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Malachowski T, Chandradoss KR, Boya R, Zhou L, Cook AL, Su C, Pham K, Haws SA, Kim JH, Ryu HS, Ge C, Luppino JM, Nguyen SC, Titus KR, Gong W, Wallace O, Joyce EF, Wu H, Rojas LA, Phillips-Cremins JE. Spatially coordinated heterochromatinization of long synaptic genes in fragile X syndrome. Cell 2023; 186:5840-5858.e36. [PMID: 38134876 PMCID: PMC10794044 DOI: 10.1016/j.cell.2023.11.019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2022] [Revised: 07/31/2023] [Accepted: 11/16/2023] [Indexed: 12/24/2023]
Abstract
Short tandem repeat (STR) instability causes transcriptional silencing in several repeat expansion disorders. In fragile X syndrome (FXS), mutation-length expansion of a CGG STR represses FMR1 via local DNA methylation. Here, we find megabase-scale H3K9me3 domains on autosomes and encompassing FMR1 on the X chromosome in FXS patient-derived iPSCs, iPSC-derived neural progenitors, EBV-transformed lymphoblasts, and brain tissue with mutation-length CGG expansion. H3K9me3 domains connect via inter-chromosomal interactions and demarcate severe misfolding of TADs and loops. They harbor long synaptic genes replicating at the end of S phase, replication-stress-induced double-strand breaks, and STRs prone to stepwise somatic instability. CRISPR engineering of the mutation-length CGG to premutation length reverses H3K9me3 on the X chromosome and multiple autosomes, refolds TADs, and restores gene expression. H3K9me3 domains can also arise in normal-length iPSCs created with perturbations linked to genome instability, suggesting their relevance beyond FXS. Our results reveal Mb-scale heterochromatinization and trans interactions among loci susceptible to instability.
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Affiliation(s)
- Thomas Malachowski
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA; Epigenetics Institute, University of Pennsylvania, Philadelphia, PA, USA; Department of Genetics, University of Pennsylvania, Philadelphia, PA, USA
| | - Keerthivasan Raanin Chandradoss
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA; Epigenetics Institute, University of Pennsylvania, Philadelphia, PA, USA; Department of Genetics, University of Pennsylvania, Philadelphia, PA, USA
| | - Ravi Boya
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA; Epigenetics Institute, University of Pennsylvania, Philadelphia, PA, USA; Department of Genetics, University of Pennsylvania, Philadelphia, PA, USA
| | - Linda Zhou
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA; Epigenetics Institute, University of Pennsylvania, Philadelphia, PA, USA; Department of Genetics, University of Pennsylvania, Philadelphia, PA, USA
| | - Ashley L Cook
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA; Epigenetics Institute, University of Pennsylvania, Philadelphia, PA, USA; Department of Genetics, University of Pennsylvania, Philadelphia, PA, USA
| | - Chuanbin Su
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA; Epigenetics Institute, University of Pennsylvania, Philadelphia, PA, USA; Department of Genetics, University of Pennsylvania, Philadelphia, PA, USA
| | - Kenneth Pham
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA; Department of Genetics, University of Pennsylvania, Philadelphia, PA, USA
| | - Spencer A Haws
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA; Epigenetics Institute, University of Pennsylvania, Philadelphia, PA, USA; Department of Genetics, University of Pennsylvania, Philadelphia, PA, USA
| | - Ji Hun Kim
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA
| | - Han-Seul Ryu
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA; Department of Genetics, University of Pennsylvania, Philadelphia, PA, USA
| | - Chunmin Ge
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA
| | - Jennifer M Luppino
- Epigenetics Institute, University of Pennsylvania, Philadelphia, PA, USA; Department of Genetics, University of Pennsylvania, Philadelphia, PA, USA
| | - Son C Nguyen
- Epigenetics Institute, University of Pennsylvania, Philadelphia, PA, USA; Department of Genetics, University of Pennsylvania, Philadelphia, PA, USA
| | - Katelyn R Titus
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA; Epigenetics Institute, University of Pennsylvania, Philadelphia, PA, USA; Department of Genetics, University of Pennsylvania, Philadelphia, PA, USA
| | - Wanfeng Gong
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA; Epigenetics Institute, University of Pennsylvania, Philadelphia, PA, USA; Department of Genetics, University of Pennsylvania, Philadelphia, PA, USA
| | - Owen Wallace
- Fulcrum Therapeutics Incorporated, Cambridge, MA, USA
| | - Eric F Joyce
- Epigenetics Institute, University of Pennsylvania, Philadelphia, PA, USA; Department of Genetics, University of Pennsylvania, Philadelphia, PA, USA
| | - Hao Wu
- Fulcrum Therapeutics Incorporated, Cambridge, MA, USA
| | | | - Jennifer E Phillips-Cremins
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA; Epigenetics Institute, University of Pennsylvania, Philadelphia, PA, USA; Department of Genetics, University of Pennsylvania, Philadelphia, PA, USA.
