Limits...
DegS and RseP homologous proteases are involved in singlet oxygen dependent activation of RpoE in Rhodobacter sphaeroides.

Nuss AM, Adnan F, Weber L, Berghoff BA, Glaeser J, Klug G - PLoS ONE (2013)

Bottom Line: Moreover, we revealed that the DegS and RseP homologs RSP_3242 and RSP_2710 contribute to (1)O2 resistance and promote ChrR proteolysis.The RpoE signaling pathway in R. sphaeroides is therefore highly similar to that of Escherichia coli, although very different anti-sigma factors control RpoE activity.Based on the acquired results, the current model for RpoE activation in response to (1)O2 exposure in R. sphaeroides was extended.

View Article: PubMed Central - PubMed

Affiliation: Institute of Microbiology and Molecular Biology, Giessen University, Giessen, Germany ; Department of Molecular Infection Biology, Helmholtz Centre for Infection Research, Braunschweig, Germany.

ABSTRACT
Singlet oxygen ((1)O2) is the main agent of photooxidative stress and is generated by photosensitizers as (bacterio)chlorophylls. It leads to the damage of cellular macromolecules and therefore photosynthetic organisms have to mount an adaptive response to (1)O2 formation. A major player of the photooxidative stress response in Rhodobacter sphaeroides is the alternative sigma factor RpoE, which is inactivated under non-stress conditions by its cognate anti-sigma factor ChrR. By using random mutagenesis we identified RSP_1090 to be required for full activation of the RpoE response under (1)O2 stress, but not under organic peroxide stress. In this study we show that both RSP_1090 and RSP_1091 are required for full resistance towards (1)O2. Moreover, we revealed that the DegS and RseP homologs RSP_3242 and RSP_2710 contribute to (1)O2 resistance and promote ChrR proteolysis. The RpoE signaling pathway in R. sphaeroides is therefore highly similar to that of Escherichia coli, although very different anti-sigma factors control RpoE activity. Based on the acquired results, the current model for RpoE activation in response to (1)O2 exposure in R. sphaeroides was extended.

Show MeSH

Related in: MedlinePlus

Genetic organization of the RSP_1091-1087 and rpoEchrR operons on the R. sphaeroides chromosome 1.The insertion site of Tn5 which resulted in reduced RpoE activity is indicated. The Tn5 inserted 683 bp downstream of the start codon of the RSP_1090 gene. RSP_1090 located in a putative operon with RSP_1091, RSP_1089, RSP_1088 and RSP_1087. Both operons are preceded by an RpoE dependent promoter. Annotated protein functions are depicted below the locus tag numbers.
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC3818230&req=5

pone-0079520-g001: Genetic organization of the RSP_1091-1087 and rpoEchrR operons on the R. sphaeroides chromosome 1.The insertion site of Tn5 which resulted in reduced RpoE activity is indicated. The Tn5 inserted 683 bp downstream of the start codon of the RSP_1090 gene. RSP_1090 located in a putative operon with RSP_1091, RSP_1089, RSP_1088 and RSP_1087. Both operons are preceded by an RpoE dependent promoter. Annotated protein functions are depicted below the locus tag numbers.

Mentions: We performed a Tn5 mutagenesis in the R. sphaeroides 2.4.1 wild type harboring the reporter plasmid pPHUphrAlacZ to identify unknown factors triggering RpoE activation. The plasmid harbors the lacZ gene preceded by the RpoE-inducible phrA promoter [15]. We screened for those Tn5 mutants which showed decreased or even no β-galactosidase activity upon exposure to 1O2. Additionally, mutants of interest should not have an insertion of Tn5 in the reporter plasmid pPHUphrAlacZ and in the rpoE gene including the rpoE upstream regulatory region, respectively, and should be more sensitive to 1O2 than the wild type. Several mutants were found that carried the transposon in the rpoE locus and the reporter plasmid, respectively. After screening around 18.000 Tn5 mutants, we finally found one mutant which passed the selection criteria. Vectorette PCR [16] identified the Tn5 insertion into the gene RSP_1090, which encodes a protein of unknown function (Figure 1), that was previously annotated to encode a protein involved in cyclopropane fatty acid synthesis [17]. RSP_1090 is part of the putative RSP_1091-1087 operon located upstream of rpoEchrR and belongs to the recently defined RpoE regulon [13,17].


