Spx

• Description: Transcriptional regulator Spx, involved in regulation of many genes.
  
  

Gene name	spx
Synonyms	yjbD
Essential	no
Product	transcriptional regulator Spx
Function	negative and positive regulator of many genes
MW, pI	15,5 kDa, 7.80
Gene length, protein length	393 bp, 131 amino acids
Immediate neighbours	yjbC, yjbE
Get the DNA and protein sequences (Barbe et al., 2009)
Genetic context This image was kindly provided by SubtiList

The gene

Basic information

• Locus tag: BSU11500

Phenotypes of a mutant

Loss of up-regulation of the methionine sulfoxide reductase (msrA-msrB) operon in response to thiol specific oxidative stress, also loss of trxA and trxB upregulation in response to thiol specific oxidative stress.

Database entries

• DBTBS entry: [1]

• SubtiList entry: link

The protein

Basic information/ Evolution

• Catalyzed reaction/ biological activity: Transcriptional regulator of many genes in response to thiol specific oxidative stress (transcription activator of trxA and trxB). In addition, Spx inhibits transcription by binding to the C-terminal domain of the alpha subunit of RNAP (RpoA), disrupting complex formation between RNAP and certain transcriptional activator proteins like ResD and ComA. In response to thiol specific oxidative stress, Spx can also activate transcription, making it a general regulator that exerts both positive and negative control over transcription initiation.

• Protein family: Spx subfamily (according to Swiss-Prot) Arsenate Reductase (ArsC) family, Spx subfamily

• Paralogous protein(s): MgsR

Extended information on the protein

• Kinetic information:

• Domains: CXXC (10-13): Acts as a disulfide switch for the redox-sensitive transcriptional regulation of genes that function in thiol homeostasis.

• Modification: Cysteine oxidation of the CXXC motif

• Cofactor(s):

• Effectors of protein activity:

• Interactions: Spx-YjbH, RpoA-Spx PubMed, Spx-RpoA (C-terminal domain PubMed)

• Localization: cytoplasm (according to Swiss-Prot)

Database entries

• Structure: 1Z3E complex with C-terminal domain of RpoA NCBI

• UniProt: O31602

• KEGG entry: [2]

• E.C. number:

Expression and regulation

• Operon: yjbC-spx, spx PubMed

• Sigma factor:
  • four promoters upstream of yjbC: SigW, SigB, SigX, and unknown sigma PubMed,
  • promoters upstream of spx: SigA, SigW PubMed, SigM PubMed

• Regulation:
  • induced by stress (SigB) PubMed
  • transcription is represed by PerR and YodB PubMed
  • repressed in the absence of hydrogen peroxide (PerR) PubMed
  • upregulated in response to enduracidin PubMed

• Regulatory mechanism: transcription repression
  • PerR: transcription repression PubMed

• Additional information:
  • post-translational control by ClpX-ClpP: Spx naturally contains a C-terminal sequence that resembles the SsrA tag and targets the protein for degradation. PubMed
  • proteolysis is enhanced by YjbH. PubMed

Biological materials

• Mutant: ORB6781 (spc), ORB6876 (tet), available in Zuber lab, also available in the Stülke lab

• Expression vector:

• lacZ fusion:

• GFP fusion:

• two-hybrid system: B. pertussis adenylate cyclase-based bacterial two hybrid system (BACTH), available in Stülke lab

• Antibody:

Labs working on this gene/protein

Peter Zuber, Oregon Health and Science University, USA Homepage

Richard Brennan, Houston, Texas, USA Homepage

References

Original Publications

Valerie Lamour, Lars F Westblade, Elizabeth A Campbell, Seth A Darst
Crystal structure of the in vivo-assembled Bacillus subtilis Spx/RNA polymerase alpha subunit C-terminal domain complex.
J Struct Biol: 2009, 168(2);352-6
[PubMed:19580872] [WorldCat.org] [DOI] (I p)

Saurabh K Garg, Sushma Kommineni, Luke Henslee, Ying Zhang, Peter Zuber
The YjbH protein of Bacillus subtilis enhances ClpXP-catalyzed proteolysis of Spx.
J Bacteriol: 2009, 191(4);1268-77
[PubMed:19074380] [WorldCat.org] [DOI] (I p)

Dindo Y Reyes, Peter Zuber
Activation of transcription initiation by Spx: formation of transcription complex and identification of a Cis-acting element required for transcriptional activation.
Mol Microbiol: 2008, 69(3);765-79
[PubMed:18687074] [WorldCat.org] [DOI] (I p)

CongHui You, Agnieszka Sekowska, Olivera Francetic, Isabelle Martin-Verstraete, YiPing Wang, Antoine Danchin
Spx mediates oxidative stress regulation of the methionine sulfoxide reductases operon in Bacillus subtilis.
BMC Microbiol: 2008, 8;128
[PubMed:18662407] [WorldCat.org] [DOI] (I e)

Falko Hochgräfe, Carmen Wolf, Stephan Fuchs, Manuel Liebeke, Michael Lalk, Susanne Engelmann, Michael Hecker
Nitric oxide stress induces different responses but mediates comparable protein thiol protection in Bacillus subtilis and Staphylococcus aureus.
J Bacteriol: 2008, 190(14);4997-5008
[PubMed:18487332] [WorldCat.org] [DOI] (I p)

Warawan Eiamphungporn, John D Helmann
The Bacillus subtilis sigma(M) regulon and its contribution to cell envelope stress responses.
Mol Microbiol: 2008, 67(4);830-48
[PubMed:18179421] [WorldCat.org] [DOI] (P p)

