scholarly journals Multiple Promoters Contribute to Swarming and the Coordination of Transcription with Flagellar Assembly in Salmonella

2010 ◽  
Vol 192 (18) ◽  
pp. 4752-4762 ◽  
Author(s):  
Christopher E. Wozniak ◽  
Fabienne F. V. Chevance ◽  
Kelly T. Hughes
Keyword(s):  
Transcriptional Regulation ◽  
Stationary Phase ◽  
Basal Body ◽  
Environmental Conditions ◽  
Swarming Motility ◽  
Multiple Promoters ◽  
Associated Proteins ◽  
Flagellar Assembly

ABSTRACT In Salmonella, there are three classes of promoters in the flagellar transcriptional hierarchy. This organization allows genes needed earlier in the construction of flagella to be transcribed before genes needed later. Four operons (fliAZY, flgMN, fliDST, and flgKL) are expressed from both class 2 and class 3 promoters. To investigate the purpose for expressing genes from multiple flagellar promoters, mutants were constructed for each operon that were defective in either class 2 transcription or class 3 transcription. The mutants were checked for defects in swimming through liquids, swarming over surfaces, and transcriptional regulation. The expression of the hook-associated proteins (FlgK, FlgL, and FliD) from class 3 promoters was found to be important for swarming motility. Both flgMN promoters were involved in coordinating class 3 transcription with the stage of assembly of the hook-basal body. Finally, the fliAZY class 3 promoter lowered class 3 transcription in stationary phase. These results indicate that the multiple flagellar promoters respond to specific environmental conditions and help coordinate transcription with flagellar assembly.

Integration host factor alleviates H-NS silencing of the Salmonella enterica serovar Typhimurium master regulator of SPI1, hilA

Microbiology ◽  
2011 ◽  
Vol 157 (9) ◽  
pp. 2504-2514 ◽  
Author(s):  
Mário H. Queiroz ◽  
Cristina Madrid ◽  
Sònia Paytubi ◽  
Carlos Balsalobre ◽  
Antonio Juárez
Keyword(s):  
Stationary Phase ◽  
Salmonella Enterica ◽  
Growth Conditions ◽  
Integration Host Factor ◽  
Band Shift ◽  
Global Regulators ◽  
Serovar Typhimurium ◽  
Associated Proteins ◽  
Transcription Data

Coordination of the expression of Salmonella enterica invasion genes on Salmonella pathogenicity island 1 (SPI1) depends on a complex circuit involving several regulators that converge on expression of the hilA gene, which encodes a transcriptional activator (HilA) that modulates expression of the SPI1 virulence genes. Two of the global regulators that influence hilA expression are the nucleoid-associated proteins Hha and H-NS. They interact and form a complex that modulates gene expression. A chromosomal transcriptional fusion was constructed to assess the effects of these modulators on hilA transcription under several environmental conditions as well as at different stages of growth. The results obtained showed that these proteins play a role in silencing hilA expression at both low temperature and low osmolarity, irrespective of the growth phase. H-NS accounts for the main repressor activity. At high temperature and osmolarity, H-NS-mediated silencing completely ceases when cells enter the stationary phase, and hilA expression is induced. Mutants lacking IHF did not induce hilA in cells entering the stationary phase, and this lack of induction was dependent on the presence of H-NS. Band-shift assays and in vitro transcription data showed that for hilA induction under certain growth conditions, IHF is required to alleviate H-NS-mediated silencing.

scholarly journals Bacterial Flagellar Filament: A Supramolecular Multifunctional Nanostructure

2021 ◽  
Vol 22 (14) ◽  
pp. 7521
Author(s):  
Marko Nedeljković ◽  
Diego Emiliano Sastre ◽  
Eric John Sundberg
Keyword(s):  
Immune Responses ◽  
Basal Body ◽  
Vaccine Development ◽  
Bacterial Species ◽  
High Variability ◽  
Bacterial Survival ◽  
Bacterial Flagellum ◽  
Capping Proteins ◽  
Flagellar Filament ◽  
Flagellar Assembly

