. We identified the replication protein A (RPA) heterotrimer as a telomerase processivity factor critical ...

Our paper in Science is out! @souravagrawal.bsky.social, @rlynn.bsky.social, @susvirkar.bsky.social, and the rest of the team show human RPA is a telomerase processivity factor essential for telomere maintenance. This reshapes our thinking about telomerase regulation. www.science.org/doi/10.1126/...

Happy to share our latest publication, in which we show that the arrangement of nucleosomes around CTCF sites contributes to higher-order organisation of chromatin into TADs: www.embopress.org/doi/full/10....

Huntington's disease successfully treated for first time One of the most devastating diseases finally has a treatment that can slow its progression and transform lives, tearful doctors tell BBC.

Wow www.bbc.com/news/article...

Philanthropies Strike a Promising Deal to Turn Back H.I.V.

This is huge: “A drug that provides near-perfect protection against H.I.V. with shots just twice a year will be made available at $40 per patient annually in low- and middle-income countries, offering new hope… making lenacapavir a realistic choice in countries with constrained resources.”

For something different, tried this approach on something on the other end of the spectrum - in situ ribosomes from low SNR 2DTM data.

Used the U2OS-grid 9 dataset from EMPIAR-12459 (699 movies; doi.org/10.1016/j.mo...).

Blob pick & 2D after denoising gave 12k particles. 2-class HR-HAIR --> 3.3 Å

Correlative MS Imaging for cellular identification and analysis of in situ cryo-ET www.biorxiv.org/content/10.1101/2025.09.16.676641v1 #cryoEM

Sub-cellular chemical mapping in bacteria using correlated cryogenic electron and mass spectrometry imaging

Congrats Hannah Ochner and authors on this important paper! Strong collaboration with @kiranrpatil.bsky.social

www.biorxiv.org/cgi/content/...
@mrclmb.bsky.social @wellcometrust.bsky.social

🏅 Congratulations to Sandra Schmid (@czbiohub) on receiving ASCB’s 2025 E.B. Wilson Medal! This award honors distinguished researchers for far-reaching contributions to cell biology over a lifetime in science—an achievement Sandra exemplifies. #ASCB #CellBiology

High-throughput investigation of cyclin docking interactions reveals the complexity of motif binding determinants - Nature Communications Many protein–protein interactions depend on Short Linear Motifs (SLiMs). In this study, the authors use large-scale binding assays, deep mutational scanning, and structural analysis to map SLiMs recog...

Just published: Our paper on high-throughput analysis of cyclin docking interactions, led by the group of Norman Davey @icr.ac.uk and with some small-complex-plus-peptide #cryoEM by @natalia-mg.bsky.social from my lab. Congratulations, everyone!
www.nature.com/articles/s41...

The small GTPase Ran defines nuclear pore complex asymmetry Nuclear pore complexes (NPCs) bridge across the nuclear envelope and mediate nucleocytoplasmic exchange. They consist of hundreds of nucleoporin build…

My PhD paper is in press @cellpress.bsky.social and now online: www.sciencedirect.com/science/arti...!

Contents: weird #NPCs in yeast and flies, #CLEM, in situ #cryoET and more!

Made possible by the amazing @becklab.bsky.social team at @mpibp.bsky.social and collaborators! #TeamTomo

Our first expansion microscopy results. Imaged today on "normal" Zeiss LSM 900, revealing chromatin and RNA polymerase II clusters at an unreal level of detail.

Our PhD student @mofrawe.bsky.social learned the protocol from amazing @mpownall.bsky.social 🙏

Months of preparation are paying off now!

Was tempted, but I'd rather not distract from the more-serious discussions posted this week 😂

A paper reports a new resolution regime: "true-atomic" resolution.

Looks like us structural cell biologists will have to be satisfied with false-atomic resolution for awhile.

