Enhanced Promoter Activity by Replenishment of Sigma Factor rpoE in Klebsiella pneumoniae

The genome of Brucella melitensis contains genes coding for the sigma factors RpoD, RpoN, RpoH1, RpoH2, RpoE1 and RpoE2. Previously published data show that B. melitensis is flagellated and that an rpoE1 mutant overexpresses the flagellar protein FlgE. In this study, we demonstrate that mutation of rpoE1 causes an overexpression of the flagellar genes fliF, flgE, fliC, flaF and flbT, correlating with the production of a longer filament and thereby demonstrating that RpoE1 acts as a flagellar repressor. Moreover, mutation of rpoE1 increases the promoter activity of the flagellar master regulator ftcR, suggesting that RpoE1 acts upstream of ftcR. Together, these data show that RpoE1 represses the flagellar synthesis and filament length in B. melitensis.

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A NAC for Regulating Metabolism: the Nitrogen Assimilation Control Protein (NAC) from Klebsiella pneumoniae

Journal of Bacteriology ◽

10.1128/jb.00266-10 ◽

2010 ◽

Vol 192 (19) ◽

pp. 4801-4811 ◽

Cited By ~ 22

Author(s):

Robert A. Bender

Keyword(s):

Klebsiella Pneumoniae ◽

Sigma Factor ◽

Nitrogen Assimilation ◽

Transcriptional Regulator ◽

Cellular Functions ◽

Limited Growth ◽

Available Nitrogen ◽

Two Component ◽

Control Protein

ABSTRACT The nitrogen assimilation control protein (NAC) is a LysR-type transcriptional regulator (LTTR) that is made under conditions of nitrogen-limited growth. NAC's synthesis is entirely dependent on phosphorylated NtrC from the two-component Ntr system and requires the unusual sigma factor σ54 for transcription of the nac gene. NAC activates the transcription of σ70-dependent genes whose products provide the cell with ammonia or glutamate. NAC represses genes whose products use ammonia and also represses its own transcription. In addition, NAC also subtly adjusts other cellular functions to keep pace with the supply of biosynthetically available nitrogen.

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RmpA Regulation of Capsular Polysaccharide Biosynthesis in Klebsiella pneumoniae CG43

Journal of Bacteriology ◽

10.1128/jb.00031-10 ◽

2010 ◽

Vol 192 (12) ◽

pp. 3144-3158 ◽

Cited By ~ 103

Author(s):

H. Y. Cheng ◽

Y. S. Chen ◽

C. Y. Wu ◽

H. Y. Chang ◽

Y. C. Lai ◽

...

Keyword(s):

Klebsiella Pneumoniae ◽

Promoter Activity ◽

Deletion Mutant ◽

Capsular Polysaccharide ◽

Activity Measurement ◽

Virulence Plasmid ◽

Dependent Manner ◽

Multicopy Plasmid ◽

Regulatory Activity ◽

Mobility Shift

ABSTRACT Sequence analysis of the large virulence plasmid pLVPK in Klebsiella pneumoniae CG43 revealed the presence of another mucoid factor encoding gene rmpA besides rmpA2. Promoter activity measurement indicated that the deletion of rmpA reduced K2 capsular polysaccharide (CPS) biosynthesis, resulting in decreased colony mucoidy and virulence in mice. Introduction of a multicopy plasmid carrying rmpA restored CPS production in the rmpA or rmpA2 mutant but not in the rcsB mutant. Transformation of the rmpA deletion mutant with an rcsB-carrying plasmid also failed to enhance CPS production, suggesting that a cooperation of RmpA with RcsB is required for regulatory activity. This was further corroborated by the demonstration of in vivo interaction between RmpA and RcsB using two-hybrid analysis and coimmunoprecipitation analysis. A putative Fur binding box was only found at the 5′ noncoding region of rmpA. The promoter activity analysis indicated that the deletion of fur increased the rmpA promoter activity. Using electrophoretic mobility shift assay, we further demonstrated that Fur exerts its regulatory activity by binding directly to the promoter. As a result, the fur deletion mutant exhibited an increase in colony mucoidy, CPS production, and virulence in mice. In summary, our results suggested that RmpA activates CPS biosynthesis in K. pneumoniae CG43 via an RcsB-dependent manner. The expression of rmpA is regulated by the availability of iron and is negatively controlled by Fur.

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A Region in Bacillus subtilisςH Required for Spo0A-Dependent Promoter Activity

Journal of Bacteriology ◽

10.1128/jb.180.18.4987-4990.1998 ◽

1998 ◽

Vol 180 (18) ◽

pp. 4987-4990 ◽

Cited By ~ 10

Author(s):

Cindy M. Buckner ◽

Charles P. Moran

Keyword(s):

