Journal articles: 'Histone-like protein H-NS'

1

Coletta, Massimo, Simona Ceschini, Giulio Lupidi, Cynthia L. Pon, Evandro Fioretti, and Mauro Angeletti. "Multimeric Self-assembly Equilibria Involving the Histone-like Protein H-NS." Journal of Biological Chemistry 275, no. 2 (January 2000): 729–34. http://dx.doi.org/10.1074/jbc.275.2.729.

Full text

APA, Harvard, Vancouver, ISO, and other styles

2

Duysak, Taner, Thanh Tuyen Tran, Aqeel Rana Afzal, and Che-Hun Jung. "Fluorescence Spectroscopic Analysis of ppGpp Binding to cAMP Receptor Protein and Histone-Like Nucleoid Structuring Protein." International Journal of Molecular Sciences 22, no. 15 (July 23, 2021): 7871. http://dx.doi.org/10.3390/ijms22157871.

Full text

Abstract:

The cyclic AMP receptor protein (CRP) is one of the best-known transcription factors, regulating about 400 genes. The histone-like nucleoid structuring protein (H-NS) is one of the nucleoid-forming proteins and is responsible for DNA packaging and gene repression in prokaryotes. In this study, the binding of ppGpp to CRP and H-NS was determined by fluorescence spectroscopy. CRP from Escherichia coli exhibited intrinsic fluorescence at 341 nm when excited at 280 nm. The fluorescence intensity decreased in the presence of ppGpp. The dissociation constant of 35 ± 3 µM suggests that ppGpp binds to CRP with a similar affinity to cAMP. H-NS also shows intrinsic fluorescence at 329 nm. The fluorescence intensity was decreased by various ligands and the calculated dissociation constant for ppGpp was 80 ± 11 µM, which suggests that the binding site was occupied fully by ppGpp under starvation conditions. This study suggests the modulatory effects of ppGpp in gene expression regulated by CRP and H-NS. The method described here may be applicable to many other proteins.

APA, Harvard, Vancouver, ISO, and other styles

3

Grainger, David C. "Structure and function of bacterial H-NS protein." Biochemical Society Transactions 44, no. 6 (December 2, 2016): 1561–69. http://dx.doi.org/10.1042/bst20160190.

Full text

Abstract:

The histone-like nucleoid structuring (H-NS) protein is a major component of the folded chromosome in Escherichia coli and related bacteria. Functions attributed to H-NS include management of genome evolution, DNA condensation, and transcription. The wide-ranging influence of H-NS is remarkable given the simplicity of the protein, a small peptide, possessing rudimentary determinants for self-association, hetero-oligomerisation and DNA binding. In this review, I will discuss our understanding of H-NS with a focus on these structural elements. In particular, I will consider how these interaction surfaces allow H-NS to exert its different effects.

APA, Harvard, Vancouver, ISO, and other styles

4

Nishino, Kunihiko, and Akihito Yamaguchi. "Role of Histone-Like Protein H-NS in Multidrug Resistance of Escherichia coli." Journal of Bacteriology 186, no. 5 (March 1, 2004): 1423–29. http://dx.doi.org/10.1128/jb.186.5.1423-1429.2004.

Full text

Abstract:

ABSTRACT The histone-like protein H-NS is a major component of the bacterial nucleoid and plays a crucial role in global gene regulation of enteric bacteria. It is known that the expression of a variety of genes is repressed by H-NS, and mutations in hns result in various phenotypes, but the role of H-NS in the drug resistance of Escherichia coli has not been known. Here we present data showing that H-NS contributes to multidrug resistance by regulating the expression of multidrug exporter genes. Deletion of the hns gene from the ΔacrAB mutant increased levels of resistance against antibiotics, antiseptics, dyes, and detergents. Decreased accumulation of ethidium bromide and rhodamine 6G in the hns mutant compared to that in the parental strain was observed, suggesting the increased expression of some drug exporter(s) in this mutant. The increased drug resistance and decreased drug accumulation caused by the hns deletion were completely suppressed by deletion of the multifunctional outer membrane channel gene tolC. At least eight drug exporter systems require TolC for their functions. Among these, increased expression of acrEF, mdtEF, and emrKY was observed in the Δhns strain by quantitative real-time reverse transcription-PCR analysis. The Δhns-mediated multidrug resistance pattern is quite similar to that caused by overproduction of the AcrEF exporter. Deletion of the acrEF gene greatly suppressed the level of Δhns-mediated multidrug resistance. However, this strain still retained resistance to some compounds. The remainder of the multidrug resistance pattern was similar to that conferred by overproduction of the MdtEF exporter. Double deletion of the mdtEF and acrEF genes completely suppressed Δhns-mediated multidrug resistance, indicating that Δhns-mediated multidrug resistance is due to derepression of the acrEF and mdtEF drug exporter genes.

APA, Harvard, Vancouver, ISO, and other styles

5

Dalai, Baolige, Rui Zhou, Yun Wan, Mingsong Kang, Lu Li, Tingting Li, Sihua Zhang, and Huanchun Chen. "Histone-like protein H-NS regulates biofilm formation and virulence of Actinobacillus pleuropneumoniae." Microbial Pathogenesis 46, no. 3 (March 2009): 128–34. http://dx.doi.org/10.1016/j.micpath.2008.11.005.

Full text

APA, Harvard, Vancouver, ISO, and other styles

6

Hulton, Christopher S. J., Alexander Seirafi, Jay C. D. Hinton, Julie M. Sidebotham, Lesley Waddell, Graham D. Pavitt, Thomas Owen-Hughes, Annick Spassky, Henri Buc, and Christopher F. Higgins. "Histone-like protein H1 (H-NS), DNA supercoiling, and gene expression in bacteria." Cell 63, no. 3 (November 1990): 631–42. http://dx.doi.org/10.1016/0092-8674(90)90458-q.

Full text

APA, Harvard, Vancouver, ISO, and other styles

7

Shiga, Yasuyuki, Yasuhiko Sekine, Yasunobu Kano, and Eiichi Ohtsubo. "Involvement of H-NS in Transpositional Recombination Mediated by IS1." Journal of Bacteriology 183, no. 8 (April 15, 2001): 2476–84. http://dx.doi.org/10.1128/jb.183.8.2476-2484.2001.

Full text

Abstract:

ABSTRACT IS1, the smallest active transposable element in bacteria, encodes a transposase that promotes inter- and intramolecular transposition. Host-encoded factors, e.g., histone-like proteins HU and integration host factor (IHF), are involved in the transposition reactions of some bacterial transposable elements. Host factors involved in the IS1 transposition reaction, however, are not known. We show that a plasmid with an IS1 derivative that efficiently produces transposase did not generate miniplasmids, the products of intramolecular transposition, in mutants deficient in a nucleoid-associated DNA-binding protein, H-NS, but did generate them in mutants deficient in histone-like proteins HU, IHF, Fis, and StpA. Nor did IS1 transpose intermolecularly to the target plasmid in the H-NS-deficient mutant. The hns mutation did not affect transcription from the indigenous promoter of IS1 for the expression of the transposase gene. These findings show that transpositional recombination mediated by IS1 requires H-NS but does not require the HU, IHF, Fis, or StpA protein in vivo. Gel retardation assays of restriction fragments of IS1-carrying plasmid DNA showed that no sites were bound preferentially by H-NS within the IS1 sequence. The central domain of H-NS, which is involved in dimerization and/or oligomerization of the H-NS protein, was important for the intramolecular transposition of IS1, but the N- and C-terminal domains, which are involved in the repression of certain genes and DNA binding, respectively, were not. The SOS response induced by the IS1 transposase was absent in the H-NS-deficient mutant strain but was present in the wild-type strain. We discuss the possibility that H-NS promotes the formation of an active IS1 DNA-transposase complex in which the IS1 ends are cleaved to initiate transpositional recombination through interaction with IS1 transposase.

APA, Harvard, Vancouver, ISO, and other styles

8

Choi, Jeongjoon, and Eduardo A. Groisman. "Salmonellaexpresses foreign genes during infection by degrading their silencer." Proceedings of the National Academy of Sciences 117, no. 14 (March 24, 2020): 8074–82. http://dx.doi.org/10.1073/pnas.1912808117.

