Mechanism of Regulation of 8-Hydroxyguanine Endonuclease by Oxidative Stress: Roles of FNR, ArcA, and Fur

Lee, Hye-Sook; Lee, Yong Kyu; Kim, Hun-Sik; Choi, Jeong‐Yun; Hassan, Hosni M.; Chung, Myung‐Hee

doi:10.1016/s0891-5849(97)00427-9

Cited by 35 publications

(26 citation statements)

References 60 publications

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“…Notwithstanding, in contrast to other OxyRregulated genes, the fpg mRNA basal level of wild-type cells and the enhanced transcript level exhibited by trxA gshA double mutant strains were not increased to a greater level in a strain constitutive in OxyR. This difference might be a consequence of the complex regulation that apparently controls 8-hydroxyguanine endonuclease in E. coli, as suggested by a recent report (45), demonstrating that this DNA repair activity increases under anaerobic conditions in mutant strains deficient in Fnr in particular, as well as in Fur, ArcA, and combinations thereof.…”

Section: Discussionmentioning

confidence: 68%

“…Here we demonstrated that fpg transcription is induced in response to oxidative stress by H 2 O 2 in an OxyR-dependent manner, therefore suggesting the possibility of the fpg gene being considered a new member of the oxyR regulon. A previous report (45) has excluded such a possibility based on the finding that H 2 O 2 (even at concentrations of up to 1000 M) failed to induce the 8-hydroxyguanine endonuclease activity of the Fpg protein. This apparent discrepancy may be explained if the putative increment in 8-hydroxyguanine endonuclease upon H 2 O 2 exposure had fallen back to basal levels after 1 h of treatment (45), in agreement with the observation that OxyRdependent genes exhibit a remarkably rapid and reversible induction in response to H 2 O 2 (31).…”

Section: Discussionmentioning

confidence: 99%

“…A previous report (45) has excluded such a possibility based on the finding that H 2 O 2 (even at concentrations of up to 1000 M) failed to induce the 8-hydroxyguanine endonuclease activity of the Fpg protein. This apparent discrepancy may be explained if the putative increment in 8-hydroxyguanine endonuclease upon H 2 O 2 exposure had fallen back to basal levels after 1 h of treatment (45), in agreement with the observation that OxyRdependent genes exhibit a remarkably rapid and reversible induction in response to H 2 O 2 (31). Besides, our data confirm at the transcriptional level that the induction of 8-hydroxyguanine endonuclease by paraquat is independent of SoxRS (45), but they further attribute such an induction to the conversion of O 2 .…”

Section: Discussionmentioning

confidence: 99%

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Transcriptional Regulation of Glutaredoxin and Thioredoxin Pathways and Related Enzymes in Response to Oxidative Stress

Prieto‐Álamo¹,

Jurado²,

Gallardo-Madueño³

et al. 2000

Journal of Biological Chemistry

127

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We examined the in vivo expression of up to 16 genes encoding for components of both glutaredoxin and thioredoxin systems and for members of the OxyR and SoxRS regulons. We demonstrated that grxA (Grx1) transcription is triggered in bacteria lacking Trx1 (trxA) and GSH (gshA) in an OxyR-dependent manner. We also indicated that, unlike OxyR, SoxR is not constitutively activated in the oxidizing environment of trxA gshA mutants. We discovered that the lack of Trx1 plus GSH increases the steady-state levels of Trx reductase (trxB) and Trx2 (trxC) transcripts. This increase and the trxB and trxC up-regulation caused by the constitutive oxyR2 allele indicate that OxyR also plays a role in the regulation of the thioredoxin pathway. On the contrary, no change in the expression of genes for Trx1, Grx2, and Grx3 was observed. Transcription of nrdAB (RRase) was not induced by oxidative stress yet was induced by hydroxyurea (RRase inhibitor). Induction level was as the enhanced nrdAB basal expression of trxA grxA mutants, indicating that RRase operation without Trx1 and Grx1 must lead to disturbances sensed as those caused by hydroxyurea. We also demonstrated an inverse relation between nrdAB expression and that of genes coding for components of both glutaredoxin (grxA, gorA) and thioredoxin (trxB, trxC) systems.

