The aldA gene of Escherichia coli is under the control of at least three transcriptional regulators

Limón, Ana; Hidalgo, Elena; Aguilar, Juan

doi:10.1099/00221287-143-6-2085

Cited by 17 publications

(18 citation statements)

References 42 publications

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“…For example, acnA expression can be activated by cyclic AMP receptor protein (CRP), FruR, Fur, and SoxRS and repressed by ArcA and FNR (15); aldA is repressed by the ArcA system and induced by an inducer-regulator complex and by CRP (32); ndh can be repressed by FNR and integration host factor (IHF) and activated by Arr (24); sodA is regulated not only by SoxS and MarA but also by FNR, ArcAB, IHF, and Fur (50); and fumC is regulated by SoxS, MarA, ArcAB and s (50).…”

Section: Resultsmentioning

confidence: 99%

Differential Expression of over 60 Chromosomal Genes in Escherichia coli by Constitutive Expression of MarA

Barbosa¹,

2000

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In Escherichia coli, the MarA protein controls expression of multiple chromosomal genes affecting resistance to antibiotics and other environmental hazards. For a more-complete characterization of the mar regulon, duplicate macroarrays containing 4,290 open reading frames of the E. coli genome were hybridized to radiolabeled cDNA populations derived from mar-deleted and mar-expressing E. coli. Strains constitutively expressing MarA showed altered expression of more than 60 chromosomal genes: 76% showed increased expression and 24% showed decreased expression. Although some of the genes were already known to be MarA regulated, the majority were newly determined and belonged to a variety of functional groups. Some of the genes identified have been associated with iron transport and metabolism; other genes were previously known to be part of the soxRS regulon. Northern blot analysis of selected genes confirmed the results obtained with the macroarrays. The findings reveal that the mar locus mediates a global stress response involving one of the largest networks of genes described.The chromosomal multiple-antibiotic-resistance (mar) locus, first described for Escherichia coli (22), is also present among other enteric bacteria (14). Molecular characterization of this locus has been performed in E. coli (11), Salmonella enterica serovar Typhimurium (51), and more recently Shigella flexneri (T. M. Barbosa and S. B. Levy, Abstr. 99th Gen. Meet. Am. Soc. Microbiol., abstr. A-42, p. 9, 1999). In all three genera, the locus consists of two divergently transcribed units, marC and marRAB, which are regulated from independent promoters (Pmar I and Pmar II , respectively) located in the marC-marR intergenic promoter/operator region. MarC has characteristics of a putative integral inner membrane protein whose function is unknown. marRAB specifies two regulatory proteins, MarR, the repressor of the operon, and MarA, a transcriptional activator. The function of MarB has not yet been defined. Increased expression of the marRAB operon results from mutations in marO or marR or from inactivation of MarR following exposure to different inducing agents, such as salicylate (1, 12). The resultant Mar phenotype includes resistance to structurally unrelated antibiotics (21, 43), organic solvents (6, 54), oxidative stress agents (4), and disinfectant products (40,42).The Mar phenotype is achieved through the differential expression of many chromosomal genes within the mar regulon. Regulation by MarA is achieved by its binding to a specific DNA sequence, "marbox," in the vicinity of the promoters of controlled genes (37) or by other mechanisms yet to be identified.Considering the broad Mar phenotype, we hypothesized that MarA affected the expression of a much wider collection of genes than is currently known. Using E. coli Panorama gene macroarrays we identified a large number of genes differentially expressed by constitutive expression of MarA, whose products may be involved in the cell's response to different environmental stresses. MATERI...

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Section: Resultsmentioning

confidence: 99%

Differential Expression of over 60 Chromosomal Genes in Escherichia coli by Constitutive Expression of MarA

Barbosa¹,

2000

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“…It should be noted, however, that such an effect was observed only in a minimal medium in the presence of glucose. Under these conditions, expression of aldA is limited (Limon et al, 1997). In M9 medium containing rhamnose in place of glucose and supplemented with Casamino acids, or in L-broth, where expression of the gene is induced, neither increase nor decrease of cellular DnaA concentration affected the level of β-galactosidase activity (data not shown).…”

Section: Discussionmentioning

confidence: 99%

“…This gene encodes NAD-linked aldehyde dehydrogenase with a broad substrate spectrum and is under control of several transcriptional regulators that bind to sites within or near the region bound by DnaA (Limon et al, 1997 ;Pellicer et al, 1999) (Fig. 4).…”

