Discovery of Functional Toxin/Antitoxin Systems in Bacteria by Shotgun Cloning

Hila Sberro, Azita Leavitt, Ruth Kiro, Eugene Koh, Yoav Peleg, Udi Qimron, Rotem Sorek*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

112 Scopus citations


Toxin-antitoxin (TA) modules, composed of a toxic protein and a counteracting antitoxin, play important roles in bacterial physiology. We examined the experimental insertion of 1.5 million genes from 388 microbial genomes into an Escherichia coli host using more than 8.5 million random clones. This revealed hundreds of genes (toxins) that could only be cloned when the neighboring gene (antitoxin) was present on the same clone. Clustering of these genes revealed TA families widespread in bacterial genomes, some of which deviate from the classical characteristics previously described for such modules. Introduction of these genes into E. coli validated that the toxin toxicity is mitigated by the antitoxin. Infection experiments with T7 phage showed that two of the new modules can provide resistance against phage. Moreover, our experiments revealed an " antidefense" protein in phage T7 that neutralizes phage resistance. Our results expose active fronts in the arms race between bacteria and phage.

Original languageEnglish
Pages (from-to)136-148
Number of pages13
JournalMolecular Cell
Issue number1
StatePublished - 11 Apr 2013


FundersFunder number
ERC-StG program260432
National Institutes of Health
National Institute of Allergy and Infectious DiseasesR01AI082376
Leona M. and Harry B. Helmsley Charitable Trust
Iowa Science Foundation1303/12
Deutsche Forschungsgemeinschaft


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