FIG 1.

Genetic organization of PA7 RGP69. The genomic island RGP69, uniquely present in P. aeruginosa strain PA7, possesses 14 predicted open reading frames encoding the 11 putative T2SS Txc components (TxcP to TxcZ) and 3 genes, a gene encoding a predicted chitin-binding protein (CbpE), a gene encoding an unorthodox sensor protein (TtsS), and PSPA7_1418, which is predicted to encode a protein belonging to the cytochrome b superfamily. RGP69 is externally flanked by the ttsR and PSPA7_1406 (1406) genes, which are homologous to the two contiguous genes PA3714 (3714) and PA3715 (3715), respectively, in strain PAO1. The two DNA sequences corresponding to the segments used to construct the PcbpE-lacZ and PtxcP-lacZ reporter fusions are also shown. The −10 and −35 boxes of the two predicted sigma 70 promoter regions of RGP69 are boxed in the corresponding DNA sequences. The ATG start codons of cbpE and txcP are indicated in boldface type. Also indicated are the two DNA regions TS1 and TS2, used to clone the RGP69 sequence in the gene capture vector pLLX13. A and B regions correspond to the DNA sequences (500 bp) cloned into pKNG208 to generate the suicide vector pKNG208Δtxc, which was used to generate the txc deletion mutant.