title: Wuho Is a New Member in Maintaining Genome Stability through its Interaction with Flap Endonuclease 1.
abstract: Replication forks are vulnerable to wayward nuclease activities. We report here our discovery of a new member in guarding genome stability at replication forks. We previously isolated a Drosophila mutation, wuho (wh, no progeny), characterized by a severe fertility defect and affecting expression of a protein (WH) in a family of conserved proteins with multiple WD40 repeats. Knockdown of WH by siRNA in Drosophila, mouse, and human cultured cells results in DNA damage with strand breaks and apoptosis through ATM/Chk2/p53 signaling pathway. Mice with mWh knockout are early embryonic lethal and display DNA damage. We identify that the flap endonuclease 1 (FEN1) is one of the interacting proteins. Fluorescence microscopy showed the localization of WH at the site of nascent DNA synthesis along with other replication proteins, including FEN1 and PCNA. We show that WH is able to modulate FEN1's endonucleolytic activities depending on the substrate DNA structure. The stimulatory or inhibitory effects of WH on FEN1's flap versus gap endonuclease activities are consistent with the proposed WH's functions in protecting the integrity of replication fork. These results suggest that wh is a new member of the guardians of genome stability because it regulates FEN1's potential DNA cleavage threat near the site of replication.
authors.affiliation: Institute of Cellular and Organismic Biology, Academia Sinica, Taipei, Taiwan.
authors.forename: I-Cheng
authors.initials: IC
authors.lastname: Cheng
authors.affiliation: Institute of Cellular and Organismic Biology, Academia Sinica, Taipei, Taiwan.
authors.forename: Betty Chamay
authors.initials: BC
authors.lastname: Chen
authors.affiliation: Institute of Cellular and Organismic Biology, Academia Sinica, Taipei, Taiwan.
authors.forename: Hung-Hsun
authors.initials: HH
authors.lastname: Shuai
authors.affiliation: Department of Optics and Photonics, National Central University, Chung-Li, Taiwan.
authors.forename: Fan-Ching
authors.initials: FC
authors.lastname: Chien
authors.affiliation: Research Center for Applied Sciences, Academia Sinica, Taipei, Taiwan.
authors.forename: Peilin
authors.initials: P
authors.lastname: Chen
authors.affiliation: Institute of Cellular and Organismic Biology, Academia Sinica, Taipei, Taiwan.|Department of Biochemistry, Duke University, Durham, North Carolina, United States of America.
authors.forename: Tao-shih
authors.initials: TS
authors.lastname: Hsieh
mesh_terms: D000818:Animals; D017209:Apoptosis; D002352:Carrier Proteins; D004261:DNA Replication; D029721:Drosophila Proteins; D004331:Drosophila melanogaster; D045585:Flap Endonucleases / Q000378:metabolism*; D019204:GTP-Binding Proteins / Q000378:metabolism*; D042822:Genomic Instability; D045325:HCT116 Cells; D006801:Humans; D051379:Mice; D018345:Mice, Knockout; D018809:Proliferating Cell Nuclear Antigen / Q000378:metabolism; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism
chemical_list: D002352:Carrier Proteins; D029721:Drosophila Proteins; D018809:Proliferating Cell Nuclear Antigen; D016159:Tumor Suppressor Protein p53; C417912:WDR4 protein, human; C513483:wuho protein, Drosophila; C572473:Fen1 protein, mouse; D045585:Flap Endonucleases; C468317:FEN1 protein, human; D019204:GTP-Binding Proteins; C000608107:WDR4 protein, mouse