Academic literature on the topic 'Expression; Function; Histone-like protein H-NS'
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Journal articles on the topic "Expression; Function; Histone-like protein H-NS"
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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.
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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.
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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.
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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.
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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.
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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.
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Paytubi, Sonia, Jesús García, and Antonio Juárez. "Bacterial Hha-like proteins facilitate incorporation of horizontally transferred DNA." Open Life Sciences 6, no. 6 (December 1, 2011): 879–86. http://dx.doi.org/10.2478/s11535-011-0071-3.
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AbstractHorizontal gene transfer (HGT), non-hereditary transfer of genetic material between organisms, accounts for a significant proportion of the genetic variability in bacteria. In Gram negative bacteria, the nucleoid-associated protein H-NS silences unwanted expression of recently acquired foreign DNA. This, in turn, facilitates integration of the incoming genes into the regulatory networks of the recipient cell. Bacteria belonging to the family Enterobacteriaceae express an additional protein, the Hha protein that, by binding to H-NS, potentiates silencing of HGT DNA. We provide here an overview of Hha-like proteins, including their structure and function, as well as their evolutionary relationship. We finally present available information suggesting that, by expressing Hha-like proteins, bacteria such as Escherichia coli facilitate HGT incorporation and hence, the impact of HGT in their genetic diversity.
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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.
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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.
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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.
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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.
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Forns, Núria, Rosa C. Baños, Carlos Balsalobre, Antonio Juárez, and Cristina Madrid. "Temperature-Dependent Conjugative Transfer of R27: Role of Chromosome- and Plasmid-Encoded Hha and H-NS Proteins." Journal of Bacteriology 187, no. 12 (June 15, 2005): 3950–59. http://dx.doi.org/10.1128/jb.187.12.3950-3959.2005.
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ABSTRACT IncHI plasmids encode multiple-antibiotic resistance in Salmonella enterica serovar Typhi. These plasmids have been considered to play a relevant role in the persistence and reemergence of this microorganism. The IncHI1 plasmid R27, which can be considered the prototype of IncHI plasmids, is thermosensitive for transfer. Conjugation frequency is highest at low temperature (25 to 30°C), decreasing when temperature increases. R27 codifies an H-NS-like protein (open reading frame 164 [ORF164]) and an Hha-like protein (ORF182). The H-NS and Hha proteins participate in the thermoregulation of gene expression in Escherichia coli. Here we investigated the hypothetical role of such proteins in thermoregulation of R27 conjugation. At a nonpermissive temperature (33°C), transcription of several ORFs in both transfer region 1 (Tra1) and Tra2 from R27 is upregulated in cells depleted of Hha-like and H-NS-like proteins. Both chromosome- and plasmid-encoded Hha and H-NS proteins appear to potentially modulate R27 transfer. The function of R27-encoded Hha-like and H-NS proteins is not restricted to modulation of R27 transfer. Different mutant phenotypes associated with both chromosomal hha and hns mutations are compensated in cells harboring R27.
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Sonden, B., and B. E. Uhlin. "Coordinated and differential expression of histone-like proteins in Escherichia coli: regulation and function of the H-NS analog StpA." EMBO Journal 15, no. 18 (September 1996): 4970–80. http://dx.doi.org/10.1002/j.1460-2075.1996.tb00877.x.
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Wang, Yan, Yiquan Zhang, Zhe Yin, Jie Wang, Yongzhe Zhu, Haoran Peng, Dongsheng Zhou, Zhongtian Qi, and Wenhui Yang. "H-NS represses transcription of the flagellin gene lafA of lateral flagella in Vibrio parahaemolyticus." Canadian Journal of Microbiology 64, no. 1 (January 2018): 69–74. http://dx.doi.org/10.1139/cjm-2017-0315.
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Swarming motility is ultimately mediated by the proton-powered lateral flagellar (laf) system in Vibrio parahaemolyticus. Expression of laf genes is tightly regulated by a number of environmental conditions and regulatory factors. The nucleoid-associated DNA-binding protein H-NS is a small and abundant protein that is widely distributed in bacteria, and H-NS-like protein-dependent expression of laf genes has been identified in Vibrio cholerae and V. parahaemolyticus. The data presented here show that H-NS acts as a repressor of the swarming motility in V. parahaemolyticus. A single σ28-dependent promoter was detected for lafA encoding the flagellin of the lateral flagella, and its activity was directly repressed by H-NS. Thus, H-NS represses swarming motility by directly acting on lafA. Briefly, this work revealed a novel function for H-NS as a repressor of the expression of lafA and swarming motility in V. parahaemolyticus.
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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.
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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.
Dissertations / Theses on the topic "Expression; Function; Histone-like protein H-NS"
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Sonnenfield, Jean Marie. "Study of the StpA protein from Salmonella typhimurium and Escherichia coli." Thesis, University of Oxford, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.389027.
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Cao, Wei, and 曹威. "Structural studies of two nucleoid-associated proteins : histone-like nucleoid-structuring protein H-NS and α-hemolysin expression-modulating protein Hha." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2014. http://hdl.handle.net/10722/208420.
