RNA-seq for PA4595

Pseudomonas aeruginosa is an important human pathogen which uses the type III secretion system 21 (T3SS) as a primary virulence factor to establish infections in humans. The results presented in this 22 report revealed that the ATP-binding protein PA4595 (named ArtR, a Regulator that is an ATP-activated 23 Repressor of T3SS) represses T3SS expression in P. aeruginosa. The expression of T3SS genes, 24 including exoS, exoY, exoT, exsCEBA and exsD-pscB-L, increased significantly when artR was 25 knockout. The effect of ArtR on ExsA is at the transcriptional level, not at the translational level. The 26 regulatory role and cytoplasm localization of ArtR suggest it belongs to the REG sub-family of 27 ATP-binding cassette (ABC) family. Purified GST-tagged ArtR showed ATPase activity in vitro. The 28 conserved aspartate residues in the dual Walker B motifs prove to be essential for the regulatory 29 function of ArtR. The regulation of T3SS by ArtR is unique, which does not involve the known 30 GacS/A-RsmY/Z-RsmA-ExsA pathway or Vfr. This is the first REG subfamily of ATP-binding 31 cassette that is reported to regulate T3SS genes in bacteria. The results specify a novel player in the 32 regulatory networks of T3SS in P. aeruginosa. RNA-seq for PA4595