Full text

Abstract:

The heat-stable nucleoid structuring (H-NS, also referred to as histone-like nucleoid structuring) protein silences transcription of foreign genes in a variety of Gram-negative bacterial species. To take advantage of the products encoded in foreign genes, bacteria must overcome the silencing effects of H-NS. Because H-NS amounts are believed to remain constant, overcoming gene silencing has largely been ascribed to proteins that outcompete H-NS for binding to AT-rich foreign DNA. However, we report here that the facultative intracellular pathogenSalmonella entericaserovar Typhimurium decreases H-NS amounts 16-fold when inside macrophages. This decrease requires both the protease Lon and the DNA-binding virulence regulator PhoP. The decrease in H-NS abundance reduces H-NS binding to foreign DNA, allowing transcription of foreign genes, including those required for intramacrophage survival. The purified Lon protease degraded free H-NS but not DNA-bound H-NS. By displacing H-NS from DNA, the PhoP protein promoted H-NS proteolysis, thereby de-repressing foreign genes—even those whose regulatory sequences are not bound by PhoP. The uncovered mechanism enables a pathogen to express foreign virulence genes during infection without the need to evolve binding sites for antisilencing proteins at each foreign gene.

APA, Harvard, Vancouver, ISO, and other styles

9

Nishino, Kunihiko, Mitsuko Hayashi-Nishino, and Akihito Yamaguchi. "H-NS Modulates Multidrug Resistance of Salmonella enterica Serovar Typhimurium by Repressing Multidrug Efflux Genes acrEF." Antimicrobial Agents and Chemotherapy 53, no. 8 (June 8, 2009): 3541–43. http://dx.doi.org/10.1128/aac.00371-09.

Full text

Abstract:

ABSTRACT Screening of Salmonella mutants for the ability to increase β-lactam resistance has led to the identification of a mutation in hns, which codes for the histone-like nucleoid structuring protein (H-NS). In this study, we report that H-NS modulates multidrug resistance through repression of the genes that encode the AcrEF multidrug efflux pump in Salmonella enterica serovar Typhimurium.

APA, Harvard, Vancouver, ISO, and other styles

10

Ito, K., T. Oshima, T. Mizuno, and Y. Nakamura. "Regulation of lysyl-tRNA synthetase expression by histone-like protein H-NS of Escherichia coli." Journal of Bacteriology 176, no. 23 (1994): 7383–86. http://dx.doi.org/10.1128/jb.176.23.7383-7386.1994.

Full text

APA, Harvard, Vancouver, ISO, and other styles

11

Müller, Claudia M., Ulrich Dobrindt, Gábor Nagy, Levente Emödy, Bernt Eric Uhlin, and Jörg Hacker. "Role of Histone-Like Proteins H-NS and StpA in Expression of Virulence Determinants of Uropathogenic Escherichia coli." Journal of Bacteriology 188, no. 15 (August 1, 2006): 5428–38. http://dx.doi.org/10.1128/jb.01956-05.

Full text

Abstract:

ABSTRACT The histone-like protein H-NS is a global regulator in Escherichia coli that has been intensively studied in nonpathogenic strains. However, no comprehensive study on the role of H-NS and its paralogue, StpA, in gene expression in pathogenic E. coli has been carried out so far. Here, we monitored the global effects of H-NS and StpA in a uropathogenic E. coli isolate by using DNA arrays. Expression profiling revealed that more than 500 genes were affected by an hns mutation, whereas no effect of StpA alone was observed. An hns stpA double mutant showed a distinct gene expression pattern that differed in large part from that of the hns single mutant. This suggests a direct interaction between the two paralogues and the existence of distinct regulons of H-NS and an H-NS/StpA heteromeric complex. hns mutation resulted in increased expression of alpha-hemolysin, fimbriae, and iron uptake systems as well as genes involved in stress adaptation. Furthermore, several other putative virulence genes were found to be part of the H-NS regulon. Although the lack of H-NS, either alone or in combination with StpA, has a huge impact on gene expression in pathogenic E. coli strains, its effect on virulence is ambiguous. At a high infection dose, hns mutants trigger more sudden lethality due to their increased acute toxicity in murine urinary tract infection and sepsis models. At a lower infectious dose, however, mutants lacking H-NS are attenuated through their impaired growth rate, which can only partially be compensated for by the higher expression of numerous virulence factors.

APA, Harvard, Vancouver, ISO, and other styles

12

Silva, Anisia J., Syed Zafar Sultan, Weili Liang, and Jorge A. Benitez. "Role of the Histone-Like Nucleoid Structuring Protein in the Regulation of rpoS and RpoS-Dependent Genes in Vibrio cholerae." Journal of Bacteriology 190, no. 22 (September 12, 2008): 7335–45. http://dx.doi.org/10.1128/jb.00360-08.

Full text

Abstract:

ABSTRACT Production of the Zn-metalloprotease hemagglutinin (HA)/protease by Vibrio cholerae has been reported to enhance enterotoxicity in rabbit ileal loops and the reactogenicity of live cholera vaccine candidates. Expression of HA/protease requires the alternate sigma factor σS (RpoS), encoded by rpoS. The histone-like nucleoid structuring protein (H-NS) has been shown to repress rpoS expression in Escherichia coli. In V. cholerae strains of the classical biotype, H-NS has been reported to silence virulence gene expression. In this study we examined the role of H-NS in the expression of HA/protease and motility in an El Tor biotype strain by constructing a Δhns mutant. The Δhns mutant exhibited multiple phenotypes, such as production of cholera toxin in nonpermissive LB medium, reduced resistance to high osmolarity, enhanced resistance to low pH and hydrogen peroxide, and reduced motility. Depletion of H-NS by overexpression of a dominant-negative allele or by deletion of hns resulted in diminished expression of HA/protease. Epistasis analysis of HA/protease expression in Δhns, ΔrpoS, and Δhns ΔrpoS mutants, analysis of RpoS reporter fusions, quantitative reverse transcription-PCR measurements, and ectopic expression of RpoS in ΔrpoS and ΔrpoS Δhns mutants showed that H-NS posttranscriptionally enhances RpoS expression. The Δhns mutant exhibited a lower degree of motility and lower levels of expression of flaA, flaC, cheR-2, and motX mRNAs than the wild type. Comparison of the mRNA abundances of these genes in wild-type, Δhns, ΔrpoS, and Δhns ΔrpoS strains revealed that deletion of rpoS had a more severe negative effect on their expression. Interestingly, deletion of hns in the rpoS background resulted in higher expression levels of flaA, flaC, and motX, suggesting that H-NS represses the expression of these genes in the absence of σS. Finally, we show that the cyclic AMP receptor protein and H-NS act along the same pathway to positively affect RpoS expression.

APA, Harvard, Vancouver, ISO, and other styles

13

Kim, Eun A., and David F. Blair. "Function of the Histone-Like Protein H-NS in Motility of Escherichia coli: Multiple Regulatory Roles Rather than Direct Action at the Flagellar Motor." Journal of Bacteriology 197, no. 19 (July 20, 2015): 3110–20. http://dx.doi.org/10.1128/jb.00309-15.

Full text

Abstract:

ABSTRACTA number of investigations ofEscherichia colihave suggested that the DNA-binding protein H-NS, in addition to its well-known functions in chromosome organization and gene regulation, interacts directly with the flagellar motor to modulate its function. Here, in a study initially aimed at characterizing the H-NS/motor interaction further, we identify problems and limitations in the previous work that substantially weaken the case for a direct H-NS/motor interaction. Nullhnsmutants are immotile, largely owing to the downregulation of the flagellar master regulators FlhD and FlhC. We, and others, previously reported that anhnsmutant remains poorly motile even when FlhDC are expressed constitutively. In the present work, we use better-engineered strains to show that the motility defect in a Δhns, FlhDC-constitutive strain is milder than that reported previously and does not point to a direct action of H-NS at the motor. H-NS regulates numerous genes and might influence motility via a number of regulatory molecules besides FlhDC. To examine the sources of the motility defect that persists in an FlhDC-constitutive Δhnsmutant, we measured transcript levels and overexpression effects of a number of genes in candidate regulatory pathways. The results indicate that H-NS influences motility via multiple regulatory linkages that include, minimally, the messenger molecule cyclic di-GMP, the biofilm regulatory protein CsgD, and the sigma factors σSand σF. The results are in accordance with the more standard view of H-NS as a regulator of gene expression rather than a direct modulator of flagellar motor performance.IMPORTANCEData from a number of previous studies have been taken to indicate that the nucleoid-organizing protein H-NS influences motility not only by its well-known DNA-based mechanisms but also by binding directly to the flagellar motor to alter function. In this study, H-NS is shown to influence motility through diverse regulatory pathways, but a direct interaction with the motor is not supported. Previous indications of a direct action at the motor appear to be related to the use of nonnull strains and, in some cases, a failure to effectively bypass the requirement for H-NS in the expression of the flagellar regulon. These findings call for a substantially revised interpretation of the literature concerning H-NS and flagellar motility and highlight the importance of H-NS in diverse regulatory processes involved in the motile-sessile transition.

