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Posts by Jan Soroczynski

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A small polymerase ribozyme that can synthesize itself and its complementary strand The emergence of a chemical system capable of self-replication and evolution is a critical event in the origin of life. RNA polymerase ribozymes can replicate RNA, but their large size and structural ...

How could a simple self-replicating system emerge at the origins of life? RNA polymerase ribozymes can replicate RNA, but existing ones are so large that their self-replication seems impossible. Could they be smaller?

Excited to share our latest work in @science.org on a new small polymerase.
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2 months ago 500 210 10 28

Interested in transcriptional regulation, enhancers and 3D genome folding?

In this new study we wondered about the role of cohesin loading at enhancers for long-range transcriptional control

www.biorxiv.org/content/10.6...

detailed 🧵👇

2 months ago 67 33 1 3
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Happy to share part of my postdoctoral work at the @lucas.farnunglab.com lab. Great collaboration with @voslab.org and @andersshansen.bsky.social. “Structural basis for CTCF-mediated chromatin organization” www.biorxiv.org/content/10.6...

2 months ago 30 10 0 0
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🧪🧬New preprint We present cryo-EM structures of reconstituted CTCF–nucleosome complexes, showing CTCF dimerization drives nucleosome oligomerization into defined higher-order assemblies. Disrupting CTCF–CTCF interfaces in mESCs reduces looping and impairs differentiation. tinyurl.com/CTCF-nucleos...

2 months ago 124 52 4 3

I’m very pleased to share our work looking at what controls condensin II cell-cycle dependant activity; a great collaboration with @eugenekimlab.bsky.social, @damlatetiker.bsky.social, Kyle Muir and Kumiko Samejima
www.biorxiv.org/content/10.6...

2 months ago 28 12 2 0
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Hybrid female sterility due to cohesin protection errors in mouse oocytes Misregulation of chromosome cohesion during female meiosis serves as a reproductive isolating barrier in mice.

Another announcement! 📣 Our work on hybrid incompatibility in cohesin protection in 🐭oocytes is published!! Congrats Warif El Yakoubi and Eddie Pan!!🎉 We found hybrids with cohesion errors in two distinct genus.
www.science.org/doi/10.1126/...

2 months ago 48 24 3 0
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Not something you see in textbooks very often: tripolar mitosis.

2 months ago 1572 274 49 22
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Our new preprint on SMCHD1! We’ve shown SMCHD1’s ATPase activity is critical for function in vivo, and excitingly a new DNA binding domain neighbouring the ATPase domain activates the enzymatic function, which is important for normal chromatin binding.
urldefense.com/v3/__https:/...

2 months ago 33 14 1 1
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Live-cell single-molecule dynamics of eukaryotic RNA polymerase machineries Eukaryotic gene expression is orchestrated by RNA polymerases (RNAPI, II, and III) and associated factors, yet their real-time dynamics remain obscure. Using single-molecule tracking in living yeast, ...

🧬🔬🎥 @science.org Live-cell single-molecule dynamics of eukaryotic RNA polymerase machineries | Science www.science.org/doi/10.1126/...

2 months ago 49 17 0 0

Cognitive decline in aging parasitoid wasps www.biorxiv.org/content/10.64898/2026.02...

2 months ago 2 1 0 0
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I’m thrilled to share our latest preprint! Inspired by isothermal Gibson assembly cloning, we wondered whether we could assemble and integrate DNA sequences at a specific genomic locus in human cells. A thread (1/7) www.biorxiv.org/content/10.1...

10 months ago 6 1 1 2
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The eukaryotic replisome intrinsically generates asymmetric daughter chromatin fibers DNA replication is molecularly asymmetric, due to distinct mechanisms for lagging and leading strand DNA synthesis. Whether chromatin assembly on newly replicated strands is also asymmetric remains un...

Some (+)ve news to lighten another heavy weekend: our latest preprint (c/o Mattiroli + Ramani labs) is up!
www.biorxiv.org/content/10.1...
A tour-de-force by 1st authors Bruna Eckhardt & @palindromephd.bsky.social, focusing on chromatin replication. RTs welcome; tweetorial in 3,2...(1/n)

7 months ago 77 41 2 2
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Induction of menstruation in mice reveals the regulation of menstrual shedding During menstruation, an inner layer of the endometrium is selectively shed, while an outer, progenitor-containing layer is preserved to support repeated regeneration. Progress in understanding this co...

