Fig. 3. The ESX-4 system is involved in EsxF export in M. tuberculosis.
a Detection of surface-accessible EsxF of the indicated Mtb strains using fluorescence microscopy. The Mtb strains were labeled with the metabolic dye DMN-trehalose (green), and stained with a polyclonal antibody against EsxF and Alexa Fluor-594 secondary antibody (red). The yellow color indicates co-localization of EsxF with the bacterial cell. b Quantification of EsxF-positive Mtb cells from images shown in a. Mtb cells were scored as EsxF-positive when a red signal was observed as compared with the Mtb cpnT operon deletion mutant (ΔcpnTop). Data are represented as mean ± SEM of three independent experiments (n = 3) and representative images are shown. Asterisks indicate significant differences (*p value ≤ 0.05, **p value ≤ 0.01, ***p value ≤ 0.001, ****p value ≤ 0.0001, calculated using the one-way ANOVA with Dunnett’s correction) compared with the Mtb mc26206 strain. Source data are provided in the Source Data file.