A prophage-encoded abortive infection protein preserves host and prophage spread

HepS, encoded by the Gifsy-1 prophage in Salmonella enterica serovar Typhimurium, detects infection by Siphoviridae phages and cleaves tRNA anticodon loops to halt phage replication. Gifsy prophages evade self-targeting through a tail-tip variant, allowing them to spread while HepS protects the host from other phages.