title: New origin firing is inhibited by APC/CCdh1 activation in S-phase after severe replication stress.
abstract: Defects in DNA replication and repair are known to promote genomic instability, a hallmark of cancer cells. Thus, eukaryotic cells have developed complex mechanisms to ensure accurate duplication of their genomes. While DNA damage response has been extensively studied in tumour cells, the pathways implicated in the response to replication stress are less well understood especially in non-transformed cells. Here we show that in non-transformed cells, APC/C(Cdh1) is activated upon severe replication stress. Activation of APC/C(Cdh1) prevents new origin firing and induces permanent arrest in S-phase. Moreover, Rad51-mediated homologous recombination is also impaired under these conditions. APC/C(Cdh1) activation in S-phase occurs after replication forks have been processed into double strand breaks. Remarkably, this activation, which correlates with decreased Emi1 levels, is not prevented by ATR/ATM inhibition, but it is abrogated in cells depleted of p53 or p21. Importantly, we found that the lack of APC/C(Cdh1) activity correlated with an increase in genomic instability. Taken together, our results define a new APC/C(Cdh1) function that prevents cell cycle resumption after prolonged replication stress by inhibiting origin firing, which may act as an additional mechanism in safeguarding genome integrity.
authors.affiliation: Departament de Biologia Cellular, Immunologia i Neurociències, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Facultat de Medicina, Universitat de Barcelona, C/ Casanova 143, 08036 Barcelona, Spain.
authors.forename: Amaia
authors.initials: A
authors.lastname: Ercilla
authors.affiliation: Departament de Biologia Cellular, Immunologia i Neurociències, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Facultat de Medicina, Universitat de Barcelona, C/ Casanova 143, 08036 Barcelona, Spain.
authors.forename: Alba
authors.initials: A
authors.lastname: Llopis
authors.affiliation: Departament de Biologia Cellular, Immunologia i Neurociències, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Facultat de Medicina, Universitat de Barcelona, C/ Casanova 143, 08036 Barcelona, Spain.
authors.forename: Sonia
authors.identifier: 0000-0002-7225-5788
authors.initials: S
authors.lastname: Feu
authors.affiliation: Center for Genomic Regulation (CRG), C/ Dr. Aiguader 88, 08003 Barcelona, Spain.
authors.forename: Sergi
authors.identifier: 0000-0003-3853-430X
authors.initials: S
authors.lastname: Aranda
authors.affiliation: Unit of Molecular Neurobiology, Department of Medical Biochemistry and Biophysics, Karolinska Institute, 17177 Stockholm, Sweden.
authors.forename: Patrik
authors.initials: P
authors.lastname: Ernfors
authors.affiliation: Unidad de Investigación, Hospital Universitario de Canarias, Instituto de Tecnologias Biomedicas, 38320 Tenerife, Spain.
authors.forename: Raimundo
authors.initials: R
authors.lastname: Freire
authors.affiliation: Departament de Biologia Cellular, Immunologia i Neurociències, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Facultat de Medicina, Universitat de Barcelona, C/ Casanova 143, 08036 Barcelona, Spain neusagell@ub.edu.
authors.forename: Neus
authors.identifier: 0000-0002-1205-6074
authors.initials: N
authors.lastname: Agell
mesh_terms: D064007:Ataxia Telangiectasia Mutated Proteins / Q000378:metabolism; D064200:Cdh1 Proteins / Q000378:metabolism*; D045744:Cell Line, Tumor; D002478:Cells, Cultured; D050759:Cyclin-Dependent Kinase Inhibitor p21 / Q000502:physiology; D004249:DNA Damage; D004261:DNA Replication; D004789:Enzyme Activation; D042822:Genomic Instability; D006801:Humans; D006918:Hydroxyurea / Q000633:toxicity; D018741:Replication Origin; D016196:S Phase / Q000235:genetics*; D013312:Stress, Physiological / Q000235:genetics; D016159:Tumor Suppressor Protein p53 / Q000502:physiology
chemical_list: D064200:Cdh1 Proteins; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016159:Tumor Suppressor Protein p53; C576597:ATR protein, human; D064007:Ataxia Telangiectasia Mutated Proteins; D006918:Hydroxyurea