Evidence that nucleosomes inhibit mismatch repair in eukaryotic cells

Feng Li, Lei Tian, Liya Gu, Guo Min Li

Research output: Contribution to journalArticlepeer-review

53 Scopus citations


The influence of chromatin structure on DNA metabolic processes, including DNA replication and repair, has been a matter of intensive studies in recent years. Although the human mismatch repair (MMR) reaction has been reconstituted using purified proteins, the influence of chromatin structure on human MMR is unknown. This study examines the interaction between human MutSα and a mismatch located within a nucleosome or between two nucleosomes. The results show that, whereas MutSα specifically recognizes both types of nucleosomal heteroduplexes, the protein bound the mismatch within a nucleosome with much lower efficiency than a naked heteroduplex or a heterology free of histone proteins but between two nucleosomes. Additionally, MutSα displays reduced ATPase- and ADP-binding activity when interacting with nucleosomal heteroduplexes. Interestingly, nucleosomes block ATP-induced MutSα sliding along the DNA helix when the mismatch is in between two nucleosomes. These findings suggest that nucleosomes may inhibit MMR in eukaryotic cells. The implications of these findings for our understanding of eukaryotic MMR are discussed.

Original languageEnglish (US)
Pages (from-to)33056-33061
Number of pages6
JournalJournal of Biological Chemistry
Issue number48
StatePublished - Nov 27 2009

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology


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