Jakob Schnabl

piRNAs are essential for transposon silencing in the animal germline.
But how do hosts trap transposon sequences in genomic loci that help establish a piRNA response?

Looking at a natural transposon invasion, Baptiste Rafanel and Kirsten Senti made some remarkable observations.

Antisense transposon insertions into host genes trigger piRNA mediated immunity https://www.biorxiv.org/content/10.1101/2025.07.28.667215v1

Uncover the hidden power of a tiny protein - the ERVK3-1 microprotein - as it interacts with the HUSH complex, a key player in silencing parasitic genomic elements, shedding light on a po...

🧵 Thread below

Full analysis: https://helixbrief.com/article/aa18903a-395a-48df-be22-64c6cf0fd0be

Just 2 weeks left!

The Vienna BioCenter PostDoc Program is still accepting applications. We have 16 fully-funded fellowships available for researchers in biology, chemistry, physics, bioinformatics, and more.

Apply now: training.vbc.ac.at/post-docs/vi...

#VBCPostDoc

How DNA packaging controls the “genome’s guardian” Our cells tightly pack DNA into structures called nucleosomes, which protect DNA but also hide important sites. The key cancer-fighting protein p53 can still access these hidden sites, especially at n...

Our cells pack DNA into tiny bundles that hide important parts. Researchers at the FMI and EPFL found this packing affects how the cancer-fighting protein p53 works, revealing new insights into cancer. www.fmi.ch/news-events/...

last call!
submit your abstract by tonight to be selected for one of the many oral presentations at the leading European Transposon Meeting. We are very much looking forward to your contribution and attendance!

📢 Open Call! The Max Perutz Labs invite applications for a Tenure-Track Professorship in Mechanistic Cell and Developmental Biology. More details ➡️ tinyurl.com/3fbkp89c

A postdoc position in the Torben Heick Jensen lab, Aarhus University, Denmark: Mammalian Nuclear RNA Production and Turnover Systems - Ledig stilling på Aarhus Universitet Ledig stilling ved Institut for Molekylærbiologi og Genetik - RNA-biologi og -innovation, Aarhus Universitet

Second call for postdoc positions in the lab. Please follow the link below to apply or get in touch for further information.
mbg.au.dk/aktuelt/ledi...

Pls. share widely

Calling all transposon fans & lovers of genetic innovation

MOBILE GENOME welcomes you in Heidelberg, Nov. 4–7 2025

→ Vibrant & friendly community
→ Cutting-edge talks from mechanisms to physiology
→ Plenty of surprises (TEs never stop innovating)

submit abstract by July 29

We found a new asymmetry in the large-scale chromosome structure: sister chromatids are systematically shifted by hundreds of kb in the 5′→3′ direction of their inherited strands! The work was led by Flavia Corsi, in close collaboration with the Daniel Gerlich lab.
www.biorxiv.org/content/10.1...
1/

Preprint by the lab of Marc Bühler with first author Josip Ahel "Remodeling Activity of ChAHP Restricts Transcription Factor Access to Chromatin" @biorxivpreprint.bsky.social
buff.ly/mTYarjo
@aheljo.bsky.social
@marcbuhler.bsky.social
@fmiscience.bsky.social

A lovely graphic from The Allied Genetics Conference 2020 depicting the many model organisms that contribute to our understanding of science. https://genetics-gsa.org/drosophila-2025/professional-development/careers-at-tagc/

CONCLUSIONS:

To promote the best science being done, we need to look at the incentives of science publishing and funding. Long-term funding produces better science. Short-term and topical agendas encourages irreproducibility.

Funding model organisms generates science we can build on! 🪰🪱🦠🐠🐁🐸

6/6 🧵

The "reproducibility crisis" in science constantly makes headlines. Repro efforts are often limited. What if you could assess reproducibility of an entire field?

That's what @brunolemaitre.bsky.social et al. have done. Fly immunity is highly replicable & offers lessons for #metascience

A 🧵 1/n

Enhancer adoption by an LTR retrotransposon generates viral-like particles, causing developmental limb phenotypes - Nature Genetics Activation of an LTR retrotransposon inserted upstream of the Fgf8 gene produces viral-like particles in the mouse developing limb, triggering apoptosis and causing limb malformation. This phenotype c...