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Chandradoss KR, Chawla B, Dhuppar S, Nayak R, Ramachandran R, Kurukuti S, Mazumder A, Sandhu KS. CTCF-Mediated Genome Architecture Regulates the Dosage of Mitotically Stable Mono-allelic Expression of Autosomal Genes. Cell Rep 2020; 33:108302. [PMID: 33113374 DOI: 10.1016/j.celrep.2020.108302] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2017] [Revised: 07/31/2020] [Accepted: 09/30/2020] [Indexed: 11/30/2022] Open
Abstract
The mechanisms that guide the clonally stable random mono-allelic expression of autosomal genes remain enigmatic. We show that (1) mono-allelically expressed (MAE) genes are assorted and insulated from bi-allelically expressed (BAE) genes through CTCF-mediated chromatin loops; (2) the cell-type-specific dynamics of mono-allelic expression coincides with the gain and loss of chromatin insulator sites; (3) dosage of MAE genes is more sensitive to the loss of chromatin insulation than that of BAE genes; and (4) inactive alleles of MAE genes are significantly more insulated than active alleles and are de-repressed upon CTCF depletion. This alludes to a topology wherein the inactive alleles of MAE genes are insulated from the spatial interference of transcriptional states from the neighboring bi-allelic domains via CTCF-mediated loops. We propose that CTCF functions as a typical insulator on inactive alleles, but facilitates transcription through enhancer-linking on active allele of MAE genes, indicating widespread allele-specific regulatory roles of CTCF.
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Affiliation(s)
- Keerthivasan Raanin Chandradoss
- Department of Biological Sciences, Indian Institute of Science Education and Research (IISER)-Mohali, Knowledge City, Sector 81, SAS Nagar 140306, India
| | - Bindia Chawla
- Department of Biological Sciences, Indian Institute of Science Education and Research (IISER)-Mohali, Knowledge City, Sector 81, SAS Nagar 140306, India
| | - Shivnarayan Dhuppar
- TIFR Centre for Interdisciplinary Sciences, Tata Institute of Fundamental Research (TIFR) Hyderabad, 36/P, Gopanpally Village, Serilingampally Mandal, Hyderabad 500046, India
| | - Rakhee Nayak
- Department of Animal Biology, School of Life Sciences, University of Hyderabad, Prof. C.R. Rao Road, Gachibowli, Hyderabad 500046, India
| | - Rajesh Ramachandran
- Department of Biological Sciences, Indian Institute of Science Education and Research (IISER)-Mohali, Knowledge City, Sector 81, SAS Nagar 140306, India
| | - Sreenivasulu Kurukuti
- Department of Animal Biology, School of Life Sciences, University of Hyderabad, Prof. C.R. Rao Road, Gachibowli, Hyderabad 500046, India
| | - Aprotim Mazumder
- TIFR Centre for Interdisciplinary Sciences, Tata Institute of Fundamental Research (TIFR) Hyderabad, 36/P, Gopanpally Village, Serilingampally Mandal, Hyderabad 500046, India
| | - Kuljeet Singh Sandhu
- Department of Biological Sciences, Indian Institute of Science Education and Research (IISER)-Mohali, Knowledge City, Sector 81, SAS Nagar 140306, India.
