Mouse CSB protein is important for gene expression in the presence of a single-strand break in the non-transcribed DNA strand

Khobta, Andriy; Lingg, Thomas; Schulz, Ina; Warken, Daniela; Kitsera, Nataliya; Epe, Bernd

doi:10.1016/j.dnarep.2010.06.011

Cited by 18 publications

(20 citation statements)

References 39 publications

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“…Moreover, we deduce from the gene expression data that strand cleavage never occurs 3′ to the lesion, because this would lead to generation of maleficent strand break with blocked 3′ end in the case of the substrate with 5′ phosphorothioate and 3′ phosphate linkages. Such futile repair intermediate would inevitably impede transcription (43), which is clearly not the case (Figure 2A). Consequently, OGG1 does not manifest a beta-lyase activity in vivo , in this resembling monofunctional DNA glycosylases.…”

Section: Discussionmentioning

confidence: 96%

Widespread transcriptional gene inactivation initiated by a repair intermediate of 8-oxoguanine

et al. 2016

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DNA damage can significantly modulate expression of the affected genes either by direct structural interference with transcription components or as a collateral outcome of cellular repair attempts. Thus, DNA glycosylases of the base excision repair (BER) pathway have been implicated in negative transcriptional response to several spontaneously generated DNA base modifications, including a common oxidative DNA base modification 8-oxoguanine (8-oxoG). Here, we report that single 8-oxoG situated in the non-transcribed DNA strand of a reporter gene has a pronounced negative effect on transcription, driven by promoters of various strength and with different structural properties, including viral, human, and artificial promoters. We further show that the magnitude of the negative effect on the gene expression correlates with excision of the modified base by OGG1 in all promoter constructs tested. Moreover, by using expression vectors with nuclease resistant backbone modifications, we demonstrate that OGG1 does not catalyse DNA strand cleavage in vivo. Rather, cleavage of the phosphate bond 5′ to 8-oxodG (catalysed by APE1) is essential and universally required for the onset of transcriptional silencing, regardless of the promoter structure. Hence, induction of transcriptional silencing emerges as a ubiquitous mode of biological response to 8-oxoG in DNA.

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Section: Discussionmentioning

confidence: 96%

Widespread transcriptional gene inactivation initiated by a repair intermediate of 8-oxoguanine

et al. 2016

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“…Hypersensitivity to ionizing radiation or oxidative stress could as well be explained by mechanisms other than defective DNA repair, such as a defective DNA damage response [60], a defective transcriptional response to oxidative stress [91], or simply generalized cellular fragility and hypersensitivity to cell killing as a result of disordered transcription [92] (see “one-hit” neurodegeneration below). Indeed, cells from CS patients are hypersensitive to other stressors in addition to oxidative stress [93, 94] The results of host-cell reactivation studies, in which plasmids encoding transcribed reporter genes are exposed to oxidative DNA damage and transfected into cells, are also difficult to interpret definitively, because they are indirect measures of DNA repair and also depend upon transcription for the experimental end-point (see [95, 96]). It is also notable that in humans, mutations in both CSA and CSB result in CS, but some cell types from Csa and Csb deficient mice are differentially susceptible to killing by oxidative stressors [90].…”

Section: Defective Repair Of Oxidative Dna Damage In Cs and Its Rementioning

confidence: 99%

Blinded by the UV light: How the focus on transcription-coupled NER has distracted from understanding the mechanisms of Cockayne syndrome neurologic disease

Brooks

2013

DNA Repair

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Cockayne syndrome (CS) is a devastating neurodevelopmental disorder, with growth abnormalities, progeriod features, and sun sensitivity. CS is typically considered to be a DNA repair disorder, since cells from CS patients have a defect in transcription-coupled nucleotide excision repair (TC-NER). However, cells from UV-sensitive syndrome patients also lack TC-NER, but these patients do not suffer from the neurologic and other abnormalities that CS patients do. Also, the neurologic abnormalities that affect CS patients (CS neurologic disease) are qualitatively different from those seen in NER-deficient XP patients. Therefore, the TC-NER defect explains the sun sensitive phenotype common to both CS and UVsS, but cannot explain CS neurologic disease. However, as CS neurologic disease is of much greater clinical significance than the sun sensitivity, there is a pressing need to understand its molecular basis. While there is evidence for defective repair of oxidative DNA damage and mitochondrial abnormalities in CS cells, here I propose that the defects in transcription by both RNA polymerases I and II that have been documented in CS cells provide a better explanation for many of the severe growth and neurodevelopmental defects in CS patients than defective DNA repair. The implications of these ideas for interpreting results from mouse models of CS, and for the development of treatments and therapies for CS patients are discussed.

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“…15-18 When present in either the TS or the non-template strand (NTS), SSBs can also lead to an overall reduction in gene expression. 19, 20 …”

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confidence: 99%

Transcription Blockage by Bulky End Termini at Single-Strand Breaks in the DNA Template: Differential Effects of 5′ and 3′ Adducts

2012

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RNA polymerases from phage-infected bacteria and mammalian cells have been shown to bypass single-strand breaks (SSBs) with a single nucleotide gap in the template DNA strand during transcription elongation; however, the SSB bypass efficiency varies significantly depending upon the backbone end-chemistries at the break. Using a reconstituted T7 phage transcription system (T7 RNAP) and RNA polymerase II (RNAPII) in HeLa cell nuclear extracts, we observe a slight reduction in transcription arrest at SSBs with no gap as compared to those with a single nucleotide gap. We have shown that biotin and carbon-chain moieties linked to the 3′ side, and in select cases the 5′ side, of a SSB in the template strand strongly increase transcription arrest when compared to unmodified SSBs. We also find that a small carbon-chain moiety linked to the upstream side of a SSB aids transcriptional bypass of SSBs for both T7 RNAP and RNAP II. Analysis of transcription across SSBs flanked by bulky 3′ adducts reveals the ability of 3′ end-chemistries to arrest T7 RNAP in a size dependent manner. T7 RNAP is also completely arrested when 3′ adducts or 3′-phosphate groups are placed opposite 5′-phosphate groups at a SSB. We have also observed that a biotinylated thymine in the template strand (without a break) does not pose a strong block to transcription. Taken together these results emphasize the importance of the size of 3′, but usually not the 5′, end-chemistries in arresting transcription at SSBs, substantiating the notion that bulky 3′ lesions (e.g. topoisomerase cleavable complexes, 3′-phosphoglycolates and 3′-unsaturated aldehydes) pose very strong blocks to transcribing RNA polymerases. These findings have implications for the processing of DNA damage through SSB intermediates and the mechanism of SSB bypass by T7 RNAP and mammalian RNAPII.

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Mouse CSB protein is important for gene expression in the presence of a single-strand break in the non-transcribed DNA strand

Cited by 18 publications

References 39 publications

Widespread transcriptional gene inactivation initiated by a repair intermediate of 8-oxoguanine

Widespread transcriptional gene inactivation initiated by a repair intermediate of 8-oxoguanine

Blinded by the UV light: How the focus on transcription-coupled NER has distracted from understanding the mechanisms of Cockayne syndrome neurologic disease

Transcription Blockage by Bulky End Termini at Single-Strand Breaks in the DNA Template: Differential Effects of 5′ and 3′ Adducts

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