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  • 1
    Electronic Resource
    Electronic Resource
    New members of the Escherichia coliσE regulon identified by a two-plasmid system (2003)
    Oxford, UK : Blackwell Publishing Ltd
    FEMS microbiology letters 225 (2003), S. 0 
    Details
    ISSN: 1574-6968
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: A previously established method, based on a two-plasmid system, was used to identify promoters recognized by RNA polymerase containing the extracytoplasmic stress response sigma factor σE in Escherichia coli. In addition to previously identified rpoE-dependent promoters, 11 new promoters potentially directing the expression of 15 genes were identified that were active only after over-expression of rpoE. The promoters were confirmed and transcriptional start points of the promoters were determined by primer extension analysis and S1-nuclease mapping. All the promoters contained sequences similar to the consensus sequence of rpoE-dependent promoters. The new rpoE-dependent promoters governed expression of genes encoding proteins involved in primary metabolism (fusA, tufA, recR), phospholipid and lipopolysaccharide biosynthesis (psd, lpxP), signal transduction (sixA), proposed inner or outer membrane proteins (bacA, sbmA, smpA, yeaY), and proteins with unknown function (ybaB, yaiW, yiiS, yiiT, yfeY).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1016/S0378-1097(03)00480-4
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Identification of nucleotides critical for activity of the σE-dependent rpoEp3 promoter in Salmonella enterica serovar Typhimurium (2004)
    Oxford, UK : Blackwell Publishing Ltd
    FEMS microbiology letters 238 (2004), S. 0 
    Details
    ISSN: 1574-6968
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: We previously described a two-plasmid system for the identification of promoters recognized by Salmonella enterica serovar Typhimurium (S. Typhimurium) σE. The S. Typhimurium σE-dependent rpoEp3 promoter was active in the E. coli two-plasmid system only after arabinose-induced expression of S. Typhimurium rpoE. In the present study, we have exploited this two-plasmid system for the identification of nucleotides critical for activity of the rpoEp3 promoter. A library of randomly mutated DNA fragments containing the rpoEp3 promoter was cloned upstream of a lacZα reporter gene and screened for activity in the presence of S. Typhimurium σE. The clones exhibiting reduced LacZ activity were sequenced to identify the mutations. The activity of the mutated rpoEp3 promoters were studied further using a luciferase-based promoter-probe plasmid. All of the important nucleotides of the rpoEp3 promoter (in capital) were located in the −35 (ggAActt) and −10 (TctaA) regions. The critical nucleotides were also the most conserved in known σE-dependent promoters. The study also revealed the importance of the 16-bp spacing between −10 and −35 region, as reducing the spacing to 15-bp greatly reduced activity of the promoter. This method should be generally applicable for the identification of important nucleotides in the cognate promoters of other σ factors.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1574-6968.2004.tb09760.x
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Disruption of a sigma factor gene, sigF, affects an intermediate stage of spore pigment production in Streptomyces aureofaciens (1997)
    Oxford, UK : Blackwell Publishing Ltd
    FEMS microbiology letters 153 (1997), S. 0 
    Details
    ISSN: 1574-6968
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: The Streptomyces aureofaciens sigF gene encodes a sigma factor. By integrative transformation, via double cross-over, a stable null mutant of sigF gene was obtained. This mutation appeared to have no obvious effect on vegetative growth, but affected the late stage of spore maturation. Microscopic examination showed that spores were deformed, and spore wall was thinner, compared with the wild-type spores. The spore pigment of sigF mutant was green, compared to wild-type grey-pink spore pigmentation. The plasmid-born wild-type sigF gene complemented the mutation after transformation of the mutant strain.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1574-6968.1997.tb12598.x
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  • 4
    Electronic Resource
    Electronic Resource
    Transcriptional analysis of the rpoE gene encoding extracytoplasmic stress response sigma factor σE in Salmonella enterica serovar Typhimurium (2003)
    Oxford, UK : Blackwell Publishing Ltd
    FEMS microbiology letters 226 (2003), S. 0 
    Details
    ISSN: 1574-6968
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: The rpoE gene of Salmonella enterica serovar Typhimurium (S. Typhimurium), which encodes the extracytoplasmic stress response sigma factor σE, is critically important for the virulence of S. Typhimurium. We analysed expression of rpoE by wild-type and mutant bacteria grown in different conditions by S1-nuclease mapping using RNA, and using in vivo reporter gene fusions. Three promoters, rpoEp1, rpoEp2 and rpoEp3, were located upstream of the S. Typhimurium rpoE gene. The promoters were differentially expressed during growth and under several stress conditions including cold shock. Expression from the rpoEp3 promoter was absent in an S. Typhimurium rpoE mutant, demonstrating its dependence upon σE. The level of mRNA corresponding to rpoEp3 was also higher in a cpxR mutant, indicating a negative regulation of the promoter by the Cpx system. Using this rpoE-dependent promoter, we optimised a two-plasmid system for identification of promoters recognised by S. Typhimurium σE. The rpoEp3 promoter was active in the Escherichia coli two-plasmid system and has an identical transcription start point as in S. Typhimurium but only after induction of S. Typhimurium rpoE expression.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1016/S0378-1097(03)00600-1
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  • 5
    Electronic Resource
    Electronic Resource
    Identification and transcriptional characterization of the gene encoding the stress-response σ factor σH in Streptomyces coelicolor A3(2) (2000)
    Oxford, UK : Blackwell Publishing Ltd
    FEMS microbiology letters 189 (2000), S. 0 
    Details
    ISSN: 1574-6968
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: We cloned a new gene, sigH, encoding an alternative σ factor in Streptomyces coelicolor A3(2). The deduced protein of 354 amino acids with an Mr of 39 486 showed greatest similarity to the sporulation σ factor (σF) of S. coelicolor, general stress-response σB of Bacillus subtilis, and stationary-phase stress-response σF of Mycobacterium tuberculosis. Sequence analysis of the upstream region revealed an ORF encoding a protein (UshX) similar to several anti-σ factors, and short ORF (UshY) containing zinc-finger DNA binding motif. Transcriptional analysis revealed that all three genes are located on the same polycistronic transcript in order ushY, ushX, and sigH. Expression of the operon was directed by four promoters differentially expressed in the course of differentiation. The first (P1) constitutive promoter was located upstream of ushY. The other three promoters (P2, P3, and P4) were located upstream of ushX, and were differentially induced after various stress conditions. The magnitude of the induction was greatest after osmotic stress and heat shock.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1574-6968.2000.tb09202.x
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