title: USP7 Is a Suppressor of PCNA Ubiquitination and Oxidative-Stress-Induced Mutagenesis in Human Cells.
abstract: Mono-ubiquitinated PCNA activates error-prone DNA polymerases; therefore, strict regulation of PCNA mono-ubiquitination is crucial in avoiding undesired mutagenesis. In this study, we used an in vitro assay system to identify USP7 as a deubiquitinating enzyme of mono-ubiquitinated PCNA. Suppression of USP1, a previously identified PCNA deubiquitinase, or USP7 increased UV- and H2O2-induced PCNA mono-ubiquitination in a distinct and additive manner, suggesting that USP1 and USP7 make different contributions to PCNA deubiquitination in human cells. Cell-cycle-synchronization analyses revealed that USP7 suppression increased H2O2-induced PCNA ubiquitination throughout interphase, whereas USP1 suppression specifically increased ubiquitination in S-phase cells. UV-induced mutagenesis was elevated in USP1-suppressed cells, whereas H2O2-induced mutagenesis was elevated in USP7-suppressed cells. These results suggest that USP1 suppresses UV-induced mutations produced in a manner involving DNA replication, whereas USP7 suppresses H2O2-induced mutagenesis involving cell-cycle-independent processes such as DNA repair.
authors.affiliation: Department of Genome Dynamics, Research Institute of Environmental Medicine, Nagoya University, Nagoya 464-8601, Japan.
authors.forename: Shu-ichiro
authors.initials: S
authors.lastname: Kashiwaba
authors.affiliation: Department of Genome Dynamics, Research Institute of Environmental Medicine, Nagoya University, Nagoya 464-8601, Japan.
authors.forename: Rie
authors.initials: R
authors.lastname: Kanao
authors.affiliation: Department of Genome Dynamics, Research Institute of Environmental Medicine, Nagoya University, Nagoya 464-8601, Japan; Department of Toxicogenomics, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan.
authors.forename: Yuji
authors.initials: Y
authors.lastname: Masuda
authors.affiliation: Department of Genome Dynamics, Research Institute of Environmental Medicine, Nagoya University, Nagoya 464-8601, Japan.
authors.forename: Rika
authors.initials: R
authors.lastname: Kusumoto-Matsuo
authors.affiliation: Faculty of Science, Gakushuin University, Tokyo 171-8588, Japan.
authors.forename: Fumio
authors.initials: F
authors.lastname: Hanaoka
authors.affiliation: Department of Genome Dynamics, Research Institute of Environmental Medicine, Nagoya University, Nagoya 464-8601, Japan. Electronic address: masutani@riem.nagoya-u.ac.jp.
authors.forename: Chikahide
authors.initials: C
authors.lastname: Masutani
mesh_terms: D002460:Cell Line; D004249:DNA Damage / Q000502:physiology; D005434:Flow Cytometry; D006801:Humans; D006861:Hydrogen Peroxide / Q000633:toxicity; D016296:Mutagenesis / Q000502:physiology*; D016297:Mutagenesis, Site-Directed; D018384:Oxidative Stress / Q000502:physiology*; D016133:Polymerase Chain Reaction; D018809:Proliferating Cell Nuclear Antigen / Q000378:metabolism*; D034741:RNA, Small Interfering; D014162:Transfection; D043222:Ubiquitin Thiolesterase / Q000378:metabolism*; D000076084:Ubiquitin-Specific Peptidase 7; D054875:Ubiquitination
chemical_list: D018809:Proliferating Cell Nuclear Antigen; D034741:RNA, Small Interfering; D006861:Hydrogen Peroxide; C464569:USP7 protein, human; D043222:Ubiquitin Thiolesterase; D000076084:Ubiquitin-Specific Peptidase 7