Related Experiment Video
Updated: Aug 7, 2026
10:30
Zygotic Fluorescence Recovery After Photo-bleaching Analysis for Chromatin Looseness That Allows Full-term Development
Published on: June 12, 2018
Effect of flap modifications on human FEN1 cleavage
C J Bornarth1, T A Ranalli, L A Henricksen
1Department of Biochemistry and Biophysics, Cancer Center, University of Rochester School of Medicine and Dentistry, New York 14642, USA.
Biochemistry
|October 21, 1999
Summary
Flap endonuclease 1 (FEN1) tracks DNA flaps during replication and repair. While FEN1 tolerates some flap modifications, certain platinum adducts inhibit its essential tracking mechanism.
Area of Science:
- Molecular Biology
- Biochemistry
- DNA Repair
Background:
- Flap endonuclease 1 (FEN1) is crucial for DNA replication and repair.
- FEN1 possesses both 5' to 3' exonucleolytic and structure-specific endonucleolytic activities.
- FEN1 cleaves primer-template junctions, releasing intact 5' flaps.
Purpose of the Study:
- To investigate the mechanism of FEN1's flap-tracking activity.
- To determine the nucleotide recognition requirements for FEN1 cleavage.
- To assess the impact of flap structural modifications on FEN1 function.
Main Methods:
- Utilized modified primer-template substrates with chemical linkers and branch structures.
- Introduced single- or double-thymine dimers and cis-platinum adducts into flap structures.
- Assessed FEN1 cleavage efficiency and tracking ability with various modified substrates.
Main Results:
- FEN1 can traverse chemical linkers within the flap, indicating flexibility.
- The FEN1 footprint at cleavage is approximately 25 nucleotides.
- While some modifications like branches and dimers are tolerated, platinum adducts, especially on branches, inhibit cleavage, suggesting tracking limitations.
Conclusions:
- FEN1's tracking mechanism is robust but can be inhibited by specific flap modifications.
- The results challenge the simple threading model, suggesting a more complex interaction between FEN1 and DNA flaps.
- Understanding FEN1's mechanistic flexibility is key to its role in maintaining genome stability.
