Disease relevance of ampR

• Pseudomonas aeruginosa isolates from patients with cystic fibrosis have different beta-lactamase expression phenotypes but are homogeneous in the ampC-ampR genetic region [1].
• The ampR gene was located upstream of the ampA gene, and the AmpR sequence of SFO-1 had homology with the AmpR sequences of the chromosomal beta-lactamases from Citrobacter diversus (80%), Proteus vulgaris (68%), and Pseudomonas aeruginosa (60%) [2].
• The complete sequence of the Pseudomonas aeruginosa beta-lactamase regulator gene ampR has been determined [3].

High impact information on ampR

• Pseudomonas aeruginosa AmpR regulates the expression of multiple virulence factors in addition to positively regulating ampC expression [4].
• The sequencing of regulatory genes (ampR, mexR, nalC, nalD, mexT, and mexZ) was also performed [5].
• All 10 ceftazidime-resistant mutants hyper-produced AmpC (beta-lactamase activities were 12- to 657-fold higher than those of the parent strains), but none of them harbored mutations in ampR or the ampC-ampR intergenic region [6].
• Four bla genes and two ampR genes are present in the fully sequenced X. campestris pv. campestris ATCC 33913 genome, with XCC3039 and XCC3040 considered the analogues of bla(XCC-1) and ampR1, respectively [7].
• One highly resistant, constitutive beta-lactamase-producing variant contained no mutations in ampD, but a point mutation was observed in ampR, resulting in an Asp-135-->Asn change [8].

Biological context of ampR

• The DNA sequence of the structural gene ampC and the regulatory genes ampR, ampD and ampE was detected [9].

Other interactions of ampR

• However, the regulatory gene ampR and a 38-bp AmpR-binding region were not present upstream from blaMOX-1, although the expression of P. aeruginosa ampC is directly regulated by AmpR [10].

References