Fig. 2

Polar localization of ClpV-5-sfGFP within B. thailandensis is not abolished in the absence of all T6SS-5 components. a, b RAW264.7 macrophages were infected with B. thailandensis a expressing a chromosomal clpV-5-sfgfp fusion in the wild type background (T6SS-5⁺ clpV-5-sfgfp) and b carrying a deletion of the entire T6SS-5 gene cluster and expressing clpV-5-sfgfp constitutively from a neutral site on the chromosome (T6SS-5⁻ clpV-5-sfgfp) at MOI 50 for 6 h. Host cell actin and DNA was stained with Texas Red-X Phalloidin and DAPI, respectively. Because the regulatory genes virA/virG, which are located within the T6SS-5 gene cluster, are required for activating the actin polymerization gene bimA, the T6SS-5⁻ mutant is unable to form actin tails. Scale bars, 5 μm and 1 μm for main figure and insets, respectively. c Quantification of ClpV-5-sfGFP foci displaying a polar localization in B. thailandensis T6SS-5⁺ clpV-5-sfgfp and T6SS-5⁻ clpV-5-sfgfp during infection of RAW264.7 macrophages. The data shown represent mean values +SD based on two experiments performed in duplicate and three randomly selected microscopic fields per sample (N ≥ 223 foci). ns, not significant/P = 0.156 (t-test)