Three RpoN-dependent genes were significantly up-regulated in the HP0256 mutant based on the microarray data and the qRT-PCR investigations, i.e. HP0115/flaB (encoding the minor flagellin FlaB), HP0870/flgE (encoding the hook protein FlgE) and HP1076 (encoding a hypothetical protein). Another RpoN-dependent gene HP1155/murG

(transferase, peptidoglycan synthesis) was 1.955 fold up-regulated with a p-value of 0.034. However, RpoN and its associated regulators FlgR, HP0244 and HP0958 were transcribed at wild-type levels. As shown in Table 2, HP0492/hpaA3 (flagellar sheath associated protein) was significantly down-regulated. This gene is known to be essential for flagellar biogenesis, but its transcriptional regulation remains unclear. PS-341 in vivo It has not yet been assigned to any flagellar gene class [8]. In the intermediate class, HP0367 (encoding a hypothetical protein) was 1.8 fold up-regulated with a p-value of 0.008. In class I genes, we did not observe significant changes. A slight down-regulation of genes encoding components of the secretion apparatus and the basal body, such as FliI, FliQ, FliB, FlgG, was noted without reaching the

fold-change cut-off for significance. The fliN gene encoding a component of the switch was up-regulated (1.758 fold) with a p-value of 0.042. Table 2 Differentially expressed flagellar genes in the HP0256 mutant. Proposed Class TIGR orf no. Putative gene product (gene) Expression ratio p-value Class I HP0019 chemotaxis protein (cheV) 1.221 0.026   HP0082 methyl-accepting of chemotaxis transducer Atezolizumab (tlpC) 0.945 0.378   HP0099 methyl-accepting chemotaxis protein (tlpA) 1.401** 0.112   HP0103 methyl-accepting chemotaxis protein (tlpB) 1.403** 0.05   HP0173 flagellar biosynthetic protein (fliR)

1.000 0.997   HP0244 signal-transducing protein, histidine kinase (atoS) 1.221 0.651   HP0246 flagellar basal-body P-ring protein (flgI) – -   HP0325 flagellar basal-body L-ring protein (flgH) 1.113 0.050   HP0326 CMP-N-acetylneuraminic acid synthetase (neuA) 0.904 0.219   HP0327 flagellar protein G (flaG) 0.749 0.238   HP0351 basal body M-ring protein (fliF) 0.889 0.508   HP0352 flagellar motor switch protein (fliG) 1.158 0.176   HP0391 purine-binding chemotaxis protein (cheW) 1.668** 0.004   HP0392 histidine kinase (cheA) 1.202 0.113   HP0393 chemotaxis protein (cheV) 1.176 0.194   HP0584 flagellar motor switch protein (fliN) 1.758** 0.042   HP0599 hemolysin secretion protein precursor (hylB) 1.201 0.366   HP0616 chemotaxis protein (cheV) 1.159** 0.162   HP0684 flagellar biosynthesis protein (fliP) 0.510 0.058   HP0685 flagellar biosynthetic protein (fliP) 0.493 0.066   HP0703 response regulator 0.715 0.158   HP0714 RNA polymerase sigma-54 factor (rpoN) 1.104 0.699   HP0770 flagellar biosynthetic protein (flhB) 0.621 0.162   HP0815 flagellar motor rotation protein (motA) 0.917 0.538   HP0816 flagellar motor rotation protein (motB) 0.651 0.