1
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Cui X, Yin Q, Gao Z, Li Z, Chen X, Lv H, Chen S, Liu Q, Zeng W, Jiang R. CREATE: cell-type-specific cis-regulatory element identification via discrete embedding. Nat Commun 2025; 16:4607. [PMID: 40382355 PMCID: PMC12085597 DOI: 10.1038/s41467-025-59780-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2024] [Accepted: 05/02/2025] [Indexed: 05/20/2025] Open
Abstract
Cis-regulatory elements (CREs), including enhancers, silencers, promoters and insulators, play pivotal roles in orchestrating gene regulatory mechanisms that drive complex biological traits. However, current approaches for CRE identification are predominantly sequence-based and typically focus on individual CRE types, limiting insights into their cell-type-specific functions and regulatory dynamics. Here, we present CREATE, a multimodal deep learning framework based on Vector Quantized Variational AutoEncoder, tailored for comprehensive CRE identification and characterization. CREATE integrates genomic sequences, chromatin accessibility, and chromatin interaction data to generate discrete CRE embeddings, enabling accurate multi-class classification and robust characterization of CREs. CREATE excels in identifying cell-type-specific CREs, and provides quantitative and interpretable insights into CRE-specific features, uncovering the underlying regulatory codes. By facilitating large-scale prediction of CREs in specific cell types, CREATE enhances the recognition of disease- or phenotype-associated biological variabilities of CREs, thus advancing our understanding of gene regulatory landscapes and their roles in health and disease.
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Affiliation(s)
- Xuejian Cui
- Ministry of Education Key Laboratory of Bioinformatics, Bioinformatics Division at the Beijing National Research Center for Information Science and Technology, Center for Synthetic and Systems Biology, Department of Automation, Tsinghua University, Beijing, China
| | - Qijin Yin
- Ministry of Education Key Laboratory of Bioinformatics, Bioinformatics Division at the Beijing National Research Center for Information Science and Technology, Center for Synthetic and Systems Biology, Department of Automation, Tsinghua University, Beijing, China
| | - Zijing Gao
- Ministry of Education Key Laboratory of Bioinformatics, Bioinformatics Division at the Beijing National Research Center for Information Science and Technology, Center for Synthetic and Systems Biology, Department of Automation, Tsinghua University, Beijing, China
| | - Zhen Li
- Ministry of Education Key Laboratory of Bioinformatics, Bioinformatics Division at the Beijing National Research Center for Information Science and Technology, Center for Synthetic and Systems Biology, Department of Automation, Tsinghua University, Beijing, China
| | - Xiaoyang Chen
- Ministry of Education Key Laboratory of Bioinformatics, Bioinformatics Division at the Beijing National Research Center for Information Science and Technology, Center for Synthetic and Systems Biology, Department of Automation, Tsinghua University, Beijing, China
| | - Hairong Lv
- Ministry of Education Key Laboratory of Bioinformatics, Bioinformatics Division at the Beijing National Research Center for Information Science and Technology, Center for Synthetic and Systems Biology, Department of Automation, Tsinghua University, Beijing, China
| | - Shengquan Chen
- School of Mathematical Sciences and LPMC, Nankai University, Tianjin, China
| | - Qiao Liu
- Department of Statistics, Stanford University, Stanford, CA, USA
| | - Wanwen Zeng
- Department of Statistics, Stanford University, Stanford, CA, USA.
| | - Rui Jiang
- Ministry of Education Key Laboratory of Bioinformatics, Bioinformatics Division at the Beijing National Research Center for Information Science and Technology, Center for Synthetic and Systems Biology, Department of Automation, Tsinghua University, Beijing, China.