APA, Harvard, Vancouver, ISO, and other styles

14

Kaidow, A., M. Wachi, J. Nakamura, J. Magae, and K. Nagai. "Anucleate cell production by Escherichia coli delta hns mutant lacking a histone-like protein, H-NS." Journal of bacteriology 177, no. 12 (1995): 3589–92. http://dx.doi.org/10.1128/jb.177.12.3589-3592.1995.

Full text

APA, Harvard, Vancouver, ISO, and other styles

15

Rimsky, Sylvie. "Structure of the histone-like protein H-NS and its role in regulation and genome superstructure." Current Opinion in Microbiology 7, no. 2 (April 2004): 109–14. http://dx.doi.org/10.1016/j.mib.2004.02.001.

Full text

APA, Harvard, Vancouver, ISO, and other styles

16

Jian, Huahua, Guanpeng Xu, Yingbao Gai, Jun Xu, and Xiang Xiao. "The Histone-Like Nucleoid Structuring Protein (H-NS) Is a Negative Regulator of the Lateral Flagellar System in the Deep-Sea Bacterium Shewanella piezotolerans WP3." Applied and Environmental Microbiology 82, no. 8 (February 12, 2016): 2388–98. http://dx.doi.org/10.1128/aem.00297-16.

Full text

Abstract:

ABSTRACTAlthough the histone-like nucleoid structuring protein (H-NS) is well known for its involvement in the adaptation of mesophilic bacteria, such asEscherichia coli, to cold environments and high-pressure stress, an understanding of the role of H-NS in the cold-adapted benthic microorganisms that live in the deep-sea ecosystem, which covers approximately 60% of the earth's surface, is still lacking. In this study, we characterized the function of H-NS inShewanella piezotoleransWP3, which was isolated from West Pacific sediment at a depth of 1,914 m. Anhnsgene deletion mutant (WP3Δhns) was constructed, and comparative whole-genome microarray analysis was performed. H-NS had a significant influence (fold change, >2) on the expression of a variety of WP3 genes (274 and 280 genes were upregulated and downregulated, respectively), particularly genes related to energy production and conversion. Notably, WP3Δhnsexhibited higher expression levels of lateral flagellar genes than WP3 and showed enhanced swarming motility and lateral flagellar production compared to those of WP3. The DNA gel mobility shift experiment showed that H-NS bound specifically to the promoter of lateral flagellar genes. Moreover, the high-affinity binding sequences of H-NS were identified by DNase I protection footprinting, and the results support the “binding and spreading” model for H-NS functioning. To our knowledge, this is the first attempt to characterize the function of the universal regulator H-NS in a deep-sea bacterium. Our data revealed that H-NS has a novel function as a repressor of the expression of genes related to the energy-consuming secondary flagellar system and to swarming motility.

APA, Harvard, Vancouver, ISO, and other styles

17

Wang, Hongxia, Julio C. Ayala, Anisia J. Silva, and Jorge A. Benitez. "The Histone-Like Nucleoid Structuring Protein (H-NS) Is a Repressor of Vibrio cholerae Exopolysaccharide Biosynthesis (vps) Genes." Applied and Environmental Microbiology 78, no. 7 (January 27, 2012): 2482–88. http://dx.doi.org/10.1128/aem.07629-11.

Full text

Abstract:

ABSTRACTThe capacity ofVibrio choleraeto form biofilms has been shown to enhance its survival in the aquatic environment and play important roles in pathogenesis and disease transmission. In this study, we demonstrated that the histone-like nucleoid structuring protein is a repressor of exopolysaccharide (vps) biosynthesis genes and biofilm formation.

APA, Harvard, Vancouver, ISO, and other styles

18

Japaridze, Aleksandre, Sylvain Renevey, Patrick Sobetzko, Liubov Stoliar, William Nasser, Giovanni Dietler, and Georgi Muskhelishvili. "Spatial organization of DNA sequences directs the assembly of bacterial chromatin by a nucleoid-associated protein." Journal of Biological Chemistry 292, no. 18 (March 18, 2017): 7607–18. http://dx.doi.org/10.1074/jbc.m117.780239.

Full text

Abstract:

Structural differentiation of bacterial chromatin depends on cooperative binding of abundant nucleoid-associated proteins at numerous genomic DNA sites and stabilization of distinct long-range nucleoprotein structures. Histone-like nucleoid-structuring protein (H-NS) is an abundant DNA-bridging, nucleoid-associated protein that binds to an AT-rich conserved DNA sequence motif and regulates both the shape and the genetic expression of the bacterial chromosome. Although there is ample evidence that the mode of H-NS binding depends on environmental conditions, the role of the spatial organization of H-NS-binding sequences in the assembly of long-range nucleoprotein structures remains unknown. In this study, by using high-resolution atomic force microscopy combined with biochemical assays, we explored the formation of H-NS nucleoprotein complexes on circular DNA molecules having different arrangements of identical sequences containing high-affinity H-NS-binding sites. We provide the first experimental evidence that variable sequence arrangements result in various three-dimensional nucleoprotein structures that differ in their shape and the capacity to constrain supercoils and compact the DNA. We believe that the DNA sequence-directed versatile assembly of periodic higher-order structures reveals a general organizational principle that can be exploited for knowledge-based design of long-range nucleoprotein complexes and purposeful manipulation of the bacterial chromatin architecture.

APA, Harvard, Vancouver, ISO, and other styles

19

Qin, L., A. M. Erkelens, F. Ben Bdira, and R. T. Dame. "The architects of bacterial DNA bridges: a structurally and functionally conserved family of proteins." Open Biology 9, no. 12 (December 2019): 190223. http://dx.doi.org/10.1098/rsob.190223.

Full text

Abstract:

Every organism across the tree of life compacts and organizes its genome with architectural chromatin proteins. While eukaryotes and archaea express histone proteins, the organization of bacterial chromosomes is dependent on nucleoid-associated proteins. In Escherichia coli and other proteobacteria, the histone-like nucleoid structuring protein (H-NS) acts as a global genome organizer and gene regulator. Functional analogues of H-NS have been found in other bacterial species: MvaT in Pseudomonas species, Lsr2 in actinomycetes and Rok in Bacillus species. These proteins complement hns − phenotypes and have similar DNA-binding properties, despite their lack of sequence homology. In this review, we focus on the structural and functional characteristics of these four architectural proteins. They are able to bridge DNA duplexes, which is key to genome compaction, gene regulation and their response to changing conditions in the environment. Structurally the domain organization and charge distribution of these proteins are conserved, which we suggest is at the basis of their conserved environment responsive behaviour. These observations could be used to find and validate new members of this protein family and to predict their response to environmental changes.

APA, Harvard, Vancouver, ISO, and other styles

20

Dorman, Charles J. "Co-operative roles for DNA supercoiling and nucleoid-associated proteins in the regulation of bacterial transcription." Biochemical Society Transactions 41, no. 2 (March 21, 2013): 542–47. http://dx.doi.org/10.1042/bst20120222.

Full text

Abstract:

DNA supercoiling and NAPs (nucleoid-associated proteins) contribute to the regulation of transcription of many bacterial genes. The horizontally acquired SPI (Salmonella pathogenicity island) genes respond positively to DNA relaxation, they are activated and repressed by the Fis (factor for inversion stimulation) and H-NS (histone-like nucleoid-structuring) NAPs respectively, and are positively controlled by the OmpR global regulatory protein. The ompR gene is autoregulated and responds positively to DNA relaxation. Binding of the Fis and OmpR proteins to their targets in DNA is differentially sensitive to its topological state, whereas H-NS binds regardless of the topological state of the DNA. These data illustrate the overlapping and complex nature of NAP and DNA topological contributions to transcription control in bacteria.

