Ralf Jansen

A consortium of group leaders from IMP, IMBA (Vienna BioCenter) and ISTA has been awarded an FWF Emerging Fields grant to study how germ cells safeguard and pass on genetic information across generations.

as always, beautiful mechanistic dissection by @86dominik.bsky.social @juliusbrennecke.bsky.social lab, taking advantage of genetics and genomics to get decisive insights into piRNAs! surprising how instructive U content is for piRNA biogenesis, but it makes total sense, the system is very clever! 🪰

The demystification of piRNA clusters

if you wonder how cells generate piRNAs specifically against transposons & you are looking for a weekend read

check out @86dominik.bsky.social's opus magna (or Dominik's great thread)

a shared project with the one and only Rippei Hayashi, lab alumnus & friend

How does the piRNA pathway solve the self vs. non-self problem? 🧬

Since piRNAs come from single-stranded RNA, how does the cell choose the right ones? For years, "piRNA clusters" were seen as THE privileged source. But are they really special and earmarked for biogenesis? (1/19)

Ulrich’s research will help advance our understanding of RNA biology & gene regulation, as well as how these mechanisms might be altered during viral infections & other diseases.
@hohmannulrich.bsky.social comes from the @impvienna.bsky.social / @imbavienna.bsky.social

www.imb.de/about-imb/ne...

@lorenzoorts.bsky.social previously worked as a postdoctoral fellow at @impvienna.bsky.social in Austria. She will establish a new lab at IMB to investigate how mRNA translation is activated in the early embryo. Welcome to IMB Laura! 💐

Read more here: www.imb.de/about-imb/ne...

Happy to see our study out! We define the sequence determinants for miRNA-target interactions in flies and provide a foundation for improving computational prediction of miRNA-mediated regulation in Drosophila.
www.nature.com/articles/s41...
#miRNA, @natcomms.nature.com, @rti-umasschan.bsky.social

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

High-resolution binding data of TFIID and cofactors show promoter-specific differences in vivo TFIID is instrumental in recognizing promoter sequences and initiating transcription, yet a cohesive understanding of how this complex interacts with and functions at different promoter types in vivo ...

The @zeitlingerlab.bsky.social is pleased to announce @sergio-gma91.bsky.social’s preprint “High-resolution binding data of TFIID and cofactors show promoter-specific differences in vivo” (www.biorxiv.org/content/10.6...).

TLDR; TFIID behaves differently depending on promoter type. More below:

Do transcriptional activators work on any promoter? Our data says no. 🙅‍♂️
Despite driving ~2/3 of mammalian genes, CpG island (CGI) promoters have remained a puzzle. We identified >50 activators that are exclusively compatible with this promoter class. 🧬

Very happy to share my postdoc work (on preprint), where we try to understand a long-standing transcription-silencing paradox, and uncovered a hidden RNA decay arm of nuclear piRNA pathway, see detailed threads quoted from @juliusbrennecke.bsky.social

Intrigued by a long-standing conundrum in small RNA biology—how nuclear Argonaute proteins silence transposons when they *need* target transcription for their own recruitment—we studied the piRNA pathway.

And found a hidden RNA-decay axis from Piwi to the RNA exosome.

Cohesin guides homology search during DNA repair using loops and sister chromatid linkages Accurate repair of DNA double-strand breaks (DSBs) is essential for genome stability, and defective repair underlies diseases such as cancer. Homologous recombination uses an intact homologous sequenc...

I am happy to share that my postdoctoral work in the @gerlichlab.bsky.social at @imbavienna.bsky.social is finally out 🎉!
Our study reveals how cohesin guides focused and accurate homology search.
Read more 👉 www.science.org/doi/10.1126/...
Follow along for key insights and updates! 🧵

Fantastic to see this out, Federico – congrats!

🪱 Selfish genes are everywhere and drive some of biology’s biggest innovations (CRISPR, antibody recombination, epigenetics). Yet almost no one asks the obvious question: how does a selfish gene begin? Our new manuscript uncovers how selfishness can emerge directly from the host genome.

Congrats to Dr. @julsportell.bsky.social
on her PhD! Her journey as a joint student (Brennecke/Our Lab) led to key insights into gene silencing. Paper: www.cell.com/molecular-ce.... Journey: www.viennabiocenter.org/about/news/t.... CP.

