Mark Pownall

Mark Pownall

@mpownall.bsky.social

https://pownall-lab.org | Sandler Fellow at UCSF | chromatin, transcription, microscopy (ChromExM), development 🐟🧬🔬

576 followers165 following9 posts

Honored to be among this year’s DP2 recipients

UCSF@ucsanfrancisco.bsky.social

Congratulations to four UCSF faculty named 2026 NIH New Innovators. Josiah Gerdts, Mark Pownall, Sakeen Kashem, and Balyn Zaro will each receive $2M+ over five years to pursue high-risk, high-reward research. https://ow.ly/9UGi50ZVFoy

❗Postdoc positions available! We have multiple fully funded openings in the lab - please reach out if you’re interested. I’ll be at CSHL Epigenetics and Chromatin this week, so come find me if you’d like to learn more about the lab or potential projects

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This could be because transcription promotes chromatin organization or RNA itself plays a role. We decoupled these possibilities by inhibiting nuclear RNA degradation, increasing nuclear RNA without increasing global Pol II elongation. This enhanced chromatin compaction without increasing H3K27me3.

Together, our results support a model where nuclear RNA is a major determinant of chromatin organization during development. Lots of open questions remain about mechanism, how this fits with Hi-C data, and how conserved it is across cell states. Feedback and discussion welcome! DM or email me

We started with improving ChromExM experimentally and computationally to reduce experimental burden and increase throughput (check out the supplement!). This enabled us to capture striking changes in chromatin organization from 3-6 hours post fertilization as embryos begin gastrulation

What drives this major reorganization of chromatin? Surprisingly, transcription inhibition prevents much of this emergent chromatin compaction, despite significantly increasing H3K27me3 and H3K9me3. Subtle differences in phenotype between inhibitors provide a clue More details in the paper!

Mark Pownall reposted

Next summer's Epigenetics GRC (I'm co-chairing with Deborah Bouch'is) is shaping up nicely with an all-star lineup of speakers working on a broad range of organisms and systems and everything from molecular mechanisms to new phenomena. Apply and put it on your calendar! www.grc.org/epigenetics-...

grc.org2027 Epigenetics Conference GRCThe 2027 Gordon Research Conference on Epigenetics will be held in Holderness, New Hampshire. Apply today to reserve your spot.

Mark Pownall reposted

Mark Pownall reposted

Our Mini Review went online last night in Current Opinion in Genetics & Development "Block copolymer concepts of how transcription organizes the stem cell genome" doi.org/10.1016/j.gd... Fig. 1: Stem cell–typical organization of the genome and transcription, and the block copolymer sorting concept.

Mark Pownall reposted

Mark Pownall reposted

Mark Pownall reposted

Mark Pownall reposted

First paper from the Pownall lab calls for a first post on bluesky! Check out our mini review on nanoscale imaging of the nucleus in vivo. We are excited to address some of these open questions and technical challenges through future work from the lab—stay tuned! portlandpress.com/biochemsoctr...

portlandpress.comMicroscopy methods for the in vivo study of nanoscale nuclear organizationEukaryotic genomes are highly compacted within the nucleus and organized into complex 3D structures across various genomic and physical scales. Organization within the nucleus plays a key role in gene...

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