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2
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Mikulski P, Tehrani SSH, Kogan A, Abdul-Zani I, Shell E, James L, Ryan BJ, Jansen LET. Heritable maintenance of chromatin modifications confers transcriptional memory of interferon-γ signaling. Nat Struct Mol Biol 2025:10.1038/s41594-025-01522-8. [PMID: 40186025 DOI: 10.1038/s41594-025-01522-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2023] [Accepted: 02/20/2025] [Indexed: 04/07/2025]
Abstract
Interferon-γ (IFNγ) transiently activates genes related to inflammation and innate immunity. A subset of targets retain a mitotically heritable memory of prior IFNγ exposure, resulting in hyperactivation upon re-exposure through poorly understood mechanisms. Here, we discover that the transcriptionally permissive chromatin marks H3K4me1, H3K14ac and H4K16ac are established during IFNγ priming and are selectively maintained on a cluster of guanylate-binding protein (GBP) genes in dividing human cells in the absence of transcription. The histone acetyltransferase KAT7 is required for H3K14ac deposition at GBP genes and for accelerated GBP reactivation upon re-exposure to IFNγ. In naive cells, the GBP cluster is maintained in a low-level repressive chromatin state, marked by H3K27me3, limiting priming through a PRC2-dependent mechanism. Unexpectedly, IFNγ priming results in transient accumulation of this repressive mark despite active gene expression. However, during the memory phase, H3K27 methylation is selectively depleted from primed GBP genes, facilitating hyperactivation. Furthermore, we identified a cis-regulatory element that forms transient, long-range contacts across the GBP cluster and acts as a repressor, curbing hyperactivation of previously IFNγ-primed cells. Our results provide insight into the chromatin basis for the long-term transcriptional memory of IFNγ signaling, which might contribute to enhanced innate immunity.
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Affiliation(s)
- Pawel Mikulski
- Department of Biochemistry, University of Oxford, Oxford, UK.
- The International Institute of Molecular Mechanisms and Machines PAS, Warsaw, Poland.
| | - Sahar S H Tehrani
- Department of Biochemistry, University of Oxford, Oxford, UK
- Instituto Gulbenkian de Ciência, Oeiras, Portugal
| | - Anna Kogan
- Department of Biochemistry, University of Oxford, Oxford, UK
| | - Izma Abdul-Zani
- Department of Biochemistry, University of Oxford, Oxford, UK
| | - Emer Shell
- Department of Biochemistry, University of Oxford, Oxford, UK
| | - Louise James
- Department of Biochemistry, University of Oxford, Oxford, UK
| | - Brent J Ryan
- Department of Physiology, Anatomy & Genetics, University of Oxford, Oxford, UK
| | - Lars E T Jansen
- Department of Biochemistry, University of Oxford, Oxford, UK.
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3
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Regner MJ, Garcia-Recio S, Thennavan A, Wisniewska K, Mendez-Giraldez R, Felsheim B, Spanheimer PM, Parker JS, Perou CM, Franco HL. Defining the regulatory logic of breast cancer using single-cell epigenetic and transcriptome profiling. CELL GENOMICS 2025; 5:100765. [PMID: 39914387 PMCID: PMC11872555 DOI: 10.1016/j.xgen.2025.100765] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2024] [Revised: 11/04/2024] [Accepted: 01/08/2025] [Indexed: 02/12/2025]
Abstract
Annotation of cis-regulatory elements that drive transcriptional dysregulation in cancer cells is critical to understanding tumor biology. Herein, we present matched chromatin accessibility (single-cell assay for transposase-accessible chromatin by sequencing [scATAC-seq]) and transcriptome (single-cell RNA sequencing [scRNA-seq]) profiles at single-cell resolution from human breast tumors and healthy mammary tissues processed immediately following surgical resection. We identify the most likely cell of origin for subtype-specific breast tumors and implement linear mixed-effects modeling to quantify associations between regulatory elements and gene expression in malignant versus normal cells. These data unveil cancer-specific regulatory elements and putative silencer-to-enhancer switching events in cells that lead to the upregulation of clinically relevant oncogenes. In addition, we generate matched scATAC-seq and scRNA-seq profiles for breast cancer cell lines, revealing a conserved oncogenic gene expression program between in vitro and in vivo cells. This work highlights the importance of non-coding regulatory mechanisms that underlie oncogenic processes and the ability of single-cell multi-omics to define the regulatory logic of cancer cells.
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Affiliation(s)
- Matthew J Regner
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Curriculum in Bioinformatics and Computational Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Susana Garcia-Recio
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Department of Genetics, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Aatish Thennavan
- Department of Systems Biology, UT MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Kamila Wisniewska
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Raul Mendez-Giraldez
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Brooke Felsheim
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Curriculum in Bioinformatics and Computational Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Philip M Spanheimer
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Department of Surgery, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Joel S Parker
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Curriculum in Bioinformatics and Computational Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Department of Genetics, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Charles M Perou
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Curriculum in Bioinformatics and Computational Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Department of Genetics, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Hector L Franco
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Curriculum in Bioinformatics and Computational Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Department of Genetics, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Division of Clinical and Translational Cancer Research, University of Puerto Rico Comprehensive Cancer Center, San Juan, PR 00935, USA.
