PMID:16707690

Citation	Robbe-Saule, V, Jaumouillé, V, Prévost, MC, Guadagnini, S, Talhouarne, C, Mathout, H, Kolb, A and Norel, F (2006) Crl activates transcription initiation of RpoS-regulated genes involved in the multicellular behavior of Salmonella enterica serovar Typhimurium. J. Bacteriol. 188:3983-94
Abstract	In Salmonella enterica serovar Typhimurium, the stationary-phase sigma factor sigma(S) (RpoS) is required for virulence, stress resistance, biofilm formation, and development of the rdar morphotype. This morphotype is a multicellular behavior characterized by expression of the adhesive extracellular matrix components cellulose and curli fimbriae. The Crl protein of Escherichia coli interacts with sigma(S) and activates expression of sigma(S)-regulated genes, such as the csgBAC operon encoding the subunit of the curli proteins, by an unknown mechanism. Here, we showed using in vivo and in vitro experiments that the Crl protein of Salmonella serovar Typhimurium is required for development of a typical rdar morphotype and for maximal expression of the csgD, csgB, adrA, and bcsA genes, which are involved in curli and cellulose biosynthesis. In vitro transcription assays and potassium permanganate reactivity experiments with purified His(6)-Crl showed that Crl directly activated sigma(S)-dependent transcription initiation at the csgD and adrA promoters. We observed no effect of Crl on sigma(70)-dependent transcription. Crl protein levels increased during the late exponential and stationary growth phases in Luria-Beratani medium without NaCl at 28 degrees C. We obtained complementation of the crl mutation by increasing sigma(S) levels. This suggests that Crl has a major physiological impact at low concentrations of sigma(S).
Links	PubMed PMC1482930 Online version:10.1128/JB.00033-06
Keywords	Bacterial Proteins/genetics; Bacterial Proteins/metabolism; Escherichia coli/genetics; Gene Deletion; Gene Expression Regulation, Bacterial; Kinetics; Microscopy, Electron; Operon; Salmonella Phages/genetics; Salmonella typhimurium/cytology; Salmonella typhimurium/genetics; Salmonella typhimurium/ultrastructure; Sigma Factor/genetics; Sigma Factor/metabolism; Transcription, Genetic; beta-Galactosidase/genetics; beta-Galactosidase/metabolism
edit table

Annotations

Gene product	Qualifier	GO Term	Evidence Code	with/from	Aspect	Extension	Notes	Status
SALTY:CRL		GO:2001008: positive regulation of cellulose biosynthetic process	ECO:0000315: mutant phenotype evidence used in manual assertion		P		Figure 5	complete CACAO 8885
SALTY:CRL		GO:0045893: positive regulation of transcription, DNA-templated	ECO:0000315: mutant phenotype evidence used in manual assertion		P		Figure 5 At the end of the section titled "crl knockout mutation decreases curli and cellulose gene transcription" the authors state: "Together, these results demonstrated that Crl plays a role in the transcription activation of the csgD, csgB, adrA, and bcsA genes required for developing a typical rdar morphotype in Salmonella"	complete CACAO 8887

References

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