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Dumont A, Mendiboure N, Savocco J, Anani L, Moreau P, Thierry A, Modolo L, Jost D, Piazza A. Mechanism of homology search expansion during recombinational DNA break repair in Saccharomyces cerevisiae. Mol Cell 2024; 84:3237-3253.e6. [PMID: 39178861 DOI: 10.1016/j.molcel.2024.08.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2023] [Revised: 06/26/2024] [Accepted: 08/02/2024] [Indexed: 08/26/2024]
Abstract
Homology search is a central step of DNA double-strand break (DSB) repair by homologous recombination (HR). How it operates in cells remains elusive. We developed a Hi-C-based methodology to map single-stranded DNA (ssDNA) contacts genome-wide in S. cerevisiae, which revealed two main homology search phases. Initial search conducted by short Rad51-ssDNA nucleoprotein filaments (NPFs) is confined in cis by cohesin-mediated chromatin loop folding. Progressive growth of stiff NPFs enables exploration of distant genomic sites. Long-range resection drives this transition from local to genome-wide search by increasing the probability of assembling extensive NPFs. DSB end-tethering promotes coordinated search by opposite NPFs. Finally, an autonomous genetic element on chromosome III engages the NPF, which stimulates homology search in its vicinity. This work reveals the mechanism of the progressive expansion of homology search that is orchestrated by chromatin organizers, long-range resection, end-tethering, and specialized genetic elements and that exploits the stiff NPF structure conferred by Rad51 oligomerization.
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Affiliation(s)
- Agnès Dumont
- Université de Lyon, ENS de Lyon, Université Claude Bernard, CNRS UMR5239, Laboratoire de Biologie et Modélisation de la Cellule, 46 Allée d'Italie, 69007 Lyon, France
| | - Nicolas Mendiboure
- Université de Lyon, ENS de Lyon, Université Claude Bernard, CNRS UMR5239, Laboratoire de Biologie et Modélisation de la Cellule, 46 Allée d'Italie, 69007 Lyon, France
| | - Jérôme Savocco
- Université de Lyon, ENS de Lyon, Université Claude Bernard, CNRS UMR5239, Laboratoire de Biologie et Modélisation de la Cellule, 46 Allée d'Italie, 69007 Lyon, France
| | - Loqmen Anani
- Université de Lyon, ENS de Lyon, Université Claude Bernard, CNRS UMR5239, Laboratoire de Biologie et Modélisation de la Cellule, 46 Allée d'Italie, 69007 Lyon, France
| | - Pierrick Moreau
- Unité Régulation spatiale des génomes, Institut Pasteur, CNRS UMR3525, 75015 Paris, France
| | - Agnès Thierry
- Unité Régulation spatiale des génomes, Institut Pasteur, CNRS UMR3525, 75015 Paris, France
| | - Laurent Modolo
- Université de Lyon, ENS de Lyon, Université Claude Bernard, CNRS UMR5239, Laboratoire de Biologie et Modélisation de la Cellule, 46 Allée d'Italie, 69007 Lyon, France
| | - Daniel Jost
- Université de Lyon, ENS de Lyon, Université Claude Bernard, CNRS UMR5239, Laboratoire de Biologie et Modélisation de la Cellule, 46 Allée d'Italie, 69007 Lyon, France
| | - Aurèle Piazza
- Université de Lyon, ENS de Lyon, Université Claude Bernard, CNRS UMR5239, Laboratoire de Biologie et Modélisation de la Cellule, 46 Allée d'Italie, 69007 Lyon, France.