I’m thrilled to share my postdoc work and the first paper from the McKinley Lab! 🎉
@karalmckinley.bsky.social
We built the first transgenic model of menstruation in mice.
We used it to uncover how the endometrium organizes and sheds during menstruation. 🧪
www.biorxiv.org/content/10.1...
🧵

6 months ago 232 83 14 15
Millions of years ago during the Silurian period, the Sahara Desert was a shallow sea full of aquatic animals like crinoids. Don’t be fooled! Crinoids are commonly called "sea lilies" but they aren't plants! They are echinoderms, like starfish and sea urchins, and many species are still alive today!

Millions of years ago during the Silurian period, the Sahara Desert was a shallow sea full of aquatic animals like crinoids. Don’t be fooled! Crinoids are commonly called "sea lilies" but they aren't plants! They are echinoderms, like starfish and sea urchins, and many species are still alive today!

Millions of years ago during the Silurian period, the Sahara Desert was a shallow sea full of aquatic animals like crinoids. Don’t be fooled! Crinoids are commonly called "sea lilies" but they aren't plants! They are echinoderms, like starfish and sea urchins, and many species are still alive today!

2 months ago 64 10 0 0

Re-analysis of human population-scale whole genome seq data elucidates genetic architecture of EBV DNA persistence, a framework for the broader human virome
@nature.com @caleblareau.bsky.social @sherrynyeo.bsky.social @erinmayc.bsky.social @ryandhindsa.bsky.social
www.nature.com/articles/s41...

2 months ago 19 5 2 0
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AlphaGenome is out in @nature.com today along with model weights! 🧬

📄 Paper: www.nature.com/articles/s41...

💻 Weights: github.com/google-deepm...

Getting here wasn’t a straight path. We discussed the story behind the model, paper & API in the following roundtable: youtu.be/V8lhUqKqzUc

2 months ago 84 40 4 1
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Have you wondered how the rules of chromatin folding have evolved? Well, this task is not easy to formalize. But here is our take on it: train species-specific DNA-to-chromatin encoder, apply to DNA of unseen species, and build chromatin rules-based tree of life. Have a look:
doi.org/10.1093/nar/...

2 months ago 19 8 0 0
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I’m happy to share the main result of my PhD, which you can find on bioRxiv www.biorxiv.org/content/10.6.... If you are interested in learning about a new way to perform DNA-PAINT multiplexing, which we call Combi-PAINT, or if you are interested in the study of mRNA conformation, keep reading! 1/10

2 months ago 74 26 3 5
screenshot of visualization from a weather site of projected snow and ice quantities. The ranges around 30 inches of snow and 0.5 inches of ice cover the same colors.

screenshot of visualization from a weather site of projected snow and ice quantities. The ranges around 30 inches of snow and 0.5 inches of ice cover the same colors.

I love how this graphic is totally unhelpful for determining whether you're going to get 30 inches of snow or half an inch of ice.

2 months ago 4899 444 371 75

Protein purification has been getting miniaturized! Hands on experience can be like doing a plasmid mini prep 😅

2 months ago 1 0 1 0
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I’ve actually gotten it down to midiprep-scale purification on the benchtop, just with magnetic StrepTactin or GFP nanobody resin (didn’t manage to squeeze that into the paper). Happy to talk more if you’d like to try it!

2 months ago 2 0 1 0

Thanks Anton! Curious what you make of the ligation-gating model in the supplementary note.

2 months ago 0 0 0 0
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Seeing into Hi-C: How our scientific connectivity revealed the close connections in our DNA to be a work of art Scientific data can be beautiful. An example where the data itself have a particularly striking appearance even before any scientific meaning has been ascribed

I had the privilege to meet artist Mary Griffiths. Mary got inspired by Hi-C maps and over zooms we spoke about Hi-C maps, patterns and drawings. Mary’s Hi-C inspired art has been exhibited eg the Royal Academy. We wrote this piece about this art-science collaboration

pubs.aip.org/aip/bpr/arti...

