Production of FlgS and FlgR and activity of FlgR proteins in FEA mutants of C. jejuni. (A) Production of FlgS and FlgR proteins in mutants of C. jejuni lacking one component of the FEA. WCLs of wild-type and C. jejuni mutant strains were prepared for immunoblot analysis. Anti-FlgS Rab11 (α-FlgS) and anti-FlgR (α-FlgR) Rab13 antisera were used to detect the FlgS (left gel) and FlgR (right gel) proteins (25). The strains used for analysis included wild-type strain DRH212 (81-176 Smr) (WT), DRH460 (81-176 Smr ΔflgS), DRH737 (81-176 Smr ΔflgR), DRH946 (81-176 Smr ΔflhA), SNJ471 (81-176 Smr ΔflhB), and DRH1065 (81-176 Smr ΔfliP). (B) Arylsulfatase assays for analysis of expression of flaB::astA and flgDE2::nemo in the C. jejuni 81-176 Smr wild-type strain and mutant strains lacking a component of the FEA and producing wild-type and FlgR mutant proteins. The results are the results of a typical assay in which each strain was tested in triplicate. The values reported for each strain are the average arylsulfatase activity ± standard deviation relative to the level of expression of each transcriptional fusion in 81-176 Smr ΔastA ΔflhA, which was defined as 1 arylsulfatase unit. For expression of flaB::astA, the strains used included (from left to right) wild-type strain DRH665, DRH1049, SNJ112, SNJ273, DRH1827, SNJ109, SNJ1021, DRH1178, SNJ261, and SNJ1015. For expression of flgDE2::nemo, the strains used included (from left to right) wild-type strain DRH533, DRH1021, SNJ115, SNJ274, DRH1827, SNJ113, SNJ1017, DRH1204, SNJ358, and SNJ1012. The FEA mutation and the type of FlgR protein produced in each strain are indicated below the graph. WT, wild type.