Amino Acids ◽

Bacillus Subtilis ◽

Amino Acid ◽

Rna Polymerase ◽

Sigma Factor ◽

Promoter Activity ◽

Amino Acid Substitutions ◽

Mutant Form ◽

Promoter Activation ◽

Affect Expression

ABSTRACT Spo0A activates transcription in Bacillus subtilis from promoters that are used by two types of RNA polymerase, RNA polymerase containing the primary sigma factor, ςA, and RNA polymerase containing a secondary sigma factor, known as ςH. The region of ςA near positions 356 to 359 is required for Spo0A-dependent promoter activation, possibly because Spo0A interacts with this region of ςA at these promoters. To determine if the amino acids in the corresponding region of ςH are also important in Spo0A-dependent promoter activation, we examined the effects of single alanine substitutions at 10 positions in ςH (201 to 210). Two alanine substitutions in ςH, at glutamine 201 (Q201A) and at arginine 205 (R205A), significantly decreased activity from the Spo0A-dependent, ςH-dependent promoterspoIIA but did not affect expression from the ςH-dependent, Spo0A-independent promoterscitGp2 and spoVG. Therefore, promoter activation by Spo0A requires homologous regions in ςA and ςH. A mutant form of Spo0A, S231F, that suppresses the sporulation defect caused by several amino acid substitutions in ςA did not suppress the sporulation defects caused by the Q201A and R205A substitutions in ςH. This result and others indicate that different surfaces of Spo0A probably interact with ςA and ςH RNA polymerases.

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An Intrinsic DNA Curvature Found in the Cyanobacterium Microcystis aeruginosa K-81 Affects the Promoter Activity of rpoDl Encoding a Principal Sigma Factor

The Journal of Biochemistry ◽

10.1093/oxfordjournals.jbchem.a022309 ◽

1999 ◽

Vol 125 (3) ◽

pp. 460-468 ◽

Cited By ~ 17

Author(s):

M. Asayama ◽

Y. Hayasaka ◽

M. Kabasawa ◽

M. Shirai ◽

T. Ohyama

Keyword(s):

Microcystis Aeruginosa ◽

Sigma Factor ◽

Promoter Activity ◽

Dna Curvature

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Dual Promoters Control Expression of the Bacillus anthracis Virulence Factor AtxA

Journal of Bacteriology ◽

10.1128/jb.00766-08 ◽

2008 ◽

Vol 190 (19) ◽

pp. 6483-6492 ◽

Cited By ~ 23

Author(s):

Cristina Bongiorni ◽

Tatsuya Fukushima ◽

Adam C. Wilson ◽

Christina Chiang ◽

M. Cecilia Mansilla ◽

...

Keyword(s):

Bacillus Anthracis ◽

Sigma Factor ◽

Promoter Activity ◽

Regulatory Mechanisms ◽

Phosphotransferase System ◽

Transcription Start ◽

Transcription Start Sites ◽

Consensus Sequences ◽

Dual Promoters ◽

Virulence Regulator

ABSTRACT The AtxA virulence regulator of Bacillus anthracis is required for toxin and capsule gene expression. AtxA is a phosphotransferase system regulatory domain-containing protein whose activity is regulated by phosphorylation/dephosphorylation of conserved histidine residues. Here we report that transcription of the atxA gene occurs from two independent promoters, P1 (previously described by Dai et al. [Z. Dai, J. C. Sirard, M. Mock, and T. M. Koehler, Mol. Microbiol. 16:1171-1181, 1995]) and P2, whose transcription start sites are separated by 650 bp. Both promoters have −10 and −35 consensus sequences compatible with recognition by σA-containing RNA polymerase, and neither promoter depends on the sporulation sigma factor SigH. The dual promoter activity and the extended untranslated mRNA suggest that as-yet-unknown regulatory mechanisms may act on this region to influence the level of AtxA in the cell.

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Symbiotic Autoregulation of nifA Expression in Rhizobium leguminosarum bv. viciae

Journal of Bacteriology ◽

10.1128/jb.186.19.6586-6594.2004 ◽

2004 ◽

Vol 186 (19) ◽

pp. 6586-6594 ◽

Cited By ~ 10

Author(s):

Marta Martínez ◽

José M. Palacios ◽

Juan Imperial ◽

Tomás Ruiz-Argüeso

Keyword(s):

Gene Expression ◽

Escherichia Coli ◽

Nitrogen Fixation ◽

Klebsiella Pneumoniae ◽

Transcription Initiation ◽

Promoter Activity ◽

Rhizobium Leguminosarum ◽

Initiation Site ◽

Diazotrophic Bacteria ◽

Low Levels

ABSTRACT NifA is the general transcriptional activator of nitrogen fixation genes in diazotrophic bacteria. In Rhizobium leguminosarum bv. viciae UPM791, the nifA gene is part of a gene cluster (orf71 orf79 fixW orf5 fixABCX nifAB) separated by 896 bp from an upstream and divergent truncated duplication of nifH (ΔnifH). Symbiotic expression analysis of genomic nifA::lacZ fusions revealed that in strain UPM791 nifA is expressed mainly from a σ54-dependent promoter (P nifA1 ) located upstream of orf71. This promoter contains canonical NifA upstream activating sequences located 91 bp from the transcription initiation site. The transcript initiated in P nifA1 spans 5.1 kb and includes nifA and nifB genes. NifA from Klebsiella pneumoniae was able to activate transcription from P nifA1 in a heterologous Escherichia coli system. In R. leguminosarum, the P nifA1 promoter is essential for effective nitrogen fixation in symbiosis with peas. In its absence, partially efficient nitrogen-fixing nodules were produced, and the corresponding bacteroids exhibited only low levels of nifA gene expression. The basal level of nifA expression resulted from a promoter activity originating upstream of the fixX-nifA intergenic region and probably from an incomplete duplication of P nifA1 located immediately upstream of fixA.

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