PMID:20709902

Citation	Waligora, EA, Ramsey, DM, Pryor, EE Jr, Lu, H, Hollis, T, Sloan, GP, Deora, R and Wozniak, DJ (2010) AmrZ beta-sheet residues are essential for DNA binding and transcriptional control of Pseudomonas aeruginosa virulence genes. J. Bacteriol. 192:5390-401
Abstract	AmrZ is a putative ribbon-helix-helix (RHH) transcriptional regulator. RHH proteins utilize residues within the β-sheet for DNA binding, while the α-helices promote oligomerization. AmrZ is of interest due to its dual roles as a transcriptional activator and as a repressor, regulating genes encoding virulence factors associated with both chronic and acute Pseudomonas aeruginosa infection. In this study, cross-linking revealed that AmrZ forms oligomers in solution but that the amino terminus, containing an unordered region and a β-sheet, were not required for oligomerization. The first 12 unordered residues (extended amino terminus) contributed minimally to DNA binding. Mutagenesis of the AmrZ β-sheet demonstrated that residues 18, 20, and 22 were essential for DNA binding at both activation and repressor sites, suggesting that AmrZ utilizes a similar mechanism for binding to these sites. Mice infected with amrZ mutants exhibited reduced bacterial burden, morbidity, and mortality. Direct in vivo competition assays showed a 5-fold competitive advantage for the wild type over an isogenic amrZ mutant. Finally, the reduced infection phenotype of the amrZ-null strain was similar to that of a strain expressing a DNA-binding-deficient AmrZ variant, indicating that DNA binding and transcriptional regulation by AmrZ is responsible for the in vivo virulence defect. These recent infection data, along with previously identified AmrZ-regulated virulence factors, suggest the necessity of AmrZ transcriptional regulation for optimal virulence during acute infection.
Links	PubMed PMC2950516 Online version:10.1128/JB.00711-10
Keywords	Alginates; Amino Acid Sequence; Animals; DNA, Bacterial/genetics; DNA, Bacterial/metabolism; Gene Expression Regulation, Bacterial/physiology; Glucuronic Acid/biosynthesis; Hexuronic Acids; Mice; Models, Molecular; Mutation; Protein Binding; Protein Structure, Secondary; Pseudomonas aeruginosa/genetics; Pseudomonas aeruginosa/pathogenicity; Pseudomonas aeruginosa/physiology; Transcription, Genetic; Virulence
edit table

Annotations

Gene product	Qualifier	GO Term	Evidence Code	with/from	Aspect	Extension	Notes	Status
PSEAE:G3XCY4		GO:0009405: pathogenesis	ECO:0000315:		P		Figure 6 demonstrates that AmrZ mutants have reduced virulence in mice.	complete CACAO 10082
PSEAE:G3XCY4	involved_in	GO:0009405: pathogenesis	ECO:0000315: mutant phenotype evidence used in manual assertion		P		Seeded From UniProt	complete

References

See Help:References for how to manage references in GONUTS.