Wild-Type and Hexahistidine-Tagged Derivatives of Leucine-Responsive Regulatory Protein from Escherichia coli

2000 ◽  
pp. 322-329 ◽  
Author(s):  
Rowena G. Matthews ◽  
Yuhai Cui ◽  
Devorah Friedberg ◽  
Joseph M. Calvo
Keyword(s):  
Escherichia Coli ◽  
Regulatory Protein ◽  
Wild Type ◽  
Derivatives Of

scholarly journals exrB: amalB-linked gene inEscherichia coliB involved in sensitivity to radiation and filament formation

1974 ◽  
Vol 23 (2) ◽  
pp. 175-184 ◽  
Author(s):  
Joseph Greenberg ◽  
Leonard J. Berends ◽  
John Donch ◽  
Michael H. L. Green
Keyword(s):  
Escherichia Coli ◽  
Normal Growth ◽  
Filament Formation ◽  
Wild Type ◽  
Sensitive Mutant ◽  
Γ Radiation ◽  
Linked Gene ◽  
Derivatives Of

SUMMARYPAM 26, a radiation-sensitive mutant ofEscherichia colistrain B, is described. Its properties are attributable to a mutation in a gene,exrB, which is cotransducible withmalB. It differs fromuvrA(alsomalB-linked) derivatives of strain B in being sensitive to 1-methyl-3-nitro-1-nitroso-guanidine and γ-radiation, and in being able to reactivate UV-irradiated phage T3. It differs fromexrA(alsomalB-linked) derivatives of strain B in forming filaments during the course of normal growth as well as after irradiation. WhenexrBwas transduced into a K12 (lon+) strain, filaments did not form spontaneously. Three-point transductions established the order of markers asmet A malB exrB. Based on an analysis of the frequency of wild-type recombinants in a reciprocal transduction betweenexrAandexrBstrains, it was inferred that they are not isogenic and that the order of markers ismalB exrA exrB.

scholarly journals Loss of Regulatory Protein RfaH Attenuates Virulence of Uropathogenic Escherichia coli

2002 ◽  
Vol 70 (8) ◽  
pp. 4406-4413 ◽  
Author(s):  
Gábor Nagy ◽  
Ulrich Dobrindt ◽  
György Schneider ◽  
A. Salam Khan ◽  
Jörg Hacker ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Urinary Tract Infection ◽  
Urinary Tract ◽  
Tract Infection ◽  
Mouse Model ◽  
Type Strain ◽  
Wild Type Strain ◽  
Regulatory Protein ◽  
Wild Type ◽  
Serovar Typhimurium

ABSTRACT RfaH is a regulatory protein in Escherichia coli and Salmonella enterica serovar Typhimurium. Although it enhances expression of different factors that are proposed to play a role in bacterial virulence, a direct effect of RfaH on virulence has not been investigated so far. We report that inactivation of rfaH dramatically decreases the virulence of uropathogenic E. coli strain 536 in an ascending mouse model of urinary tract infection. The mortality rate caused by the wild-type strain in this assay is 100%, whereas that of its isogenic rfaH mutant does not exceed 18%. In the case of coinfection, the wild-type strain 536 shows higher potential to colonize the urinary tract even when it is outnumbered 100-fold by its rfaH mutant in the inoculum. In contrast to the wild-type strain, serum resistance of strain 536rfaH::cat is fully abolished. Furthermore, we give evidence that, besides a major decrease in the amount of hemin receptor ChuA (G. Nagy, U. Dobrindt, M. Kupfer, L. Emody, H. Karch, and J. Hacker, Infect. Immun. 69:1924-1928, 2001), loss of the RfaH protein results in an altered lipopolysaccharide phenotype as well as decreased expression of K15 capsule and alpha-hemolysin, whereas levels of other pathogenicity factors such as siderophores, flagella, Prf, and S fimbriae appear to be unaltered in strain 536rfaH::cat in comparison to the wild-type strain. trans complementation of the mutant strain with the rfaH gene restores wild-type levels of the affected virulence factors and consequently restitutes virulence in the mouse model of ascending urinary tract infection.

scholarly journals Characterization and nucleotide sequence of the cryptic cel operon of Escherichia coli K12.

