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Edda Schulz @eddaschulz.bsky.social · 20/01/2026

⚒️ Through constructing a synthetic antisense locus, Verena then showed that gene repression, induced by antisense transcription can be stable for several days, when ESCs differentiate.

Top: scheme of synthetic antisense locus; bottom: experimental setup where a Dox pulse induces antisense-mediated repression that leads to a sustained down-regulation of the sense gene.

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Edda Schulz @eddaschulz.bsky.social · 20/01/2026

🧬 Till then found experimental evidence for promoter-repression by antisense transcription through a genome-wide analysis of nascent transcription during ESC differentiation. Here promoter-overlapping antisense pairs show mutual exclusive expression.

genome browser tracks of nascent transcription of the region surrounding the Nfatc4 gene for 3 time points: at day 0 transcription mostly comes from an antisense transcript, which disappears at day 4, where the Nfatc4 gene now is transcribed.

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Edda Schulz @eddaschulz.bsky.social · 20/01/2026

💻 Through extensive stochastic simulations 📈 Verena showed that (convergent) antisense transcription ➡️⬅️ can store stable memory, if antisense txn goes through the gene promoter and induces a stable repressed state.

Scheme of convergent antisense locus and scheme of expression memory where one antisense partner is high and the other one is low until they switch and memory is lost.

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Edda Schulz @eddaschulz.bsky.social · 17/11/2025

📣 SAVE THE DATE Next X-inactivation meeting in Sapporo, Japan, 19-23 October 2026. Visit x-inactivation-meeting.org to join our mailing list. 🧬 speakers @dandergassen.bsky.social @marnieblewitt.bsky.social @heard65.bsky.social @crougeulle.bsky.social @sexchrlab.bsky.social @zhouqi1982.bsky.social

Poster advertising the 6th X-inactivation meeting from Oct 19-23 2026 in Sapporo, Japan. The organizers are Asato Kuriowa, Edda Schulz, Ikuhiro Okamoto, Rafael Galupa, Takashi Sado, Mitinori Saitou.

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Edda Schulz @eddaschulz.bsky.social · 06/10/2025

🎯 Why It Matters: High Xist Levels are required for silencing the entire chromosome. 🎛️ Using CasTuner and enhancer deletions we show that Xist expression and silencing efficiency are dose-dependent 📈: reduced Xist RNA = impaired X-chromosome silencing

$Violin plots showing the fraction of X-linked reads coming from the inactive X as a function of Xist expression level. The plot shows that lower Xist expression results in weaker X-chromosome silencing.$

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Edda Schulz @eddaschulz.bsky.social · 06/10/2025

🔹 Phase 2 (High-Level Boost): Late TFs activate distal enhancers → They drive high Xist RNA levels needed for robust silencing.

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Edda Schulz @eddaschulz.bsky.social · 06/10/2025

The Xist switch has two distinct phases: 🔹 Phase 1 (Binary ON/OFF): Early TFs target proximal regulatory elements → They sense X-chromosome number (XX vs XY) to trigger initial Xist upregulation—ensuring female-specific activation.

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