title: Introduction of an AmpR-L2 intergenic segment attenuates the induced beta-lactamase activity of Stenotrophomonas maltophilia.
abstract: Expression of the L1 and L2 beta-lactamase genes is generally regulated by a LysR type regulator of the AmpR in Stenotrophomonas maltophilia. The ampR gene is located immediately upstream of L2 and is transcribed divergently, forming an ampR-L2 module. The ampR-L2 modules of 16 S. maltophilia isolates were analyzed, revealing that the ampR-L2 intergenic (IG) regions show a significant genetic diversity, whereas AmpR proteins are highly conserved. The induction potential of the different AmpR toward the different ampR-L2 IG regions was evaluated by introducing the various IG-xylE transcriptional fusion constructs into a wild S. maltophilia strain. The induction levels achieved in the various AmpR-IG pairs display quantitative differences; meanwhile, the host beta-lactamase activity, in some cases, is attenuated by the introduced IG segment. Similar beta-lactamase attenuation phenomenon was observed in Enterobacter cloacae with an ampR-L2 IG segment of S. maltophilia. A concept of oligonucleotides attenuator for the development of an antimicrobial agent is proposed.
authors.affiliation: Department of Veterinary Medicine, National Chung-Hsing University, Taichung, 402, Taiwan, People's Republic of China.
authors.forename: Y-C
authors.initials: YC
authors.lastname: Chang
authors.forename: Y-W
authors.initials: YW
authors.lastname: Huang
authors.forename: K-H
authors.initials: KH
authors.lastname: Chiang
authors.forename: T-C
authors.initials: TC
authors.lastname: Yang
authors.forename: T-C
authors.initials: TC
authors.lastname: Chung
mesh_terms: D001426:Bacterial Proteins / Q000096:biosynthesis* / Q000235:genetics; D016000:Cluster Analysis; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D021901:DNA, Intergenic; D016972:Enterobacter cloacae / Q000201:enzymology / Q000235:genetics; D008969:Molecular Sequence Data; D016254:Mutagenesis, Insertional; D010802:Phylogeny; D011110:Polymorphism, Genetic; D017422:Sequence Analysis, DNA; D020615:Stenotrophomonas maltophilia / Q000201:enzymology* / Q000235:genetics*; D001618:beta-Lactamases / Q000096:biosynthesis*
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D021901:DNA, Intergenic; C071526:AmpR protein, Bacteria; C425104:beta-lactamase L2; D001618:beta-Lactamases
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