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4
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Song W, Ovcharenko I. Abundant repressor binding sites in human enhancers are associated with the fine-tuning of gene regulation. iScience 2025; 28:111658. [PMID: 39868043 PMCID: PMC11761325 DOI: 10.1016/j.isci.2024.111658] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2024] [Revised: 08/04/2024] [Accepted: 11/25/2024] [Indexed: 01/28/2025] Open
Abstract
The regulation of gene expression relies on the coordinated action of transcription factors (TFs) at enhancers, including both activator and repressor TFs. We employed deep learning (DL) to dissect HepG2 enhancers into positive (PAR), negative (NAR), and neutral activity regions. Sharpr-MPRA and STARR-seq highlight the dichotomy impact of NARs and PARs on modulating and catalyzing the activity of enhancers, respectively. Approximately 22% of HepG2 enhancers, termed "repressive impact enhancers" (RIEs), are predominantly populated by NARs and transcriptional repression motifs. Genes flanking RIEs exhibit a stage-specific decline in expression during late development, suggesting RIEs' role in trimming enhancer activities. About 16.7% of human NARs emerge from neutral rhesus macaque DNA. This gain of repressor binding sites in RIEs is associated with a 30% decrease in the average expression of flanking genes in humans compared to rhesus macaque. Our work reveals modulated enhancer activity and adaptable gene regulation through the evolutionary dynamics of TF binding sites.
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Affiliation(s)
- Wei Song
- Computational Biology Branch, National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD, USA
| | - Ivan Ovcharenko
- Computational Biology Branch, National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD, USA
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5
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Friedman RZ, Ramu A, Lichtarge S, Wu Y, Tripp L, Lyon D, Myers CA, Granas DM, Gause M, Corbo JC, Cohen BA, White MA. Active learning of enhancers and silencers in the developing neural retina. Cell Syst 2025; 16:101163. [PMID: 39778579 PMCID: PMC11827711 DOI: 10.1016/j.cels.2024.12.004] [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: 03/26/2024] [Revised: 10/17/2024] [Accepted: 12/06/2024] [Indexed: 01/11/2025]
Abstract
Deep learning is a promising strategy for modeling cis-regulatory elements. However, models trained on genomic sequences often fail to explain why the same transcription factor can activate or repress transcription in different contexts. To address this limitation, we developed an active learning approach to train models that distinguish between enhancers and silencers composed of binding sites for the photoreceptor transcription factor cone-rod homeobox (CRX). After training the model on nearly all bound CRX sites from the genome, we coupled synthetic biology with uncertainty sampling to generate additional rounds of informative training data. This allowed us to iteratively train models on data from multiple rounds of massively parallel reporter assays. The ability of the resulting models to discriminate between CRX sites with identical sequence but opposite functions establishes active learning as an effective strategy to train models of regulatory DNA. A record of this paper's transparent peer review process is included in the supplemental information.
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Affiliation(s)
- Ryan Z Friedman
- The Edison Family Center for Genome Sciences & Systems Biology, Saint Louis, MO 63110, USA; Department of Genetics, Saint Louis, MO 63110, USA
| | - Avinash Ramu
- The Edison Family Center for Genome Sciences & Systems Biology, Saint Louis, MO 63110, USA; Department of Genetics, Saint Louis, MO 63110, USA
| | - Sara Lichtarge
- The Edison Family Center for Genome Sciences & Systems Biology, Saint Louis, MO 63110, USA; Department of Genetics, Saint Louis, MO 63110, USA
| | - Yawei Wu
- The Edison Family Center for Genome Sciences & Systems Biology, Saint Louis, MO 63110, USA; Department of Genetics, Saint Louis, MO 63110, USA
| | - Lloyd Tripp
- The Edison Family Center for Genome Sciences & Systems Biology, Saint Louis, MO 63110, USA; Department of Genetics, Saint Louis, MO 63110, USA
| | - Daniel Lyon
- The Edison Family Center for Genome Sciences & Systems Biology, Saint Louis, MO 63110, USA; Department of Genetics, Saint Louis, MO 63110, USA
| | - Connie A Myers
- Department of Pathology and Immunology, Washington University School of Medicine, Saint Louis, MO 63110, USA
| | - David M Granas
- The Edison Family Center for Genome Sciences & Systems Biology, Saint Louis, MO 63110, USA; Department of Genetics, Saint Louis, MO 63110, USA
| | - Maria Gause
- Department of Pathology and Immunology, Washington University School of Medicine, Saint Louis, MO 63110, USA
| | - Joseph C Corbo
- Department of Pathology and Immunology, Washington University School of Medicine, Saint Louis, MO 63110, USA
| | - Barak A Cohen
- The Edison Family Center for Genome Sciences & Systems Biology, Saint Louis, MO 63110, USA; Department of Genetics, Saint Louis, MO 63110, USA
| | - Michael A White
- The Edison Family Center for Genome Sciences & Systems Biology, Saint Louis, MO 63110, USA; Department of Genetics, Saint Louis, MO 63110, USA.
