title: Widespread transcriptional gene inactivation initiated by a repair intermediate of 8-oxoguanine.
abstract: 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.
authors.affiliation: Institute of Pharmacy and Biochemistry, Johannes Gutenberg University of Mainz, Mainz 55128, Germany.
authors.forename: Julia
authors.initials: J
authors.lastname: Allgayer
authors.affiliation: Institute of Pharmacy and Biochemistry, Johannes Gutenberg University of Mainz, Mainz 55128, Germany Institute of Toxicology, University Medical Center Mainz, Mainz 55131, Germany.
authors.forename: Nataliya
authors.initials: N
authors.lastname: Kitsera
authors.affiliation: Institute of Pharmacy and Biochemistry, Johannes Gutenberg University of Mainz, Mainz 55128, Germany.
authors.forename: Solveig
authors.initials: S
authors.lastname: Bartelt
authors.affiliation: Institute of Pharmacy and Biochemistry, Johannes Gutenberg University of Mainz, Mainz 55128, Germany.
authors.forename: Bernd
authors.initials: B
authors.lastname: Epe
authors.affiliation: Institute of Pharmacy and Biochemistry, Johannes Gutenberg University of Mainz, Mainz 55128, Germany Institute of Toxicology, University Medical Center Mainz, Mainz 55131, Germany khobta@uni-mainz.de.
authors.forename: Andriy
authors.initials: A
authors.lastname: Khobta
mesh_terms: D004247:DNA / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D045647:DNA Glycosylases / Q000378:metabolism; D004260:DNA Repair; D043603:DNA-(Apurinic or Apyrimidinic Site) Lyase / Q000378:metabolism; D020868:Gene Silencing / Q000187:drug effects; D006147:Guanine / Q000031:analogs & derivatives* / Q000378:metabolism / Q000494:pharmacology; D006367:HeLa Cells; D006801:Humans; D006877:Hydroxamic Acids / Q000494:pharmacology; D010957:Plasmids / Q000235:genetics; D011401:Promoter Regions, Genetic / Q000235:genetics*; D020218:Response Elements / Q000235:genetics; D017384:Sequence Deletion / Q000235:genetics; D014158:Transcription, Genetic / Q000187:drug effects
chemical_list: D006877:Hydroxamic Acids; C012589:trichostatin A; C024829:8-hydroxyguanine; D006147:Guanine; D004247:DNA; D045647:DNA Glycosylases; C479058:oxoguanine glycosylase 1, human; C085108:APEX1 protein, human; D043603:DNA-(Apurinic or Apyrimidinic Site) Lyase