Section: Binding Of Dnaa To the Alda Regulatory Region In Vivomentioning

confidence: 99%

“…The aldA gene encodes an aldehyde dehydrogenase of broad substrate specificity (Hidalgo et al, 1991 ;Limon et al, 1997 intermediates of various carbohydrates and amino acids (Quintilla et al, 1991). In addition, expression of the gene is activated by Crp-cAMP and is repressed under anaerobic growth conditions by ArcA-P, the phosphorylated response regulator of the ArcB\A two-component signal-transduction system (Pellicer et al, 1999).…”

Section: Introductionmentioning

confidence: 99%

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Anomalous DnaA protein binding to the regulatory region of the Escherichia coli aldA gene

et al. 2001

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“…Mapped at min 32 on the E. coli chromosome, aldA has been studied extensively at both the genetic and protein levels (2,13). The gene product of aldA, also known as lactaldehyde dehydrogenase, is an NAD-dependent aldehyde dehydrogenase participating in various metabolic pathways (6,16,19). To the best of our knowledge, there is no available literature citation on the catalytic properties of the gene product of aldB.…”

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Isolation and Characterization of an Aldehyde Dehydrogenase Encoded by thealdBGene ofEscherichia coli

Weiner

2005

J Bacteriol

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An aldehyde dehydrogenase was detected in crude cell extracts of Escherichia coli DH5␣. Growth studies indicated that the aldehyde dehydrogenase activity was growth phase dependent and increased in cells grown with ethanol. The N-terminal amino acid sequence of the purified enzyme identified the latter as an aldehyde dehydrogenase encoded by aldB, which was thought to play a role in the removal of aldehydes and alcohols in cells that were under stress. The purified enzyme showed an estimated molecular mass of 220 ؎ 8 kDa, consisting of four identical subunits, and preferred to use NADP and acetaldehyde. MgCl 2 increased the activity of the NADP-dependent enzyme with various substrates. A comparison of the effect of Mg 2؉ ions on the bacterial enzyme with the effect of Mg 2؉ ions on human liver mitochondrial aldehyde dehydrogenase revealed that the bacterial enzyme shared kinetic properties with the mammalian enzyme. An R197E mutant of the bacterial enzyme appeared to retain very little NADP-dependent activity on acetaldehyde.Aldehyde dehydrogenases (ALDH) are members of a diverse group of related enzymes catalyzing the oxidation of aldehydes to their corresponding carboxylic acids, with some using NAD and others using NADP as the coenzyme. Their important roles in cellular metabolism have been studied extensively in organisms ranging from bacteria to humans (30). In Escherichia coli, more than 10 aldehyde dehydrogenase genes have been identified (26), and one of the genes, aldB, mapped from min 80 to 86 on the bacterial chromosome has been predicted to encode an aldehyde dehydrogenase of 512 amino acids (32). Sequence alignments of the deduced amino acid sequence showed 68% similarity and 70% identity with an aldehyde dehydrogenase from Vibrio cholerae (22) and an NAD-dependent acetaldehyde dehydrogenase from Alcaligenes eutrophus (24), respectively. Expression studies (32, 33) indicated that aldB was repressed by Fis (factor for inversion stimulation) but activated by RpoS (RNA polymerase sigma factor) and Crp (cyclic AMP receptor protein), and that the level of expression was highest in the early stationary phase. It was also shown that ethanol induced aldB expression. The latter finding, together with the high similarity to the A. eutrophus enzyme, suggests that the gene product of aldB functions as an acetaldehyde dehydrogenase and that it plays a role in ethanol metabolism through its oxidation of acetaldehyde derived from ethanol. Many free-living, gram-negative bacteria, including E. coli, express genes that are crucial to survival at the early stationary phase, and a number of these genes are RpoS dependent (12,14,25). The fact that aldB is positively regulated by RpoS suggests that it is an important stationaryphase gene (33). With the exception of its gene sequence, little is known about aldB at the protein level. The presumed gene product of aldB has been classified as an aldehyde dehydrogenase at the EcoCyc website (http://ecocyc.org) and is thought to catalyze some of the reactions ascribed to the g...

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The aldA gene of Escherichia coli is under the control of at least three transcriptional regulators

Cited by 17 publications

References 42 publications

Differential Expression of over 60 Chromosomal Genes in Escherichia coli by Constitutive Expression of MarA

Differential Expression of over 60 Chromosomal Genes in Escherichia coli by Constitutive Expression of MarA

Anomalous DnaA protein binding to the regulatory region of the Escherichia coli aldA gene

Isolation and Characterization of an Aldehyde Dehydrogenase Encoded by thealdBGene ofEscherichia coli

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