2 months ago 31 10 1 0

Preprint alert: Jiangyuan Liu developed a new workflow for chromatin loop calling across Hi-C datasets, e.g., during differentiation. Most loops are shared between datasets/cell states. Important work for all interested in chromatin loops and how to identify them!

www.biorxiv.org/content/10.6...

3 months ago 26 16 0 0

Chromatin fatigue: DNA repair alters the chromatin environment and introduces heritable variation in gene expression in a larger region around the lesion! Amazing achievement by @sbantele.bsky.social and Jiri Lukas published in @science.org 🙌 Happy we could contribute. See 👇

5 months ago 39 10 0 0
CAD-C: An engineered nuclease enables repair-free in situ proximity ligation and nucleosome-resolution chromosome walks in human cells Chromosome conformation capture (3C)-derived methods have become an indispensable tool in the study of gene regulation. The three-dimensional contacts they are able to assay depend strongly on the properties of the enzyme used to fragment chromatin prior to proximity-driven ligation. Micrococcal nuclease (MNase), used in Micro-C, increases resolution at the expense of low ligation efficiency and the need for extensive enzyme titration. To overcome these limitations, we engineered a highly active, TEV protease-activatable caspase-activated DNase (CAD) to enable an efficient, low-sequence-bias, and high-resolution proximity ligation assay we call CAD-C. CAD-C was successful on the first attempt for each human cell line tested and the resulting datasets capture loops, TADs, compartments, and stripes similarly to Micro-C. However, compared to Micro-C and Hi-C, CAD-C shows enhanced sensitivity for promoter-enhancer loops. Leveraging the ligation-competent DNA ends produced by CAD cleavage, we show that CAD-C is compatible with a highly streamlined, repair-free protocol and produces multi-step CADwalks, consecutive ligations between nucleosomal or sub-nucleosomal fragments. With these walks, we probe local chromatin fiber folding contacts, nucleosomal and sub-nucleosomal footprints, and long-range nuclear organization regimes in human cell lines. CAD-C is an efficient, robust chromatin structure assay that can span sub-nucleosomal to chromosomal length scales in a single experiment. ### Competing Interest Statement V.I.R. and J.S. are inventors on a related patent application covering CAD-C (PCT application filed 2024). NIH Common Fund, https://ror.org/001d55x84, 1DP2GM150021 Irma T. Hirschl Trust, https://ror.org/01yaqvf46, Career Scientist Award Rita Allen Foundation, https://ror.org/0515k5w36, Scholar Award Stavros Niarchos Foundation, https://ror.org/0210rze73, Institute for Global Infectious Disease Research at Rockefeller University Grant Robertson Technology Development Fund at Rockefeller University Boehringer Ingelheim (Germany), https://ror.org/00q32j219, PhD Fellowship to JS U.S. National Science Foundation, https://ror.org/021nxhr62, GRFP to LAW International Human Frontier Science Program Organization, https://ror.org/02ebx7v45, Postdoctoral Cross-Disciplinary Fellowship to AO Natural Sciences and Engineering Research Council of Canada, Postgraduate fellowship to HC, Postgraduate fellowship to JLY

Preprint: doi.org/10.64898/202...
Huge thanks to the Risca Lab @riscalab.bsky.social and collaborators @laurenands.bsky.social @1001hak.bsky.social, @erichjarvis.bsky.social VGL 🙏
Also see independent CAD-C work in yeast from @axeldelamarre.bsky.social (Whitehouse lab, MSKCC).
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2 months ago 1 2 0 0
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At CTCF boundaries, walk polarity is asymmetric between flanking nucleosomes—biased toward the loop interior. Consistent with directional cohesin extrusion, resolved at nucleosome scale. CADwalks span sub-nucleosomal to chromosomal scales in a single assay.
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2 months ago 0 0 1 0
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Analyzing fragment order in CADwalks, we find shuttling at long range – consecutive steps that venture out and back. Fragments making distal contacts are enriched for active regulatory chromatin. We also probe local fiber folding and nucleosomal footprints.
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2 months ago 0 0 1 0
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This unlocks CADwalks: consecutive ligations between nucleosomal and sub-nucleosomal fragments, sequenced as intact concatemers. Each walk from a single nucleus. Reduced base-composition bias, no end repair.
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