APA, Harvard, Vancouver, ISO, and other styles

21

Melkina, O. E., I. I. Goryanin, and G. B. Zavilgelsky. "Histone-like protein H-NS as a negative regulator of quorum sensing systems in gram-negative bacteria." Russian Journal of Genetics 53, no. 2 (February 2017): 187–94. http://dx.doi.org/10.1134/s1022795417020065.

Full text

APA, Harvard, Vancouver, ISO, and other styles

22

Coker, Christopher, Olubunmi O. Bakare, and Harry L. T. Mobley. "H-NS Is a Repressor of the Proteus mirabilis Urease Transcriptional Activator GeneureR." Journal of Bacteriology 182, no. 9 (May 1, 2000): 2649–53. http://dx.doi.org/10.1128/jb.182.9.2649-2653.2000.

Full text

Abstract:

ABSTRACT Expression of Proteus mirabilis urease is governed by UreR, an AraC-like positive transcriptional activator. A poly(A) tract nucleotide sequence, consisting of A6TA2CA2TGGTA5GA6TGA5, is located 16 bp upstream of the ς70-likeureR promoter P2. Since poly(A) tracts of DNA serve as binding sites for the gene repressor histone-like nucleoid structuring protein (H-NS), we measured β-galactosidase activity of wild-typeEscherichia coli MC4100 (H-NS+) and its isogenic derivative ATM121 (hns::Tn10) (H-NS−) harboring a ureR-lacZ operon fusion plasmid (pLC9801). β-Galactosidase activity in the H-NS− host strain was constitutive and sevenfold greater (P < 0.0001) than that in the H-NS+ host. A recombinant plasmid containing cloned P. mirabilis hns was able to complement and restore repression of the ureR promoter in the H-NS−host when provided in trans. Deletion of the poly(A) tract nucleotide sequence from pLC9801 resulted in an increase in β-galactosidase activity in the H-NS+ host to nearly the same levels as that observed for wild-type pLC9801 harbored by the H-NS−host. Urease activity in strains harboring the recombinant plasmid pMID1010 (encoding the entire urease gene cluster of P. mirabilis) was equivalent in both the H-NS−background and the H-NS+ background in the presence of urea but was eightfold greater (P = 0.0001) in the H-NS− background in the absence of urea. We conclude that H-NS represses ureR expression in the absence of urea induction.

APA, Harvard, Vancouver, ISO, and other styles

23

Ono, Shusuke, Martin D. Goldberg, Tjelvar Olsson, Diego Esposito, Jay C. D. Hinton, and John E. Ladbury. "H-NS is a part of a thermally controlled mechanism for bacterial gene regulation." Biochemical Journal 391, no. 2 (October 10, 2005): 203–13. http://dx.doi.org/10.1042/bj20050453.

Full text

Abstract:

Temperature is a primary environmental stress to which micro-organisms must be able to adapt and respond rapidly. Whereas some bacteria are restricted to specific niches and have limited abilities to survive changes in their environment, others, such as members of the Enterobacteriaceae, can withstand wide fluctuations in temperature. In addition to regulating cellular physiology, pathogenic bacteria use temperature as a cue for activating virulence gene expression. This work confirms that the nucleoid-associated protein H-NS (histone-like nucleoid structuring protein) is an essential component in thermoregulation of Salmonella. On increasing the temperature from 25 to 37 °C, more than 200 genes from Salmonella enterica serovar Typhimurium showed H-NS-dependent up-regulation. The thermal activation of gene expression is extremely rapid and change in temperature affects the DNA-binding properties of H-NS. The reduction in gene repression brought about by the increase in temperature is concomitant with a conformational change in the protein, resulting in the decrease in size of high-order oligomers and the appearance of increasing concentrations of discrete dimers of H-NS. The present study addresses one of the key complex mechanisms by which H-NS regulates gene expression.

APA, Harvard, Vancouver, ISO, and other styles

24

Brunet, Yannick R., Ahmad Khodr, Laureen Logger, Laurent Aussel, Tâm Mignot, Sylvie Rimsky, and Eric Cascales. "H-NS Silencing of the Salmonella Pathogenicity Island 6-Encoded Type VI Secretion System Limits Salmonella enterica Serovar Typhimurium Interbacterial Killing." Infection and Immunity 83, no. 7 (April 27, 2015): 2738–50. http://dx.doi.org/10.1128/iai.00198-15.

Full text

Abstract:

The secretion of bacterial toxin proteins is achieved by dedicated machineries called secretion systems. The type VI secretion system (T6SS) is a widespread versatile machine used for the delivery of protein toxins to both prokaryotic and eukaryotic cells. InSalmonella entericaserovar Typhimurium, the expression of the T6SS genes is activated during macrophage or mouse infection. Here, we show that the T6SS gene cluster is silenced by the histone-like nucleoid structuring H-NS protein using a combination of reporter fusions, electrophoretic mobility shift assays, DNase footprinting, and fluorescence microscopy. We further demonstrate that derepression of theS. Typhimurium T6SS genes induces T6SS-dependent intoxication of competing bacteria. Our results suggest that relieving T6SS H-NS silencing may be used as a sense-and-kill mechanism that will helpS. Typhimurium to homogenize and synchronize the microbial population to gain efficiency during infection.

APA, Harvard, Vancouver, ISO, and other styles

25

Ho, Chun-Han, Hao-Ching Wang, Tzu-Ping Ko, Yuan-Chih Chang, and Andrew H. J. Wang. "The T4 Phage DNA Mimic Protein Arn Inhibits the DNA Binding Activity of the Bacterial Histone-like Protein H-NS." Journal of Biological Chemistry 289, no. 39 (August 12, 2014): 27046–54. http://dx.doi.org/10.1074/jbc.m114.590851.

Full text

APA, Harvard, Vancouver, ISO, and other styles

26

Yun, Choong-Soo, Chiho Suzuki, Kunihiko Naito, Toshiharu Takeda, Yurika Takahashi, Fumiya Sai, Tsuguno Terabayashi, et al. "Pmr, a Histone-Like Protein H1 (H-NS) Family Protein Encoded by the IncP-7 Plasmid pCAR1, Is a Key Global Regulator That Alters Host Function." Journal of Bacteriology 192, no. 18 (July 16, 2010): 4720–31. http://dx.doi.org/10.1128/jb.00591-10.

Full text

Abstract:

ABSTRACT Histone-like protein H1 (H-NS) family proteins are nucleoid-associated proteins (NAPs) conserved among many bacterial species. The IncP-7 plasmid pCAR1 is transmissible among various Pseudomonas strains and carries a gene encoding the H-NS family protein, Pmr. Pseudomonas putida KT2440 is a host of pCAR1, which harbors five genes encoding the H-NS family proteins PP_1366 (TurA), PP_3765 (TurB), PP_0017 (TurC), PP_3693 (TurD), and PP_2947 (TurE). Quantitative reverse transcription-PCR (qRT-PCR) demonstrated that the presence of pCAR1 does not affect the transcription of these five genes and that only pmr, turA, and turB were primarily transcribed in KT2440(pCAR1). In vitro pull-down assays revealed that Pmr strongly interacted with itself and with TurA, TurB, and TurE. Transcriptome comparisons of the pmr disruptant, KT2440, and KT2440(pCAR1) strains indicated that pmr disruption had greater effects on the host transcriptome than did pCAR1 carriage. The transcriptional levels of some genes that increased with pCAR1 carriage, such as the mexEF-oprN efflux pump genes and parI, reverted with pmr disruption to levels in pCAR1-free KT2440. Transcriptional levels of putative horizontally acquired host genes were not altered by pCAR1 carriage but were altered by pmr disruption. Identification of genome-wide Pmr binding sites by ChAP-chip (chromatin affinity purification coupled with high-density tiling chip) analysis demonstrated that Pmr preferentially binds to horizontally acquired DNA regions. The Pmr binding sites overlapped well with the location of the genes differentially transcribed following pmr disruption on both the plasmid and the chromosome. Our findings indicate that Pmr is a key factor in optimizing gene transcription on pCAR1 and the host chromosome.