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In prokaryotic cells, the nucleoid contains almost all the genetic materials as well as a number of nucleoid structuring factors. The nucleoid-associated proteins (NAPs) are known to have low molecular weight and the ability to form dimer or oligomer, and most of them can bind to DNA for regulation of gene expression. The Histone-like nucleoid structuring protein H-NS, well studied as one of the NAPs, acts as a global transcriptional repressor. It has independent functional N-terminal domain for oligomerization and C-terminal domain for DNA binding, joined by a flexible linker. H-NS contributes to horizontal genes transfer and responses to environmental factors like temperature or pH, which would influence the oligomerization ability of H-NS and DNA binding. The α-hemolysin expression-modulating protein Hha is a member of the Hha-YmoA family, expressed only in Gram-negative Enterobacteriaceae as a modulator of virulence factors expression. In E. coli, the binding of Hha to H-NS can modulate the expression of α-hemolysin operon, which is essential for the H-NS-regulated gene expression. In this study, both Hha and the oligomerization domain of H-NS (H-NS64) were expressed in E. coli and the purified proteins were crystallized. The Hha crystals diffracted to 2.2 Å; and the HhA/H-NS complex crystals diffracted to 1.8 Å. Both structures were successfully determined by molecular replacement method. Comparisons were carried out between the published apo Hha and H-NS structures and our complex structures. The structures showed the binding details between H-NS and Hha and also conformational changes of each protein, which may indicate how Hha regulates gene expressions through H-NS.published_or_final_version
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Book chapters on the topic "Expression; Function; Histone-like protein H-NS"
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Wang, Huayan, Weidong Yang, and Larry Fliegel. "Identification of an HMG-like protein involved in regulation of Na+/H+ exchanger expression." In The Cellular Basis of Cardiovascular Function in Health and Disease, 99–106. Boston, MA: Springer US, 1997. http://dx.doi.org/10.1007/978-1-4615-5765-4_13.
Full textConference papers on the topic "Expression; Function; Histone-like protein H-NS"
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Baker, J. B., M. P. McGrogan, C. Simonsen, R. L. Gronke, and B. W. Festoff. "STRUCTURE AND PROPERTIES OF PROTEASE NEXIN I." In XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1644765.
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Human foreskin fibroblasts secrete several different serine protease inhibitors which differ in size and protease specificities. These proteins, called protease nexins (PNs) all form SDS-resistant complexes with their protease targets. Fibroblast surface receptors recognize the protease-PN complexes and mediate their delivery to lysosomes. PNI is a 45 kilodalton glycoprotein that rapidly inhibits several arg or lys-specific proteases including trypsin, thrombin, and urokinase (k assoc.∼ 4×l06,∼ 6×105 and ∼ 2×105, m−1s−1 respectively). Like antithrombin III, PNI binds heparin and inhibits thrombin at a vastly accelerated rate in the presence of this glycoaminoglycan. Immunofluorescence studies show that in addition to secreting PNI foreskin fibroblasts carry this inhibitor on their surfaces. PNI cDNA has been cloned and sequenced. A mixed oligonucleotide probe derived from PNI N-terminal sequence was used to probe a foreskin fibroblast cDNA library constructed with λGT10. Identification of PNI cDNAs has been verified by sequencing and by expressing active PNI protein in mammalian cells. The full amino acid sequence of PNI, deduced from cDNA sequencing, is 392 residues long and has 30% homology to antithrombin III. An arg-ser pair 32 residues from the C-terminus of the inhibitor is proposed as the reactive center P1-P1 residues. In the hinge region a lys residue is present in a position occupied by a ginor glu residue in other serpins. PNI mRNA exists in 2 slightly different forms:One (αPNI) yields a thr-arg-ser sequence wherethe other βPNI) yields a thr-thr-gly-ser sequence. The presence of the appropriate splice acceptor sites in the genome indicates that these forms are generated from a single gene by alternative splicing. Expressed aPNI and 0PNI proteins both bind thrombin and urokinase. In foreskin fibroblaststhe α form of PNI mRNA predominates over the β form by about 2:1. In foreskin fibroblast cultures secreted PNI inhibits the mitogenic response to thrombin and regulate secreted urokinase. Purified PNI added to human fibrosarcoma (HT1080) cells inhibitsthe tumor cell-mediated destruction of extracellular matrix and transiently, but dramatically, inhibits tumor cell growth. PNI or PNI-like inhibitors may function at multiple physiological sites. The β form of PNI is virtually identical to a glia-derived neurite promoting factor, the cDNA for which has been recently cloned and sequenced by Gloor et al (1). The neurite outgrowth activity of PNI may result from inhibition of a thrombin-like protease that is associated with neurons, since a number of thrombin inhibitors stimulate neurite extension. Recent immunofluoresence experiments, carried out with D. Hantai (Inserm; Paris) demonstrate that anti-PNI antibody intensely stains neuromuscular synapses. In addition, a PNI-like inhibitor is associated with platelets. At low (0.5 nM <) 125I-thrombin concentrations formation of 125I-thrombin-platelet PNI complexes accounts for most of the specific binding of 125I-thrombin to platelets (2). Although the platelet-associated form of PNI is electrophoretically and immunologically indistinguishable from fibroblast PNI, it does not bind urokinase, suggesting that it may be distinct.(1) Gloor, S., K. Odink, J. Guenther, H. Nick, and D. Monard. (1986) Cell 47:687-693.(2) Gronke, R.S., B.L. Bergman, and J.B. Baker. (1987) J. Biol. Chem. (in press)