ArgR is an essential local transcriptional regulator of the arcABC operon in Streptococcus suis and is crucial for biological fitness in an acidic environment.
Streptococcus suis is one of the most important pathogens in pigs and can also cause severe infections in humans. Despite its clinical relevance, very little is known about the factors that contribute to its virulence. Recently, we identified a new putative virulence factor in S. suis, the arginine deiminase system (ADS), an arginine catabolic enzyme system encoded by the arcABC operon, which enables S. suis to survive in an acidic environment. In this study, we focused on ArgR, an ADS-associated regulator belonging to the ArgR/AhrC arginine repressor family. Using an argR knockout strain we were able to show that ArgR is essential for arcABC operon expression and necessary for the biological fitness of S. suis. By cDNA expression microarray analyses and quantitative real-time RT-PCR we found that the arcABC operon is the only gene cluster regulated by ArgR, which is in contrast to the situation in many other bacteria. Reporter gene analysis with gfp under the control of the arcABC promoter demonstrated that ArgR is able to activate the arcABC promoter. Electrophoretic mobility shift assays with fragments of the arcABC promoter and recombinant ArgR, and chromatin immunoprecipitation with antibodies directed against ArgR, revealed that ArgR interacts with the arcABC promoter in vitro and in vivo by binding to a region from -147 to -72&emsp14;bp upstream of the transcriptional start point. Overall, our results show that in S. suis, ArgR is an essential, system-specific transcriptional regulator of the ADS that interacts directly with the arcABC promoter in vivo.
Institut für Mikrobiologie, Zentrum für Infektionsmedizin, Stiftung Tierärztliche Hochschule Hannover, 30173 Hannover, Germany.
Marcus
M
Fulde
Institut für Mikrobiologie, Zentrum für Infektionsmedizin, Stiftung Tierärztliche Hochschule Hannover, 30173 Hannover, Germany.
Joerg
J
Willenborg
Animal Sciences Group (ASG), Wageningen UR, PO Box 65, 8200 AB Lelystad, The Netherlands.
Astrid
A
de Greeff
Institut für Mikrobiologie, Zentrum für Infektionsmedizin, Stiftung Tierärztliche Hochschule Hannover, 30173 Hannover, Germany.
Laurentiu
L
Benga
Animal Sciences Group (ASG), Wageningen UR, PO Box 65, 8200 AB Lelystad, The Netherlands.
Hilde E
HE
Smith
Institut für Mikrobiologie, Zentrum für Infektionsmedizin, Stiftung Tierärztliche Hochschule Hannover, 30173 Hannover, Germany.
Peter
P
Valentin-Weigand
Institut für Mikrobiologie, Zentrum für Infektionsmedizin, Stiftung Tierärztliche Hochschule Hannover, 30173 Hannover, Germany.
Ralph
R
Goethe
D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D002460:Cell Line; D004269:DNA, Bacterial / Q000235:genetics; D015964:Gene Expression Regulation, Bacterial; D055786:Gene Knockout Techniques; D006801:Humans; D005810:Multigene Family; D016254:Mutagenesis, Insertional; D020411:Oligonucleotide Array Sequence Analysis; D009876:Operon; D011401:Promoter Regions, Genetic; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017011:Streptococcus suis / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism
C087018:ArgR protein, Bacteria; D001426:Bacterial Proteins; D004269:DNA, Bacterial; D011994:Recombinant Proteins; D012097:Repressor Proteins