APA, Harvard, Vancouver, ISO, and other styles

27

Liu, Baomo, Lili Shui, Kai Zhou, Ying Jiang, Xiaoyu Li, Jing Guan, Qi Li, and Chao Zhuo. "Impact of Plasmid-Encoded H-NS–like Protein on blaNDM-1-Bearing IncX3 Plasmid in Escherichia coli." Journal of Infectious Diseases 221, Supplement_2 (March 16, 2020): S229—S236. http://dx.doi.org/10.1093/infdis/jiz567.

Full text

Abstract:

Abstract Background This study was performed to assess the role of the histone-like nucleoid-structuring (H-NS)–like protein, carried by blaNDM-1-encoding IncX3-type plasmids, in the dissemination of IncX3 plasmids. Methods The blaNDM-1-encoding IncX3 plasmids were analyzed using southern blot, conjugation, and competition assays. Virulence was evaluated with a Galleria mellonella infection model. An hns-knockout IncX3 plasmid was also constructed to identify the functions of plasmid-borne H-NS–like protein in Escherichia coli. Results The assasys detected blaNDM-1-encoding IncX3-type plasmids with similar fingerprint patterns in all New Delhi metallo-β-lactamase (NDM) 1–producing carbapenem-resistant Enterobacteriaceae. The IncX3 plasmid conferred a fitness advantage to E. coli J53 but had no effect on host virulence. Moreover, the transconjugation frequency of the hns-null IncX3 plasmid pHN330-△hns was increased by 2.5-fold compared with the wild type. This was caused by up-regulation of conjugation-related plasmid-borne genes and the partition-related gene, in the J330-pHN330-△hns strain. In addition, decreased virulence was detected with this variant. Conclusions Our results highlight the important role of IncX3 plasmids in the dissemination of blaNDM-1 in south China. Plasmid-encoded H-NS–like protein can inhibit plasmid conjugation, partition, and the expression of related genes, in addition to promoting virulence in the host.

APA, Harvard, Vancouver, ISO, and other styles

28

Tippner, Detlev, Henning Afflerbach, Christiane Bradaczek, and Rolf Wagner. "Evidence for a regulatory function of the histone-like Escherichia coli protein H-NS in ribosomal RNA synthesis." Molecular Microbiology 11, no. 3 (February 1994): 589–604. http://dx.doi.org/10.1111/j.1365-2958.1994.tb00339.x.

Full text

APA, Harvard, Vancouver, ISO, and other styles

29

Franzon, J. H., and D. S. Santos. "A role for histone-like protein H1 (H-NS) in the regulation of hemolysin expression by Serratia marcescens." Brazilian Journal of Medical and Biological Research 37, no. 12 (December 2004): 1763–69. http://dx.doi.org/10.1590/s0100-879x2004001200001.

Full text

APA, Harvard, Vancouver, ISO, and other styles

30

Oshima, T., S. Ishikawa, K. Kurokawa, H. Aiba, and N. Ogasawara. "Escherichia coli Histone-Like Protein H-NS Preferentially Binds to Horizontally Acquired DNA in Association with RNA Polymerase." DNA Research 13, no. 4 (January 1, 2006): 141–53. http://dx.doi.org/10.1093/dnares/dsl009.

Full text

APA, Harvard, Vancouver, ISO, and other styles

31

Dole, Sudhanshu, V. Nagarajavel, and Karin Schnetz. "The histone-like nucleoid structuring protein H-NS represses the Escherichia coli bgl operon downstream of the promoter." Molecular Microbiology 52, no. 2 (March 4, 2004): 589–600. http://dx.doi.org/10.1111/j.1365-2958.2004.04001.x.

Full text

APA, Harvard, Vancouver, ISO, and other styles

32

Park, Kwon-Sam, Michiko Arita, Tetsuya Iida, and Takeshi Honda. "vpaH, a Gene Encoding a Novel Histone-Like Nucleoid Structure-Like Protein That Was Possibly Horizontally Acquired, Regulates the Biogenesis of Lateral Flagella in trh-Positive Vibrio parahaemolyticus TH3996." Infection and Immunity 73, no. 9 (September 2005): 5754–61. http://dx.doi.org/10.1128/iai.73.9.5754-5761.2005.

Full text

Abstract:

ABSTRACT A histone-like nucleoid structure (H-NS) is a major component of the bacterial nucleoid and plays a crucial role in the global gene regulation of enteric bacteria. Here, we cloned and characterized the gene for the H-NS-like protein VpaH in Vibrio parahaemolyticus. vpaH encodes a protein of 134 amino acids that shows approximately 55%, 54%, and 41% identities with VicH in Vibrio cholerae, H-NS in V. parahaemolyticus, and H-NS in Escherichia coli, respectively. The vpaH gene was found in only trh-positive V. parahaemolyticus strains and not in Kanagawa-positive or in trh-negative environmental strains. Moreover, the G+C content of the vpaH gene was 38.6%, which is lower than the average G+C content of the whole genome of this bacterium (45.4%). These data suggest that vpaH was transmitted to trh-possessing V. parahaemolyticus strains by lateral transfer. The vpaH gene was located about 2.6 kb downstream of the trh gene, in the convergent direction of the trh transcription. An in-frame deletion mutant of vpaH lacked motility on semisolid motility assay plates. Western blot analysis and electron microscopy observations revealed that the mutant was deficient in lateral flagella biogenesis, whereas there was no defect in the expression of polar flagella. Additionally, the vpaH mutant showed a decreased adherence to HeLa cells and a decrease in biofilm formation compared with the wild-type strain. Introduction of the vpaH gene in the vpaH-negative strain increased the expression of lateral flagella compared with the wild-type strain. In conclusion, our findings suggest that VpaH affects lateral flagellum biogenesis in trh-positive V. parahaemolyticus strain TH3996.

APA, Harvard, Vancouver, ISO, and other styles

33

Ali Azam, Talukder, Akira Iwata, Akiko Nishimura, Susumu Ueda, and Akira Ishihama. "Growth Phase-Dependent Variation in Protein Composition of the Escherichia coli Nucleoid." Journal of Bacteriology 181, no. 20 (October 15, 1999): 6361–70. http://dx.doi.org/10.1128/jb.181.20.6361-6370.1999.

Full text

Abstract:

ABSTRACT The genome DNA of Escherichia coli is associated with about 10 DNA-binding structural proteins, altogether forming the nucleoid. The nucleoid proteins play some functional roles, besides their structural roles, in the global regulation of such essential DNA functions as replication, recombination, and transcription. Using a quantitative Western blot method, we have performed for the first time a systematic determination of the intracellular concentrations of 12 species of the nucleoid protein in E. coli W3110, including CbpA (curved DNA-binding protein A), CbpB (curved DNA-binding protein B, also known as Rob [right origin binding protein]), DnaA (DNA-binding protein A), Dps (DNA-binding protein from starved cells), Fis (factor for inversion stimulation), Hfq (host factor for phage Qβ), H-NS (histone-like nucleoid structuring protein), HU (heat-unstable nucleoid protein), IciA (inhibitor of chromosome initiation A), IHF (integration host factor), Lrp (leucine-responsive regulatory protein), and StpA (suppressor oftd mutant phenotype A). Intracellular protein levels reach a maximum at the growing phase for nine proteins, CbpB (Rob), DnaA, Fis, Hfq, H-NS, HU, IciA, Lrp, and StpA, which may play regulatory roles in DNA replication and/or transcription of the growth-related genes. In descending order, the level of accumulation, calculated in monomers, in growing E. coli cells is Fis, Hfq, HU, StpA, H-NS, IHF*, CbpB (Rob), Dps*, Lrp, DnaA, IciA, and CbpA* (stars represent the stationary-phase proteins). The order of abundance, in descending order, in the early stationary phase is Dps*, IHF*, HU, Hfq, H-NS, StpA, CbpB (Rob), DnaA, Lrp, IciA, CbpA, and Fis, while that in the late stationary phase is Dps*, IHF*, Hfq, HU, CbpA*, StpA, H-NS, CbpB (Rob), DnaA, Lrp, IciA, and Fis. Thus, the major protein components of the nucleoid change from Fis and HU in the growing phase to Dps in the stationary phase. The curved DNA-binding protein, CbpA, appears only in the late stationary phase. These changes in the composition of nucleoid-associated proteins in the stationary phase are accompanied by compaction of the genome DNA and silencing of the genome functions.

