TABLE 2.

Activity of mexAB-oprM PI and PII promoters in P. aeruginosaa

StrainbPlasmidPromotercβ-Galactosidase activity (Miller units) ± SDd
K767ePI232 ± 1
PII14 ± 4
PI+PII211 ± 43
K2543 (NalD)PI360 ± 11
PII196 ± 7
PI+PII489 ± 17
K2568 (MexR)PI771 ± 70
PII25 ± 16
PI+PII625 ± 127
K2569 (NalD MexR)PI826 ± 133
PII90 ± 63
PI+PII524 ± 109
K2543 (NalD)fpDSK519PI101 ± 23
PII55 ± 25
pMLS003 (nalD)PI131 ± 48
PII16 ± 7
pLC66 (mexR)PI46 ± 12
PII122 ± 31
  • a The indicated P. aeruginosa strains carrying plasmid pMP190 derivates pYM025 (PI), pYM030 (PII) and pYM031 (PI+PII) with the mexAB-oprM PI and/or PII promoter regions cloned upstream of the promoterless lacZ gene of this vector were grown to late log phase and assayed for β-galactosidase activity to obtain a measure of PI and/or PII promoter activity.

  • b The relevant phenotypes of the strains are highlighted in parentheses.

  • c The indicated mexAB-oprM promoter regions (delineated in Fig. 1B) were cloned into pMP190 to yield lacZ transcriptional fusions to assess PI (pYM025), PII (pYM030), or PI plus PII (pYM031) activity. The larger PII promoter fragment, PII-2 (Fig. 1B), was used in these studies. For PI plus PII, the entire mexR-mexA intergenic region was cloned into pMP190.

  • d Data shown are the means of three independent experiments ± the standard deviation. The data have been corrected for background β-galactosidase activity, measured for control strains carrying pMP190 without promoter insert.

  • e —, not applicable.

  • f Results for K2543 carrying pDSK519 and its derivatives (pMLS003 = pDSK519::nalD; pLC66 = pDSK519::mexR) in addition to the indicated PI or PII fusion vectors do not compare with the remaining data presented here because of the presence of two plasmids and, thus, the need to include two antibiotics in the growth medium.