Genetics ◽  
1990 ◽  
Vol 124 (3) ◽  
pp. 455-471 ◽  
Author(s):  
L L Parker ◽  
B G Hall
Keyword(s):  
Escherichia Coli ◽  
Nucleotide Sequence ◽  
Regulatory Protein ◽  
Wild Type ◽  
Phosphotransferase System ◽  
E Coli ◽  
Significant Homology ◽  
Chromosomal Genes ◽  
Alpha Galactosidase ◽  
Beta Glucosidase

Abstract Wild-type Escherichia coli are not able to utilize beta-glucoside sugars because the genes for utilization of these sugars are cryptic. Spontaneous mutations in the cel operon allow its expression and enable the organism to ferment cellobiose, arbutin and salicin. In this report we describe the structure and nucleotide sequence of the cel operon. The cel operon consists of five genes: celA, whose function is unknown; celB and celC which encode phosphoenolpyruvate-dependent phosphotransferase system enzyme IIcel and enzyme IIIcel, respectively, for the transport and phosphorylation of beta-glucoside sugars; celD, which encodes a negative regulatory protein; and celF, which encodes a phospho-beta-glucosidase that acts on phosphorylated cellobiose, arbutin and salicin. The mutationally activated cel operon is induced in the presence of its substrates, and is repressed in their absence. A comparison of proteins encoded by the cel operon with functionally equivalent proteins of the bgl operon, another cryptic E. coli gene system responsible for the catabolism of beta-glucoside sugars, revealed no significant homology between these two systems despite common functional characteristics. The celD and celF encoded repressor and phospho-beta-glucosidase proteins are homologous to the melibiose regulatory protein and to the melA encoded alpha-galactosidase of E. coli, respectively. Furthermore, the celC encoded PEP-dependent phosphotransferase system enzyme IIIcel is strikingly homologous to an enzyme IIIlac of the Gram-positive organism Staphylococcus aureus. We conclude that the genes for these two enzyme IIIs diverged much more recently than did their hosts, indicating that E. coli and S. aureus have undergone relatively recent exchange of chromosomal genes.

scholarly journals Characterization of the Opposing Roles of H-NS and TraJ in Transcriptional Regulation of the F-Plasmid tra Operon

2006 ◽  
Vol 188 (2) ◽  
pp. 507-514 ◽  
Author(s):  
William R. Will ◽  
Laura S. Frost
Keyword(s):  
Escherichia Coli ◽  
Promoter Region ◽  
Regulatory Protein ◽  
Plasmid Transfer ◽  
Wild Type ◽  
F Plasmid ◽  
Transcriptional Fusion ◽  
Mobility Shift ◽  
Electrophoretic Mobility Shift Assays

ABSTRACT The transfer (tra) operon of the conjugative F plasmid of Escherichia coli is a polycistronic 33-kb operon which encodes most of the proteins necessary for F-plasmid transfer. Here, we report that transcription from PY, the tra operon promoter, is repressed by the host nucleoid-associated protein, H-NS. Electrophoretic mobility shift assays indicate that H-NS binds preferentially to the tra promoter region, while Northern blot and transcriptional fusion analyses indicate that transcription of traY, the first gene in the tra operon, is derepressed in an hns mutant throughout growth. The plasmid-encoded regulatory protein TraJ is essential for transcription of the tra operon in wild-type Escherichia coli; however, TraJ is not necessary for plasmid transfer or traY operon transcription in an hns mutant. This indicates that H-NS represses transcription from PY directly and not indirectly via its effects on TraJ levels. These results suggest that TraJ functions to disrupt H-NS silencing at PY, allowing transcription of the tra operon.

scholarly journals In Vitro Properties of RpoS (σS) Mutants of Escherichia coli with Postulated N-Terminal Subregion 1.1 or C-Terminal Region 4 Deleted

2003 ◽  
Vol 185 (8) ◽  
pp. 2673-2679 ◽  
Author(s):  
J. Gowrishankar ◽  
Kaneyoshi Yamamoto ◽  
P. R. Subbarayan ◽  
Akira Ishihama
Keyword(s):  
Escherichia Coli ◽  
Stationary Phase ◽  
Electrophoretic Mobility ◽  
Sigma Factor ◽  
Transcription Initiation ◽  
Terminal Region ◽  
Wild Type ◽  
Dna Templates ◽  
Derivatives Of