APA, Harvard, Vancouver, ISO, and other styles

34

Dole, Sudhanshu, Yvonne Klingen, V. Nagarajavel, and Karin Schnetz. "The Protease Lon and the RNA-Binding Protein Hfq Reduce Silencing of the Escherichia coli bgl Operon by H-NS." Journal of Bacteriology 186, no. 9 (May 1, 2004): 2708–16. http://dx.doi.org/10.1128/jb.186.9.2708-2716.2004.

Full text

Abstract:

ABSTRACT The histone-like nucleoid structuring protein H-NS represses the Escherichia coli bgl operon at two levels. H-NS binds upstream of the promoter, represses transcription initiation, and binds downstream within the coding region of the first gene, where it induces polarity of transcription elongation. In hns mutants, silencing of the bgl operon is completely relieved. Various screens for mutants in which silencing of bgl is reduced have yielded mutations in hns and in genes encoding the transcription factors LeuO and BglJ. In order to identify additional factors that regulate bgl, we performed a transposon mutagenesis screen for mutants in which silencing of the operon is strengthened. This screen yielded mutants with mutations in cyaA, hfq, lon, and pgi, encoding adenylate cyclase, RNA-binding protein Hfq, protease Lon, and phosphoglucose isomerase, respectively. In cyaA mutants, the cyclic AMP receptor protein-dependent promoter is presumably inactive. The specific effect of the pgi mutants on bgl is low. Interestingly, in the hfq and lon mutants, the downstream silencing of bgl by H-NS (i.e., the induction of polarity) is more efficient, while the silencing of the promoter by H-NS is unaffected. Furthermore, in an hns mutant, Hfq has no significant effect and the effect of Lon is reduced. These data provide evidence that the specific repression by H-NS can (directly or indirectly) be modulated and controlled by other pleiotropic regulators.

APA, Harvard, Vancouver, ISO, and other styles

35

Salomon, Dor, John A. Klimko, and Kim Orth. "H-NS regulates the Vibrio parahaemolyticus type VI secretion system 1." Microbiology 160, no. 9 (September 1, 2014): 1867–73. http://dx.doi.org/10.1099/mic.0.080028-0.

Full text

Abstract:

The marine bacterium Vibrio parahaemolyticus, a major cause of food-borne gastroenteritis, employs a type VI secretion system 1 (T6SS1), a recently discovered protein secretion system, to combat competing bacteria. Environmental signals such as temperature, salinity, cell density and surface sensing, as well as the quorum-sensing master regulator OpaR, were previously reported to regulate T6SS1 activity and expression. In this work, we set out to identify additional transcription regulators that control the tightly regulated T6SS1 activity. To this end, we determined the effect of deletions in several known virulence regulators and in two regulators encoded within the T6SS1 gene cluster on expression and secretion of the core T6SS component Hcp1 and on T6SS1-mediated anti-bacterial activity. We report that VP1391 and VP1407, transcriptional regulators encoded within the T6SS1 gene cluster, are essential for T6SS1 activity. Moreover, we found that H-NS, a bacterial histone-like nucleoid structuring protein, which mediates transcription silencing of horizontally acquired genes, serves as a repressor of T6SS1. We also show that activation of surface sensing and high salt conditions alleviate the H-NS-mediated repression. Our results shed light on the complex network of environmental signals and transcription regulators that govern the tight regulation over T6SS1 activity.

APA, Harvard, Vancouver, ISO, and other styles

36

Yasunobu, Kano, Yasuzawa Kayoko, Tanaka Hiromitu, and Imamoto Fumio. "Propagation of phage Mu in IHF-dencient Escherichia coli in the absence of the H-NS histone-like protein." Gene 126, no. 1 (April 1993): 93–97. http://dx.doi.org/10.1016/0378-1119(93)90594-s.

Full text

APA, Harvard, Vancouver, ISO, and other styles

37

Stratmann, Thomas, S. Madhusudan, and Karin Schnetz. "Regulation of the yjjQ-bglJ Operon, Encoding LuxR-Type Transcription Factors, and the Divergent yjjP Gene by H-NS and LeuO." Journal of Bacteriology 190, no. 3 (November 30, 2007): 926–35. http://dx.doi.org/10.1128/jb.01447-07.

Full text

Abstract:

ABSTRACT The yjjQ and bglJ genes encode LuxR-type transcription factors conserved in several enterobacterial species. YjjQ is a potential virulence factor in avian pathogenic Escherichia coli. BglJ counteracts the silencing of the bgl (β-glucoside) operon by H-NS in E. coli K-12. Here we show that yjjQ and bglJ form an operon carried by E. coli K-12, whose expression is repressed by the histone-like nucleoid structuring (H-NS) protein. The LysR-type transcription factor LeuO counteracts this repression. Furthermore, the yjjP gene, encoding a membrane protein of unknown function and located upstream in divergent orientation to the yjjQ-bglJ operon, is likewise repressed by H-NS. Mapping of the promoters as well as the H-NS and LeuO binding sites within the 555-bp intergenic region revealed that H-NS binds to the center of the AT-rich regulatory region and distal to the divergent promoters. LeuO sites map to the center and to positions distal to the yjjQ promoters, while one LeuO binding site overlaps with the divergent yjjP promoter. This latter LeuO site is required for full derepression of the yjjQ promoters. The arrangement of regulatory sites suggests that LeuO restructures the nucleoprotein complex formed by H-NS. Furthermore, the data support the conclusion that LeuO, whose expression is likewise repressed by H-NS and which is a virulence factor in Salmonella enterica, is a master regulator that among other loci, also controls the yjjQ-bglJ operon and thus indirectly the presumptive targets of YjjQ and BglJ.

APA, Harvard, Vancouver, ISO, and other styles

38

Gowrishankar, J., and A. J. Pittard. "Superimposition of TyrR Protein-Mediated Regulation on Osmoresponsive Transcription of Escherichia coli proUIn Vivo." Journal of Bacteriology 180, no. 24 (December 15, 1998): 6743–48. http://dx.doi.org/10.1128/jb.180.24.6743-6748.1998.

Full text

Abstract:

ABSTRACT Osmotic regulation of proU expression in the enterobacteria is achieved, at least in part, by a repression mechanism involving the histone-like nucleoid protein H-NS. By the creation of binding sites for the TyrR regulator protein in the vicinity of the ς70-controlled promoter of proU inEscherichia coli, we were able to demonstrate a superposed TyrR-mediated activation by l-phenylalanine (Phe), as well as repression by l-tyrosine, of proU expression in vivo. Based on the facts that pronounced activation in the presence of Phe was observed even at a low osmolarity and that the affinity of binding of TyrR to its cognate sites on DNA is not affected by Phe, we argue that H-NS-mediated repression of proU at a low osmolarity may not involve a classical silencing mechanism. Our data also suggest the involvement of recruited RNA polymerase in the mechanism of antirepression in E. coli.

APA, Harvard, Vancouver, ISO, and other styles

39

Eijkelkamp, Bart A., Uwe H. Stroeher, Karl A. Hassan, Liam D. H. Elbourne, Ian T. Paulsen, and Melissa H. Brown. "H-NS Plays a Role in Expression of Acinetobacter baumannii Virulence Features." Infection and Immunity 81, no. 7 (May 6, 2013): 2574–83. http://dx.doi.org/10.1128/iai.00065-13.

Full text

Abstract:

ABSTRACTAcinetobacter baumanniihas become a major problem in the clinical setting with the prevalence of infections caused by multidrug-resistant strains on the increase. Nevertheless, only a limited number of molecular mechanisms involved in the success ofA. baumanniias a human pathogen have been described. In this study, we examined the virulence features of a hypermotile derivative ofA. baumanniistrain ATCC 17978, which was found to display enhanced adherence to human pneumocytes and elevated levels of lethality towardCaenorhabditis elegansnematodes. Analysis of cellular lipids revealed modifications to the fatty acid composition, providing a possible explanation for the observed changes in hydrophobicity and subsequent alteration in adherence and motility. Comparison of the genome sequences of the hypermotile variant and parental strain revealed that an insertion sequence had disrupted anhns-like gene in the variant. This gene encodes a homologue of the histone-like nucleoid structuring (H-NS) protein, a known global transcriptional repressor. Transcriptome analysis identified the global effects of this mutation on gene expression, with major changes seen in the autotransporter Ata, a type VI secretion system, and a type I pilus cluster. Interestingly, isolation and analysis of a second independent hypermotile ATCC 17978 variant revealed a mutation to a residue within the DNA binding region of H-NS. Taken together, these mutants indicate that the phenotypic and transcriptomic differences seen are due to loss of regulatory control effected by H-NS.

