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. Author manuscript; available in PMC: 2023 Feb 1.
Published in final edited form as: Nat Microbiol. 2022 Jul 11;7(8):1210–1220. doi: 10.1038/s41564-022-01162-4

Fig. 4 |. avcID homologues provide phage defence.

Fig. 4 |

a, Fold reduction in the number of plaques conferred by four homologous avcID systems to a naïve E. coli host challenged with a panel of coliphages. Fold reduction determined by serial dilution plaque assays comparing the efficiency of plaquing on an E. coli host maintaining a plasmid borne avcID system and its native promotor against a vector control strain. b, Efficiency of plaquing on strains encoding WT avcIDVP from V. parahaemolyticus (pAvcIDVP) or point mutations in the PLN (S49K), DCD (E376A) or a double domain point mutant (pAvcIDVP-avcDS49K+E376A) against a vector control strain. Data represent the mean ± s.e.m. of three biological replicate cultures, one-way ANOVA with Dunnett’s post-hoc test. P values for T3: WT versus S49K, < 0.001; WT versus E376A, <0.001; WT versus S49K + E376A, <0.001. P values for T5: WT versus S49K, <0.001; WT versus E376A, 0.0002; WT versus S49K + E376A, <0.0001. P values for T6: WT versus S49K, 0.0012; WT versus E376A, 0.0008; WT versus S49K + E376A, 0.0011. P values for SECФ18: WT versus S49K, <0.0001; WT versus E376A, <0.0001; WT versus S49K_E376A, <0.0001. c, The relative genome abundance of T5 infecting E. coli expressing pAvcIDVP or its double point mutation variants pAvcIDVP-avcDS49K+E376A. Data represent the mean ± s.e.m. of three biological replicate cultures, two-way ANOVA with two-sided Šídák’s multiple-comparison test. P values at 40 min: 0.0004. NS, not significant. d–g, In vivo abundance of dCTP (d), dCMP (e), dUTP (f) and dUMP (g) in an E. coli host carrying a vector control, pAvcIDVP or the avcID system with its native promoter from E. coli ETEC (pAvcIDETEC) before and after addition of T3 phage (MOI 5). Nucleotides measured using UPLC–MS/MS and normalized to total protein. Data represent the mean ± s.e.m. of three biological replicate cultures, two-way ANOVA with Dunnett’s post-hoc test (d–g). NS, not significant. For dCTP, P values: EV versus ETEC at 5 min, <0.0001; EV versus VP at 12.5 min, <0.0001; EV versus VP at 20 min, 0.0009; EV versus ETEC at 20 min, 0.001. For dCMP, P values: EV versus VP at 12.5 min, <0.0001; EV versus ETEC at 12.5 min, 0.0358. For dUMP, P values: EV versus ETEC at 5 min, 0.0017; EV versus VP at 12.5 min, <0.0001; EV versus ETEC at 12.5 min, 0.0001.