Structurally related phage helicases trigger type III-A3 retron-mediated anti-phage defense across diverse tailed phage families.

ABSTRACT: Retrons are tripartite bacterial systems composed of non-coding RNA (ncRNA), reverse transcriptase (RT), and effector proteins with diverse enzymatic domains. Here, we characterized Retron-Eco11, a type III-A3 retron associated with a phosphoribosyltransferase-like effector, and demonstrated that it mediates anti-phage defense and can be harnessed for genome editing. All three components-ncRNA, RT, and effector-are essential for defense. Retron-Eco11 protects Escherichia coli against multiple phages and is specifically activated by structurally related, phage-encoded helicases, including UvsW and D10 from phages T4 and T5. We show that these helicases trigger effector-mediated toxicity, leading to abortive infection, which is associated with phosphoribosyl pyrophosphate depletion due to PR

SUBMITTER: Garcia-Rodriguez FM 

PROVIDER: S-EPMC12746101 | biostudies-literature | 2025 Nov

REPOSITORIES: biostudies-literature