Fig. 3

tfec function counteracts enhanced microbicidal capacity of cxcr3.2 mutants (A–D) We inhibited Tfec function with the DN-tfec construct (A and B) or overexpressed the gene with the CMV:tfec construct (C and D) in WT embryos (AB/TL) and subsequently infected them with M. marinum mCherry (representative examples are shown). Larvae injected with DN-tfec had a lower bacterial burden than did PBS injected controls at 4 days post-infection (dpi) (A and B), while CMV:tfec injected larvae had a higher bacterial burden (C and D). (E and F) M. marinum ΔERP-infected WT larvae (AB/TL) previously injected with DN-tfec developed fewer (E) and smaller (F) bacterial clusters than did PBS controls and phenocopied cxcr3.2 mutants in their capacity to clear bacteria. (G and H) CMV:tfec-injected cxcr3.2 mutants (cxcr3.2−/−) infected with M. marinum ΔERP lost their enhanced microbicidal capacity and had more (G) and larger (H) bacterial clusters than did WT controls (cxcr3.2+/+). Overall bacterial burden data were analyzed using a two-tailed t test (A–D). Total bacterial clusters per fish were analyzed using a Mann-Whitney test and combined data of three independent replicates of 20–30 larvae (E and G). A Kolmogorov-Smirnov test was used to analyze the distribution of bacterial cluster sizes (F and H). All data are shown as mean ± SEM (∗p ≤ 0.05, ∗∗p ≤ 0.01, ∗∗∗p ≤ 0.001 ∗∗∗∗p ≤ 0.0001; ns, not significant [p > 0.05]).