scholarly journals Expression of a Cryptic Secondary Sigma Factor Gene Unveils Natural Competence for DNA Transformation in Staphylococcus aureus

2012 ◽  
Vol 8 (11) ◽  
pp. e1003003 ◽  
Author(s):  
Kazuya Morikawa ◽  
Aya J. Takemura ◽  
Yumiko Inose ◽  
Melody Tsai ◽  
Le Thuy Nguyen Thi ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Sigma Factor ◽  
Dna Transformation ◽  
Natural Competence ◽  
Factor Gene

scholarly journals Construction and Characterization of aMycobacterium tuberculosis Mutant Lacking the Alternate Sigma Factor Gene, sigF

2000 ◽  
Vol 68 (10) ◽  
pp. 5575-5580 ◽  
Author(s):  
Ping Chen ◽  
Rafael E. Ruiz ◽  
Qing Li ◽  
Richard F. Silver ◽  
William R. Bishai
Keyword(s):  
Stationary Phase ◽  
Sigma Factor ◽  
Type Strain ◽  
Wild Type Strain ◽  
Axenic Culture ◽  
Wild Type ◽  
Intracellular Growth ◽  
Factor Gene ◽  
Time To Death

ABSTRACT The alternate RNA polymerase sigma factor gene, sigF, which is expressed in stationary phase and under stress conditions in vitro, has been deleted in the virulent CDC1551 strain ofMycobacterium tuberculosis. The growth rate of the ΔsigF mutant was identical to that of the isogenic wild-type strain in exponential phase, although in stationary phase the mutant achieved a higher density than the wild type. The mutant showed increased susceptibility to rifampin and rifapentine. Additionally, the ΔsigF mutant displayed diminished uptake of chenodeoxycholate, and this effect was reversed by complementation with a wild-type sigF gene. No differences in short-term intracellular growth between mutant and wild-type organisms within human monocytes were observed. Similarly, the organisms did not differ in their susceptibilities to lymphocyte-mediated inhibition of intracellular growth. However, mice infected with the ΔsigF mutant showed a median time to death of 246 days compared with 161 days for wild-type strain-infected animals (P < 0.001). These data indicate that M. tuberculosis sigF is a nonessential alternate sigma factor both in axenic culture and for survival in macrophages in vitro. While the ΔsigF mutant produces a lethal infection of mice, it is less virulent than its wild-type counterpart by time-to-death analysis.

scholarly journals Sigma Factor SigB Is Crucial to Mediate Staphylococcus aureus Adaptation during Chronic Infections

2015 ◽  
Vol 11 (4) ◽  
pp. e1004870 ◽  
Author(s):  
Lorena Tuchscherr ◽  
Markus Bischoff ◽  
Santiago M. Lattar ◽  
Mariangeles Noto Llana ◽  
Henrike Pförtner ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Sigma Factor ◽  
Chronic Infections

scholarly journals DNA base sequence variability inkatF(putative sigma factor) gene ofEscherichia coli

1992 ◽  
Vol 20 (20) ◽  
pp. 5479-5480 ◽  
Author(s):  
Anna Ivanova ◽  
Mary Renshaw ◽  
Ramareddy V. Guntaka ◽  
Gerald Cohen
Keyword(s):  
Sigma Factor ◽  
Ofescherichia Coli ◽  
Base Sequence ◽  
Sequence Variability ◽  
Factor Gene ◽  
Dna Base

Activation of the alternative sigma factor SigB of Staphylococcus aureus following internalization by epithelial cells – An in vivo proteomics perspective

2014 ◽  
Vol 304 (2) ◽  
pp. 177-187 ◽  
Author(s):  
Henrike Pförtner ◽  
Marc S. Burian ◽  
Stephan Michalik ◽  
Maren Depke ◽  
Petra Hildebrandt ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Epithelial Cells ◽  
Sigma Factor ◽  
Alternative Sigma Factor

scholarly journals Transcription of the Staphylococcus aureus cid and lrg Murein Hydrolase Regulators Is Affected by Sigma Factor B

2004 ◽  
Vol 186 (10) ◽  
pp. 3029-3037 ◽  
Author(s):  
Kelly C. Rice ◽  
Toni Patton ◽  
Soo-Jin Yang ◽  
Alexis Dumoulin ◽  
Markus Bischoff ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Northern Blot ◽  
Exponential Growth ◽  
Sigma Factor ◽  
Positive Impact ◽  
Consensus Sequence ◽  
Hydrolase Activity ◽  
Factor B ◽  
Sigma Factor B ◽  
Murein Hydrolase

ABSTRACT The Staphylococcus aureus lrg and cid loci are homologous operons that have been shown to regulate murein hydrolase activity and affect sensitivity to penicillin. Although the mode of action of these operons has not been demonstrated, a model based on the similarities of the lrgA and cidA gene products to the bacteriophage holin family of proteins has been proposed. In this study, the transcription organization and regulation of these operons were examined by Northern blot analyses. Unexpectedly, cidB and a gene located immediately downstream, designated cidC, were found to be cotranscribed on a 2.7-kb transcript. Maximal cidBC transcription occurred during early exponential growth, and high-level transcription of cidBC was dependent on the rsbU-mediated activation of the alternative sigma factor B (σB). In contrast, lrgAB transcription in stationary phase was negatively regulated by σB. Although cidABC transcription was not detected by Northern blot analysis, reverse transcriptase PCR revealed that these genes are also cotranscribed as a single RNA message in early exponential growth. Primer extension analysis revealed the presence of two cidBC transcription start sites, but no apparent σB-dependent promoter consensus sequence was identified in these regions. The rsbU gene was also shown to have a positive impact on murein hydrolase activity but a negligible effect on sensitivity to penicillin-induced killing. These results suggest that the lrgAB and cidBC genes may be part of the S. aureus σB-controlled stress regulon.

Conservation of Putative Promoter Sequences Located Upstream of Chlamydial Major Sigma Factor Gene,sigAamongChlamydiaSpp.

1999 ◽  
Vol 43 (5) ◽  
pp. 419-424 ◽  
Author(s):  
Yoshitsugu Ochiai ◽  
Hideto Fukushi ◽  
Yan Cai ◽  
Tsuyoshi Yamaguchi ◽  
Katsuya Hirai
Keyword(s):  
Sigma Factor ◽  
Putative Promoter ◽  
Factor Gene ◽  
Promoter Sequences
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