Disease relevance of ssrB

• Identification and characterization of mutants with increased expression of hilA, the invasion gene transcriptional activator of Salmonella typhimurium [1].
• Protein crosslinking studies suggest that Rhizobium meliloti C4-dicarboxylic acid transport protein D, a sigma 54-dependent transcriptional activator, interacts with sigma 54 and the beta subunit of RNA polymerase [2].
• Expression of the cysteine regulon in Salmonella typhimurium and Escherichia coli is controlled by the LysR-type transcriptional activator CysB and by the inducer N-acetyl-L-serine [3].

High impact information on ssrB

• Genes belonging to the adaptive response are positively regulated by the ada gene; the Ada protein acts as a transcriptional activator when methylated in one of its cysteine residues at position 69 [4].
• The traJ gene of the virulence plasmid of Salmonella enterica serovar Typhimurium (pSLT) encodes a transcriptional activator of the transfer operon [5].
• The isolated C-terminus of SsrB binds to DNA and protects regions upstream of ssrA, ssrB and srfH from DNase I digestion [6].
• However, despite the improved interaction with the transcriptional activator, the altered regulatory region was poorer at promoting spvR gene transcription than the wild type [7].
• Conjugation of Agrobacterium tumefaciens wide-host-range octopine-type Ti plasmids is regulated by the LuxR-type transcriptional activator TraR in conjunction with an acylated homoserine lactone designated AAI [8].

Chemical compound and disease context of ssrB

• In both Salmonella typhimurium and Escherichia coli, CysB is a LysR family transcriptional activator, which regulates genes of the cysteine regulon [9].
• Hydroxyl radical footprints and half-site arrangements of binding sites for the CysB transcriptional activator of Salmonella typhimurium [10].
• A rationale for autoinduction of a transcriptional activator: ethanolamine ammonia-lyase (EutBC) and the operon activator (EutR) compete for adenosyl-cobalamin in Salmonella typhimurium [11].
• Homology between virF, the transcriptional activator of the Yersinia virulence regulon, and AraC, the Escherichia coli arabinose operon regulator [12].

Biological context of ssrB

• Results from DNase I protection assays provide direct evidence that SsrB binds at ssrA and ssrB, although the binding sites lie within the transcribed regions [6].
• The hilA gene, encoded on Salmonella pathogenicity island 1 (SPI-1), is a transcriptional activator which is required for invasion and whose expression is modulated by oxygen, pH, and osmolarity [1].
• The transcriptional activator FlhD2C2 is the master regulator of bacterial flagellum biogenesis and swarming migration, activating the "early" class II promoters of the large flagellar gene hierarchy [13].
• The genetic regulation of gogB in Salmonella is influenced by the transcriptional activator, SsrB, under SPI-2-inducing conditions, but the modular nature of the gogB gene allows for autonomous expression and type III secretion following horizontal gene transfer into a heterologous pathogen [14].
• In vivo titration of transcriptional activator UhpA by the intact or mutant promoters on multicopy plasmids identified the -64 element as the UhpA-binding site [15].

Anatomical context of ssrB

• Transcription of the hilA gene, which encodes an OmpR/ToxR-type transcriptional activator of downstream invasion genes, is increased during growth under high-osmolarity and low-oxygen conditions, which presumably mimic the environment found within the small intestine [16].
• However, neither SirA nor HilA is believed to directly activate the promoters of these genes. invF, the first gene of the inv-spa gene cluster, is predicted to encode an AraC-type transcriptional activator and is required for invasion into cultured epithelial cells [17].

Associations of ssrB with chemical compounds

• These data are consistent with a role for PchR as a transcriptional activator of pyochelin and ferripyochelin receptor synthesis in P. aeruginosa [18].
• A model for control of this regulon suggests that the PocR protein is a transcriptional activator of both the cob and pdu operons and that both glycerol and propanediol can individually serve as effectors of the PocR protein [19].
• These activities are thought to be mediated by interactions of the ATPase subunit, MalK, with the transcriptional activator, MalT, and nonphosphorylated enzyme IIA of the glucose phosphotransferase system, respectively [20].

Other interactions of ssrB

• Strains with mutations in either gene of the regulatory pair (phoP [transcriptional activator] or phoQ [membrane sensor kinase]) had increased sensitivities to defensin [21].
• We also provide direct evidence for the regulation of SPI-2 by the Salmonella transcription factors ompR and ssrB in vivo [22].

Analytical, diagnostic and therapeutic context of ssrB

• Transcriptional fusions and Northern blot analysis demonstrated that the aarG1 allele also resulted in a large increase in the expression of aarP, a gene encoding a transcriptional activator of aac(2')-Ia [23].

References