title: A novel role of human holliday junction resolvase GEN1 in the maintenance of centrosome integrity.
abstract: The maintenance of genomic stability requires accurate genome replication, repair of DNA damage, and the precise segregation of chromosomes in mitosis. GEN1 possesses Holliday junction resolvase activity in vitro and presumably functions in homology driven repair of DNA double strand breaks. However, little is currently known about the cellular functions of human GEN1. In the present study we demonstrate that GEN1 is a novel centrosome associated protein and we characterize the various phenotypes associated with GEN1 deficiency. We identify an N-terminal centrosome localization signal in GEN1, which is required and sufficient for centrosome localization. We report that GEN1 depletion results in aberrant centrosome numbers associated with the formation of multiple spindle poles in mitosis, an increased number of cells with multi-nuclei, increased apoptosis and an elevated level of spontaneous DNA damage. We find homologous recombination severely impaired in GEN1 deficient cells, suggesting that GEN1 functions as a Holliday junction resolvase in vivo as well as in vitro. Complementation of GEN1 depleted cells with various GEN1 constructs revealed that centrosome association but not catalytic activity of GEN1 is required for preventing centrosome hyper-amplification, formation of multiple mitotic spindles, and multi-nucleation. Our findings provide novel insight into the biological functions of GEN1 by uncovering an important role of GEN1 in the regulation of centrosome integrity.
authors.affiliation: Disease Genomics and Individualized Medicine Laboratory, Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing, P.R. China.
authors.forename: Min
authors.initials: M
authors.lastname: Gao
authors.forename: Jannie
authors.initials: J
authors.lastname: Rendtlew Danielsen
authors.forename: Lei-Zhen
authors.initials: LZ
authors.lastname: Wei
authors.forename: Dong-Ping
authors.initials: DP
authors.lastname: Zhou
authors.forename: Qian
authors.initials: Q
authors.lastname: Xu
authors.forename: Miao-Miao
authors.initials: MM
authors.lastname: Li
authors.forename: Zhao-Qi
authors.initials: ZQ
authors.lastname: Wang
authors.forename: Wei-Min
authors.initials: WM
authors.lastname: Tong
authors.forename: Yun-Gui
authors.initials: YG
authors.lastname: Yang
mesh_terms: D000595:Amino Acid Sequence; D017209:Apoptosis; D002460:Cell Line; D018385:Centrosome / Q000378:metabolism*; D053903:DNA Breaks, Double-Stranded; D042822:Genomic Instability; D045565:Holliday Junction Resolvases / Q000737:chemistry / Q000172:deficiency / Q000378:metabolism*; D059765:Homologous Recombination; D006801:Humans; D008938:Mitosis; D008969:Molecular Sequence Data; D054730:Protein Interaction Domains and Motifs; D021381:Protein Transport
chemical_list: C533748:GEN1 protein, human; D045565:Holliday Junction Resolvases