Finally out! 🥳 Our paper showing how a transposable element (TE) insertion can cause developmental phenotypes is now published @natgenet.nature.com 🧬🦠🐁
Below is a brief description of the major findings. Check the full version of the paper for more details: www.nature.com/articles/s41588-025-02248-5

Preprint by the lab of Marc Bühler with first author Jakob Schnabl-Baumgartner "ChAHP Silences SINE Retrotransposons by Inhibiting TFIIIB Recruitment" @biorxivpreprint.bsky.social
buff.ly/hAXKoZ3
@jakobschnabl.bsky.social
@marcbuhler.bsky.social
@fmiscience.bsky.social

Postdoc Research Group Schur The Schur lab at the Institute of Science and Technology Austria (ISTA) has an open postdoc position for a highly motivated candidate to be part of our ERC-funded project ActinID. Our Group ...

We're hiring a postdoc!
Join our ActinID project to explore an uncharacterized actin-binding protein.

- Background in cell and/or structural biology?
- Eager to bridge both fields?

Get in touch if you're curious or have questions!
#cellbiology #cryoEM #cryoET #actin

ista.ac.at/en/job/postd...

🧵 New preprint!
How does a chromatin remodeler know where to act?
In our latest study, we show how the transcription factor ADNP targets CHD4 remodeling activity to silence transposons and block CTCF.
👇 A thread on the ChAHP complex and how it weaves chromatin
🧬🔬🧵
www.biorxiv.org/content/10.1...

More ChAHP within the same week! Check out the work from @aheljo.bsky.social dissecting the molecular activities within the complex

preprint alert: www.biorxiv.org/content/10.1...

For more molecular dissection of ChAHP stay tuned for another preprint from the lab coming soon. Thanks to all the co-authors Especially Fabio, @xxxmichixxx.bsky.social and of course
@marcbuhler.bsky.social

💡 Taken together we establish ChAHP as a sequence specific regulator of POL III transcription, which is different from Maf1, a well-established POL III repressor which leads to global POL III repression.

🎯 ChAHP’s action is also very precise: We see only SINE transcription affected but other POL III transcripts, like tRNAs are not affected. This precision is fascinating as these elements share the same promoter architecture.

⚙️ The mechanism: ChAHP doesn't prevent TFIIIC from binding SINEs. Instead, it blocks the next step - TFIIIB recruitment. Think of it as letting someone find the door (TFIIIC) but hiding the key (TFIIIB) needed to open it.

🔍 How do cells silence thousands of SINEs without affecting normal genes? We tested the usual suspects (DNA methylation, heterochromatin) but they had no effect. Then we tested ChAHP and within one hour of ChAHP removal SINEs are up regulated! We use mESCs as a model to study SINE regulation.

🧬 Large proportions of genomes come from "jumping genes" - DNA sequences that can copy themselves. SINEs are a special kind of transposons. They are: Short DNA sequences (~200bp) that use POL III for their transcription and still actively transpose!

ChAHP Silences SINE Retrotransposons by Inhibiting TFIIIB Recruitment Short interspersed nuclear elements (SINEs) are abundant non-autonomous transposable elements derived from RNA polymerase III (POL III)-transcribed short non-coding RNAs. SINEs retain sequence feature...

📖 Happy to share our recent preprint! www.biorxiv.org/content/10.1... We discovered how SINEs are kept silent: the ChAHP protein complex acts as a molecular brake on POL III transcription retrotransposons. A 🧵:

MORC2 directs transcription-dependent CpG methylation of human LINE-1 transposons in early neurodevelopment Methylation of CpG dinucleotides is essential for silencing genomic repeats such as LINE-1 retrotransposons (L1s) in the germline and soma. Evolutionarily-young L1s are transcribed in human pluripoten...

Very proud of this work where we define how the MORC2 ATPase directs CpG methylation of active human L1 transposons in early development.

Thanks to co-authors, funders & wonderful environment @lundstem.bsky.social

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

Brief thread below (do people still do that?) 1/X

🆕 publication! Cells don’t just fight infection - they fine-tune their immune response. A new study from the Versteeg lab in @narjournal.bsky.social led by Adrian Söderholm uncovers how RNA processing of JAK2 helps regulate immune signals ➡️ tinyurl.com/2py27c8u
@univie.ac.at
@meduniwien.ac.at