APA, Harvard, Vancouver, ISO, and other styles

40

Purtov, Yuri A., Olga A. Glazunova, Sergey S. Antipov, Viktoria O. Pokusaeva, Eugeny E. Fesenko, Elena V. Preobrazhenskaya, Konstantin S. Shavkunov, Maria N. Tutukina, Viktor I. Lukyanov, and Olga N. Ozoline. "Promoter islandsas a platform for interaction with nucleoid proteins and transcription factors." Journal of Bioinformatics and Computational Biology 12, no. 02 (April 2014): 1441006. http://dx.doi.org/10.1142/s0219720014410066.

Full text

Abstract:

Seventy-eight promoter islands with an extraordinarily high density of potential promoters have been recently found in the genome of Escherichia coli. It has been shown that RNA polymerase binds internal promoters of these islands and produces short oligonucleotides, while the synthesis of normal mRNAs is suppressed. This quenching may be biologically relevant, as most islands are associated with foreign genes, which expression may deplete cellular resources. However, a molecular mechanism of silencing with the participation of these promoter-rich regions remains obscure. It has been demonstrated that all islands interact with histone-like protein H-NS — a specific sentinel of foreign genes. In this study, we demonstrated the inhibitory effect of H-NS using Δhns mutant of Escherichia coli and showed that deletion of dps, encoding another protein of bacterial nucleoid, tended to decrease rather than increase the amount of island-specific transcripts. This observation precluded consideration of promoter islands as sites for targeted heterochromatization only and a computer search for the binding sites of 53 transcription factors (TFs) revealed six proteins, which may specifically regulate their transcriptional output.

APA, Harvard, Vancouver, ISO, and other styles

41

Soutourina, O., A. Kolb, E. Krin, C. Laurent-Winter, S. Rimsky, A. Danchin, and P. Bertin. "Multiple Control of Flagellum Biosynthesis in Escherichia coli: Role of H-NS Protein and the Cyclic AMP-Catabolite Activator Protein Complex in Transcription of the flhDC Master Operon." Journal of Bacteriology 181, no. 24 (December 15, 1999): 7500–7508. http://dx.doi.org/10.1128/jb.181.24.7500-7508.1999.

Full text

Abstract:

ABSTRACT Little is known about the molecular mechanism by which histone-like nucleoid-structuring (H-NS) protein and cyclic AMP-catabolite activator protein (CAP) complex control bacterial motility. In the present paper, we show that crp and hns mutants are nonmotile due to a complete lack of flagellin accumulation. This results from a reduced expression in vivo of fliA and fliC, which encode the specific flagellar sigma factor and flagellin, respectively. Overexpression of the flhDC master operon restored, at least in part, motility in crp andhns mutant strains, suggesting that this operon is the main target for both regulators. Binding of H-NS and CAP to the regulatory region of the master operon was demonstrated by gel retardation experiments, and their DNA binding sites were identified by DNase I footprinting assays. In vitro transcription experiments showed that CAP activates flhDC expression while H-NS represses it. In agreement with this observation, the activity of a transcriptional fusion carrying the flhDC promoter was decreased in thecrp strain and increased in the hns mutant. In contrast, the activity of a transcriptional fusion encompassing the entire flhDC regulatory region extending to the ATG translational start codon was strongly reduced in both hnsand crp mutants. These results suggest that the region downstream of the +1 transcriptional start site plays a crucial role in the positive control by H-NS of flagellum biosynthesis in vivo. Finally, the lack of complementation of the nonmotile phenotype in acrp mutant by activation-deficient CAP mutated proteins and characterization of cfs, a mutation resulting in a CAP-independent motility behavior, demonstrate that CAP activatesflhDC transcription by binding to its promoter and interacting with RNA polymerase.

APA, Harvard, Vancouver, ISO, and other styles

42

Martínez-Santos, Verónica I., Abraham Medrano-López, Zeus Saldaña, Jorge A. Girón, and José L. Puente. "Transcriptional Regulation of theecpOperon by EcpR, IHF, and H-NS in Attaching and Effacing Escherichia coli." Journal of Bacteriology 194, no. 18 (July 13, 2012): 5020–33. http://dx.doi.org/10.1128/jb.00915-12.

Full text

Abstract:

ABSTRACTEnteropathogenic (EPEC) and enterohemorrhagic (EHEC)Escherichia coliare clinically important diarrheagenic pathogens that adhere to the intestinal epithelial surface. TheE. colicommon pili (ECP), or meningitis-associated and temperature-regulated (MAT) fimbriae, are ubiquitous among both commensal and pathogenicE. colistrains and play a role as colonization factors by promoting the interaction between bacteria and host epithelial cells and favoring interbacterial interactions in biofilm communities. The first gene of theecpoperon encodes EcpR (also known as MatA), a proposed regulatory protein containing a LuxR-like C-terminal helix-turn-helix (HTH) DNA-binding motif. In this work, we analyzed the transcriptional regulation of theecpgenes and the role of EcpR as a transcriptional regulator. EHEC and EPECecpRmutants produce less ECP, while plasmids expressing EcpR increase considerably the expression of EcpA and production of ECP. Theecpgenes are transcribed as an operon from a promoter located 121 bp upstream of the start codon ofecpR. EcpR positively regulates this promoter by binding to two TTCCT boxes distantly located upstream of theecppromoter, thus enhancing expression of downstreamecpgenes, leading to ECP production. EcpR mutants in the putative HTH DNA-binding domain are no longer able to activateecpexpression or bind to the TTCCT boxes. EcpR-mediated activation is aided by integration host factor (IHF), which is essential for counteracting the repression exerted by histone-like nucleoid-structuring protein (H-NS) on theecppromoter. This work demonstrates evidence about the interplay between a novel member of a diverse family of regulatory proteins and global regulators in the regulation of a fimbrial operon.

APA, Harvard, Vancouver, ISO, and other styles

43

Shin, M. "DNA looping-mediated repression by histone-like protein H-NS: specific requirement of E 70 as a cofactor for looping." Genes & Development 19, no. 19 (October 1, 2005): 2388–98. http://dx.doi.org/10.1101/gad.1316305.

Full text

APA, Harvard, Vancouver, ISO, and other styles

44

Ayala, Julio C., Hongxia Wang, Jorge A. Benitez, and Anisia J. Silva. "RNA-Seq analysis and whole genome DNA-binding profile of the Vibrio cholerae histone-like nucleoid structuring protein (H-NS)." Genomics Data 5 (September 2015): 147–50. http://dx.doi.org/10.1016/j.gdata.2015.05.039.

Full text

APA, Harvard, Vancouver, ISO, and other styles

45

Castang, Sandra, and Simon L. Dove. "Basis for the Essentiality of H-NS Family Members in Pseudomonas aeruginosa." Journal of Bacteriology 194, no. 18 (July 20, 2012): 5101–9. http://dx.doi.org/10.1128/jb.00932-12.

Full text

Abstract:

ABSTRACTMembers of the histone-like nucleoid-structuring (H-NS) family of proteins have been shown to play important roles in silencing gene expression and in nucleoid compaction. InPseudomonas aeruginosa, the two H-NS family members MvaT and MvaU are thought to bind the same AT-rich regions of the chromosome and function coordinately to control a common set of genes. Here we present evidence that the loss of both MvaT and MvaU cannot be tolerated because it results in the production of Pf4 phage that superinfect and kill cells or inhibit their growth. Using a ClpXP-based protein depletion system in combination with transposon mutagenesis, we identify mutants ofP. aeruginosathat can tolerate the depletion of MvaT in an ΔmvaUmutant background. Many of these mutants contain insertions in genes encoding components, assembly factors, or regulators of type IV pili or contain insertions in genes of the prophage Pf4. We demonstrate that cells that no longer produce type IV pili or that no longer produce the replicative form of the Pf4 genome can tolerate the loss of both MvaT and MvaU. Furthermore, we show that the loss of both MvaT and MvaU results in an increase in expression of Pf4 genes and that cells that cannot produce type IV pili are resistant to infection by Pf4 phage. Our findings suggest that type IV pili are the receptors for Pf4 phage and that the essential activities of MvaT and MvaU are to repress the expression of Pf4 genes.