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6
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Ozturan D, de Boer CG. Silent silencers: Leave no trace. Mol Cell 2024; 84:4473-4475. [PMID: 39642851 DOI: 10.1016/j.molcel.2024.11.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2024] [Revised: 11/07/2024] [Accepted: 11/07/2024] [Indexed: 12/09/2024]
Abstract
The regulatory mechanisms of silencers have remained poorly understood. In this issue, Hofbauer et al.1 conduct a genome-wide screen in Drosophila melanogaster and reveal three silencer types that appear to work alone-without the need for combinatorial action, traditional chromatin marks, or open chromatin regions.
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Affiliation(s)
- Dogancan Ozturan
- School of Biomedical Engineering, University of British Columbia, Vancouver, British Columbia, Canada
| | - Carl G de Boer
- School of Biomedical Engineering, University of British Columbia, Vancouver, British Columbia, Canada.
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7
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Hofbauer L, Pleyer LM, Reiter F, Schleiffer A, Vlasova A, Serebreni L, Huang A, Stark A. A genome-wide screen identifies silencers with distinct chromatin properties and mechanisms of repression. Mol Cell 2024; 84:4503-4521.e14. [PMID: 39571581 DOI: 10.1016/j.molcel.2024.10.041] [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: 02/12/2024] [Revised: 08/20/2024] [Accepted: 10/29/2024] [Indexed: 12/08/2024]
Abstract
Differential gene transcription enables development and homeostasis in all animals and is regulated by two major classes of distal cis-regulatory DNA elements (CREs): enhancers and silencers. Although enhancers have been thoroughly characterized, the properties and mechanisms of silencers remain largely unknown. By an unbiased genome-wide functional screen in Drosophila melanogaster S2 cells, we discover a class of silencers that bind one of three transcription factors (TFs) and are generally not included in chromatin-defined CRE catalogs as they mostly lack detectable DNA accessibility. The silencer-binding TF CG11247, which we term Saft, safeguards cell fate decisions in vivo and functions via a highly conserved domain we term zinc-finger-associated C-terminal (ZAC) and the corepressor G9a, independently of G9a's H3K9-methyltransferase activity. Overall, our identification of silencers with unexpected properties and mechanisms has important implications for the understanding and future study of repressive CREs, as well as the functional annotation of animal genomes.
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Affiliation(s)
- Lorena Hofbauer
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), Campus-Vienna-Biocenter 1, 1030 Vienna, Austria; Vienna BioCenter PhD Program, Doctoral School of the University of Vienna and Medical University of Vienna, 1030 Vienna, Austria
| | - Lisa-Marie Pleyer
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), Campus-Vienna-Biocenter 1, 1030 Vienna, Austria
| | - Franziska Reiter
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), Campus-Vienna-Biocenter 1, 1030 Vienna, Austria; Vienna BioCenter PhD Program, Doctoral School of the University of Vienna and Medical University of Vienna, 1030 Vienna, Austria
| | - Alexander Schleiffer
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), Campus-Vienna-Biocenter 1, 1030 Vienna, Austria
| | - Anna Vlasova
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), Campus-Vienna-Biocenter 1, 1030 Vienna, Austria
| | - Leonid Serebreni
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), Campus-Vienna-Biocenter 1, 1030 Vienna, Austria; Vienna BioCenter PhD Program, Doctoral School of the University of Vienna and Medical University of Vienna, 1030 Vienna, Austria
| | - Annie Huang
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), Campus-Vienna-Biocenter 1, 1030 Vienna, Austria
| | - Alexander Stark
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), Campus-Vienna-Biocenter 1, 1030 Vienna, Austria; Medical University of Vienna, Vienna BioCenter (VBC), Vienna, Austria.
