Kotaro Chihara

Our work on bacterial Schlafens in phage defense is out today @natmicrobiol.nature.com!

Check out the final version here:
rdcu.be/e7Bmz

We are looking for postdocs and students to expand our team! Official postings are coming soon.

Please reach out if you're interested!
#phage #phagesky #microsky

Bacterial Schlafen proteins mediate phage defence Nature Microbiology, Published online: 09 March 2026; doi:10.1038/s41564-026-02277-8This study highlights that Schlafens are ancient, mechanistically conserved immune effectors that mediate antiviral immunity in organisms ranging from humans to bacteria.

Out Now! Bacterial Schlafen proteins mediate phage defence #MicroSky

After >10 years of our lab studying bacterial cGAS-like enzymes, @hobbslabutah.bsky.social finally reconstitutes viral sensing in vitro and discovers how these ancient receptors sense phage protease enzymes to detect virion assembly and activate antiviral immunity

www.biorxiv.org/content/10.6...

Stunning new structural analysis and mechanism for Tmn anti-phage defense by @fnobrega.bsky.social

www.biorxiv.org/content/10.6...

Rapid modular evolution of antiviral repertoires in P2 phages and their P4 satellites: shuttling, swapping and mixing https://www.biorxiv.org/content/10.64898/2026.02.27.708500v1

Unraveling posttranscriptional regulatory networks in phage infection Phages employ sophisticated transcriptional regulatory networks to optimize replication. Recently, Silverman et al. used RIL-seq (RNA interaction by l…

Like bacteria, phages use sRNAs to regulate gene expression! Out today in @cp-trendsmicrobiol.bsky.social, @mvelascogomariz.bsky.social and I highlight a recent RIL-seq study from the @saharmelamed.bsky.social lab that looked into posttranscriptional regulation of lambda!

tinyurl.com/lambda-RIL-seq

1/5
Happy by a recent biorxiv pre-print about DARNA (PD-T7-3) anti-phage defense system. This system is activated by binding to ssDNA, presented by phage SSB, to cleave tRNA in the anti-codon loop.
www.biorxiv.org/content/10.6...

Two cartoon images of children with plasmids for faces about to fight. Commentators are saying "Plasmid-borne CRISPR-Cas systems provide significant defensive benefits" and "Yes, but toxin-antitoxin systems on competitor plasmids constrain the offensive CRISPR-Cas benefit"

Out now in @plosbiology.org : our big joint effort on the role of #CRISPR in plasmid competition. Read on for a really fun (I’m biased ok) analysis of how a defence system has new selective pressures when it’s mobile
journals.plos.org/plosbiology/... 1/6

Structure and mechanism of antiphage retron Eco2 Nature Structural & Molecular Biology - This study shows how the bacterial retron Eco2 defends against viruses. Phage nucleases trigger activation of Eco2, which cuts RNAs, shuts down protein...

1/6) Hot off the press @natsmb.nature.com 🔥! Jasnauskaite et al. reveal how the minimal bacterial retron Eco2 defends against #phage 🛡️. Phage nucleases trigger Eco2, which cuts RNA, shuts down protein production and stops phage replication 🦠🚫. #phagesky #immunity #microbiology #cryo-em rdcu.be/e4AyH

Molecular basis for anti-jumbo phage #immunity by AVAST type 5.

Avs5 detects an early jumbo‑phage activator and halts infection by rapidly hydrolyzing NAD+.

www.sciencedirect.com/science/arti... #phage #bacteriophage #MicroSky

My first paper from my undergraduate work is out today :)

A phage protein screen identifies triggers of the bacterial innate immune system Nature Microbiology, Published online: 16 January 2026; doi:10.1038/s41564-025-02239-6A library of 400 phage protein-coding genes is used to find a trove of antiphage systems, revealing systems that target tail fibre and major capsid proteins.

Out Now! A phage protein screen identifies triggers of the bacterial innate immune system #MicroSky

Happy to share our recent preprint:
"DNA-intercalating antiphage molecules trigger abortive infection through mutual destruction and synergize with bacterial immunity"

www.biorxiv.org/content/10.6...

@spp2330.bsky.social, @mibinet.bsky.social, @dfg.de @hhu.de @fzj.bsky.social

Phold's manuscript is now available @narjournal.bsky.social thanks to @susiegriggo.bsky.social @npbhavya.bsky.social @vijinim.bsky.social @linsalrob.bsky.social @martinsteinegger.bsky.social @milot.bsky.social @eunbelivable.bsky.social & others not on bsky #phagesky academic.oup.com/nar/article/...

Secret life of prophages: template-directed synthesis of DNA superstructures via prophage activation and rolling circle replication in bacterial biofilms Extracellular DNA (eDNA) plays crucial roles in biofilm formation and function, yet the role of bacteriophages (phages) in controlling eDNA synthesis, structure and activity remains obscure. Here, we ...

Secret life of prophages: template-directed synthesis of DNA superstructures via prophage activation and rolling circle replication in bacterial biofilms

bioRxiv by Gabriel Antonio S. Minero et al
with @thethormannden.bsky.social, Rikke Louise Meyer

www.biorxiv.org/content/10.6...

