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This Article Full Text Full Text (PDF) All Versions of this Article: mic.0.028993-0v1 155/10/3312    most recent Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via CrossRef Google Scholar Articles by Yamamoto, M. Articles by Ishigatsubo, Y. PubMed PubMed Citation Articles by Yamamoto, M. Articles by Ishigatsubo, Y. Agricola Articles by Yamamoto, M. Articles by Ishigatsubo, Y.

Role of MexZ and PA5471 in transcriptional regulation of mexXY in Pseudomonas aeruginosa

¹ Department of Internal Medicine and Clinical Immunology, Yokohama City University Graduate School of Medicine, Yokohama 236-0004, Japan
² Department of Biotechnology, Akita Prefectural University, Akita 010-0195, Japan
³ Antimicrobial Research Center, Kitasato Institute, Kitasato University, Sagamihara 228-8555, Japan
⁴ Department of Pulmonary Medicine, Yokohama City University Medical Center, Yokohama 232-0024, Japan

MexXY, a drug efflux pump in Pseudomonas aeruginosa, confers resistance to aminoglycoside antibiotics. We recently reported that MexZ binds to the promoter region of the mexXY operon. Electrophoretic mobility shift assay (EMSA) using recombinant MexZ and oligonucleotide probes prepared from the intergenic region between mexZ and mexX revealed that MexZ binds to a 20 bp palindromic sequence. Culture of P. aeruginosa in the presence of tetracycline induced higher levels of MexX and MexZ, as measured by immunoblotting and EMSA, than in the absence of antibiotics. When MexZ was expressed by a mexZ expression plasmid, the plasmid-borne MexZ repressed drug-induced MexX production, further confirming that MexZ acts as a repressor of the mexXY operon. PA5471 protein has been reported to be essential for drug-induced MexXY production. Similarly to that report, we observed that plasmid-borne PA5471 induced both MexX and MexZ production in PAO1 cells. Interestingly, interaction between MexZ and PA5471 was observed in a yeast two-hybrid assay. Furthermore, EMSA and in vitro transcription assays revealed that interaction between PA5471 and MexZ reduced MexZ DNA-binding ability, leading to mexXY transcription. These findings contribute to the understanding of the molecular mechanisms underlying the transcriptional regulation of mexZ and mexXY by drug-induced PA5471 expression.

Correspondence
Yoshiaki Ishigatsubo
ishigats{at}med.yokohama-cu.ac.jp