Isolation and characterization of a substitution mutation in the ompR gene of Salmonella typhimurium LT2

Liljeström, Peter; Luokkamäki, Mikko; Palva, E. Tapio

doi:10.1128/jb.169.1.438-441.1987

Cited by 11 publications

(5 citation statements)

References 35 publications

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“…The production of both OmpC and OmpF by serovar Typhimurium is dependent on envZ. A mutant derivative of LT2, SC2, with an envZ1005::Mud-P insertion makes neither OmpC nor OmpF, as reported previously (10). In contrast, the relative abundance of OmpD in the outer membrane does not change in response to changes in osmolarity, nor is it dependent on envZ function.…”

mentioning

confidence: 60%

Global Regulation of the Salmonella enterica Serovar Typhimurium Major Porin, OmpD

et al. 2003

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The OmpD porin is the most abundant outer membrane protein in Salmonella enterica serovar Typhimurium and represents about 1% of total cell protein. Unlike the case with the less abundant OmpC and OmpF porins, the stoichiometry of OmpD in the outer membrane does not change in response to changes in osmolarity. The abundance of OmpD increases in response to anaerobiosis and decreases in response to low pH, conditions encountered by serovar Typhimurium during the infection of its murine host. By constructing an operon fusion of the lacZY genes with the ompD promoter, we show that the abundance of OmpD in the outer membrane is regulated primarily at the level of transcription and is subject to catabolite repression. In response to anaerobiosis, the abundance of OmpD in the outer membrane also appears to be controlled posttranscriptionally by a function dependent on Fnr.

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confidence: 60%

Global Regulation of the Salmonella enterica Serovar Typhimurium Major Porin, OmpD

et al. 2003

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“…This hypothesis is supported by the lack of complementation of the mutant strain ΔhrpG with the expression of the plasmid-encoded variant R210C. Similarly, a change of Arg to Cys at position 220 in a plasmid-encoded OmpR in a wild type background also exhibited dominance and it has been suggested that the loss of function phenotype may be caused by the interaction between wild-type and mutant polypeptides, the latter overproduced due to the multicopy state [ 29 ]. Moreover, Xcc-R210C could not elicit an HR in non-host plants, suggesting that even if a lower expression of hrp genes in this strain allows the T3SS assembly during host plants infection, it is not sufficient to elicit the rapid plant defense response that occurs during HR and in which the bacteria is not growing inside the non-host plant tissue [ 3 ].…”

Section: Discussionmentioning

confidence: 99%

The Amino Acid Arginine 210 of the Response Regulator HrpG of Xanthomonas citri subsp. citri Is Required for HrpG Function in Virulence

et al. 2015

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Xanthomonas citri subsp. citri colonizes its hosts through the trafficking of effector proteins to the plant cell by the type III protein secretion system. In X. citri subsp. citri, as in other plant pathogens, the hrp cluster encodes the type III protein secretion system and is regulated by the transcription factors HrpG and HrpX. HrpG belongs to the OmpR family’s response regulator of EnvZ/OmpR two-component signal transduction system. Here, we show that the arginine 210 residue is crucial for the transcriptional activity of HrpG revealed by the absence of disease in host plants and hypersensitive response in non-host plants when a strain carrying this point mutation is used in plant infiltration assays. Also, this strain showed decreased expression levels of hrp genes in bacteria grown in culture or when they were recovered from citrus leaves. Moreover, we show for the first time that HrpG binds to both hrpX and its own promoter, and the change of the arginine 210 by a cysteine does not prevent the binding to both promoters. Nevertheless, in vitro hrpX transcription was observed only with HrpG whereas no transcription was detected with the R210C mutant. HrpG was able to interact with itself as well as with the mutant R210C suggesting that it functions as a dimer. The mutant protein R210C showed altered protease sensitivity, suggesting that Arg210 is essential for protein active conformation and thus for transcriptional activity. Our results indicate that arginine 210 in HrpG, as it may occur with this conserved residue in other members of this family of response regulators, is not required for DNA binding whereas is essential for hrp genes transcription and therefore for pathogenicity and HR induction.

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“…In addition, it has been shown that MH760 remains OmpC-even in the presence of increased amounts of the altered OmpR protein (25,33). Perhaps high expression of ompB in IHF mutants leads to changed levels of EnvZ in relation to OmpR.…”

Section: Methodsmentioning

confidence: 99%

Integration host factor is a negative effector of in vivo and in vitro expression of ompC in Escherichia coli

1990

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Isolation and characterization of a substitution mutation in the ompR gene of Salmonella typhimurium LT2

Cited by 11 publications

References 35 publications

Global Regulation of the Salmonella enterica Serovar Typhimurium Major Porin, OmpD

Global Regulation of the Salmonella enterica Serovar Typhimurium Major Porin, OmpD

The Amino Acid Arginine 210 of the Response Regulator HrpG of Xanthomonas citri subsp. citri Is Required for HrpG Function in Virulence

Integration host factor is a negative effector of in vivo and in vitro expression of ompC in Escherichia coli

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