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Abstract
The mammary gland undergoes extensive expansion of a ductal network through the stroma during puberty and is an excellent model for understanding epithelial tube morphogenesis. To investigate a role for Numb, a multifaceted adapter protein, in epithelial tube morphogenesis, we conditionally deleted it from the mammary epithelium. We report that Numb-depletion results in altered extracellular-matrix organization, reduced cell tension, altered cell shape, and increased cell packing density, which results in a 50% reduction in mammary duct elongation. Using laser ablation in vitro and geometric-based cell force inference in vivo, we determined that Numb-deficient cells have altered cortical tension. Duct elongation defects were associated with altered E-cadherin distribution, but were independent of proliferation, apoptosis in ducts or end buds. This highlights a critical role for Numb in a mechanical mechanism that is required to maintain cell packing density during epithelial tube elongation.
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Affiliation(s)
- Sudipa June Chatterjee
- Rosalind and Morris Goodman Cancer Research Centre, McGill University, Montreal, QC H3A 1A3, Canada.,Division of Experimental Medicine, McGill University, Montreal, QC H4A 3J1, Canada
| | - Ruba Halaoui
- Rosalind and Morris Goodman Cancer Research Centre, McGill University, Montreal, QC H3A 1A3, Canada.,Division of Experimental Medicine, McGill University, Montreal, QC H4A 3J1, Canada
| | - Rebecca Catherine Deagle
- Rosalind and Morris Goodman Cancer Research Centre, McGill University, Montreal, QC H3A 1A3, Canada.,Department of Physiology, McGill University, Montreal, QC H3G 1Y6, Canada
| | - Carlis Rejon
- Rosalind and Morris Goodman Cancer Research Centre, McGill University, Montreal, QC H3A 1A3, Canada
| | - Luke McCaffrey
- Rosalind and Morris Goodman Cancer Research Centre, McGill University, Montreal, QC H3A 1A3, Canada .,Division of Experimental Medicine, McGill University, Montreal, QC H4A 3J1, Canada.,Gerald Bronfman Department of Oncology, McGill University, Montreal, QC H4A 3T2, Canada
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Hilmi K, Jangal M, Marques M, Zhao T, Saad A, Zhang C, Luo VM, Syme A, Rejon C, Yu Z, Krum A, Fabian MR, Richard S, Alaoui-Jamali M, Orthwein A, McCaffrey L, Witcher M. CTCF facilitates DNA double-strand break repair by enhancing homologous recombination repair. Sci Adv 2017; 3:e1601898. [PMID: 28560323 PMCID: PMC5443639 DOI: 10.1126/sciadv.1601898] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2016] [Accepted: 03/29/2017] [Indexed: 05/06/2023]
Abstract
The repair of DNA double-strand breaks (DSBs) is mediated via two major pathways, nonhomologous end joining (NHEJ) and homologous recombination (HR) repair. DSB repair is vital for cell survival, genome stability, and tumor suppression. In contrast to NHEJ, HR relies on extensive homology and templated DNA synthesis to restore the sequence surrounding the break site. We report a new role for the multifunctional protein CCCTC-binding factor (CTCF) in facilitating HR-mediated DSB repair. CTCF is recruited to DSB through its zinc finger domain independently of poly(ADP-ribose) polymers, known as PARylation, catalyzed by poly(ADP-ribose) polymerase 1 (PARP-1). CTCF ensures proper DSB repair kinetics in response to γ-irradiation, and the loss of CTCF compromises HR-mediated repair. Consistent with its role in HR, loss of CTCF results in hypersensitivity to DNA damage, inducing agents and inhibitors of PARP. Mechanistically, CTCF acts downstream of BRCA1 in the HR pathway and associates with BRCA2 in a PARylation-dependent manner, enhancing BRCA2 recruitment to DSB. In contrast, CTCF does not influence the recruitment of the NHEJ protein 53BP1 or LIGIV to DSB. Together, our findings establish for the first time that CTCF is an important regulator of the HR pathway.
