Transcriptional regulation of the aconitase genes (acnA and acnB) of Escherichia coli.

Escherichia coli contains two differentially regulated aconitase genes, acnA and acnB. Two acnA promoters transcribing from start points located 407 bp (P1acnA) and 50 bp (P2acnA) upstream of the acnA coding region, and one acnB promoter (PacnB) with a start point 95 bp upstream of the acnB coding region, were identified by primer extension analysis. A 2.8 kb acnA monocistronic transcript was detected by Northern blot hybridization, but only in redox-stressed (methyl-viologen-treated) cultures, and a 2.5 kb acnB monocistronic transcript was detected in exponential- but not stationary-phase cultures. These findings are consistent with previous observations that acnA is specifically subject to SoxRS-mediated activation, whereas acnB encodes the major aconitase that is synthesized earlier in the growth cycle than AcnA. Further studies with acn-lacZ gene fusions and a wider range of transcription regulators indicated that acnA expression is initiated by sigma 38 from P1acnA, and from P2acnA it is activated directly or indirectly by CRP, FruR, Fur and SoxRS, and repressed by ArcA and FNR. In contrast, acnB expression is activated by CRP and repressed by ArcA, FruR and Fis from PacnB. Comparable studies with fum-lacZ fusions indicated that transcription of fumC, but not of fumA or fumB, is initiated by RNA polymerase containing sigma 38. It is concluded that AcnB is the major citric acid cycle enzyme, whereas AcnA is an aerobic stationary-phase enzyme that is specifically induced by iron and redox-stress.

[1]  B Demple,et al.  Sequence specificity for DNA binding by Escherichia coli SoxS and Rob proteins , 1996, Molecular microbiology.

[2]  J. Guest,et al.  Differential roles of the Escherichia coli fumarases and fnr-dependent expression of fumarase B and aspartase , 1987 .

[3]  Jeffrey H. Miller.  Experiments in molecular genetics , 1972 .

[4]  B Demple,et al.  Positive control of a global antioxidant defense regulon activated by superoxide-generating agents in Escherichia coli. , 1990, Proceedings of the National Academy of Sciences of the United States of America.

[5]  J. Sambrook,et al.  Molecular Cloning: A Laboratory Manual , 2001 .

[6]  R. Hengge-aronis,et al.  Survival of hunger and stress: The role of rpoS in early stationary phase gene regulation in E. coli , 1993, Cell.

[7]  J. Guest,et al.  Construction and properties of aconitase mutants of Escherichia coli. , 1997, Microbiology.

[8]  Jeffrey Green,et al.  The FNR Modulon and FNR-Regulated Gene Expression , 1996 .

[9]  R. C. Johnson,et al.  The Fis protein: it's not just for DNA inversion anymore , 1992, Molecular microbiology.

[10]  R. Hengge-aronis,et al.  Back to log phase: σS as a global regulator in the osmotic control of gene expression in Escherichia coli , 1996, Molecular microbiology.

[11]  H. Mori,et al.  Systematic sequencing of the Escherichia coli genome: analysis of the 2.4-4.1 min (110,917-193,643 bp) region. , 1994, Nucleic acids research.

[12]  A. S. Lynch,et al.  Transcriptional control mediated by the ArcA two-component response regulator protein of Escherichia coli: characterization of DNA binding at target promoters , 1996, Journal of bacteriology.

[13]  J. Guest,et al.  Two genetically-distinct and differentially-regulated aconitases (AcnA and AcnB) in Escherichia coli. , 1994, Microbiology.

[14]  S. Park,et al.  Oxygen, iron, carbon, and superoxide control of the fumarase fumA and fumC genes of Escherichia coli: role of the arcA, fnr, and soxR gene products , 1995, Journal of bacteriology.

[15]  R. Klausner,et al.  A double life: cytosolic aconitase as a regulatory RNA binding protein. , 1993, Molecular biology of the cell.

[16]  D. Frishman,et al.  Conservation of aconitase residues revealed by multiple sequence analysis. Implications for structure/function relationships. , 1996, European journal of biochemistry.

[17]  M. Chamberlin,et al.  RNA Chain Initiation and Promoter Escape by RNA Polymerase , 1996 .

