Relative Strengths of Promoters Provided by Common Mobile Genetic Elements Associated with Resistance Gene Expression in Gram-Negative Bacteria.

Comparison of green fluorescent protein expression from outward-facing promoters (POUT) of ISAba1, ISEcp1, and ISAba125 revealed approximate equivalence in strength, intermediate between PCS (strong) and PCWTGN-10 (weak) class 1 integron promoter variants, >30-fold stronger than POUT of ISCR1, and >5 times stronger than Ptac. Consistent with its usual role, PCWTGN-10 produces more mRNA from a "downstream" gfp gene transcriptionally linked to a "usual" PCWTGN-10-associated gene cassette than does POUT of ISAba1.