Check out 🧐 our new preprint 📜:
www.biorxiv.org/content/10.1...
Congrats🎉 to @vasilgaisin.bsky.social and Corina Hadjicharalambous, who studied contractile injection systems directly in hot spring♨️ bacterial mats🦠
#microsky #teamtomo #Chloroflexota

Check out our new preprint on the discovery of a molecular switch in NAC that mediates nascent chain sorting on the ribosome and prevents mitochondrial protein mistargeting by SRP. A great collaboration with the Shan Lab @Caltech and the Qi Lab @UVA: www.biorxiv.org/content/10.1...

Sub-3 Å resolution protein structure determination by single-particle cryo-EM at 100 keV Cryoelectron microscopy (cryo-EM) has transformed structural biology by providing high-resolution insights into biological macromolecules. We report s…

Now out in Structure: Paper on high-resolution #cryoEM using the 100 kV Tundra cryo-TEM by Dimple Karia, Adrian Koh, @abhaykot.bsky.social, @lingboyu.bsky.social, @landerlab.bsky.social and many others. Happy to have contributed to this effort. Check it out:
www.sciencedirect.com/science/arti...

Global inhibition of deadenylation stabilizes the transcriptome in mitotic cells In the presence of cell division errors, mammalian cells can pause in mitosis for tens of hours with little to no transcription, while still requiring continued translation for viability. These unique...

New preprint! We solve a mystery you didn't know existed. Mitotic cells lack new transcription but require ongoing translation. Interphase mRNA half life is only 2-4 hrs. So how do cells arrest in mitosis for hours without depleting their transcriptomes?

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

And here it is now in print! www.cell.com/cell-reports...

With a front cover splash 😍

This seems like a really important paper comparing chromosome tracing methods, demonstrating that classical denaturing DNA-FISH and chromosome tracing leads to substantial distortion of 3D genome structure, likely due to the high-temperatures involved (70-90C):
www.nature.com/articles/s41...

Happy to share our latest work on the structure and assembly of holocentric kinetochores! Huge thanks to Ines for a very fruitful collaboration, Claudio for all the support, and congratulations to Christine and all co-authors!

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

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Cryo-EM structure of human telomerase dimer reveals H/ACA RNP-mediated dimerization Telomerase ribonucleoprotein (RNP) synthesizes telomeric repeats at chromosome ends using a telomerase reverse transcriptase (TERT) and a telomerase RNA (hTR in humans). Previous structural work showe...

Proud to share our work where we resolved a longstanding question regarding the existence of a human telomerase dimer and provided insights into its function. Led by 3 amazing lab members in collaboration with @yiliangding.bsky.social and @rdaslab.bsky.social.
www.science.org/doi/10.1126/...

CryoET tomogram with the gap junction (green), ribosomes (cyan) and microtubules (pink)

In our latest preprint on bioRxiv, we present the in situ structure of
the human gap junction at 14 Å resolution using cryo-ET.

The structure provides a blueprint for investigating how connexin
regulation shapes intercellular communication in health and disease.

Awesome! Congrats!

Excited and honored to be joining the EMBO Member community 🥳 Congratulations also to all the other newly elected members! -Martin

Whoever gets the resolution of raw tomograms to <10 Å within the sampled parts of Fourier space would probably deserve a Nobel. Or they'd get one anyway for the crazy new physics they discovered to achieve that.

Proposed cuts could have ‘catastrophic effect,’ 110 biomedical, health sciences industry leaders tell Congress Proposed cuts will have “a catastrophic effect on the advancement of biomedical and biotechnology capabilities in the United States,” more than 100 leaders of biomedical/health sciences companies tell...

Much appreciated support from biotech execs and investors 🙏

www.statnews.com/2025/06/27/b...

Truly honoured to be awarded a Lister Prize this year. I am grateful for all the lab members and collaborators for their amazing work in the last nearly 6 years. More exciting science to come with this support.

Pit stop for our Aquilos dewar got even easier with the 3D printed funnel from friendly Zurich team (shout-out to blueskyless Piotr Szwedziak)!

Very cool (pun intended)! Would you or Piotr be willing to share what kind of filament / resin is safe for cryogenic tools such as this one? Thanks!