Mutagenic potential of DNA-peptide crosslinks mediated by acrolein-derived DNA adducts

Irina G. Minko, Ivan D. Kozekov, Albena Kozekova, Thomas M. Harris, Carmelo J. Rizzo, R. Stephen Lloyd

Research output: Contribution to journalArticle

44 Scopus citations

Abstract

Current data suggest that DNA-peptide crosslinks are formed in cellular DNA as likely intermediates in the repair of DNA-protein crosslinks. In addition, a number of naturally occurring peptides are known to efficiently conjugate with DNA, particularly through the formation of Schiff-base complexes at aldehydic DNA adducts and abasic DNA sites. Since the potential role of DNA-peptide crosslinks in promoting mutagenesis is not well elucidated, here we report on the mutagenic properties of Schiff-base-mediated DNA-peptide crosslinks in mammalian cells. Site-specific DNA-peptide crosslinks were generated by covalently trapping a lysine-tryptophan-lysine-lysine peptide to the N6 position of deoxyadenosine (dA) or the N2 position of deoxyguanosine (dG) via the aldehydic forms of acrolein-derived DNA adducts (γ-hydroxypropano-dA or γ-hydroxypropano-dG, respectively). In order to evaluate the potential of DNA-peptide crosslinks to promote mutagenesis, we inserted the modified oligodeoxynucleotides into a single-stranded pMS2 shuttle vector, replicated these vectors in simian kidney (COS-7) cells and tested the progeny DNAs for mutations. Mutagenic analyses revealed that at the site of modification, the γ-hydroxypropano-dA-mediated crosslink induced mutations at only ∼0.4%. In contrast, replication bypass of the γ-hydroxypropano-dG-mediated crosslink resulted in mutations at the site of modification at an overall frequency of ∼8.4%. Among the types of mutations observed, single base substitutions were most common, with a prevalence of G to T transversions. Interestingly, while covalent attachment of lysine-tryptophan-lysine-lysine at γ-hydroxypropano-dG caused an increase in mutation frequencies relative to γ-hydroxypropano-dG, similar modification of γ-hydroxypropano-dA resulted in decreased levels of mutations. Thus, certain DNA-peptide crosslinks can be mutagenic, and their potential to cause mutations depends on the site of peptide attachment. We propose that in order to avoid error-prone replication, proteolytic degradation of proteins covalently attached to DNA and subsequent steps of DNA repair should be tightly coordinated.

Original languageEnglish (US)
Pages (from-to)161-172
Number of pages12
JournalMutation Research - Fundamental and Molecular Mechanisms of Mutagenesis
Volume637
Issue number1-2
DOIs
StatePublished - Jan 1 2008

Keywords

  • Acrolein
  • DNA-peptide crosslinks
  • DNA-protein crosslinks
  • Hydroxypropano DNA adducts
  • Mutagenesis

ASJC Scopus subject areas

  • Molecular Biology
  • Genetics
  • Health, Toxicology and Mutagenesis

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