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Sridalla K, Woodhouse MV, Hu J, Scheer J, Ferlez B, Crickard JB. The translocation activity of Rad54 reduces crossover outcomes during homologous recombination. Nucleic Acids Res 2024; 52:7031-7048. [PMID: 38828785 PMCID: PMC11229335 DOI: 10.1093/nar/gkae474] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2024] [Revised: 05/16/2024] [Accepted: 05/21/2024] [Indexed: 06/05/2024] Open
Abstract
Homologous recombination (HR) is a template-based DNA double-strand break repair pathway that requires the selection of an appropriate DNA sequence to facilitate repair. Selection occurs during a homology search that must be executed rapidly and with high fidelity. Failure to efficiently perform the homology search can result in complex intermediates that generate genomic rearrangements, a hallmark of human cancers. Rad54 is an ATP dependent DNA motor protein that functions during the homology search by regulating the recombinase Rad51. How this regulation reduces genomic exchanges is currently unknown. To better understand how Rad54 can reduce these outcomes, we evaluated several amino acid mutations in Rad54 that were identified in the COSMIC database. COSMIC is a collection of amino acid mutations identified in human cancers. These substitutions led to reduced Rad54 function and the discovery of a conserved motif in Rad54. Through genetic, biochemical and single-molecule approaches, we show that disruption of this motif leads to failure in stabilizing early strand invasion intermediates, causing increased crossovers between homologous chromosomes. Our study also suggests that the translocation rate of Rad54 is a determinant in balancing genetic exchange. The latch domain's conservation implies an interaction likely fundamental to eukaryotic biology.
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Affiliation(s)
- Krishay Sridalla
- Deparment of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA
| | - Mitchell V Woodhouse
- Deparment of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA
| | - Jingyi Hu
- Deparment of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA
| | - Jessica Scheer
- Deparment of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA
| | - Bryan Ferlez
- Deparment of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA
| | - J Brooks Crickard
- Deparment of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA
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Hu J, Crickard JB. All who wander are not lost: the search for homology during homologous recombination. Biochem Soc Trans 2024; 52:367-377. [PMID: 38323621 PMCID: PMC10903458 DOI: 10.1042/bst20230705] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2023] [Revised: 01/10/2024] [Accepted: 01/12/2024] [Indexed: 02/08/2024]
Abstract
Homologous recombination (HR) is a template-based DNA double-strand break repair pathway that functions to maintain genomic integrity. A vital component of the HR reaction is the identification of template DNA to be used during repair. This occurs through a mechanism known as the homology search. The homology search occurs in two steps: a collision step in which two pieces of DNA are forced to collide and a selection step that results in homologous pairing between matching DNA sequences. Selection of a homologous template is facilitated by recombinases of the RecA/Rad51 family of proteins in cooperation with helicases, translocases, and topoisomerases that determine the overall fidelity of the match. This menagerie of molecular machines acts to regulate critical intermediates during the homology search. These intermediates include recombinase filaments that probe for short stretches of homology and early strand invasion intermediates in the form of displacement loops (D-loops) that stabilize paired DNA. Here, we will discuss recent advances in understanding how these specific intermediates are regulated on the molecular level during the HR reaction. We will also discuss how the stability of these intermediates influences the ultimate outcomes of the HR reaction. Finally, we will discuss recent physiological models developed to explain how the homology search protects the genome.
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Affiliation(s)
- Jingyi Hu
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, U.S.A
| | - J. Brooks Crickard
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, U.S.A
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Kargbo RB. Innovations in Precision Oncology: Biomarker-Driven Approaches for Enhanced Cancer Therapy. ACS Med Chem Lett 2024; 15:169-170. [PMID: 38352835 PMCID: PMC10860168 DOI: 10.1021/acsmedchemlett.4c00002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2024] [Indexed: 02/16/2024] Open
Abstract
Precision oncology is revolutionized by targeted therapies like talazoparib, a PARP inhibitor, leveraging advanced understanding of DNA repair mechanisms such as ribonucleotide excision repair and homologous recombination repair. CRISPR-Cas technology has been pivotal in unraveling these pathways, facilitating personalized treatment strategies. The identification of genomic loss of heterozygosity as a biomarker targets HRR-deficient cancers, enhancing talazoparib's efficacy. These breakthroughs represent a significant advancement in precision medicine, offering more effective, individualized cancer therapies.
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