AP endonuclease-independent DNA base excision repair in human cells

Lee Wiederhold, John B. Leppard, Padmini Kedar, Feridoun Karimi-Busheri, Aghdass Rasouli-Nia, Michael Weinfeld, Alan E. Tomkinson, Tadahide Izumi, Rajendra Prasad, Samuel H. Wilson, Sankar Mitra, Tapas K. Hazra

Research output: Contribution to journalArticlepeer-review

409 Scopus citations


The paradigm for repair of oxidized base lesions in genomes via the base excision repair (BER) pathway is based on studies in Escherichia coli, in which AP endonuclease (APE) removes all 3′ blocking groups (including 3′ phosphate) generated by DNA glycosylase/AP lyases after base excision. The recently discovered mammalian DNA glycosylase/AP lyases, NEIL1 and NEIL2, unlike the previously characterized OGG1 and NTH1, generate DNA strand breaks with 3′ phosphate termini. Here we show that in mammalian cells, removal of the 3′ phosphate is dependent on polynucleotide kinase (PNK), and not APE. NEIL1 stably interacts with other BER proteins, DNA polymerase β (pol β) and DNA ligase IIIα. The complex of NEIL1, pol β, and DNA ligase IIIα together with PNK suggests coordination of NEIL1-initiated repair. That NEIL1/PNK could also repair the products of other DNA glycosylases suggests a broad role for this APE-independent BER pathway in mammals.

Original languageEnglish
Pages (from-to)209-220
Number of pages12
JournalMolecular Cell
Issue number2
StatePublished - Jul 23 2004

Bibliographical note

Funding Information:
This research was supported by USPHS grants CA92584 (S.M. and A.E.T.), CA81063, CA53791, and ES06676 (S.M.), and GM47251 and GM57479 (A.E.T.), Training Grant T32-07254 (A.E.T.), and Canadian Institutes of Health Research grant MOP-15385 (M.W.). We thank Rabindra Roy for supplying human NTH1, Keith W. Caldecott for the DNA ligase IIIα expression plasmid, Michael P. Thelen for anti-XRCC1 antibody, and Kosuke Akiyama for the APE2 cDNA clone. We thank David Konkel for editing and Bruce Demple, Ella Englander, R.S. Lloyd, and Priscilla Cooper for critically reviewing the manuscript.

ASJC Scopus subject areas

  • Molecular Biology
  • Cell Biology


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