DNA interstrand cross-links induce futile repair synthesis in mammalian cell extracts

David Mu, Tadayoshi Bessho, Lubomir V. Nechev, David J. Chen, Thomas M. Harris, John E. Hearst, Aziz Sancar

Research output: Contribution to journalArticlepeer-review

114 Scopus citations


DNA interstrand cross-links are induced by many carcinogens and anticancer drugs. It was previously shown that mammalian DNA excision repair nuclease makes dual incisions 5' to the cross-linked base of a psoralen cross-link, generating a gap of 22 to 28 nucleotides adjacent to the cross- link. We wished to find the fates of the gap and the cross-link in this complex structure under conditions conducive to repair synthesis, using cell extracts from wild-type and cross-linker-sensitive mutant cell lines. We found that the extracts from both types of strains filled in the gap but were severely defective in ligating the resulting nick and incapable of removing the cross-link. The net result was a futile damage-induced DNA synthesis which converted a gap into a nick without removing the damage. In addition, in this study, we showed that the structure-specific endonuclease, the XPF- ERCC1 heterodimer, acted as a 3'-to-5' exonuclease on cross-linked DNA in the presence of RPA. Collectively, these observations shed some light on the cellular processing of DNA cross-links and reveal that cross-links induce a futile DNA synthesis cycle that may constitute a signal for specific cellular responses to cross-linked DNA.

Original languageEnglish (US)
Pages (from-to)2446-2454
Number of pages9
JournalMolecular and cellular biology
Issue number7
StatePublished - Apr 2000

ASJC Scopus subject areas

  • Molecular Biology
  • Cell Biology


Dive into the research topics of 'DNA interstrand cross-links induce futile repair synthesis in mammalian cell extracts'. Together they form a unique fingerprint.

Cite this