Improved vector toolkit for genome writing in mammalian cells
www.biorxiv.org/content/10.6...
Posts by The Dark Matter Project
Mammalian genome writing: Unlocking new length scales for genome engineering
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Happy to share that our review on mammalian genome writing with Jack Atwater, Ran Brosh, Jef Boeke, @jshendure.bsky.social and Matt Maurano is now out in @cellpress.bsky.social!
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๐งฌSign up to our free online 2026 Genome Writing Workshop ๐งฌ
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www.biorxiv.org/content/10.6...
Congrats to Dr. Noor Chalhoub who managed to defend her thesis and publish this paper on the same day!
Enhancer cooperativity in the folded genome www.sciencedirect.com/science/arti...
Structure and evolution-guided design of minimal RNA-guided nucleases www.biorxiv.org/content/10.6...
Did it work?
Hell yeah!
Read our two companion preprints to learn more:
bsky.app/profile/dark...
This recombination fuses mouse Taf1's exons 1-24 with human TAF1's exons 25-38 to form a fully functional gene that encodes mouse TAF1 protein. The recombination also removes all marker cassettes, making the final "converted" allele scarless.
The final step of engineering is what we call "conversion". It includes introducing Cre enzyme that induces recombination between the 1st loxP site in mouse Taf1 intron 24, and a 2nd loxP site located in human TAF1 intron 24.
This feat of engineering was performed using a variant of a method we recently published called mSwAP-In (mammalian switching antibiotic resistance markers progressively for integration).
www.nature.com/articles/s41...
Next, we engineered mouse embryonic stem cells (mESCs), first with a loxP site in Taf1's intron 24, followed by integration of a marker cassette (a landing pad) downstream of the gene, and finally we replaced this cassette with the 78-kb human fragment.
Using CREEPY (CRISPR-mediated editing of synthetic episomes in yeast) we've substituted every amino acid that is different between humans and mice so that the expressed protein would be identical to mouse TAF1.
doi.org/10.1093/nar/...
But we were worried that the human TAF1 protein would be incompatible when expressed in mice (TAF1 is the largest subunit of the TFIID complex, a large protein group that is essential for initiating transcription of most genes).
We assembled this region from an XDP patient-derived BAC, using the superpower of S. cerevisiae (yeast), into a delivery-ready vector.
The pathogenic SVA insertion is in TAF1's intron 32, but we wanted to generate a partially humanized mouse model, and decided to include a 78 kb human region that spans TAF1 exons 25-38, including all intervening introns and the SVA.
Our solution? A "hybrid-convertible" allele:
This is the problem we had to tackle when we engineered the first mouse model of X-linked Dystonia Parkinsonism, a disease caused by an SVA (SINE-VNTR-Alu) retrotransposon insertion in the essential TAF1 gene.
The answer is quite simple of course: make it conditional.
But what if the lethality is induced by a 2.7 kb retrotransposon insertion into an X-linked gene? How would you CONDITIONALLY introduce this element?
How could one engineer a mouse carrying a LETHAL allele? A thread ๐งต
One step closer to an LLM that understands novel DNA๐งฌ
๐๐๐ฒ๐ฟ๐ฎ๐๐ถ๐๐ฒ ๐ถ๐บ๐ฝ๐ฟ๐ผ๐๐ฒ๐บ๐ฒ๐ป๐ ๐ผ๐ณ ๐ฑ๐ฒ๐ฒ๐ฝ ๐น๐ฒ๐ฎ๐ฟ๐ป๐ถ๐ป๐ด ๐บ๐ผ๐ฑ๐ฒ๐น๐ ๐๐๐ถ๐ป๐ด ๐๐๐ป๐๐ต๐ฒ๐๐ถ๐ฐ ๐ฟ๐ฒ๐ด๐๐น๐ฎ๐๐ผ๐ฟ๐ ๐ด๐ฒ๐ป๐ผ๐บ๐ถ๐ฐ๐.
pubmed.ncbi.nlm.nih.gov/41125441
Congrats Andre Ribeiro-Dos-Santos and Matt Maurano!
I am proud to share our work on X-linked Dystonia-Parkinsonism โ a rare neurodegenerative movement disorder driven by a SINE-VNTR-Alu retrotransposon insertion in the TAF1 gene.
Read our two companion papers:
๐น www.biorxiv.org/content/10.1...
๐น www.biorxiv.org/content/10.1...
๐งต Highlights below!
Congrats to all authors, including Yu (Jeremy) Zhao, Ran Brosh, @liddelowsa.bsky.social, @jefboeke.bsky.social, Cris Bragg and others. This work was primarily funded by the Collaborative Center for XDP and NHGRI's CEGS program.
In the 2nd preprint @pryprk.bsky.social et al. describe deep behavioral and histological analysis of XDP mice and reveal a surprising myelin pathology.
www.biorxiv.org/content/10.1...
In the 1st preprint Zhang et al. describe the engineering of the first XDP mouse model and the splicing defects induced by the presence of a pathogenic intronic SVA retrotransposon.
www.biorxiv.org/content/10.1...
We're thrilled to publish 2 exciting preprints today on the molecular pathology of X-linked Dystonia Parkinsonism!
biorxiv.org/content/10.1...
AND
biorxiv.org/content/10.1...
@nyulangone.bsky.social
Megabase-scale human genome rearrangement with programmable bridge recombinases | Science www.science.org/doi/10.1126/...
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