Open AccessThe human Rad9–Rad1–Hus1 checkpoint complex stimulates flap endonuclease 1
Author(s) -
Wensheng Wang,
Patrick D. Brandt,
Marie L. Rossi,
Laura A. Lindsey-Boltz,
Vladimir N. Podust,
Ellen Fanning,
Aziz Sancar,
Robert A. Bambara
Publication year - 2004
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.0407686101
Subject(s) - proliferating cell nuclear antigen , okazaki fragments , dna repair , dna clamp , dna polymerase delta , nuclease , dna polymerase , microbiology and biotechnology , biology , dna damage , dna replication , dna , polymerase , biochemistry , eukaryotic dna replication , rna , gene , reverse transcriptase
The toroidal damage checkpoint complex Rad9-Rad1-Hus1 (9-1-1) has been characterized as a sensor of DNA damage. Flap endonuclease 1 (FEN1) is a structure-specific nuclease involved both in removing initiator RNA from Okazaki fragments and in DNA repair pathways. FEN1 activity is stimulated by proliferating cell nuclear antigen (PCNA), a toroidal sliding clamp that acts as a platform for DNA replication and repair complexes. We show that 9-1-1 also binds and stimulates FEN1. Stimulation is observed on a variety of flap, nick, and gapped substrates simulating repair intermediates. Blocking 9-1-1 entry to the double strands prevents a portion of the stimulation. Like PCNA stimulation, 9-1-1 stimulation cannot circumvent the tracking mechanism by which FEN1 enters the substrate; however, 9-1-1 does not substitute for PCNA in the stimulation of DNA polymerase beta. This suggests that 9-1-1 is a damage-specific activator of FEN1.