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Section: Discussionmentioning

confidence: 68%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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Transcriptional Regulation of Glutaredoxin and Thioredoxin Pathways and Related Enzymes in Response to Oxidative Stress

Prieto‐Álamo¹,

Jurado²,

Gallardo-Madueño³

et al. 2000

Journal of Biological Chemistry

127

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“…-generating compound paraquat (31,35). This response still occurs in mutants defective in SoxR and SoxS, demonstrating that fpg (Fpg) is not part of the SoxRS regulon (31,35 (40).…”

Section: ⅐ϫmentioning

confidence: 99%

“…This response still occurs in mutants defective in SoxR and SoxS, demonstrating that fpg (Fpg) is not part of the SoxRS regulon (31,35 (40). There have been no reported studies on endo III regulation.…”

Section: ⅐ϫmentioning

confidence: 99%

Multiprobe RNase Protection Assay Analysis of mRNA Levels for the Escherichia coli Oxidative DNA Glycosylase Genes under Conditions of Oxidative Stress

2000

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Escherichia coli formamidopyrimidine DNA glycosylase (Fpg), MutY DNA glycosylase, endonuclease VIII, and endonuclease III are oxidative base excision repair DNA glycosylases that remove oxidized bases from DNA, or an incorrect base paired with an oxidized base in the case of MutY. Since genes encoding other base excision repair proteins have been shown to be part of adaptive responses in E. coli, we wanted to determine whether the oxidative DNA glycosylase genes are induced in response to conditions that cause the type of damage their encoded proteins remove. The genes fpg, mutY, nei, and nth encode Fpg, MutY, endonuclease VIII, and endonuclease III, respectively. Multiprobe RNase protection assays were used to examine the transcript levels of these genes under conditions that induce the SoxRS, OxyR, and SOS regulons after a shift from anaerobic to aerobic growth and at different stages along the growth curve. Transcript levels for all four genes decreased as cells progressed from log-phase growth to stationary phase and increased after cells were shifted from anaerobic to aerobic growth. None of the genes were induced by hydrogen peroxide, paraquat, X rays, or conditions that induce the SOS response.In Escherichia coli, as in other prokaryotes and eukaryotes, a form of DNA repair called base excision repair removes oxidatively damaged bases from DNA (for reviews see references 14 and 60). Oxidatively damaged bases result from attack by oxygen free radicals generated during normal oxidative metabolism and by exposure to exogenous agents such as X rays and redox-generating chemicals. Base excision repair proteins called DNA glycosylases hydrolyze the N-glycosylic bond between the damaged or incorrect base and the sugar, leaving an abasic site or a strand break, depending on the type of glycosylase, which is then acted on by other proteins to complete the repair process.Formamidopyrimidine DNA glycosylase (Fpg) and MutY DNA glycosylase work together to protect cells from the mutagenic effects of the common oxidative damage 7,8-dihydro-8-oxoguanine (8-oxoG) (41). Fpg removes 8-oxoG from 8-oxoG-C pairs, giving the repair DNA polymerase a chance to put in G (10, 58). If 8-oxoG is not removed before DNA replication occurs, it can mispair with A. MutY removes A in 8-oxoG-A mispairs (41, 42). Failure of this process results in a GC 3 TA transversion. The DNA glycosylases endonuclease III (endo III) and endo VIII have overlapping substrate specificities and recognize and remove a wide range of oxidized pyrimidines. Some of these oxidized pyrimidines, such as thymine glycol, act as blocks to DNA polymerase and are lethal to cells (34, 44); oxidized cytosines such as uracil glycol, 5-hydroxyuracil, and 5-hydroxycytosine pair with A and are premutagenic, leading to GC3AT transitions (32,48,49).Using reverse transcription-PCR, we have previously shown that all four oxidative DNA glycosylase genes are transcribed as part of operons (18,19) and have determined transcription initiation and termination sites by RNase protection ...

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Aberrant Processing of Oxidative DNA Damage in Systemic Lupus Erythematosus

Evans

Cooke

Akıl

et al. 2000

Biochemical and Biophysical Research Communications

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Mechanism of Regulation of 8-Hydroxyguanine Endonuclease by Oxidative Stress: Roles of FNR, ArcA, and Fur

Cited by 35 publications

References 60 publications

Transcriptional Regulation of Glutaredoxin and Thioredoxin Pathways and Related Enzymes in Response to Oxidative Stress

Transcriptional Regulation of Glutaredoxin and Thioredoxin Pathways and Related Enzymes in Response to Oxidative Stress

Multiprobe RNase Protection Assay Analysis of mRNA Levels for the Escherichia coli Oxidative DNA Glycosylase Genes under Conditions of Oxidative Stress

Aberrant Processing of Oxidative DNA Damage in Systemic Lupus Erythematosus

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