Jonas T Larsson, Annika Rogstam, Claes von Wachenfeldt
YjbH is a novel negative effector of the disulphide stress regulator, Spx, in Bacillus subtilis.
Mol Microbiol: 2007, 66(3);669-84
[PubMed:17908206] [WorldCat.org] [DOI] (P p)

Ying Zhang, Peter Zuber
Requirement of the zinc-binding domain of ClpX for Spx proteolysis in Bacillus subtilis and effects of disulfide stress on ClpXP activity.
J Bacteriol: 2007, 189(21);7669-80
[PubMed:17827297] [WorldCat.org] [DOI] (P p)

Adrian J Jervis, Penny D Thackray, Chris W Houston, Malcolm J Horsburgh, Anne Moir
SigM-responsive genes of Bacillus subtilis and their promoters.
J Bacteriol: 2007, 189(12);4534-8
[PubMed:17434969] [WorldCat.org] [DOI] (P p)

Montira Leelakriangsak, Kazuo Kobayashi, Peter Zuber
Dual negative control of spx transcription initiation from the P3 promoter by repressors PerR and YodB in Bacillus subtilis.
J Bacteriol: 2007, 189(5);1736-44
[PubMed:17158660] [WorldCat.org] [DOI] (P p)

Soon-Yong Choi, Dindo Reyes, Montira Leelakriangsak, Peter Zuber
The global regulator Spx functions in the control of organosulfur metabolism in Bacillus subtilis.
J Bacteriol: 2006, 188(16);5741-51
[PubMed:16885442] [WorldCat.org] [DOI] (P p)

Ying Zhang, Shunji Nakano, Soon-Yong Choi, Peter Zuber
Mutational analysis of the Bacillus subtilis RNA polymerase alpha C-terminal domain supports the interference model of Spx-dependent repression.
J Bacteriol: 2006, 188(12);4300-11
[PubMed:16740936] [WorldCat.org] [DOI] (P p)

Kate J Newberry, Shunji Nakano, Peter Zuber, Richard G Brennan
Crystal structure of the Bacillus subtilis anti-alpha, global transcriptional regulator, Spx, in complex with the alpha C-terminal domain of RNA polymerase.
Proc Natl Acad Sci U S A: 2005, 102(44);15839-44
[PubMed:16249335] [WorldCat.org] [DOI] (P p)

Kyle N Erwin, Shunji Nakano, Peter Zuber
Sulfate-dependent repression of genes that function in organosulfur metabolism in Bacillus subtilis requires Spx.
J Bacteriol: 2005, 187(12);4042-9
[PubMed:15937167] [WorldCat.org] [DOI] (P p)

Dirk Höper, Uwe Völker, Michael Hecker
Comprehensive characterization of the contribution of individual SigB-dependent general stress genes to stress resistance of Bacillus subtilis.
J Bacteriol: 2005, 187(8);2810-26
[PubMed:15805528] [WorldCat.org] [DOI] (P p)

Shunji Nakano, Kyle N Erwin, Martina Ralle, Peter Zuber
Redox-sensitive transcriptional control by a thiol/disulphide switch in the global regulator, Spx.
Mol Microbiol: 2005, 55(2);498-510
[PubMed:15659166] [WorldCat.org] [DOI] (P p)

Peter Zuber
Spx-RNA polymerase interaction and global transcriptional control during oxidative stress.
J Bacteriol: 2004, 186(7);1911-8
[PubMed:15028674] [WorldCat.org] [DOI] (P p)

Shunji Nakano, Elke Küster-Schöck, Alan D Grossman, Peter Zuber
Spx-dependent global transcriptional control is induced by thiol-specific oxidative stress in Bacillus subtilis.
Proc Natl Acad Sci U S A: 2003, 100(23);13603-8
[PubMed:14597697] [WorldCat.org] [DOI] (P p)

Penny D Thackray, Anne Moir
SigM, an extracytoplasmic function sigma factor of Bacillus subtilis, is activated in response to cell wall antibiotics, ethanol, heat, acid, and superoxide stress.
J Bacteriol: 2003, 185(12);3491-8
[PubMed:12775685] [WorldCat.org] [DOI] (P p)

Shunji Nakano, Michiko M Nakano, Ying Zhang, Montira Leelakriangsak, Peter Zuber
A regulatory protein that interferes with activator-stimulated transcription in bacteria.
Proc Natl Acad Sci U S A: 2003, 100(7);4233-8
[PubMed:12642660] [WorldCat.org] [DOI] (P p)

Shunji Nakano, Guolu Zheng, Michiko M Nakano, Peter Zuber
Multiple pathways of Spx (YjbD) proteolysis in Bacillus subtilis.
J Bacteriol: 2002, 184(13);3664-70
[PubMed:12057962] [WorldCat.org] [DOI] (P p)

M M Nakano, F Hajarizadeh, Y Zhu, P Zuber
Loss-of-function mutations in yjbD result in ClpX- and ClpP-independent competence development of Bacillus subtilis.
Mol Microbiol: 2001, 42(2);383-94
[PubMed:11703662] [WorldCat.org] [DOI] (P p)

A Petersohn, J Bernhardt, U Gerth, D Höper, T Koburger, U Völker, M Hecker
Identification of sigma(B)-dependent genes in Bacillus subtilis using a promoter consensus-directed search and oligonucleotide hybridization.
J Bacteriol: 1999, 181(18);5718-24
[PubMed:10482513] [WorldCat.org] [DOI] (P p)