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8
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McDonald JMC, Reed RD. Beyond modular enhancers: new questions in cis-regulatory evolution. Trends Ecol Evol 2024; 39:1035-1046. [PMID: 39266441 DOI: 10.1016/j.tree.2024.07.005] [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: 10/26/2023] [Revised: 06/28/2024] [Accepted: 07/08/2024] [Indexed: 09/14/2024]
Abstract
Our understanding of how cis-regulatory elements work has advanced rapidly, outpacing our evolutionary models. In this review, we consider the implications of new mechanistic findings for evolutionary developmental biology. We focus on three different debates: whether evolutionary innovation occurs more often via the modification of old cis-regulatory elements or the emergence of new ones; the extent to which individual elements are specific and autonomous or multifunctional and interdependent; and how the robustness of cis-regulatory architectures influences the rate of trait evolution. These discussions lead us to propose new questions for the evo-devo of cis-regulation.
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Affiliation(s)
- Jeanne M C McDonald
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY, USA.
| | - Robert D Reed
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY, USA
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9
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Qiu K, Vu DC, Wang L, Nguyen NN, Bookstaver AK, Sol-Church K, Li H, Dinh TN, Goldfarb AN, Tenen DG, Trinh BQ. Chromatin structure and 3D architecture define the differential functions of PU.1 regulatory elements in blood cell lineages. Epigenetics Chromatin 2024; 17:33. [PMID: 39487555 PMCID: PMC11531149 DOI: 10.1186/s13072-024-00556-4] [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: 03/29/2024] [Accepted: 10/22/2024] [Indexed: 11/04/2024] Open
Abstract
The precise spatiotemporal expression of the hematopoietic ETS transcription factor PU.1, a key determinant of hematopoietic cell fates, is tightly regulated at the chromatin level. However, how chromatin signatures are linked to this dynamic expression pattern across different blood cell lineages remains uncharacterized. Here, we performed an in-depth analysis of the relationships between gene expression, chromatin structure, 3D architecture, and trans-acting factors at PU.1 cis-regulatory elements (PCREs). By identifying phylogenetically conserved DNA elements within chromatin-accessible regions in primary human blood lineages, we discovered multiple novel candidate PCREs within the upstream region of the human PU.1 locus. A subset of these elements localizes within an 8-kb-wide cluster exhibiting enhancer features, including open chromatin, demethylated DNA, enriched enhancer histone marks, present enhancer RNAs, and PU.1 occupation, presumably mediating PU.1 autoregulation. Importantly, we revealed the presence of a common 35-kb-wide CTCF-flanked insulated neighborhood that contains the PCRE cluster (PCREC), forming a chromatin territory for lineage-specific and PCRE-mediated chromatin interactions. These include functional PCRE-promoter interactions in myeloid and B cells that are absent in erythroid and T cells. By correlating chromatin structure and 3D architecture with PU.1 expression in various lineages, we were able to attribute enhancer versus silencer functions to individual elements. Our findings provide mechanistic insights into the interplay between dynamic chromatin structure and 3D architecture in the chromatin regulation of PU.1 expression. This study lays crucial groundwork for additional experimental studies that validate and dissect the role of PCREs in epigenetic regulation of normal and malignant hematopoiesis.
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Affiliation(s)
- Kevin Qiu
- Department of Pathology, University of Virginia School of Medicine, Charlottesville, VA, 22908, USA
| | - Duc C Vu
- Department of Pathology, University of Virginia School of Medicine, Charlottesville, VA, 22908, USA
| | - Leran Wang
- Department of Pathology, University of Virginia School of Medicine, Charlottesville, VA, 22908, USA
| | - Nicholas N Nguyen
- Department of Pathology, University of Virginia School of Medicine, Charlottesville, VA, 22908, USA
| | - Anna K Bookstaver
- Department of Pathology, University of Virginia School of Medicine, Charlottesville, VA, 22908, USA
| | - Katia Sol-Church
- Department of Pathology, University of Virginia School of Medicine, Charlottesville, VA, 22908, USA
| | - Hui Li
- Department of Pathology, University of Virginia School of Medicine, Charlottesville, VA, 22908, USA
- Molecular Genetics & Epigenetics Program, University of Virginia Comprehensive Cancer Center, Charlottesville, VA, 22908, USA
| | - Thang N Dinh
- Department of Computer Science, Virginia Commonwealth University, Richmond, VA, 23284, USA
| | - Adam N Goldfarb
- Department of Pathology, University of Virginia School of Medicine, Charlottesville, VA, 22908, USA
| | - Daniel G Tenen
- Cancer Science Institute, National University of Singapore, Singapore, 117599, Singapore
- Harvard Stem Cell Institute, Harvard Medical School, Boston, MA, 02115, USA
| | - Bon Q Trinh
- Department of Pathology, University of Virginia School of Medicine, Charlottesville, VA, 22908, USA.
