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Volume 21, No 7, Jul 2011
ISSN: 1001-0602
EISSN: 1748-7838 2018
impact factor 17.848*
(Clarivate Analytics, 2019)
Volume 21 Issue 7, July 2011: 1052-1067
Li Zheng1, Huifang Dai1, Muralidhar L Hegde2, Mian Zhou1, Zhigang Guo1, Xiwei Wu3, Jun Wu4, Lei Su3, Xueyan Zhong1, Sankar Mitra2, Qin Huang5
1Department of Cancer Biology, City of Hope National Medical Center and Beckman Research Institute, 1500 East Duarte Road, Duarte, CA 91010, USA;
2Department of Biochemistry and Molecular Biology, Sealy Center for Molecular Science, The University of Texas Medical Branch at Galveston, 301 University Boulevard, Galveston, TX 77555, USA;
3Department of Molecular Medicine, City of Hope National Medical Center and Beckman Research Institute, 1500 East Duarte Road, Duarte, CA 91010, USA;
4Department of Molecular Pharmacology, City of Hope National Medical Center and Beckman Research Institute, 1500 East Duarte Road, Duarte, CA 91010, USA;
5Department of Pathology, City of Hope National Medical Center and Beckman Research Institute, 1500 East Duarte Road, Duarte, CA 91010, USA;
6Department of Surgery, City of Hope National Medical Center and Beckman Research Institute, 1500 East Duarte Road, Duarte, CA 91010, USA
Correspondence: Binghui Shen, Li Zheng,(bshen@coh.org; lzheng@coh.org)
DNA replication and repair are critical processes for all living organisms to ensure faithful duplication and transmission of genetic information. Flap endonuclease 1 (Fen1), a structure-specific nuclease, plays an important role in multiple DNA metabolic pathways and maintenance of genome stability. Human FEN1 mutations that impair its exonuclease activity have been linked to cancer development. FEN1 interacts with multiple proteins, including proliferation cell nuclear antigen (PCNA), to form various functional complexes. Interactions with these proteins are considered to be the key molecular mechanisms mediating FEN1's key biological functions. The current challenge is to experimentally demonstrate the biological consequence of a specific interaction without compromising other functions of a desired protein. To address this issue, we established a mutant mouse model harboring a FEN1 point mutation (F343A/F344A, FFAA), which specifically abolishes the FEN1/PCNA interaction. We show that the FFAA mutation causes defects in RNA primer removal and long-patch base excision repair, even in the heterozygous state, resulting in numerous DNA breaks. These breaks activate the G2/M checkpoint protein, Chk1, and induce near-tetraploid aneuploidy, commonly observed in human cancer, consequently elevating the transformation frequency. Consistent with this, inhibition of aneuploidy formation by a Chk1 inhibitor significantly suppressed the cellular transformation. WT/FFAA FEN1 mutant mice develop aneuploidy-associated cancer at a high frequency. Thus, this study establishes an exemplary case for investigating the biological significance of protein-protein interactions by knock-in of a point mutation rather than knock-out of a whole gene.
Cell Research (2011) 21:1052-1067. doi:10.1038/cr.2011.35; published online 8 March 2011
