Andrew Santiago-Frangos
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asantiagofrangos.bsky.social
Andrew Santiago-Frangos
@asantiagofrangos.bsky.social
Asst Prof @Penn. CRISPR Biology & Applications | DNA folding and Bacterial/Archaeal defense systems | Biochem & CryoEM | #NIHMOSAIC K99/R00.
https://web.sas.upenn.edu/sanfrango-lab/
Reposted by Andrew Santiago-Frangos
Please re-post:

Interested in chromatin and its evolution? Good news! There's still time to join us in beautiful Catalonia (9-12 Dec) to discuss eukaryotic, bacterial, archaeal, and viral chromatin and how it all hangs together meetings.embo.org/event/24-evo...

Abstract deadline: 30 September
EvoChromo: Evolutionary approaches to research in chromatin
Chromatin is the complex of DNA, RNA and protein that is found making up the chromosomes in eukaryotic cells. Chromatin is essential for proper genome function and is involved in chromosome segregati…
meetings.embo.org
September 8, 2025 at 11:14 AM
Reposted by Andrew Santiago-Frangos
PhD student @lainahall.bsky.social will be giving a talk about our measurements of FIB-milling damage in cryo-lamellae (with new data!) at M&M on Tuesday next week.
July 25, 2025 at 8:04 PM
Awesome structural biology with a unique Cas interference-adaptation supercomplex to understand how these systems adapt to phage infection!
'Structural insights into Cas9-mediated prespacer selection in CRISPR-Cas adaptation'
Check out our preprint on #bioRxiv on the #Cas9-Cas1-Cas2-Csn2 supercomplex involved in #CRISPR spacer acquisition: www.biorxiv.org/cgi/content/...
Thread below.
July 2, 2025 at 1:45 PM
Reposted by Andrew Santiago-Frangos
News from the world of pAgos:
We explored a distinct clade of short pAgos associated with HNH nuclease partners, which we named SPARHA, and discovered that they protect bacteria from phages and plasmids via abortive infection. Upon activation, SPARHA oligomerizes, forming filaments.
A long 🧵
April 7, 2025 at 1:03 PM
New cryo-EM ❄️🔬 structures shine light on key steps in CRISPR-based adaptive immunity!
Viral DNA binding to the Cas1-2/3 integrase induces a conformational change needed to recruit the integrase to the CRISPR.
We capture how CRISPR repeat is unwound to allow complete integration. Congrats Will + co!
June 22, 2025 at 7:41 PM
Reposted by Andrew Santiago-Frangos
Hello BlueSky! Inaugural post here from the Sternberg Lab. We're excited to share our latest work, in which we teamed up with the @WiedenheftLab to study how DRT9 reverse transcriptases provide antiviral immunity. Here’s what we found: www.biorxiv.org/content/10.1...
Protein-primed DNA homopolymer synthesis by an antiviral reverse transcriptase
Bacteria defend themselves from viral predation using diverse immune systems, many of which sense and target foreign DNA for degradation. Defense-associated reverse transcriptase (DRT) systems provide...
www.biorxiv.org
March 26, 2025 at 10:13 PM
Reposted by Andrew Santiago-Frangos
Scientists, now more than ever, need to explain their work to the public. Many years ago now, I gave a TEDMED talk about my lab’s research. 🧠 🧪 www.tedmed.com/talks/show?i...
How an ancient virus spread the ability to remember
Do you remember your oldest memory? Jason Shepherd clearly recalls a childhood filled with questioning the world around him, which naturally lead to a life of scientific discovery. As a Neurobiologist...
www.tedmed.com
February 11, 2025 at 8:43 PM
Reposted by Andrew Santiago-Frangos
Published on my birthday 🎉

Another paper in collaboration with @themaxwelllab.bsky.social

Phage reprogramming of Pseudomonas aeruginosa amino acid metabolism drives efficient phage replication
doi.org/10.1128/mbio...
🦠🧫🧪🧬
February 7, 2025 at 3:38 PM
Reposted by Andrew Santiago-Frangos
As my first on Bluesky post, I'm glad to announce my work on PFOA has been published! Please check it out! During our work we have uncovered a new mechanism which implicates PFOA in hyperandrogenism, as has been speculated in the past!
www.sciencedirect.com/science/arti...
December 2, 2024 at 6:38 PM
Reposted by Andrew Santiago-Frangos
Just because it's a homo-oligomer, don't assume it's symmetric! @benjabsnt.bsky.social & collaborators used cryo-EM to study the transthyretin (TTR) tetramer (55 kDa), shedding light on its misfolding pathways linked to amyloid disease. Now in peer-reviewed form: www.nature.com/articles/s41...
January 22, 2025 at 4:45 PM
Reposted by Andrew Santiago-Frangos
Here’s my spreadsheet of starter packs (>80!) related to broadly ‘mechanistic biology’ plus some intriguing extras

Complete with collective nouns

I’ve been tracking these but now can’t keep up

Hope it’s helpful

2/2

docs.google.com/spreadsheets...
@mjafreeman.bsky.social's BlueSky starter packs for 'mechanistic' biologists
docs.google.com
November 19, 2024 at 9:58 PM
Reposted by Andrew Santiago-Frangos
If you work on bacterial immune systems, this founding paper by Burroughs and Aravind is a must-read (and must-cite). pubmed.ncbi.nlm.nih.gov/32868406/
November 18, 2024 at 11:17 AM
Reposted by Andrew Santiago-Frangos
I started a list of MOSAIC scholars to help find and support each other. I'm sure I've missed many people, lmk if you want to be added!
go.bsky.app/9Ui711k
November 17, 2024 at 3:20 PM
Reposted by Andrew Santiago-Frangos
Bacterial DNA encapsidation by viruses and virus-like particles appears to be widespread in the microbiome with up to 5.4% of capsid-packaged DNA in the gut virome being of bacterial (non-prophage) origin.

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

2/2
Large scale capsid-mediated mobilisation of bacterial genomic DNA in the gut microbiome
Here, we present a novel approach to study packaging and mobilisation of bacterial DNA in complex microbial communities, such as the human gut microbiome, by viral or virus-like capsids. Transducing b...
www.biorxiv.org
November 17, 2024 at 10:41 PM
Reposted by Andrew Santiago-Frangos
Hello 👋🏼—I’m a first-gen college student from Puerto Rico & currently serve as an Associate Dean at a major medical center. I’ve dedicated my career to developing programs focused on recruiting/training STEM leaders. I’m passionate about mentoring & providing opportunities for all to thrive.
November 11, 2024 at 12:57 AM
Excited to be going to ABRCMS this year! Looking forward to meeting new (and old) friends and sharing work! :D
November 13, 2024 at 6:25 PM
📢I'm hiring a Postdoc to join me at Dept. of Biology at UPenn! We'll use bioinformatics 🖥️, biochem 🧪, and cryo-EM ❄️🔬, to study how CRISPR systems work & applications. Work on cool science with a supportive mentor!
I'm still building up my Bluesky profile, so Reposts are appreciated!!!
January 12, 2024 at 4:18 PM
The Santiago-Frangos lab is open and ready to do some exciting research on CRISPR biology and CRISPR applications! Ecstatic to be on UPenn's campus amongst such a supportive group of excellent scientists! 🤓
January 4, 2024 at 10:20 PM