Only in Shenzhen: Science Nature coffee bar. If you’ve published in @science.org or @nature.com, they give you coffee for free. 100% real!

Very fascinating! can’t help wondering whether mimivirus tRNAs — together with its local translation compartment — might play a failsafe role against host immunity.

www.nature.com/articles/s41564-025-02234-x

RNA-triggered Cas12a3 cleaves tRNA tails to execute bacterial immunity - Nature Cas12a3 nucleases constitute a distinct clade of type V CRISPR–Cas bacterial immune systems that preferentially cleave the 3′ tails of tRNAs after recognition of target RNA to induce growth arres...

Our paper is out! Hiding in plain sight among Cas12a nucleases, Cas12a3 cleaves not its RNA target but the 3′ ends of tRNA. Huge thanks to all who made this possible, especially the Beisel lab, Biao & Dirk for the structure, & @sebastianglatt.bsky.social for all things tRNA. doi.org/10.1038/s415...

Diverse bacterial pattern recognition receptors sense the conserved phage proteome Recognition of foreign molecules inside cells is critical for immunity in all domains of life. Proteins of the STAND NTPase superfamily, including eukaryotic nucleotide-binding oligomerization domain ...

A systematic analysis of STAND NTPases and their associated sensor domains in bacterial immunity 🤯 Mind-blowing work !

Phage-encoded small RNA hijacks host replication machinery to support the phage lytic cycle Using RIL-seq, Silverman et al. map the RNA interactome of E. coli during phage lambda infection and uncover a conserved phage-encoded sRNA that activates host replication machinery. Their findings re...

Do viruses use RNA to rewire bacteria?
Yes!
In our paper in @cp-molcell.bsky.social RIL-seq reveals interkingdom RNA interactions during λ infection. Phages don’t just encode proteins, they use small RNAs to hijack bacterial replication and fine-tune infection.
#RNA #Phage
doi.org/10.1016/j.mo...

Phages are full of genes of unknown function that are likely adaptive in specific conditions.
New preprint: Phage TnSeq identifies essential genes rapidly and knocks all non-essentials. We would like to send a pool of phiKZ mutants to anyone wanting it! Reach out
tinyurl.com/bdcfrejh

Releases · tseemann/abricate :mag_right: :pill: Mass screening of contigs for antimicrobial and virulence genes - tseemann/abricate

💾 ABRicate 1.2.0 has been released!

This 'oversight' lasted 6 years, but with help from @finlaym.bsky.social we got CI working and updated all the databases. #bioconda #conda #bioinformatics #microbiology #genomics

github.com/tseemann/abr...

Cohesin drives chromatin scanning during the RAD51-mediated homology search Cohesin folds genomes into chromatin loops, the roles of which are under debate. We found that double-strand breaks (DSBs) induce de novo formation of chromatin loops in human cells, with the loop bas...

Thrilled to share that my postdoc research is published today in @science.org! We found that DNA repair uses cohesin complexes to build new chromatin loops that guide the homology search and boost accurate repair! 1/n
www.science.org/doi/10.1126/...

Preprint: Systematic discovery of TIR-based immune signaling systems in bacteria

Conservation of TIR-derived signals accross the tree of life! We found bacterial TIR immune systems that signal via canonical cADPR (like in humans) and 2'cADPR (a plant immune signal).

Documented 11 Thoeris types

Structural mechanism of the Retron-Eco7 anti-phage defense system - Nature Communications The Retron-Eco7 is a genetic element involved in anti-phage defense that encodes two effector proteins (PtuA and PtuB) and cleaves the host tRNA. Here, the authors solved the Retron-Eco7 complex struc...

www.nature.com/articles/s41...

Structural mechanism of the Retron-Eco7 anti-phage defense system

Check this out for the 2026 SISB (phage defense) meeting in NYC. Mark your calendar! (and note the Zoom option, if needed)
sisb2026.rockefeller.edu

Our SPARHA story is out in Nature Communications!
doi.org/10.1038/s414...
We investigated a new short pAgo-HNH defense system, showing that it assembles into filaments degrading cellular DNA, inducing abortive infection, resolved their structure, and uncovered the activation mechanism 🧵

🧬🛡️How are new immune mechanisms created?

We show how Lamassu antiphage system, originated from a DNA-repair complex and evolved into a compact and modular immune machine, wt Dinshaw Patel lab in @pnas.org.
👏 @matthieu-haudiquet.bsky.social, Arpita Chakravarti & all authors!

doi.org/10.1073/pnas...

⭐ NAR Breakthrough! ⭐
🔬 New study reveals how the Retron-Eco7 system helps bacteria sense and fight phage attacks, identifying a clever immune-sensing mechanism in the bacteria–phage arms race.
🧬 Read more: doi.org/10.1093/nar/...
#NARBreakthrough #Microbiology #PhageBiology #BacterialDefense

KlebPhaCol paper is now out! Go check it out and see all that we offer.

And when ready, visit our website for more: www.klebphacol.org