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

This study has revealed that a Clostridium perfringens ferredoxin gene (per-fdx) possesses a novel type of DNA curvature, which is formed by five phased A-tracts extending from upstream to downstream of the −35 region. The three A-tracts upstream of the promoter and the two within the promoter are located at the positions corresponding to A-tracts present in a C. perfringens phospholipase C gene (plc) and a Clostridium pasteurianum ferredoxin gene (pas-fdx), respectively. DNA fragments of the per-fdx, pas-fdx and plc genes (nucleotide positions −69 to +1 relative to the transcription initiation site) were fused to a chloramphenicol acetyltransferase reporter gene on a plasmid, pPSV, and their in vivo promoter activities were examined by assaying the chloramphenicol acetyltransferase activity of each C. perfringens transformant. Comparison of the three constructs showed that the order of promoter activity is, in descending order, per-fdx, pas-fdx and plc. Deletion of the three upstream A-tracts of the per-fdx gene drastically decreased the promoter activity, as demonstrated previously for the plc promoter. Substitution of the most downstream A-tract decreased the promoter activities of the per-fdx and pas-fdx genes. These results indicate that not only the phased A-tracts upstream of the promoter but also those within the promoter stimulate the promoter activity, and suggest that the high activity of the per-fdx promoter is due to the combined effects of these two types of A-tracts.

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RpoE1, an extracytoplasmic function sigma factor, is a repressor of the flagellar system in Brucella melitensis

Microbiology ◽

10.1099/mic.0.044875-0 ◽

2011 ◽

Vol 157 (5) ◽

pp. 1263-1268 ◽

Cited By ~ 10

Author(s):

Jonathan Ferooz ◽

Julien Lemaire ◽

Marie Delory ◽

Xavier De Bolle ◽

Jean-Jacques Letesson

Keyword(s):

Sigma Factor ◽

Promoter Activity ◽

Brucella Melitensis ◽

Sigma Factors ◽

Published Data ◽

Filament Length ◽

Master Regulator ◽

Flagellar Protein ◽

Extracytoplasmic Function Sigma Factor ◽

Flagellar Genes

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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Cloning, sequencing and characterization of the gene encoding a principal sigma factor homolog from the cyanobacterium Microcystis aeruginosa K-81

Gene ◽

10.1016/s0378-1119(96)00517-3 ◽

1996 ◽

Vol 181 (1-2) ◽

pp. 213-217 ◽

Cited By ~ 13

Author(s):

Munehiko Asayama ◽

Kan Tanaka ◽

Hideo Takahashi ◽

Akio Sato ◽

Tokujiro Aida ◽

...

Keyword(s):

Microcystis Aeruginosa ◽

Sigma Factor ◽

Gene Encoding

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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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The rpoD1 Gene Product Is a Principal Sigma Factor of RNA Polymerase in Microcystis aeruginosa K-81

The Journal of Biochemistry ◽

10.1093/oxfordjournals.jbchem.a021475 ◽

1996 ◽

Vol 120 (4) ◽

pp. 752-758 ◽

Cited By ~ 21

Author(s):

M. Asayama ◽

H. Suzuki ◽

A. Sato ◽

T. Aida ◽

K. Tanaka ◽

...

Keyword(s):

Rna Polymerase ◽

Gene Product ◽

Microcystis Aeruginosa ◽

Sigma Factor

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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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