title: Human BRCA1-BARD1 ubiquitin ligase activity counteracts chromatin barriers to DNA resection.
abstract: The opposing activities of 53BP1 and BRCA1 influence pathway choice in DNA double-strand-break repair. How BRCA1 counteracts the inhibitory effect of 53BP1 on DNA resection and homologous recombination is unknown. Here we identify the site of BRCA1-BARD1 required for priming ubiquitin transfer from E2∼ubiquitin and demonstrate that BRCA1-BARD1's ubiquitin ligase activity is required for repositioning 53BP1 on damaged chromatin. We confirm H2A ubiquitination by BRCA1-BARD1 and show that an H2A-ubiquitin fusion protein promotes DNA resection and repair in BARD1-deficient cells. BRCA1-BARD1's function in homologous recombination requires the chromatin remodeler SMARCAD1. SMARCAD1 binding to H2A-ubiquitin and optimal localization to sites of damage and activity in DNA repair requires its ubiquitin-binding CUE domains. SMARCAD1 is required for 53BP1 repositioning, and the need for SMARCAD1 in olaparib or camptothecin resistance is alleviated by 53BP1 loss. Thus, BRCA1-BARD1 ligase activity and subsequent SMARCAD1-dependent chromatin remodeling are critical regulators of DNA repair.
authors.affiliation: Birmingham Centre for Genome Biology, Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham, UK.
authors.forename: Ruth M
authors.initials: RM
authors.lastname: Densham
authors.affiliation: Birmingham Centre for Genome Biology, Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham, UK.
authors.forename: Alexander J
authors.initials: AJ
authors.lastname: Garvin
authors.affiliation: Birmingham Centre for Genome Biology, Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham, UK.
authors.forename: Helen R
authors.initials: HR
authors.lastname: Stone
authors.affiliation: Birmingham Centre for Genome Biology, Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham, UK.
authors.forename: Joanna
authors.initials: J
authors.lastname: Strachan
authors.affiliation: Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Brighton, UK.
authors.forename: Robert A
authors.initials: RA
authors.lastname: Baldock
authors.affiliation: Birmingham Centre for Genome Biology, Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham, UK.
authors.forename: Manuel
authors.initials: M
authors.lastname: Daza-Martin
authors.affiliation: Birmingham Centre for Genome Biology, Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham, UK.
authors.forename: Alice
authors.initials: A
authors.lastname: Fletcher
authors.affiliation: Birmingham Centre for Genome Biology, Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham, UK.
authors.forename: Sarah
authors.initials: S
authors.lastname: Blair-Reid
authors.affiliation: Birmingham Centre for Genome Biology, Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham, UK.
authors.forename: James
authors.initials: J
authors.lastname: Beesley
authors.affiliation: Birmingham Centre for Genome Biology, Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham, UK.
authors.forename: Balraj
authors.initials: B
authors.lastname: Johal
authors.affiliation: Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Brighton, UK.
authors.forename: Laurence H
authors.identifier: 0000-0002-6910-1809
authors.initials: LH
authors.lastname: Pearl
authors.affiliation: School of Chemistry, University of Birmingham, Birmingham, UK.
authors.forename: Robert
authors.initials: R
authors.lastname: Neely
authors.affiliation: Department of Biological Sciences, Institute for Structural and Molecular Biology, Birkbeck, University of London, London, UK.
authors.forename: Nicholas H
authors.identifier: 0000-0002-5042-1837
authors.initials: NH
authors.lastname: Keep
authors.affiliation: Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Brighton, UK.
authors.forename: Felicity Z
authors.initials: FZ
authors.lastname: Watts
authors.affiliation: Birmingham Centre for Genome Biology, Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham, UK.
authors.forename: Joanna R
authors.initials: JR
authors.lastname: Morris
mesh_terms: D019313:BRCA1 Protein / Q000235:genetics* / Q000378:metabolism; D001665:Binding Sites; D002166:Camptothecin / Q000494:pharmacology; D002843:Chromatin / Q000737:chemistry / Q000187:drug effects / Q000378:metabolism*; D003001:Cloning, Molecular; D053903:DNA Breaks, Double-Stranded; D053837:DNA Cleavage / Q000187:drug effects; D004265:DNA Helicases / Q000235:genetics* / Q000378:metabolism; D004273:DNA, Neoplasm / Q000235:genetics* / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D015870:Gene Expression; D015972:Gene Expression Regulation, Neoplastic; D006367:HeLa Cells; D006657:Histones / Q000235:genetics / Q000378:metabolism; D006801:Humans; D008958:Models, Molecular; D010793:Phthalazines / Q000494:pharmacology; D010879:Piperazines / Q000494:pharmacology; D011485:Protein Binding; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D059767:Recombinational DNA Repair; D015398:Signal Transduction; D025521:Tumor Suppressor Proteins / Q000235:genetics* / Q000378:metabolism; D000071857:Tumor Suppressor p53-Binding Protein 1 / Q000235:genetics / Q000378:metabolism; D025801:Ubiquitin / Q000235:genetics / Q000378:metabolism; D044767:Ubiquitin-Protein Ligases / Q000235:genetics* / Q000378:metabolism; D054875:Ubiquitination / Q000187:drug effects
chemical_list: D019313:BRCA1 Protein; C492913:BRCA1 protein, human; D002843:Chromatin; D004273:DNA, Neoplasm; D006657:Histones; D010793:Phthalazines; D010879:Piperazines; D011994:Recombinant Proteins; C498301:TP53BP1 protein, human; D025521:Tumor Suppressor Proteins; D000071857:Tumor Suppressor p53-Binding Protein 1; D025801:Ubiquitin; C102449:BARD1 protein, human; D044767:Ubiquitin-Protein Ligases; C561641:SMARCAD1 protein, human; D004265:DNA Helicases; C531550:olaparib; D002166:Camptothecin