Disease relevance of sodA

• Use of site-directed mutagenesis to identify an upstream regulatory sequence of sodA gene of Escherichia coli K-12 [1].
• The deduced amino-acid sequence of the H. ducreyi sodA gene product is 74 and 70% identical to the Mn-SODs of Haemophilus influenzae and E. coli, respectively [2].
• Thus, the gene encoding the manganese-containing SOD (sodA) was cloned from Streptococcus thermophilus AO54 and expressed in four intestinal lactobacilli [3].
• The sodA gene from Erwinia chrysanthemi strain 3937 was cloned by functional complementation of an Escherichia coli sodA sodB mutant and sequenced [4].
• Genes from Pseudomonas putida (Pp), sodA, encoding manganese-superoxide dismutase (MnSOD) and, sodB, iron-superoxide dismutase (FeSOD) were cloned by hybridization with digoxigenin (dig)-labeled PCR products generated from Pp genomic DNA [5].

High impact information on sodA

• Transcriptional regulation of the sodA gene, a member of the soxRS regulon encoding the manganese-containing superoxide dismutase (MnSOD; superoxide:superoxide oxidoreductase, EC 1.15.1.1) of Escherichia coli, was examined in a variety of regulatory mutants [6].
• Thus, E. coli harboring a plasmid containing the mutated sodA gene (pSNM6) were uninducible by paraquat in aerobiosis or by 2,2'-dipyridyl in aerobiosis or anaerobiosis [1].
• The DNA sequence of sodA shows the presence of a potential binding site for a regulatory protein(s) at the -35 region [1].
• Recent studies have shown that sodA expression is regulated by three iron-dependent regulatory proteins, Fur (ferric uptake regulation), Fnr (fumarate nitrate regulation) and SoxR (superoxide regulon), and by the ArcA/ArcB (aerobic respiration control) system [7].
• The potential Fur-, Fnr- and ArcA-binding sites in the sodA promoter region have been identified by using different cis-acting regulatory mutations that caused anaerobic derepression of the gene.(ABSTRACT TRUNCATED AT 250 WORDS)[7]

Chemical compound and disease context of sodA

• The precise location of the rhaT gene, encoding rhamnose permease, has been established between sodA and rhaC at 3605-3607 kb of Kohara's physical map, which corresponds to 88.4 min on the Escherichia coli chromosomal map [8].
• Strains of E. coli with an inactivating insertion in the sodA gene do not induce inactive, reconstitutable MnSOD in response to NO3- plus PQ2+ and lack the immunoreactive MnSOD band [9].
• Moreover, using fusions of sodA promoter to lacZ, we showed that sodA transcription was diminished in flavin reductase-deficient E. coli and that the induction of MnSOD by flavin reductase was SoxRS-independent [10].
• We report the unexpected result that Escherichia coli isolates containing a multicopy plasmid (pDT1.5) carrying the manganese-superoxide dismutase gene sodA were more sensitive than the wild type to paraquat-mediated growth inhibition [11].

Biological context of sodA

• The action of these effectors on the sodA promoter was investigated by using chromosomal sodA-lacZ operon fusions with intact or deleted promoters, different environmental conditions, and strains carrying different combinations of null mutations in the effector genes [12].
• In aerobiosis, activation of sodA transcription by SoxRS was compatible with CfxB activation or Fur repression, whereas cfxB and fur controls were mutually exclusive [12].
• Also, a second putative Fnr-binding site that straddles the ribosomal binding-site was identified in the sodA gene [13].
• The sequence of the sodA-rhaC interval displayed a single ORF corresponding to rhaT, which is transcribed counterclockwise on the E. coli chromosome [8].
• A strain of E. coli bearing a multicopy plasmid carrying the MnSOD gene (sodA) overproduces inactive MnSOD 19-fold compared to the parent strain under anaerobic conditions [9].

Associations of sodA with chemical compounds

• Protein and operon fusions between the manganese superoxide dismutase (MnSOD) gene, sodA, and genes of the lactose operon were constructed in an attempt to explore the effects of various factors on MnSOD expression and the level at which they operate [14].
• In sodA mutant cells lacking manganese superoxide dismutase activity but expressing the cloned gor gene (QC772:pJIK1) increased cellular glutathione reductase activity did not provide protection against methylviologen [15].
• Paraquat-mediated selection for mutations in the manganese-superoxide dismutase gene sodA [11].
• To our best knowledge, this is the first report of a sodA from S. thermophilus being expressed in other lactic acid bacteria [3].
• Transcriptional analysis revealed that the sodA gene of S. agalactiae NEM318 was transcribed monocistronically from a promoter, the activity of which is neither regulated by pH, O2, nor CO2 concentrations of the culture medium [16].

Other interactions of sodA

• In a soxR mutant, the expression of sodA, unlike that of nfo, was also regulated independently by oxygen tension [17].
• Nucleotide sequence of the rhaR-sodA interval specifying rhaT in Escherichia coli [8].
• In vivo, sodA-lacZ fusion activity was increased 3-fold by introducing plasmid pPL341, containing the hmp gene, or by growth with paraquat [18].
• A total of six recombinant Escherichia coli strains with the promoters from three oxidative-stress responsive genes, i.e. the katG, sodA and pqi-5 genes, fused to either the lux genes from Vibrio fischeri or X. luminescens were characterized and their responses to different chemicals compared [19].
• The sodF gene strongly complemented an Escherichia coli triple mutant (sodA sodB recA), restoring aerobic growth when the gene was expressed from the synthetic tac promoter but when expressed from its own promoter showed only slight rescue, suggesting that it was poorly recognized by the E. coli RNA polymerase [20].

Analytical, diagnostic and therapeutic context of sodA

• A 1.2-kb PCR product containing the sodA gene was cloned into the shuttle vector pTRK563, to yield pSodA, which was functionally expressed and complemented an Escherichia coli strain deficient in Mn and FeSODs [3].
• Gel retardation assays demonstrate high-affinity binding of pure, Mn2(+)-Fur protein to DNA fragments containing the sodA promoter [21].
• Analysis by high resolution agarose gel electrophoresis of the AluI DNA polymorphism of the sodA locus in wild-type strains of S. agalactiae belonging to serogroups I, II, or III revealed no detectable difference [16].

References