DegS and RseP homologous proteases are involved in singlet oxygen dependent activation of RpoE in Rhodobacter sphaeroides.

Nuss AM, Adnan F, Weber L, Berghoff BA, Glaeser J, Klug G - PLoS ONE (2013)

Genetic organization of the RSP_1091-1087 and rpoEchrR operons on the R. sphaeroides chromosome 1.The insertion site of Tn5 which resulted in reduced RpoE activity is indicated. The Tn5 inserted 683 bp downstream of the start codon of the RSP_1090 gene. RSP_1090 located in a putative operon with RSP_1091, RSP_1089, RSP_1088 and RSP_1087. Both operons are preceded by an RpoE dependent promoter. Annotated protein functions are depicted below the locus tag numbers.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3818230&req=5

pone-0079520-g001: Genetic organization of the RSP_1091-1087 and rpoEchrR operons on the R. sphaeroides chromosome 1.The insertion site of Tn5 which resulted in reduced RpoE activity is indicated. The Tn5 inserted 683 bp downstream of the start codon of the RSP_1090 gene. RSP_1090 located in a putative operon with RSP_1091, RSP_1089, RSP_1088 and RSP_1087. Both operons are preceded by an RpoE dependent promoter. Annotated protein functions are depicted below the locus tag numbers.
Mentions: We performed a Tn5 mutagenesis in the R. sphaeroides 2.4.1 wild type harboring the reporter plasmid pPHUphrAlacZ to identify unknown factors triggering RpoE activation. The plasmid harbors the lacZ gene preceded by the RpoE-inducible phrA promoter [15]. We screened for those Tn5 mutants which showed decreased or even no β-galactosidase activity upon exposure to 1O2. Additionally, mutants of interest should not have an insertion of Tn5 in the reporter plasmid pPHUphrAlacZ and in the rpoE gene including the rpoE upstream regulatory region, respectively, and should be more sensitive to 1O2 than the wild type. Several mutants were found that carried the transposon in the rpoE locus and the reporter plasmid, respectively. After screening around 18.000 Tn5 mutants, we finally found one mutant which passed the selection criteria. Vectorette PCR [16] identified the Tn5 insertion into the gene RSP_1090, which encodes a protein of unknown function (Figure 1), that was previously annotated to encode a protein involved in cyclopropane fatty acid synthesis [17]. RSP_1090 is part of the putative RSP_1091-1087 operon located upstream of rpoEchrR and belongs to the recently defined RpoE regulon [13,17].

Bottom Line: Moreover, we revealed that the DegS and RseP homologs RSP_3242 and RSP_2710 contribute to (1)O2 resistance and promote ChrR proteolysis.The RpoE signaling pathway in R. sphaeroides is therefore highly similar to that of Escherichia coli, although very different anti-sigma factors control RpoE activity.Based on the acquired results, the current model for RpoE activation in response to (1)O2 exposure in R. sphaeroides was extended.

View Article: PubMed Central - PubMed

Affiliation: Institute of Microbiology and Molecular Biology, Giessen University, Giessen, Germany ; Department of Molecular Infection Biology, Helmholtz Centre for Infection Research, Braunschweig, Germany.

ABSTRACT
Singlet oxygen ((1)O2) is the main agent of photooxidative stress and is generated by photosensitizers as (bacterio)chlorophylls. It leads to the damage of cellular macromolecules and therefore photosynthetic organisms have to mount an adaptive response to (1)O2 formation. A major player of the photooxidative stress response in Rhodobacter sphaeroides is the alternative sigma factor RpoE, which is inactivated under non-stress conditions by its cognate anti-sigma factor ChrR. By using random mutagenesis we identified RSP_1090 to be required for full activation of the RpoE response under (1)O2 stress, but not under organic peroxide stress. In this study we show that both RSP_1090 and RSP_1091 are required for full resistance towards (1)O2. Moreover, we revealed that the DegS and RseP homologs RSP_3242 and RSP_2710 contribute to (1)O2 resistance and promote ChrR proteolysis. The RpoE signaling pathway in R. sphaeroides is therefore highly similar to that of Escherichia coli, although very different anti-sigma factors control RpoE activity. Based on the acquired results, the current model for RpoE activation in response to (1)O2 exposure in R. sphaeroides was extended.

Show MeSH
Related in: MedlinePlus