ABSTRACT Derivatives of the stationary-phase sigma factor σS of Escherichia coli lacking either of two conserved domains, the postulated N-terminal subregion 1.1 or the C-terminal region 4, were shown to be competent in vitro for transcription initiation from several σS-dependent promoters on supercoiled DNA templates. Unlike wild-type σS, however, the deletion derivatives were inactive on relaxed templates. The anomalous slow electrophoretic mobility of σS on denaturing gels was corrected by deletion of subregion 1.1, suggesting that this domain in σS may be structurally and functionally analogous to subregion 1.1 of σ70, substitutions in which have previously been shown to rectify the anomalous electrophoretic migration of σ70 (V. Gopal and D. Chatterji, Eur. J. Biochem. 244:614-618, 1997).

scholarly journals Expression of Hemin Receptor Molecule ChuA Is Influenced by RfaH in Uropathogenic Escherichia coliStrain 536

2001 ◽  
Vol 69 (3) ◽  
pp. 1924-1928 ◽  
Author(s):  
Gábor Nagy ◽  
Ulrich Dobrindt ◽  
Maren Kupfer ◽  
Levente Emödy ◽  
Helge Karch ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Membrane Protein ◽  
Type Strain ◽  
Wild Type Strain ◽  
Regulatory Protein ◽  
Wild Type ◽  
Receptor Molecule ◽  
E Coli ◽  
Protein Levels ◽  
In The Wild

ABSTRACT The outer membrane protein ChuA responsible for hemin utilization has been recently identified in several pathogenic Escherichia coli strains. We report that the regulatory protein RfaH influences ChuA expression in the uropathogenic E. colistrain 536. In an rfaH mutant, the chuAtranscript as well as the ChuA protein levels were significantly decreased in comparison with those in the wild-type strain. Within thechuA gene, a consensus motif known as the JUMPStart (just upstream of many polysaccharide associated gene starts) sequence was found, which is shared by RfaH-affected operons. Furthermore, the presence of two different subclasses of thechuA determinant and their distribution in E. coli pathogroups are described.

scholarly journals CRYPTIC OPERON FOR β-GLUCOSIDE METABOLISM IN ESCHERICHIA COLI K12: GENETIC EVIDENCE FOR A REGULATORY PROTEIN

Genetics ◽  
1981 ◽  
Vol 97 (1) ◽  
pp. 11-25
Author(s):  
Roberto Defez ◽  
Maurilio De Felice
Keyword(s):  
Escherichia Coli ◽  
Cyclic Amp ◽  
Single Gene ◽  
Regulatory Protein ◽  
Regulatory Site ◽  
Structural Genes ◽  
Wild Type ◽  
Cis Acting ◽  
E Coli ◽  
Escherichia Coli K12

ABSTRACT Escherichia coli K12 does not metabolize β-glucosides such as arbutin and salicin because of lack of expression of the bglBSRC operon, which contains structural genes for transport (bglC) and hydrolysis (bglB) of phospho-β-glucosides. Mutants carrying lesions in the cis-acting regulatory site bglR metabolize β-glucosides as a consequence of expression of this cryptic operon (Prasad and Schaefler 1974). We isolated mutations promoting β-glucoside metabolism that were unlinked to bglR; some of these mutations were shown to be amber. All of them were mapped at 27 min on the E. coli K12 linkage map and appeared to define a single gene, for which we propose the designation bglY. Utilization of β-glucosides in bglY mutants appeared to be a consequence of expression of the bglBSRC operon, since bglB bglR and bglB bglY double mutants had the same phenotype. All bglY mutations analyzed were recessive to the wild-type bglY  + allele. Phospho-β-glucosidase B and β-glucoside transport activities are inducible in bglY mutants, as they are in bglR mutants. Metabolism of β-glucosides in both bglR and bglY mutants required cyclic AMP. We propose that bglY encodes a protein acting as a repressor of the bglBSRC operon, active in both the presence and absence of β-glucosides, whose recognition site would be within the bglR locus.

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