Fen1 mutations that specifically disrupt its interaction ~vith PCNA cause aneuploidy-associated cancer  

作　　者：Li Zheng Huifang Dai Muralidhar L Hegde Mian Zhou Zhigang Guo Xiwei Wu Jun Wu Lei Su Xueyan Zhong Sankar Mitra Qin Huang Kemp H Kernstine Gerd P Pfeifer Binghui Shen 

机构地区：[1]Department of Cancer Biology, City of Hope National Medical Center and Beckman Research Institute, 1500 East Duarte Road, Duarte, CA 91010, USA [2]Department of Biochemistry and Molecular Biology, Scaly Center for Molecular Science, The Uni- versity of Texas Medical Branch at Galveston, 301 University Boulevard, Galveston, TX 77555, USA [3]Department of Molecular Medicine, City of Hope National Medical Center and Beckman Research Institute, 1500 East Duarte Road, Duarte, CA 91010, USA [4]Department of Molecular Pharmacology, City of Hope National Medical Center and Beckman Research Institute, 1500 East Duarte Road, Duarte, CA 91010, USA [5]Department of Pathology, City of Hope National Medical Center and Beckman Research Institute, 1500 East Duarte Road, Duarte, CA 91010, USA [6]Department of Surgery, City of Hope National Medical Center and Beckman Research Institute, 1500 East Duarte Road, Duarte, CA 91010, USA

出　　处：《Cell Research》2011年第7期1052-1067,共16页细胞研究（英文版）

摘　　要：DNA replication and repair are critical processes for all living organisms to ensure faithful duplication and transmission of genetic information. Flap endonuclease 1 （Fenl）, 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 FENI＇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, Chkl, and induce near- tetraploid aneuploidy, commonly observed in human cancer, consequently elevating the transformation frequency. Consistent with this, inhibition of aneuploidy formation by a Chkl 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.

关 键 词：FEN 1 PCNA Okazaki fragment maturation long patch base excision repair TETRAPLOIDY ANEUPLOIDY CANCER 

分 类 号：Q954.4[生物学—动物学] Q754