biostudies-literatureHsueh BYNIAID NIH HHSMichigan State UniversityU.S. Department of Health & Human Services | National Institutes of HealthNIGMS NIH HHSNational Science Foundation1210-1220https://www.ebi.ac.uk/biostudies/studies/S-EPMC9830645biostudies-literatureUnknown7(8)Vibrio cholerae biotype El Tor is perpetuating the longest cholera pandemic in recorded history. The genomic islands VSP-1 and VSP-2 distinguish El Tor from previous pandemic V. cholerae strains. Using a co-occurrence analysis of VSP genes in >200,000 bacterial genomes we built gene networks to infer biological functions encoded in these islands. This revealed that dncV, a component of the cyclic-oligonucleotide-based anti-phage signalling system (CBASS) anti-phage defence system, co-occurs with an uncharacterized gene vc0175 that we rename avcD for anti-viral cytodine deaminase. We show that AvcD is a deoxycytidylate deaminase and that its activity is post-translationally inhibited by a non-coding RNA named AvcI. AvcID and bacterial homologues protect bacterial populations against phage iNature microbiologyPhage defence by deaminase-mediated depletion of deoxynucleotides in bacteria.PMC9830645AI143098R41 AI143098R35 GM139537R01 GM110444GM109259R01 GM110185R01 AI158433GM139537GM1104441842399R01 GM109259AI158433DBI-0939454GM1101851750125Elg CANeiditch MBHsueh BYParent KNRidenhour BJTop EMWaters CMSeverin GBWessel AJRavi JKant ADover JAWaldron EJRhoades CRfalsePhage defence by deaminase-mediated depletion of deoxynucleotides in bacteria.Vibrio cholerae biotype El Tor is perpetuating the longest cholera pandemic in recorded history. The genomic islands VSP-1 and VSP-2 distinguish El Tor from previous pandemic V. cholerae strains. Using a co-occurrence analysis of VSP genes in >200,000 bacterial genomes we built gene networks to infer biological functions encoded in these islands. This revealed that dncV, a component of the cyclic-oligonucleotide-based anti-phage signalling system (CBASS) anti-phage defence system, co-occurs with an uncharacterized gene vc0175 that we rename avcD for anti-viral cytodine deaminase. We show that AvcD is a deoxycytidylate deaminase and that its activity is post-translationally inhibited by a non-coding RNA named AvcI. AvcID and bacterial homologues protect bacterial populations against phage i2022-01-01T00:00:00Z2022 Aug2026-06-04T05:49:38.779Z2025-04-19T13:31:48.829ZS-EPMC98306453581789010.1038/s41564-022-01162-4