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Chandradoss KR, Guthikonda PK, Kethavath S, Dass M, Singh H, Nayak R, Kurukuti S, Sandhu KS. Biased visibility in Hi-C datasets marks dynamically regulated condensed and decondensed chromatin states genome-wide. BMC Genomics 2020; 21:175. [PMID: 32087673 PMCID: PMC7036197 DOI: 10.1186/s12864-020-6580-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2019] [Accepted: 02/13/2020] [Indexed: 01/29/2023] Open
Abstract
Background Proximity ligation based techniques, like Hi-C, involve restriction digestion followed by ligation of formaldehyde cross-linked chromatin. Distinct chromatin states can impact the restriction digestion, and hence the visibility in the contact maps, of engaged loci. Yet, the extent and the potential impact of digestion bias remain obscure and under-appreciated in the literature. Results Through analysis of 45 Hi-C datasets, lamina-associated domains (LADs), inactive X-chromosome in mammals, and polytene bands in fly, we first established that the DNA in condensed chromatin had lesser accessibility to restriction endonucleases used in Hi-C as compared to that in decondensed chromatin. The observed bias was independent of known systematic biases, was not appropriately corrected by existing computational methods, and needed an additional optimization step. We then repurposed this bias to identify novel condensed domains outside LADs, which were bordered by insulators and were dynamically associated with the polycomb mediated epigenetic and transcriptional states during development. Conclusions Our observations suggest that the corrected one-dimensional read counts of existing Hi-C datasets can be reliably repurposed to study the gene-regulatory dynamics associated with chromatin condensation and decondensation, and that the existing Hi-C datasets should be interpreted with cautions.
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Affiliation(s)
- Keerthivasan Raanin Chandradoss
- Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) - Mohali, Knowledge City, Sector 81, SAS Nagar, 140306, India
| | - Prashanth Kumar Guthikonda
- Department of Animal Biology, School of Life Sciences, University of Hyderabad (UoH), Central University, Prof. CN Rao Road, P O, Gachibowli, Hyderabad, Telangana, 500046, India
| | - Srinivas Kethavath
- Department of Animal Biology, School of Life Sciences, University of Hyderabad (UoH), Central University, Prof. CN Rao Road, P O, Gachibowli, Hyderabad, Telangana, 500046, India
| | - Monika Dass
- Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) - Mohali, Knowledge City, Sector 81, SAS Nagar, 140306, India
| | - Harpreet Singh
- Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) - Mohali, Knowledge City, Sector 81, SAS Nagar, 140306, India
| | - Rakhee Nayak
- Department of Animal Biology, School of Life Sciences, University of Hyderabad (UoH), Central University, Prof. CN Rao Road, P O, Gachibowli, Hyderabad, Telangana, 500046, India
| | - Sreenivasulu Kurukuti
- Department of Animal Biology, School of Life Sciences, University of Hyderabad (UoH), Central University, Prof. CN Rao Road, P O, Gachibowli, Hyderabad, Telangana, 500046, India.
| | - Kuljeet Singh Sandhu
- Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) - Mohali, Knowledge City, Sector 81, SAS Nagar, 140306, India.
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Singh A, Choudhuri P, Chandradoss KR, Lal M, Mishra SK, Sandhu KS. Does genome surveillance explain the global discrepancy between binding and effect of chromatin factors? FEBS Lett 2020; 594:1339-1353. [PMID: 31930486 DOI: 10.1002/1873-3468.13729] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Revised: 12/16/2019] [Accepted: 12/19/2019] [Indexed: 11/11/2022]
Abstract
Knocking out a chromatin factor often does not alter the transcription of its binding targets. What explains the observed disconnect between binding and effect? We hypothesize that this discrepancy could be associated with the role of chromatin factors in maintaining genetic and epigenetic integrity at promoters, and not necessarily with transcription. Through re-analysis of published datasets, we present several lines of evidence that support our hypothesis and deflate the popular assumptions. We also tested the hypothesis through mutation accumulation assays on yeast knockouts of chromatin factors. Altogether, the proposed hypothesis presents a simple explanation for the global discord between chromatin factor binding and effect. Future work in this direction might fortify the hypothesis and elucidate the underlying mechanisms.
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Affiliation(s)
- Arashdeep Singh
- Department of Biological Sciences, Indian Institute of Science Education and Research (IISER)-Mohali, India
| | - Poulami Choudhuri
- Department of Biological Sciences, Indian Institute of Science Education and Research (IISER)-Mohali, India
| | | | - Mohan Lal
- Department of Biological Sciences, Indian Institute of Science Education and Research (IISER)-Mohali, India
| | - Shravan Kumar Mishra
- Department of Biological Sciences, Indian Institute of Science Education and Research (IISER)-Mohali, India
| | - Kuljeet Singh Sandhu
- Department of Biological Sciences, Indian Institute of Science Education and Research (IISER)-Mohali, India
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