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Transcriptional control of the hydrogen cyanide biosynthetic genes hcnABC by the anaerobic regulator ANR and the quorum-sensing regulators LasR and RhlR in Pseudomonas aeruginosa.
J Bacteriol. 2000 Dec; 182(24):6940-9.JB

Abstract

Virulence factors of Pseudomonas aeruginosa include hydrogen cyanide (HCN). This secondary metabolite is maximally produced at low oxygen tension and high cell densities during the transition from exponential to stationary growth phase. The hcnABC genes encoding HCN synthase were identified on a genomic fragment complementing an HCN-deficient mutant of P. aeruginosa PAO1. The hcnA promoter was found to be controlled by the FNR-like anaerobic regulator ANR and by the quorum-sensing regulators LasR and RhlR. Primer extension analysis revealed two transcription starts, T1 and T2, separated by 29 bp. Their function was confirmed by transcriptional lacZ fusions. The promoter sequence displayed an FNR/ANR box at -42.5 bp upstream of T2 and a lux box centered around -42.5 bp upstream of T1. Expression of the hcn genes was completely abolished when this lux box was deleted or inactivated by two point mutations in conserved nucleotides. The lux box was recognized by both LasR [activated by N-(oxododecanoyl)-homoserine lactone] and RhlR (activated by N-butanoyl-homoserine lactone), as shown by expression experiments performed in quorum-sensing-defective P. aeruginosa mutants and in the N-acyl-homoserine lactone-negative heterologous host P. fluorescens CHA0. A second, less conserved lux box lying 160 bp upstream of T1 seems to account for enhanced quorum-sensing-dependent expression. Without LasR and RhlR, ANR could not activate the hcn promoter. Together, these data indicate that expression of the hcn promoter from T1 can occur under quorum-sensing control alone. Enhanced expression from T2 appears to rely on a synergistic action between LasR, RhlR, and ANR.

Authors+Show Affiliations

Laboratoire de Biologie Microbienne, Université de Lausanne, CH-1015 Lausanne, Switzerland.No affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

11092854

Citation

Pessi, G, and D Haas. "Transcriptional Control of the Hydrogen Cyanide Biosynthetic Genes hcnABC By the Anaerobic Regulator ANR and the Quorum-sensing Regulators LasR and RhlR in Pseudomonas Aeruginosa." Journal of Bacteriology, vol. 182, no. 24, 2000, pp. 6940-9.
Pessi G, Haas D. Transcriptional control of the hydrogen cyanide biosynthetic genes hcnABC by the anaerobic regulator ANR and the quorum-sensing regulators LasR and RhlR in Pseudomonas aeruginosa. J Bacteriol. 2000;182(24):6940-9.
Pessi, G., & Haas, D. (2000). Transcriptional control of the hydrogen cyanide biosynthetic genes hcnABC by the anaerobic regulator ANR and the quorum-sensing regulators LasR and RhlR in Pseudomonas aeruginosa. Journal of Bacteriology, 182(24), 6940-9.
Pessi G, Haas D. Transcriptional Control of the Hydrogen Cyanide Biosynthetic Genes hcnABC By the Anaerobic Regulator ANR and the Quorum-sensing Regulators LasR and RhlR in Pseudomonas Aeruginosa. J Bacteriol. 2000;182(24):6940-9. PubMed PMID: 11092854.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Transcriptional control of the hydrogen cyanide biosynthetic genes hcnABC by the anaerobic regulator ANR and the quorum-sensing regulators LasR and RhlR in Pseudomonas aeruginosa. AU - Pessi,G, AU - Haas,D, PY - 2000/11/28/pubmed PY - 2001/2/28/medline PY - 2000/11/28/entrez SP - 6940 EP - 9 JF - Journal of bacteriology JO - J. Bacteriol. VL - 182 IS - 24 N2 - Virulence factors of Pseudomonas aeruginosa include hydrogen cyanide (HCN). This secondary metabolite is maximally produced at low oxygen tension and high cell densities during the transition from exponential to stationary growth phase. The hcnABC genes encoding HCN synthase were identified on a genomic fragment complementing an HCN-deficient mutant of P. aeruginosa PAO1. The hcnA promoter was found to be controlled by the FNR-like anaerobic regulator ANR and by the quorum-sensing regulators LasR and RhlR. Primer extension analysis revealed two transcription starts, T1 and T2, separated by 29 bp. Their function was confirmed by transcriptional lacZ fusions. The promoter sequence displayed an FNR/ANR box at -42.5 bp upstream of T2 and a lux box centered around -42.5 bp upstream of T1. Expression of the hcn genes was completely abolished when this lux box was deleted or inactivated by two point mutations in conserved nucleotides. The lux box was recognized by both LasR [activated by N-(oxododecanoyl)-homoserine lactone] and RhlR (activated by N-butanoyl-homoserine lactone), as shown by expression experiments performed in quorum-sensing-defective P. aeruginosa mutants and in the N-acyl-homoserine lactone-negative heterologous host P. fluorescens CHA0. A second, less conserved lux box lying 160 bp upstream of T1 seems to account for enhanced quorum-sensing-dependent expression. Without LasR and RhlR, ANR could not activate the hcn promoter. Together, these data indicate that expression of the hcn promoter from T1 can occur under quorum-sensing control alone. Enhanced expression from T2 appears to rely on a synergistic action between LasR, RhlR, and ANR. SN - 0021-9193 UR - https://www.unboundmedicine.com/medline/citation/11092854/Transcriptional_control_of_the_hydrogen_cyanide_biosynthetic_genes_hcnABC_by_the_anaerobic_regulator_ANR_and_the_quorum_sensing_regulators_LasR_and_RhlR_in_Pseudomonas_aeruginosa_ L2 - http://jb.asm.org/cgi/pmidlookup?view=long&pmid=11092854 DB - PRIME DP - Unbound Medicine ER -