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Carlier F, Castro Ramirez S, Kilani J, Chehboub S, Loïodice I, Taddei A, Gladyshev E. Remodeling of perturbed chromatin can initiate de novo transcriptional and post-transcriptional silencing. Proc Natl Acad Sci U S A 2024; 121:e2402944121. [PMID: 39052837 PMCID: PMC11295056 DOI: 10.1073/pnas.2402944121] [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: 02/20/2024] [Accepted: 06/17/2024] [Indexed: 07/27/2024] Open
Abstract
In eukaryotes, repetitive DNA can become silenced de novo, either transcriptionally or post-transcriptionally, by processes independent of strong sequence-specific cues. The mechanistic nature of such processes remains poorly understood. We found that in the fungus Neurospora crassa, de novo initiation of both transcriptional and post-transcriptional silencing was linked to perturbed chromatin, which was produced experimentally by the aberrant activity of transcription factors at the tetO operator array. Transcriptional silencing was mediated by canonical constitutive heterochromatin. On the other hand, post-transcriptional silencing resembled repeat-induced quelling but occurred normally when homologous recombination was inactivated. All silencing of the tetO array was dependent on SAD-6, fungal ortholog of the SWI/SNF chromatin remodeler ATRX (Alpha Thalassemia/Mental Retardation Syndrome X-Linked), which was required to maintain nucleosome occupancy at the perturbed locus. In addition, we found that two other types of sequences (the lacO array and native AT-rich DNA) could also undergo recombination-independent quelling associated with perturbed chromatin. These results suggested a model in which the de novo initiation of transcriptional and post-transcriptional silencing is coupled to the remodeling of perturbed chromatin.
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Affiliation(s)
- Florian Carlier
- Institut Pasteur, Department of Mycology, Molecular Genetics and Epigenetics Unit, Université Paris Cité, Paris75015, France
| | - Sebastian Castro Ramirez
- Institut Pasteur, Department of Mycology, Molecular Genetics and Epigenetics Unit, Université Paris Cité, Paris75015, France
| | - Jaafar Kilani
- Institut Pasteur, Department of Mycology, Molecular Genetics and Epigenetics Unit, Université Paris Cité, Paris75015, France
| | - Sara Chehboub
- Institut Pasteur, Department of Mycology, Molecular Genetics and Epigenetics Unit, Université Paris Cité, Paris75015, France
| | - Isabelle Loïodice
- Institut Curie, UMR3664 Nuclear Dynamics, CNRS, Université Paris Sciences et Lettres, Sorbonne Université, Paris75005, France
| | - Angela Taddei
- Institut Curie, UMR3664 Nuclear Dynamics, CNRS, Université Paris Sciences et Lettres, Sorbonne Université, Paris75005, France
| | - Eugene Gladyshev
- Institut Pasteur, Department of Mycology, Molecular Genetics and Epigenetics Unit, Université Paris Cité, Paris75015, France
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Hou H, Kyriacou E, Thadani R, Klutstein M, Chapman JH, Cooper JP. Centromeres are dismantled by foundational meiotic proteins Spo11 and Rec8. Nature 2021; 591:671-676. [PMID: 33658710 PMCID: PMC8843027 DOI: 10.1038/s41586-021-03279-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Accepted: 01/22/2021] [Indexed: 01/31/2023]
Abstract
Meiotic processes are potentially dangerous to genome stability and could be disastrous if activated in proliferative cells. Here we show that two key meiosis-defining proteins, the topoisomerase Spo11 (which forms double-strand breaks) and the meiotic cohesin Rec8, can dismantle centromeres. This dismantlement is normally observable only in mutant cells that lack the telomere bouquet, which provides a nuclear microdomain conducive to centromere reassembly1; however, overexpression of Spo11 or Rec8 leads to levels of centromere dismantlement that cannot be countered by the bouquet. Specific nucleosome remodelling factors mediate centromere dismantlement by Spo11 and Rec8. Ectopic expression of either protein in proliferating cells leads to the loss of mitotic kinetochores in both fission yeast and human cells. Hence, while centromeric chromatin has been characterized as extraordinarily stable, Spo11 and Rec8 challenge this stability and may jeopardize kinetochores in cancers that express meiotic proteins.
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Affiliation(s)
- Haitong Hou
- Department of Biochemistry and Molecular Genetics, University of Colorado Anschutz Medical Campus, 12801 E. 17th Ave, Aurora, CO 80045, Phone 303-724-3203,Former address: Telomere Biology Laboratory, Laboratory of Biochemistry and Molecular Biology, Center for Cancer Research, NCI, NIH, Bethesda, MD 20892,Co-corresponding authors: ;
| | - Eftychia Kyriacou
- Former address: Telomere Biology Laboratory, Laboratory of Biochemistry and Molecular Biology, Center for Cancer Research, NCI, NIH, Bethesda, MD 20892,Current address: Swiss Institute for Experimental Cancer Research (ISREC), School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Rahul Thadani
- Department of Biochemistry and Molecular Genetics, University of Colorado Anschutz Medical Campus, 12801 E. 17th Ave, Aurora, CO 80045, Phone 303-724-3203,Former address: Telomere Biology Laboratory, Laboratory of Biochemistry and Molecular Biology, Center for Cancer Research, NCI, NIH, Bethesda, MD 20892
| | - Michael Klutstein
- Chromatin and Aging Research Laboratory, Institute of Dental Science, Hebrew University of Jerusalem PO 12272, Israel 91120
| | - Joseph H. Chapman
- Former address: Telomere Biology Laboratory, Laboratory of Biochemistry and Molecular Biology, Center for Cancer Research, NCI, NIH, Bethesda, MD 20892,Current address: Single Molecular Biophysics Laboratory, NHLBI, NIH
| | - Julia Promisel Cooper
- Department of Biochemistry and Molecular Genetics, University of Colorado Anschutz Medical Campus, 12801 E. 17th Ave, Aurora, CO 80045, Phone 303-724-3203,Former address: Telomere Biology Laboratory, Laboratory of Biochemistry and Molecular Biology, Center for Cancer Research, NCI, NIH, Bethesda, MD 20892,Co-corresponding authors: ;
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