Enhanced Binding of Altered H-NS Protein to Flagellar Rotor Protein FliG Causes Increased Flagellar Rotational Speed and Hypermotility in Escherichia coli

Donato, Gina M.; Kawula, Thomas H.

doi:10.1074/jbc.273.37.24030

Cited by 37 publications

(31 citation statements)

References 55 publications

(51 reference statements)

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“…Interaction of H-NS with proteins other than Hha has been previously reported, but the significance of such interactions remains unclear (8,22,25,31). In contrast, the phenotype of the hha/hns double mutants, which have lost both thermo-and osmoregulation (35), indicates a clear role of the Hha-H-NS complex in the thermo-osmotic regulation of the hly operon.…”

mentioning

confidence: 77%

Temperature- and H-NS-Dependent Regulation of a Plasmid-Encoded Virulence Operon Expressing Escherichia coli Hemolysin

et al. 2002

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Proteins H-NS and Hha form a nucleoprotein complex that modulates expression of the thermoregulated hly operon of Escherichia coli. We have been able to identify two H-NS binding sites in the hly regulatory region. One of them partially overlaps the promoter region (site II), and the other is located about 2 kbp upstream (site I). In contrast, Hha protein did not show any preference for specific sequences. In vitro, temperature influences the affinity of H-NS for a DNA fragment containing both binding sites and H-NS-mediated repression of hly operon transcription. Deletion analysis of the hly regulatory region confirms the relevance of site I for thermoregulation of this operon. We present a model to explain the temperature-modulated repression of the hly operon, based on the experiments reported here and other, preexisting data.

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confidence: 77%

Temperature- and H-NS-Dependent Regulation of a Plasmid-Encoded Virulence Operon Expressing Escherichia coli Hemolysin

et al. 2002

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“…The observed regulation raises the question of why the hns mutant is less motile in spite of being flagellated and having elevated flaA expression. One possibility is that the altered cell morphology of this mutant (12). In this case, the lack of H-NS leads to a paralyzed flagellum.…”

Section: Discussionmentioning

confidence: 99%

Interaction of the Histone-Like Nucleoid Structuring Protein and the General Stress Response Regulator RpoS at Vibrio cholerae Promoters That Regulate Motility and Hemagglutinin/Protease Expression

Wang

Ayala

Benítez

et al. 2011

Journal of Bacteriology

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The bacterium Vibrio cholerae colonizes the human small intestine and secretes cholera toxin (CT) to cause the rice-watery diarrhea characteristic of this illness. The ability of this pathogen to colonize the small bowel, express CT, and return to the aquatic environment is controlled by a complex network of regulatory proteins. Two global regulators that participate in this process are the histone-like nucleoid structuring protein (H-NS) and the general stress response regulator RpoS. In this study, we address the role of RpoS and H-NS in the coordinate regulation of motility and hemagglutinin (HA)/protease expression. In addition to initiating transcription of hapA encoding HA/protease, RpoS enhanced flrA and rpoN transcription to increase motility. In contrast, H-NS was found to bind to the flrA, rpoN, and hapA promoters and represses their expression. The strength of H-NS repression at the above-mentioned promoters was weaker for hapA, which exhibited the strongest RpoS dependency, suggesting that transcription initiation by RNA polymerase containing S could be more resistant to H-NS repression. Occupancy of the flrA and hapA promoters by H-NS was demonstrated by chromatin immunoprecipitation (ChIP). We show that the expression of RpoS in the stationary phase significantly diminished H-NS promoter occupancy. Furthermore, RpoS enhanced the transcription of integration host factor (IHF), which positively affected the expression of flrA and rpoN by diminishing the occupancy of H-NS at these promoters. Altogether, we propose a model for RpoS regulation of motility gene expression that involves (i) attenuation of H-NS repression by IHF and (ii) RpoS-dependent transcription initiation resistant to H-NS.

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“…The significance of this interaction seems clear, since it would favor bacteriophage T7 multiplication by inhibiting H-NS repressive function (25). H-NS also binds to the flagellar rotor protein FliG, but the significance of this interaction is unclear (11,26). The significance of the interaction of H-NS with HF-I (21), an RNA-binding protein that participates in translation of rpoS RNA (31), is also unclear.…”

Section: Discussionmentioning

confidence: 99%

Evidence for Direct Protein-Protein Interaction between Members of the Enterobacterial Hha/YmoA and H-NS Families of Proteins

et al. 2002

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Escherichia coli nucleoid-associated H-NS protein interacts with the Hha protein, a member of a new family of global modulators that also includes the YmoA protein from Yersinia enterocolitica. This interaction has been found to be involved in the regulation of the expression of the toxin ␣-hemolysin. In this study, we further characterize the interaction between H-NS and Hha. We show that the presence of DNA in preparations of copurified His-Hha and H-NS is not directly implicated in the interaction between the proteins. The precise molecular mass of the H-NS protein retained by Hha, obtained by mass spectrometry analysis, does not show any posttranslational modification other than removal of the N-terminal Met residue. We constructed an H-NS-His recombinant protein and found that, as expected, it interacts with Hha. We used a Ni 2؉ -nitrilotriacetic acid agarose method for affinity chromatography copurification of proteins to identify the H-NS protein of Y. enterocolitica. We constructed a six-His-YmoA recombinant protein derived from YmoA, the homologue of Hha in Y. enterocolitica, and found that it interacts with Y. enterocolitica H-NS. We also cloned and sequenced the hns gene of this microorganism. In the course of these experiments we found that His-YmoA can also retain H-NS from E. coli. We also found that the hns gene of Y. enterocolitica can complement an hns mutation of E. coli. Finally, we describe for the first time systematic characterization of missense mutant alleles of hha and truncated Hha proteins, and we report a striking and previously unnoticed similarity of the Hha family of proteins to the oligomerization domain of the H-NS proteins.

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Enhanced Binding of Altered H-NS Protein to Flagellar Rotor Protein FliG Causes Increased Flagellar Rotational Speed and Hypermotility in Escherichia coli

Abstract: H-NS is an

Cited by 37 publications

References 55 publications

Temperature- and H-NS-Dependent Regulation of a Plasmid-Encoded Virulence Operon Expressing Escherichia coli Hemolysin

Temperature- and H-NS-Dependent Regulation of a Plasmid-Encoded Virulence Operon Expressing Escherichia coli Hemolysin

Interaction of the Histone-Like Nucleoid Structuring Protein and the General Stress Response Regulator RpoS at Vibrio cholerae Promoters That Regulate Motility and Hemagglutinin/Protease Expression

Evidence for Direct Protein-Protein Interaction between Members of the Enterobacterial Hha/YmoA and H-NS Families of Proteins

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