- Molecular Genetics & Epigenetics Program, University of Virginia Comprehensive Cancer Center, Charlottesville, VA, 22908, USA.
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10
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Jores T, Mueth NA, Tonnies J, Char SN, Liu B, Grillo-Alvarado V, Abbitt S, Anand A, Deschamps S, Diehn S, Gordon-Kamm B, Jiao S, Munkvold K, Snowgren H, Sardesai N, Fields S, Yang B, Cuperus JT, Queitsch C. Small DNA elements that act as both insulators and silencers in plants. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.09.13.612883. [PMID: 39345455 PMCID: PMC11429706 DOI: 10.1101/2024.09.13.612883] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 10/01/2024]
Abstract
Insulators are cis-regulatory elements that separate transcriptional units, whereas silencers are elements that repress transcription regardless of their position. In plants, these elements remain largely uncharacterized. Here, we use the massively parallel reporter assay Plant STARR-seq with short fragments of eight large insulators to identify more than 100 fragments that block enhancer activity. The short fragments can be combined to generate more powerful insulators that abolish the capacity of the strong viral 35S enhancer to activate the 35S minimal promoter. Unexpectedly, when tested upstream of weak enhancers, these fragments act as silencers and repress transcription. Thus, these elements are capable of both insulating or repressing transcription dependent upon regulatory context. We validate our findings in stable transgenic Arabidopsis, maize, and rice plants. The short elements identified here should be useful building blocks for plant biotechnology efforts.
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Affiliation(s)
- Tobias Jores
- Department of Genome Sciences, University of Washington, Seattle, WA, USA
- Institute of Synthetic Biology, Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany
- CEPLAS – Cluster of Excellence on Plant Sciences, Düsseldorf, Germany
| | - Nicholas A. Mueth
- Department of Genome Sciences, University of Washington, Seattle, WA, USA
| | - Jackson Tonnies
- Department of Genome Sciences, University of Washington, Seattle, WA, USA
- Graduate Program in Biology, University of Washington, Seattle, WA, USA
| | - Si Nian Char
- Division of Plant Science and Technology, Bond Life Sciences Center, University of Missouri, Columbia, MO, USA
| | - Bo Liu
- Division of Plant Science and Technology, Bond Life Sciences Center, University of Missouri, Columbia, MO, USA
| | - Valentina Grillo-Alvarado
- Department of Genome Sciences, University of Washington, Seattle, WA, USA
- Molecular & Cellular Biology Graduate Program, University of Washington, Seattle, WA, USA
| | | | - Ajith Anand
- Corteva Agriscience, Johnston, IA, USA
- Present address: MyFloraDNA, Sacramento, CA, USA
| | | | | | | | | | - Kathy Munkvold
- Corteva Agriscience, Johnston, IA, USA
- Present address: Foundation for Food & Agriculture Research, Washington, DC, USA
| | | | | | - Stanley Fields
- Department of Genome Sciences, University of Washington, Seattle, WA, USA
- Department of Medicine, University of Washington, Seattle, WA, USA
| | - Bing Yang
- Division of Plant Science and Technology, Bond Life Sciences Center, University of Missouri, Columbia, MO, USA
- Donald Danforth Plant Science Center, St. Louis, MO, USA
| | - Josh T. Cuperus
- Department of Genome Sciences, University of Washington, Seattle, WA, USA
| | - Christine Queitsch
- Department of Genome Sciences, University of Washington, Seattle, WA, USA
- Brotman Baty Institute for Precision Medicine, University of Washington, Seattle, WA, USA
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11
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Fu X, Rabadan R. Understanding variants of unknown significance: the computational frontier. Oncologist 2024; 29:653-657. [PMID: 38848164 PMCID: PMC11299926 DOI: 10.1093/oncolo/oyae103] [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: 04/07/2024] [Accepted: 04/16/2024] [Indexed: 06/09/2024] Open
Abstract
The rapid advancement of sequencing technologies has led to the identification of numerous mutations in cancer genomes, many of which are variants of unknown significance (VUS). Computational models are increasingly being used to predict the functional impact of these mutations, in both coding and noncoding regions. Integration of these models with emerging genomic datasets will refine our understanding of mutation effects and guide clinical decision making. Future advancements in modeling protein interactions and transcriptional regulation will further enhance our ability to interpret VUS. Periodic incorporation of these developments into VUS reclassification practice has the potential to significantly improve personalized cancer care.
