PMID:17074910

Citation	Teplitski, M, Al-Agely, A and Ahmer, BM (2006) Contribution of the SirA regulon to biofilm formation in Salmonella enterica serovar Typhimurium. Microbiology (Reading, Engl.) 152:3411-24
Abstract	Orthologues of the Salmonella enterica serovar Typhimurium (S. typhimurium) BarA/SirA two-component system are important for biofilm formation and virulence in many gamma-Proteobacteria. In S. typhimurium, SirA activates the csrB and csrC carbon storage regulatory RNAs and the virulence gene regulators hilA and hilC. The regulatory RNAs antagonize the activity of the CsrA protein, allowing translation of those same virulence genes, and inhibiting the translation of flagellar genes. In this report, it was determined that SirA and the Csr system also control the fim operon that encodes type 1 fimbriae. sirA orthologues in other bacterial species, and the fim operon of S. typhimurium, are known to play a role in biofilm formation; therefore, all members of the S. typhimurium sirA regulon were tested for in vitro biofilm production. A sirA mutant, a csrB csrC double mutant, and a fimI mutant, were all defective in biofilm formation. Conversely, inactivation of flhDC increased biofilm formation. Therefore, SirA activates csrB, csrC and the fim operon to promote biofilm formation. In turn, csrB and csrC promote the translation of the fim operon, while at the same time inhibiting the translation of flagella, which are inhibitory to biofilm formation.
Links	PubMed Online version:10.1099/mic.0.29118-0
Keywords	Bacterial Proteins/genetics; Bacterial Proteins/physiology; Biofilms/growth & development; Fimbriae Proteins/genetics; Fimbriae, Bacterial/genetics; Flagella/genetics; Gene Expression Regulation, Bacterial; Genes, Bacterial/genetics; Mutation; Regulon/genetics; Regulon/physiology; Salmonella typhimurium/genetics; Salmonella typhimurium/physiology; Trans-Activators/genetics; Trans-Activators/physiology
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Annotations

Gene product	Qualifier	GO Term	Evidence Code	with/from	Aspect	Extension	Notes	Status
SALTI:P96058		GO:0003677: DNA binding	ECO:0000315:		F		Protein: sirA Organism: Salmonella typhimurium strain 14028 As shown in Figure 2, sirA mutants of Salmonella typhimurium 14028 showed decreased biofilm formation when compared to the wild type strain.	complete CACAO 12428
SALT1:A0A0F6B2T8		GO:1900188: negative regulation of cell adhesion involved in single-species biofilm formation	ECO:0000315:		P		Protein: fliA Organism: Salmonella typhimurium strain 14028 As shown in Figure 2, fliA mutants of Salmonella typhimurium 14028 showed increased biofilm formation when compared to the wild type strain.	complete CACAO 12453
SALT1:A0A0F6B2Q6		GO:1900232: negative regulation of single-species biofilm formation on inanimate substrate	ECO:0000315:		P		Organism: Salmonella typhimurium strain 14028s Protein: motA According to figure 2, salmonella typhimurium stran 14028s mutants lacking motA exhibited lower biofilm formation than the wild type strain. Mutants did not colonize surfaces above or below the meniscus, and formed only a thin ring on the meniscus	complete CACAO 12455
SALT1:A0A0F6B2Q9		GO:1900188: negative regulation of cell adhesion involved in single-species biofilm formation	ECO:0000315:		P		Protein: flhD Organism: Salmonella typhimurium strain 14028 As shown in Figure 2, flhD mutants of Salmonella typhimurium 14028 showed increased biofilm formation when compared to the wild type strain.	complete CACAO 12454
SALT1:A0A0F6B2Q8		GO:1900188: negative regulation of cell adhesion involved in single-species biofilm formation	ECO:0000315:		P		Protein: flhC Organism: Salmonella typhimurium strain 14028 As shown in Figure 2, flhC mutants of Salmonella typhimurium 14028 showed increased biofilm formation when compared to the wild type strain.	complete CACAO 12457
SALT1:A0A0F6B632		GO:1900233: positive regulation of single-species biofilm formation on inanimate substrate	ECO:0000315:		P		Organism: Salmonella typhimurium strain 14028s Protein: barA According to figure 2, salmonella typhimurium strain 14028s mutants of barA showed reduced biofilm formation when compared to wild type strain	complete CACAO 12459

References

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