Finally out in @nature.com! We uncovered a mechanistic framework for a general and conserved mRNA nuclear export pathway. www.nature.com/articles/s41.... 1/

just in time for the opening of the @hohmannulrich.bsky.social group at @imbmainz.bsky.social
what started as a project on how cells export piRNA precursors, ended up as a tour de force in mRNA export. truly wonderful collaboration with @plaschkalab.bsky.social at the @viennabiocenter.bsky.social

New paper alert! Scientists in Julius Brennecke’s lab at IMBA and Clemens Plaschka’s lab at @impvienna.bsky.social solved a decade-old puzzle, uncovering how the information molecule mRNA travels from the cell’s nucleus to its periphery. More: https://imba.science/3Xl2hJ3

Wilkinson Lab We discover and study reverse transcriptases

The Wilkinson Lab is open for science! @mskcancercenter.bsky.social

🧬We'll be finding funky new RNA biology, mainly by looking at reverse transcriptases (i.e. the Best Enzymes In The World)🧬

annnd: I'm hiring - come join! Especially postdocs and PhD students - please get in touch (NYC is great)

What’s it like doing a PhD between two labs? In our latest Behind the Science, Júlia Portell i de Montserrat, shared PhD student in the Plaschka lab at the IMP and the Brennecke lab at @imbavienna.bsky.social, tells us more about her unusual but rewarding PhD journey: bit.ly/3IHXtdp

When transposons jump, genomes diverge - even in cultured cells.
I am happy to share our new preprint: a chromosome-scale genome assembly for Drosophila OSC cells, one of the key model systems in the piRNA field, especially for nuclear piRNA biology. 🧬🧵 (1/12)

Thrilled to share that I’ll be joining @imbmainz.bsky.social in February 2026 to start my own group!
We will explore new mechanisms in eukaryotic gene expression, leveraging ‘evolutionary play’ to uncover how regulation, repurposing, and hijacking shape RNA biology.
PhD positions available!

Molecular basis of polyadenylated RNA fate determination in the nucleus Eukaryotic genomes generate a plethora of polyadenylated (pA+) RNAs[1][1],[2][2], that are packaged into ribonucleoprotein particles (RNPs). To ensure faithful gene expression, functional pA+ RNPs, in...

How are RNAs sorted for export vs. degradation in the nucleus? In collaboration with @heick.bsky.social’s lab we (@clemensplaschka.bsky.social and @juliusbrennecke.bsky.social labs) discovered a direct mechanistic link between the export and decay machineries: www.biorxiv.org/content/10.1... (1/x)

I am excited to announce that I will be moving to IMB Mainz next year! The Winter call for the IPP PhD program is now open; if you are interested in maternal #mRNA regulation and #translation in early vertebrate development, please apply! Deadline: 16 October.

More info: www.imb.de/students-pos...

Love RNA biology?

Join us to explore the piRNA pathway with structural and genetic approaches (see 👇👇).

PhD student/postdoc position co-supervised by Clemens Plaschka & myself.

DM or email us if you’d like to know more!

@vbcscitraining.bsky.social @imbavienna.bsky.social @impvienna.bsky.social

My first first-author paper is out!🎉
Here we propose a model where a silencing complex, PIWI*, assembles on target RNAs to recruit effectors and shut down transposon activity.
Huge thanks to the Brennecke and Plaschka labs, especially Julius and Clemens, and all co-authors!

PIWI clade Argonautes are essential for transposon silencing. Without them, animals are sterile due to massive transposon activity.

But how does piRNA-guided target interaction translate into silencing?

PhD student Júlia Portell Montserrat has an intriguing answer

www.cell.com/molecular-ce...

Close inter-lab collaborations with shared PhD students and postdocs are the future!
Julia is the hero of this work, she is currently looking for postdoc labs …

Target RNA recognition drives PIWI∗ complex assembly for transposon silencing Portell-Montserrat et al. reveal that target RNA recognition by PIWI-piRNA complexes triggers the assembly of conserved PIWI∗ complexes, molecular platforms that recruit silencing effectors in both the nucleus and cytoplasm. This mechanism, conserved across animals, explains how piRNA pathways couple target recognition to transposon silencing.

Target RNA recognition drives PIWI∗ complex assembly for transposon silencing