[18]  R. C. Johnson,et al.  Identification of genes negatively regulated by Fis: Fis and RpoS comodulate growth-phase-dependent gene expression in Escherichia coli , 1995, Journal of bacteriology.

[19]  C. Prodromou,et al.  The aconitase of Escherichia coli: purification of the enzyme and molecular cloning and map location of the gene (acn). , 1991, Journal of general microbiology.

[20]  G. Sawers,et al.  Anaerobic induction of pyruvate formate-lyase gene expression is mediated by the ArcA and FNR proteins , 1992, Journal of bacteriology.

[21]  M. Saier,et al.  The catabolite repressor/activator (Cra) protein of enteric bacteria , 1996, Journal of bacteriology.

[22]  D. Touati,et al.  Anaerobic activation of arcA transcription in Escherichia coli: roles of Fnr and ArcA , 1994, Molecular microbiology.

[23]  J. Guest,et al.  Nucleotide sequence of the FNR-regulated fumarase gene (fumB) of Escherichia coli K-12 , 1989, Journal of bacteriology.

[24]  P. Dürre,et al.  mRNA analysis of the adc gene region of Clostridium acetobutylicum during the shift to solventogenesis , 1992, Journal of bacteriology.

[25]  H. Aiba,et al.  Evidence for two functional gal promoters in intact Escherichia coli cells. , 1981, The Journal of biological chemistry.

[26]  Martin Buck,et al.  Specific binding of the transcription factor sigma-54 to promoter DNA , 1992, Nature.

[27]  P. Loewen,et al.  Cloning and physical characterization of katE and katF required for catalase HPII expression in Escherichia coli. , 1988, Gene.

[28]  J. S. Miles,et al.  Structural and functional relationships between fumarase and aspartase. Nucleotide sequences of the fumarase (fumC) and aspartase (aspA) genes of Escherichia coli K12. , 1986, The Biochemical journal.

[29]  A. Kumar,et al.  The minus 35-recognition region of Escherichia coli sigma 70 is inessential for initiation of transcription at an "extended minus 10" promoter. , 1993, Journal of molecular biology.

[30]  C. Stout,et al.  The structure of aconitase , 1989, Proteins.

[31]  M. Anjum,et al.  The nd7‐binding protein (Nbp) regulates the ndh gene of Escherichia coti in response to growth phase and is identical to Fis , 1996, Molecular microbiology.

[32]  T Nyström,et al.  Bacterial defense against aging: role of the Escherichia coli ArcA regulator in gene expression, readjusted energy flux and survival during stasis. , 1996, The EMBO journal.

[33]  Helmut Beinert,et al.  ACONITASE AS IRON-SULFUR PROTEIN, ENZYME, AND IRON-REGULATORY PROTEIN , 1996 .

[34]  F. de la Cruz,et al.  Construction and properties of a family of pACYC184-derived cloning vectors compatible with pBR322 and its derivatives. , 1991, Gene.

[35]  S. Busby,et al.  The CAP Modulon , 1996 .

[36]  M. Hentze,et al.  Molecular control of vertebrate iron metabolism: mRNA-based regulatory circuits operated by iron, nitric oxide, and oxidative stress. , 1996, Proceedings of the National Academy of Sciences of the United States of America.

[37]  L. Enquist,et al.  Experiments With Gene Fusions , 1984 .

[38]  K. Rudd,et al.  The second aconitase (AcnB) of Escherichia coli. , 1996, Microbiology.

[39]  M Aldea,et al.  The role of the ‘gearbox’ in the transcription of essential genes , 1991, Molecular microbiology.

[40]  M H Saier,et al.  In vitro binding of the pleiotropic transcriptional regulatory protein, FruR, to the fru, pps, ace, pts and icd operons of Escherichia coli and Salmonella typhimurium. , 1993, Journal of molecular biology.

[41]  J. Guest,et al.  FNR‐dependent repression of the ndh gene of Escherichia coli and metal ion requirement for FNR‐regulated gene expression , 1989, Molecular microbiology.

[42]  J. Guest,et al.  Complexes and complexities of the citric acid cycle in Escherichia coli. , 1992, Current topics in cellular regulation.

[43]  P. Artymiuk,et al.  The aconitase family: three structural variations on a common theme. , 1997, Trends in biochemical sciences.