APA, Harvard, Vancouver, ISO, and other styles

46

Choi, Garam, Kyung Ku Jang, Jong Gyu Lim, Zee-Won Lee, Hanhyeok Im, and Sang Ho Choi. "The transcriptional regulator IscR integrates host-derived nitrosative stress and iron starvation in activation of the vvhBA operon in Vibrio vulnificus." Journal of Biological Chemistry 295, no. 16 (March 13, 2020): 5350–61. http://dx.doi.org/10.1074/jbc.ra120.012724.

Full text

Abstract:

For successful infection of their hosts, pathogenic bacteria recognize host-derived signals that induce the expression of virulence factors in a spatiotemporal manner. The fulminating food-borne pathogen Vibrio vulnificus produces a cytolysin/hemolysin protein encoded by the vvhBA operon, which is a virulence factor preferentially expressed upon exposure to murine blood and macrophages. The Fe-S cluster containing transcriptional regulator IscR activates the vvhBA operon in response to nitrosative stress and iron starvation, during which the cellular IscR protein level increases. Here, electrophoretic mobility shift and DNase I protection assays revealed that IscR directly binds downstream of the vvhBA promoter PvvhBA, which is unusual for a positive regulator. We found that in addition to IscR, the transcriptional regulator HlyU activates vvhBA transcription by directly binding upstream of PvvhBA, whereas the histone-like nucleoid-structuring protein (H-NS) represses vvhBA by extensively binding to both downstream and upstream regions of its promoter. Of note, the binding sites of IscR and HlyU overlapped with those of H-NS. We further substantiated that IscR and HlyU outcompete H-NS for binding to the PvvhBA regulatory region, resulting in the release of H-NS repression and vvhBA induction. We conclude that concurrent antirepression by IscR and HlyU at regions both downstream and upstream of PvvhBA provides V. vulnificus with the means of integrating host-derived signal(s) such as nitrosative stress and iron starvation for precise regulation of vvhBA transcription, thereby enabling successful host infection.

APA, Harvard, Vancouver, ISO, and other styles

47

Feng, Jia-Xun, Zhi-Zhong Song, Cheng-Jie Duan, Shuai Zhao, Ying-Qiao Wu, Chao Wang, J. Maxwell Dow, and Ji-Liang Tang. "The xrvA gene of Xanthomonas oryzae pv. oryzae, encoding an H-NS-like protein, regulates virulence in rice." Microbiology 155, no. 9 (September 1, 2009): 3033–44. http://dx.doi.org/10.1099/mic.0.028910-0.

Full text

Abstract:

Xanthomonas oryzae pv. oryzae (Xoo) causes bacterial blight disease in rice, one of the most serious rice diseases. The xrvA gene from Xoo strain 13751 encodes a protein containing a histone-like nucleoid-structuring protein (H-NS) domain. The expression of xrvA in strain 13751 was enhanced in XOM2 minimal medium. Mutation of the xrvA gene of strain 13751 led to a significant reduction in virulence in the host plant rice, a delayed hypersensitive response in the nonhost castor-oil plant, a decrease in extracellular polysaccharide and diffusible signal factor production, and an increase in intracellular glycogen accumulation. Northern hybridization analyses revealed that the virulence-associated genes hrpG, hrpX, rpfC, rpfF, rpfG and gumB were downregulated in the xrvA mutant compared to the wild-type and complemented strains. Interestingly, increase of copy number of xrvA in the wild-type strain 13751 resulted in a strain showing similar phenotypes as the xrvA mutant and a reduction of the expression of gumB, hrpX, rpfC, rpfF and rpfG. These findings indicate that the xrvA gene, which is highly conserved in the sequenced strains of Xanthomonas, encodes an important regulatory factor for the virulence of Xoo.

APA, Harvard, Vancouver, ISO, and other styles

48

Madhusudan, S., Andreas Paukner, Yvonne Klingen, and Karin Schnetz. "Independent regulation of H-NS-mediated silencing of the bgl operon at two levels: upstream by BglJ and LeuO and downstream by DnaKJ." Microbiology 151, no. 10 (October 1, 2005): 3349–59. http://dx.doi.org/10.1099/mic.0.28080-0.

Full text

Abstract:

Silencing of the Escherichia coli bgl operon by the histone-like nucleoid-structuring protein H-NS occurs at two levels. Binding of H-NS upstream of the promoter represses transcription initiation, whilst binding within the coding region is also proposed to repress transcription elongation. The latter, downstream level of repression is counteracted by the protease Lon and, thus, silencing of the bgl operon is more effective in lon mutants. Transposon-mutagenesis screens for suppression of this lon phenotype on bgl were performed and insertion mutations disrupting rpoS and crl were obtained, as well as mutations mapping upstream of the open reading frames of bglJ, leuO and dnaK. In rpoS and crl mutants, bgl promoter activity is known to be higher. Likewise, as shown here, bgl promoter activity is increased in the bglJ and leuO mutants, which express BglJ and LeuO constitutively. However, BglJ and LeuO have no impact on downstream repression. A dnaKJ mutant was isolated for the first time in the context of the bgl operon. The mutant expresses lower levels of DnaK than the wild-type. Interestingly, in this dnaKJ : : miniTn10 mutant, downstream repression of bgl by H-NS is less effective, whilst upstream repression by H-NS remains unaffected. Together, the data show that the two levels of bgl silencing by H-NS are regulated independently.

APA, Harvard, Vancouver, ISO, and other styles

49

Lease, Richard A., Dorie Smith, Kathleen McDonough, and Marlene Belfort. "The Small Noncoding DsrA RNA Is an Acid Resistance Regulator in Escherichia coli." Journal of Bacteriology 186, no. 18 (September 15, 2004): 6179–85. http://dx.doi.org/10.1128/jb.186.18.6179-6185.2004.

Full text

Abstract:

ABSTRACT DsrA RNA is a small (87-nucleotide) regulatory RNA of Escherichia coli that acts by RNA-RNA interactions to control translation and turnover of specific mRNAs. Two targets of DsrA regulation are RpoS, the stationary-phase and stress response sigma factor (σs), and H-NS, a histone-like nucleoid protein and global transcription repressor. Genes regulated globally by RpoS and H-NS include stress response proteins and virulence factors for pathogenic E. coli. Here, by using transcription profiling via DNA arrays, we have identified genes induced by DsrA. Steady-state levels of mRNAs from many genes increased with DsrA overproduction, including multiple acid resistance genes of E. coli. Quantitative primer extension analysis verified the induction of individual acid resistance genes in the hdeAB, gadAX, and gadBC operons. E. coli K-12 strains, as well as pathogenic E. coli O157:H7, exhibited compromised acid resistance in dsrA mutants. Conversely, overproduction of DsrA from a plasmid rendered the acid-sensitive dsrA mutant extremely acid resistant. Thus, DsrA RNA plays a regulatory role in acid resistance. Whether DsrA targets acid resistance genes directly by base pairing or indirectly via perturbation of RpoS and/or H-NS is not known, but in either event, our results suggest that DsrA RNA may enhance the virulence of pathogenic E. coli.

APA, Harvard, Vancouver, ISO, and other styles

50

SUZUKI, Chiho, Choong-Soo YUN, Takashi UMEDA, Tsuguno TERABAYASHI, Kazuya WATANABE, Hisakazu YAMANE, and Hideaki NOJIRI. "Oligomerization and DNA-Binding Capacity of Pmr, a Histone-Like Protein H1 (H-NS) Family Protein Encoded on IncP-7 Carbazole-Degradative Plasmid pCAR1." Bioscience, Biotechnology, and Biochemistry 75, no. 4 (April 23, 2011): 711–17. http://dx.doi.org/10.1271/bbb.100841.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Journal articles on the topic 'Histone-like protein H-NS'

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles