Restriction of Ku translocation protects telomere ends
Abstract Safeguarding chromosome ends against fusions via nonhomologous end joining (NHEJ) is essential for genome integrity. Paradoxically, the conserved NHEJ core factor Ku binds telomere ends. How it is prevented from promoting NHEJ remains unclear, as does the mechanism that allows Ku to coexist...
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Nature Portfolio
2025-07-01
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| Series: | Nature Communications |
| Online Access: | https://doi.org/10.1038/s41467-025-61864-1 |
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| author | Stefano Mattarocci Sonia Baconnais Florian Roisné-Hamelin Sabrina Pobiega Olivier Alibert Vincent Morin Alice Deshayes Xavier Veaute Virginie Ropars Maelenn Chevreuil Johannes Mehringer Didier Busso Gerard Mazon Paloma Fernandez Varela Éric Le Cam Jean-Baptiste Charbonnier Philippe Cuniasse Stéphane Marcand |
| author_facet | Stefano Mattarocci Sonia Baconnais Florian Roisné-Hamelin Sabrina Pobiega Olivier Alibert Vincent Morin Alice Deshayes Xavier Veaute Virginie Ropars Maelenn Chevreuil Johannes Mehringer Didier Busso Gerard Mazon Paloma Fernandez Varela Éric Le Cam Jean-Baptiste Charbonnier Philippe Cuniasse Stéphane Marcand |
| author_sort | Stefano Mattarocci |
| collection | DOAJ |
| description | Abstract Safeguarding chromosome ends against fusions via nonhomologous end joining (NHEJ) is essential for genome integrity. Paradoxically, the conserved NHEJ core factor Ku binds telomere ends. How it is prevented from promoting NHEJ remains unclear, as does the mechanism that allows Ku to coexist with telomere-protective DNA binding proteins, Rap1 in Saccharomyces cerevisiae. Here, we find that Rap1 directly inhibits Ku’s NHEJ function at telomeres. A single Rap1 molecule near a double-stand break suppresses NHEJ without displacing Ku in cells. Furthermore, Rap1 and Ku form a complex on short DNA duplexes in vitro. Cryo-EM shows Rap1 blocks Ku’s inward translocation on DNA – an essential step for NHEJ at DSBs. Nanopore sequencing of telomere fusions confirms this mechanism protects native telomere ends. These findings uncover a telomere protection mechanism where Rap1 restricts Ku’s inward translocation. This switches Ku from a repair-promoting to a protective role preventing NHEJ at telomeres. |
| format | Article |
| id | doaj-art-97d785ff1d104f6ea35e05251692319b |
| institution | Kabale University |
| issn | 2041-1723 |
| language | English |
| publishDate | 2025-07-01 |
| publisher | Nature Portfolio |
| record_format | Article |
| series | Nature Communications |
| spelling | doaj-art-97d785ff1d104f6ea35e05251692319b2025-08-20T04:02:56ZengNature PortfolioNature Communications2041-17232025-07-0116111310.1038/s41467-025-61864-1Restriction of Ku translocation protects telomere endsStefano Mattarocci0Sonia Baconnais1Florian Roisné-Hamelin2Sabrina Pobiega3Olivier Alibert4Vincent Morin5Alice Deshayes6Xavier Veaute7Virginie Ropars8Maelenn Chevreuil9Johannes Mehringer10Didier Busso11Gerard Mazon12Paloma Fernandez Varela13Éric Le Cam14Jean-Baptiste Charbonnier15Philippe Cuniasse16Stéphane Marcand17Université Paris-Saclay, Université Paris Cité, CEA, Inserm, Institut de biologie François Jacob, UMR Stabilité Génétique Cellules Souches et RadiationsGenome Integrity and Cancer, UMR 9019 CNRS, Université Paris-Saclay, Gustave RoussyUniversité Paris-Saclay, Université Paris Cité, CEA, Inserm, Institut de biologie François Jacob, UMR Stabilité Génétique Cellules Souches et RadiationsUniversité Paris-Saclay, Université Paris Cité, CEA, Inserm, Institut de biologie François Jacob, UMR Stabilité Génétique Cellules Souches et RadiationsCNRGH, CEA, Université Paris-SaclayUniversité Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC)Université Paris-Saclay, Université Paris Cité, CEA, Inserm, Institut de biologie François Jacob, UMR Stabilité Génétique Cellules Souches et RadiationsUniversité Paris-Saclay, Université Paris Cité, CEA, Inserm, Institut de biologie François Jacob, UMR Stabilité Génétique Cellules Souches et RadiationsUniversité Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC)Plateforme de biophysique moléculaire, C2RT, Institut PasteurKurt-Schwabe-InstituteUniversité Paris-Saclay, Université Paris Cité, CEA, Inserm, Institut de biologie François Jacob, UMR Stabilité Génétique Cellules Souches et RadiationsGenome Integrity and Cancer, UMR 9019 CNRS, Université Paris-Saclay, Gustave RoussyUniversité Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC)Genome Integrity and Cancer, UMR 9019 CNRS, Université Paris-Saclay, Gustave RoussyUniversité Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC)Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC)Université Paris-Saclay, Université Paris Cité, CEA, Inserm, Institut de biologie François Jacob, UMR Stabilité Génétique Cellules Souches et RadiationsAbstract Safeguarding chromosome ends against fusions via nonhomologous end joining (NHEJ) is essential for genome integrity. Paradoxically, the conserved NHEJ core factor Ku binds telomere ends. How it is prevented from promoting NHEJ remains unclear, as does the mechanism that allows Ku to coexist with telomere-protective DNA binding proteins, Rap1 in Saccharomyces cerevisiae. Here, we find that Rap1 directly inhibits Ku’s NHEJ function at telomeres. A single Rap1 molecule near a double-stand break suppresses NHEJ without displacing Ku in cells. Furthermore, Rap1 and Ku form a complex on short DNA duplexes in vitro. Cryo-EM shows Rap1 blocks Ku’s inward translocation on DNA – an essential step for NHEJ at DSBs. Nanopore sequencing of telomere fusions confirms this mechanism protects native telomere ends. These findings uncover a telomere protection mechanism where Rap1 restricts Ku’s inward translocation. This switches Ku from a repair-promoting to a protective role preventing NHEJ at telomeres.https://doi.org/10.1038/s41467-025-61864-1 |
| spellingShingle | Stefano Mattarocci Sonia Baconnais Florian Roisné-Hamelin Sabrina Pobiega Olivier Alibert Vincent Morin Alice Deshayes Xavier Veaute Virginie Ropars Maelenn Chevreuil Johannes Mehringer Didier Busso Gerard Mazon Paloma Fernandez Varela Éric Le Cam Jean-Baptiste Charbonnier Philippe Cuniasse Stéphane Marcand Restriction of Ku translocation protects telomere ends Nature Communications |
| title | Restriction of Ku translocation protects telomere ends |
| title_full | Restriction of Ku translocation protects telomere ends |
| title_fullStr | Restriction of Ku translocation protects telomere ends |
| title_full_unstemmed | Restriction of Ku translocation protects telomere ends |
| title_short | Restriction of Ku translocation protects telomere ends |
| title_sort | restriction of ku translocation protects telomere ends |
| url | https://doi.org/10.1038/s41467-025-61864-1 |
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