title: The SAGA Deubiquitination Module Promotes DNA Repair and Class Switch Recombination through ATM and DNAPK-Mediated γH2AX Formation.
abstract: Class switch recombination (CSR) requires activation-induced deaminase (AID) to instigate double-stranded DNA breaks at the immunoglobulin locus. DNA breaks activate the DNA damage response (DDR) by inducing phosphorylation of histone H2AX followed by non-homologous end joining (NHEJ) repair. We carried out a genome-wide screen to identify CSR factors. We found that Usp22, Eny2, and Atxn7, members of the Spt-Ada-Gcn5-acetyltransferase (SAGA) deubiquitination module, are required for deubiquitination of H2BK120ub following DNA damage, are critical for CSR, and function downstream of AID. The SAGA deubiquitinase activity was required for optimal irradiation-induced γH2AX formation, and failure to remove H2BK120ub inhibits ATM- and DNAPK-induced γH2AX formation. Consistent with this effect, these proteins were found to function upstream of various double-stranded DNA repair pathways. This report demonstrates that deubiquitination of histone H2B impacts the early stages of the DDR and is required for the DNA repair phase of CSR.
authors.affiliation: Department of Immunology, University of Toronto, Medical Sciences Building, Toronto, ON M5S 1A8, Canada.
authors.forename: Shaliny
authors.initials: S
authors.lastname: Ramachandran
authors.affiliation: Department of Immunology, University of Toronto, Medical Sciences Building, Toronto, ON M5S 1A8, Canada.
authors.forename: Dania
authors.initials: D
authors.lastname: Haddad
authors.affiliation: Department of Immunology, University of Toronto, Medical Sciences Building, Toronto, ON M5S 1A8, Canada.
authors.forename: Conglei
authors.initials: C
authors.lastname: Li
authors.affiliation: Department of Immunology, University of Toronto, Medical Sciences Building, Toronto, ON M5S 1A8, Canada.
authors.forename: Michael X
authors.initials: MX
authors.lastname: Le
authors.affiliation: Department of Immunology, University of Toronto, Medical Sciences Building, Toronto, ON M5S 1A8, Canada.
authors.forename: Alexanda K
authors.initials: AK
authors.lastname: Ling
authors.affiliation: Department of Immunology, University of Toronto, Medical Sciences Building, Toronto, ON M5S 1A8, Canada.
authors.forename: Clare C
authors.initials: CC
authors.lastname: So
authors.affiliation: Department of Immunology, University of Toronto, Medical Sciences Building, Toronto, ON M5S 1A8, Canada.
authors.forename: Rajeev M
authors.initials: RM
authors.lastname: Nepal
authors.affiliation: Department of Immunology, University of Toronto, Medical Sciences Building, Toronto, ON M5S 1A8, Canada.
authors.forename: Jennifer L
authors.initials: JL
authors.lastname: Gommerman
authors.affiliation: Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI 48824, USA.
authors.forename: Kefei
authors.initials: K
authors.lastname: Yu
authors.affiliation: Princess Margaret Genomics Centre, University Health Network, Toronto, ON M5G 1L7, Canada.
authors.forename: Troy
authors.initials: T
authors.lastname: Ketela
authors.affiliation: Donnelly Centre and Banting and Best Department of Medical Research, University of Toronto, Toronto, ON M5S 1A8, Canada.
authors.forename: Jason
authors.initials: J
authors.lastname: Moffat
authors.affiliation: Department of Immunology, University of Toronto, Medical Sciences Building, Toronto, ON M5S 1A8, Canada. Electronic address: alberto.martin@utoronto.ca.
authors.forename: Alberto
authors.initials: A
authors.lastname: Martin
mesh_terms: D000818:Animals; D064007:Ataxia Telangiectasia Mutated Proteins / Q000378:metabolism*; D003564:Cytidine Deaminase; D053903:DNA Breaks, Double-Stranded; D059766:DNA End-Joining Repair / Q000528:radiation effects; D004260:DNA Repair / Q000528:radiation effects; D051747:DNA-Activated Protein Kinase / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000378:metabolism*; D010450:Endopeptidases / Q000378:metabolism; D006657:Histones / Q000378:metabolism*; D059765:Homologous Recombination / Q000528:radiation effects; D017578:Immunoglobulin Class Switching / Q000235:genetics*; D051379:Mice; D046912:Multiprotein Complexes / Q000378:metabolism*; D009687:Nuclear Proteins / Q000378:metabolism*; D034622:RNA Interference; D011839:Radiation, Ionizing; D027041:Somatic Hypermutation, Immunoglobulin / Q000528:radiation effects; D014157:Transcription Factors / Q000378:metabolism; D043222:Ubiquitin Thiolesterase; D054875:Ubiquitination / Q000528:radiation effects; D000098830:AICDA (Activation-Induced Cytidine Deaminase)
chemical_list: D064007:Ataxia Telangiectasia Mutated Proteins; D003564:Cytidine Deaminase; D051747:DNA-Activated Protein Kinase; D004268:DNA-Binding Proteins; D010450:Endopeptidases; D006657:Histones; D046912:Multiprotein Complexes; D009687:Nuclear Proteins; D014157:Transcription Factors; D043222:Ubiquitin Thiolesterase; D000098830:AICDA (Activation-Induced Cytidine Deaminase); C575561:Eny2 protein, mouse; C497264:Prkdc protein, mouse; C584444:USP22 protein, mouse; C475961:gamma-H2AX protein, mouse