The bacterial flagellum is a complex and dynamic nanomachine that propels bacteria through liquids. It consists of a basal body, a hook, and a long filament. The flagellar filament is composed of thousands of copies of the protein flagellin (FliC) arranged helically and ending with a filament cap composed of an oligomer of the protein FliD. The overall structure of the filament core is preserved across bacterial species, while the outer domains exhibit high variability, and in some cases are even completely absent. Flagellar assembly is a complex and energetically costly process triggered by environmental stimuli and, accordingly, highly regulated on transcriptional, translational and post-translational levels. Apart from its role in locomotion, the filament is critically important in several other aspects of bacterial survival, reproduction and pathogenicity, such as adhesion to surfaces, secretion of virulence factors and formation of biofilms. Additionally, due to its ability to provoke potent immune responses, flagellins have a role as adjuvants in vaccine development. In this review, we summarize the latest knowledge on the structure of flagellins, capping proteins and filaments, as well as their regulation and role during the colonization and infection of the host.

scholarly journals Killer Immunoglobulin-Like Receptor Transcriptional Regulation: A Fascinating Dance of Multiple Promoters

2011 ◽  
Vol 3 (3) ◽  
pp. 242-248 ◽  
Author(s):  
Frank Cichocki ◽  
Jeffrey S. Miller ◽  
Stephen K. Anderson
Keyword(s):  
Transcriptional Regulation ◽  
Multiple Promoters

scholarly journals Regulation of the CRISPR-Associated Genes by Rv2837c (CnpB) via an Orn-Like Activity in Tuberculosis Complex Mycobacteria

2018 ◽  
Vol 200 (8) ◽  
Author(s):  
Yang Zhang ◽  
Jun Yang ◽  
Guangchun Bai
Keyword(s):  
Transcriptional Regulation ◽  
Adaptive Immunity ◽  
Parent Strain ◽  
Tuberculosis Complex ◽  
Content Type ◽  
Multifunctional Protein ◽  
Type Iii ◽  
Associated Proteins ◽  
Cyclic Dinucleotides ◽  
Insight Into

ABSTRACT Clustered regularly interspaced short palindromic repeats (CRISPR) and the CRISPR-associated proteins (Cas) provide bacteria and archaea with adaptive immunity to specific DNA invaders. Mycobacterium tuberculosis encodes a type III CRISPR-Cas system that has not been experimentally explored. In this study, we found that the CRISPR-Cas systems of both M. tuberculosis and Mycobacterium bovis BCG were highly upregulated by deletion of Rv2837c ( cnpB ), which encodes a multifunctional protein that hydrolyzes cyclic di-AMP (c-di-AMP), cyclic di-GMP (c-di-GMP), and nanoRNAs (short oligonucleotides of 5 or fewer residues). By using genetic and biochemical approaches, we demonstrated that the CnpB-controlled transcriptional regulation of the CRISPR-Cas system is mediated by an Orn-like activity rather than by hydrolyzing the cyclic dinucleotides. Additionally, our results revealed that tuberculosis (TB) complex mycobacteria are functional in processing CRISPR RNAs (crRNAs), which are also more abundant in the Δ cnpB strain than in the parent strain. The elevated crRNA levels in the Δ cnpB strain could be partially reduced by expressing Escherichia coli orn . Our findings provide new insight into transcriptional regulation of bacterial CRISPR-Cas systems. IMPORTANCE Clustered regularly interspaced short palindromic repeats (CRISPR) and the CRISPR-associated proteins (Cas) provide adaptive immunity to specific DNA invaders. M. tuberculosis encodes a type III CRISPR-Cas system that has not been experimentally explored. In this study, we first demonstrated that the CRISPR-Cas systems in tuberculosis (TB) complex mycobacteria are functional in processing CRISPR RNAs (crRNAs). We also showed that Rv2837c (CnpB) controls the expression of the CRISPR-Cas systems in TB complex mycobacteria through an oligoribonuclease (Orn)-like activity, which is very likely mediated by nanoRNA. Since little is known about regulation of CRISPR-Cas systems, our findings provide new insight into transcriptional regulation of bacterial CRISPR-Cas systems.

scholarly journals Novel Role of mfd: Effects on Stationary-Phase Mutagenesis in Bacillus subtilis

2006 ◽  
Vol 188 (21) ◽  
pp. 7512-7520 ◽  
Author(s):  
Christian Ross ◽  
Christine Pybus ◽  
Mario Pedraza-Reyes ◽  
Huang-Mo Sung ◽  
Ronald E. Yasbin ◽  
...  
Keyword(s):  
Bacillus Subtilis ◽  
Rna Polymerase ◽  
Stationary Phase ◽  
Coupling Factor ◽  
Dna Lesions ◽  
Adaptive Mutagenesis ◽  
Associated Proteins ◽  
Mutagenic Process ◽  
Protein Transcription

