Arrest of human mitochondrial RNA polymerase transcription by the biological aldehyde adduct of DNA, M 1dG

Susan D. Cline, M. Fernanda Lodeiro, Lawrence J. Marnett, Craig E. Cameron, Jamie J. Arnold

Research output: Contribution to journalArticlepeer-review

18 Scopus citations


The biological aldehydes, malondialdehyde and base propenal, react with DNA to form a prevalent guanine adduct, M1dG. The exocyclic ring of M1dG opens to the acyclic N 2-OPdG structure when paired with C but remains closed in single-stranded DNA or when mispaired with T. M1dG is a target of nucleotide excision repair (NER); however, NER is absent in mitochondria. An in vitro transcription system with purified human mitochondrial RNA polymerase (POLRMT) and transcription factors, mtTFA and mtTFB2, was used to determine the effect of M1dG on POLRMT elongation. DNA templates contained a single adduct opposite either C or T downstream of either the light-strand (LSP) or heavy-strand (HSP1) promoter for POLRMT. M1dG in the transcribed strand arrested 60-90 POLRMT elongation complexes with greater arrest by the adduct when opposite T. POLRMT was more sensitive to N 2-OPdG and M1dG after initiation at LSP, which suggests promoter-specific differences in the function of POLRMT complexes. A closed-ring analog of M1dG, PdG, blocked 95 of transcripts originating from either promoter regardless of base pairing, and the transcripts remained associated with POLRMT complexes after stalling at the adduct. This work suggests that persistent M1dG adducts in mitochondrial DNA hinder the transcription of mitochondrial genes.

Original languageEnglish (US)
Pages (from-to)7546-7557
Number of pages12
JournalNucleic acids research
Issue number21
StatePublished - Nov 2010

All Science Journal Classification (ASJC) codes

  • Genetics


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