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Affiliation(s)
- Khalid Hilmi
- Departments of Oncology and Experimental Medicine, Lady Davis Institute and Segal Cancer Centre, Jewish General Hospital, McGill University, 3755 Chemin Côte-Ste-Catherine, Montréal, Quebec H3T 1E2, Canada
| | - Maïka Jangal
- Departments of Oncology and Experimental Medicine, Lady Davis Institute and Segal Cancer Centre, Jewish General Hospital, McGill University, 3755 Chemin Côte-Ste-Catherine, Montréal, Quebec H3T 1E2, Canada
| | - Maud Marques
- Departments of Oncology and Experimental Medicine, Lady Davis Institute and Segal Cancer Centre, Jewish General Hospital, McGill University, 3755 Chemin Côte-Ste-Catherine, Montréal, Quebec H3T 1E2, Canada
| | - Tiejun Zhao
- Departments of Oncology and Experimental Medicine, Lady Davis Institute and Segal Cancer Centre, Jewish General Hospital, McGill University, 3755 Chemin Côte-Ste-Catherine, Montréal, Quebec H3T 1E2, Canada
| | - Amine Saad
- Departments of Oncology and Experimental Medicine, Lady Davis Institute and Segal Cancer Centre, Jewish General Hospital, McGill University, 3755 Chemin Côte-Ste-Catherine, Montréal, Quebec H3T 1E2, Canada
| | - Chenxi Zhang
- Departments of Oncology and Experimental Medicine, Lady Davis Institute and Segal Cancer Centre, Jewish General Hospital, McGill University, 3755 Chemin Côte-Ste-Catherine, Montréal, Quebec H3T 1E2, Canada
| | - Vincent M. Luo
- Departments of Oncology and Experimental Medicine, Lady Davis Institute and Segal Cancer Centre, Jewish General Hospital, McGill University, 3755 Chemin Côte-Ste-Catherine, Montréal, Quebec H3T 1E2, Canada
- Department of Microbiology and Immunology, McGill University, 3775 University Street, Montréal, Quebec H3A 2B4, Canada
| | - Alasdair Syme
- Department of Radiation Oncology, Medical Physics Unit, Jewish General Hospital, McGill University, Montréal, Quebec H3T 1E2, Canada
| | - Carlis Rejon
- Department of Oncology, Rosalind and Morris Goodman Cancer Research Centre, McGill University, 1160 Pine Avenue West, Montréal, Quebec H3A 1A3, Canada
| | - Zhenbao Yu
- Departments of Oncology and Experimental Medicine, Lady Davis Institute and Segal Cancer Centre, Jewish General Hospital, McGill University, 3755 Chemin Côte-Ste-Catherine, Montréal, Quebec H3T 1E2, Canada
| | - Asiev Krum
- Department of Radiation Oncology, Medical Physics Unit, Jewish General Hospital, McGill University, Montréal, Quebec H3T 1E2, Canada
| | - Marc R. Fabian
- Departments of Oncology and Experimental Medicine, Lady Davis Institute and Segal Cancer Centre, Jewish General Hospital, McGill University, 3755 Chemin Côte-Ste-Catherine, Montréal, Quebec H3T 1E2, Canada
| | - Stéphane Richard
- Departments of Oncology and Experimental Medicine, Lady Davis Institute and Segal Cancer Centre, Jewish General Hospital, McGill University, 3755 Chemin Côte-Ste-Catherine, Montréal, Quebec H3T 1E2, Canada
| | - Moulay Alaoui-Jamali
- Departments of Oncology and Experimental Medicine, Lady Davis Institute and Segal Cancer Centre, Jewish General Hospital, McGill University, 3755 Chemin Côte-Ste-Catherine, Montréal, Quebec H3T 1E2, Canada
| | - Alexander Orthwein
- Departments of Oncology and Experimental Medicine, Lady Davis Institute and Segal Cancer Centre, Jewish General Hospital, McGill University, 3755 Chemin Côte-Ste-Catherine, Montréal, Quebec H3T 1E2, Canada
- Department of Microbiology and Immunology, McGill University, 3775 University Street, Montréal, Quebec H3A 2B4, Canada
| | - Luke McCaffrey
- Department of Oncology, Rosalind and Morris Goodman Cancer Research Centre, McGill University, 1160 Pine Avenue West, Montréal, Quebec H3A 1A3, Canada
| | - Michael Witcher
- Departments of Oncology and Experimental Medicine, Lady Davis Institute and Segal Cancer Centre, Jewish General Hospital, McGill University, 3755 Chemin Côte-Ste-Catherine, Montréal, Quebec H3T 1E2, Canada
- Corresponding author.
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