ABSTRACT Previously, using a chromosomal reversion assay system, we established that an adaptive mutagenic process occurs in nongrowing Bacillus subtilis cells under stress, and we demonstrated that multiple mechanisms are involved in generating these mutations (41, 43). In an attempt to delineate how these mutations are generated, we began an investigation into whether or not transcription and transcription-associated proteins influence adaptive mutagenesis. In B. subtilis, the Mfd protein (transcription repair coupling factor) facilitates removal of RNA polymerase stalled at transcriptional blockages and recruitment of repair proteins to DNA lesions on the transcribed strand. Here we demonstrate that the loss of Mfd has a depressive effect on stationary-phase mutagenesis. An association between Mfd mutagenesis and aspects of transcription is discussed.

scholarly journals The Growth Advantage in Stationary-Phase PhenotypeConferred by rpoS Mutations Is Dependent on the pH andNutrientEnvironment

2003 ◽  
Vol 185 (24) ◽  
pp. 7044-7052 ◽  
Author(s):  
Michael J. Farrell ◽  
Steven E. Finkel
Keyword(s):  
Stationary Phase ◽  
Batch Culture ◽  
Environmental Conditions ◽  
Sole Source ◽  
Culture Conditions ◽  
Luria Bertani ◽  
Relative Fitness ◽  
Wild Type ◽  
Fitness Advantage ◽  
Casamino Acids

ABSTRACT Escherichia coli cells that are aged in batch culture display an increased fitness referred to as the growth advantage in stationary phase, or GASP, phenotype. A common early adaptation to this culture environment is a mutant rpoS allele, such as rpoS819, that results in attenuated RpoS activity. However, it is important to note that during long-term batch culture, environmental conditions are in flux. To date, most studies of the GASP phenotype have focused on identifying alleles that render an advantage in a specific environment, Luria-Bertani broth (LB) batch culture. To determine what role environmental conditions play in rendering relative fitness advantages to E. coli cells carrying either the wild-type or rpoS819 alleles, we performed competitions under a variety of culture conditions in which either the available nutrients, the pH, or both were manipulated. In LB medium, we found that while the rpoS819 allele confers a strong competitive fitness advantage at basic pH, it confers a reduced advantage under neutral conditions, and it is disadvantageous under acidic conditions. Similar results were found using other media. rpoS819 conferred its greatest advantage in basic minimal medium in which either glucose or Casamino Acids were the sole source of carbon and energy. In acidic medium supplemented with either Casamino Acids or glucose, the wild-type allele conferred a slight advantage. In addition, populations were dynamic under all pH conditions tested, with neither the wild-type nor mutant rpoS alleles sweeping a culture. We also found that the strength of the fitness advantage gained during a 10-day incubation is pH dependent.

scholarly journals Transcriptional Regulation of Divergent Capsule Biosynthesis and Transport Operon Promoters in Serogroup BNeisseria meningitidis

2001 ◽  
Vol 69 (4) ◽  
pp. 2502-2511 ◽  
Author(s):  
Yih-Ling Tzeng ◽  
John S. Swartley ◽  
Yoon K. Miller ◽  
Rachel E. Nisbet ◽  
Li-Jun Liu ◽  
...  
Keyword(s):  
Transcriptional Regulation ◽  
Sialic Acid ◽  
Stationary Phase ◽  
Intergenic Region ◽  
Direct Repeat ◽  
Intergenic Sequence ◽  
Transcriptional Level ◽  
Phase Growth ◽  
Specific Regulation ◽  
Species Specific

