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bioRxiv · 10.1101/2025.04.30.651551

Anoxia activates CRISPR-Cas immunity in the intestine

Campbell, I. W.·Basta, D. W.·Zingl, F. G.·Sullivan, E. J.·Doranga, S.·Waldor, M. K.
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Abstract

The natural context in which CRISPR-Cas systems are active in Enterobacteriaceae has remained enigmatic. Here, we find that the Citrobacter rodentium Type I-E CRISPR-Cas system is activated by the oxygen-responsive transcriptional regulator Fnr in the anoxic mouse intestine. Since Fnr-dependent regulation is predicted in ~41% of Enterobacteriaceae cas3 orthologs, we propose that anoxic regulation of CRISPR-Cas immunity is an adaptation that protects Enterobacteriaceae against threats arising from the intestinal microbiome.

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Campbell, I. W., Basta, D. W., Zingl, F. G., Sullivan, E. J., Doranga, S., Waldor, M. K.. 2025-04-30. Anoxia activates CRISPR-Cas immunity in the intestine. https://doi.org/10.1101/2025.04.30.651551

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