ABSTRACT The clinically important serogroups B, C, Y, and W-135 ofNeisseria meningitidis produce sialic acid capsules that are critical in pathogenesis. In each of these serogroups, the capsule transport (ctrABCD) and capsule biosynthesis (synABCD) operons are divergently transcribed from putative promoters located in a 134-bp intergenic region (J. S. Swartley, J. H. Ahn, L. J. Liu, C. M. Kahler, and D. S. Stephens, J. Bacteriol. 178:4052–4059, 1996). In this study we further assessed the role of the intergenic sequence in the transcriptional regulation of the sialic acid capsules of N. meningitidis. Insertional mutagenesis or deletions of the 134-bp sequence in the serogroup B meningococcal strain NMB resulted in a marked reduction or elimination of ctrABCD and synABCDtranscription, with a concomitant loss of encapsulation. Chromosomal transcriptional lacZ-ermC reporter fusions ofsyn and ctr promoters were constructed through allelic exchange. Using these constructs, both operons were found to be constitutively transcribed in meningococci, the biosynthesis operon about fourfold higher than the transport operon. Both promoters showed increased activity during stationary-phase growth. In addition to the promoters, a 70-bp 5′ untranslated region (UTR) upstream ofsynA was found to have a direct repeat and an inverted repeat that overlapped three putative integration host factor binding sites. Mutation of this 70-bp UTR and of the direct repeat upregulated both syn and ctr transcription. Regulation through the synA UTR was absent in a K1 Escherichia coli strain that produces identical capsular polysaccharide, implicating species-specific regulation. Meningococcal sialic acid capsule expression is initiated by divergent promoters in a 134-bp intergenic region, is repressed at the transcriptional level by the 5′ UTR of synA, is increased during stationary-phase growth, and shows species-specific regulation. Transcriptional regulation is another important control point for sialic capsule expression inN. meningitidis.

scholarly journals Borrelia burgdorferi Proteins Whose Expression Is Similarly Affected by Culture Temperature and pH

2001 ◽  
Vol 69 (4) ◽  
pp. 2739-2742 ◽  
Author(s):  
Ramesh Ramamoorthy ◽  
Dorothy Scholl-Meeker
Keyword(s):  
Borrelia Burgdorferi ◽  
Stationary Phase ◽  
Growth Phase ◽  
Environmental Conditions ◽  
Stationary Growth Phase ◽  
Culture Temperature ◽  
Stationary Growth ◽  
Encoding Genes ◽  
Midgut Ph ◽  
Tick Midgut

ABSTRACT Previously, we had demonstrated the upregulation in the expression of several proteins, including the lipoproteins OspC and P35, ofBorrelia burgdorferi in the stationary growth phase. Since the expression of OspC is also known to be affected by culture temperature and pH, we examined the effects of both variables on the expression of the remaining stationary-phase-upregulated proteins. Our study revealed that the expression of each of the remaining stationary-phase-upregulated proteins, P35 included, was also influenced by culture temperature; these proteins were selectively expressed at 34°C but not at 24°C. Significantly, the expression of a majority of these proteins was also affected by culture pH, since they were abundantly expressed at pH 7.0 (resembling the tick midgut pH of 6.8 during feeding) but only sparsely at pH 8.0 (a condition closer to that of the unfed tick midgut pH of 7.4). We propose that this group of B. burgdorferi proteins, which in culture is selectively expressed under conditions of 34°C and pH 7.0, may be induced in the tick midgut during the feeding event. Furthermore, the differential and coordinate expression of these proteins under different environmental conditions suggests that the encoding genes may be coregulated.

scholarly journals Distribution of Genes Encoding Nucleoid-Associated Protein Homologs in Plasmids

2011 ◽  
Vol 2011 ◽  
pp. 1-30 ◽  
Author(s):  
Toshiharu Takeda ◽  
Choong-Soo Yun ◽  
Masaki Shintani ◽  
Hisakazu Yamane ◽  
Hideaki Nojiri
Keyword(s):  
Transcriptional Regulation ◽  
Conjugative Transfer ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Ns Gene ◽  
Expression Of Genes ◽  
Bacterial Nucleoid ◽  
Genes Encoding ◽  
Associated Proteins ◽  
Nucleoprotein Complexes

Bacterial nucleoid-associated proteins (NAPs) form nucleoprotein complexes and influence the expression of genes. Recent studies have shown that some plasmids carry genes encoding NAP homologs, which play important roles in transcriptional regulation networks between plasmids and host chromosomes. In this study, we determined the distributions of the well-known NAPs Fis, H-NS, HU, IHF, and Lrp and the newly found NAPs MvaT and NdpA among the whole-sequenced 1382 plasmids found in Gram-negative bacteria. Comparisons between NAP distributions and plasmid features (size, G+C content, and putative transferability) were also performed. We found that larger plasmids frequently have NAP gene homologs. Plasmids with H-NS gene homologs had less G+C content. It should be noted that plasmids with the NAP gene homolog also carried the relaxase gene involved in the conjugative transfer of plasmids more frequently than did those without the NAP gene homolog, implying that plasmid-encoded NAP homologs positively contribute to transmissible plasmids.

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