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Affiliation(s)
- Xi Fu
- Columbia University Irving Medical Center, New York, NY, USA
| | - Raul Rabadan
- Columbia University Irving Medical Center, New York, NY, USA
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12
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Li Y, Tan M, Akkari-Henić A, Zhang L, Kip M, Sun S, Sepers JJ, Xu N, Ariyurek Y, Kloet SL, Davis RP, Mikkers H, Gruber JJ, Snyder MP, Li X, Pang B. Genome-wide Cas9-mediated screening of essential non-coding regulatory elements via libraries of paired single-guide RNAs. Nat Biomed Eng 2024; 8:890-908. [PMID: 38778183 PMCID: PMC11310080 DOI: 10.1038/s41551-024-01204-8] [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: 09/05/2023] [Accepted: 03/27/2024] [Indexed: 05/25/2024]
Abstract
The functions of non-coding regulatory elements (NCREs), which constitute a major fraction of the human genome, have not been systematically studied. Here we report a method involving libraries of paired single-guide RNAs targeting both ends of an NCRE as a screening system for the Cas9-mediated deletion of thousands of NCREs genome-wide to study their functions in distinct biological contexts. By using K562 and 293T cell lines and human embryonic stem cells, we show that NCREs can have redundant functions, and that many ultra-conserved elements have silencer activity and play essential roles in cell growth and in cellular responses to drugs (notably, the ultra-conserved element PAX6_Tarzan may be critical for heart development, as removing it from human embryonic stem cells led to defects in cardiomyocyte differentiation). The high-throughput screen, which is compatible with single-cell sequencing, may allow for the identification of druggable NCREs.
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Affiliation(s)
- Yufeng Li
- Department of Cell and Chemical Biology, Leiden University Medical Center, Leiden, the Netherlands
| | - Minkang Tan
- Department of Cell and Chemical Biology, Leiden University Medical Center, Leiden, the Netherlands
| | - Almira Akkari-Henić
- Department of Cell and Chemical Biology, Leiden University Medical Center, Leiden, the Netherlands
| | - Limin Zhang
- Department of Cell and Chemical Biology, Leiden University Medical Center, Leiden, the Netherlands
| | - Maarten Kip
- Department of Cell and Chemical Biology, Leiden University Medical Center, Leiden, the Netherlands
| | - Shengnan Sun
- Department of Cell and Chemical Biology, Leiden University Medical Center, Leiden, the Netherlands
| | - Jorian J Sepers
- Department of Cell and Chemical Biology, Leiden University Medical Center, Leiden, the Netherlands
| | - Ningning Xu
- Department of Cell and Chemical Biology, Leiden University Medical Center, Leiden, the Netherlands
| | - Yavuz Ariyurek
- Leiden Genome Technology Center, Department of Human Genetics, Leiden University Medical Center, Leiden, the Netherlands
| | - Susan L Kloet
- Leiden Genome Technology Center, Department of Human Genetics, Leiden University Medical Center, Leiden, the Netherlands
| | - Richard P Davis
- Department of Anatomy and Embryology, The Novo Nordisk Foundation Center for Stem Cell Medicine (reNEW), Leiden University Medical Center, Leiden, the Netherlands
| | - Harald Mikkers
- Department of Cell and Chemical Biology, Leiden University Medical Center, Leiden, the Netherlands
| | - Joshua J Gruber
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | | | - Xiao Li
- Department of Biochemistry, The Center for RNA Science and Therapeutics, Department of Computer and Data Sciences, Case Western Reserve University, Cleveland, OH, USA.
| | - Baoxu Pang
- Department of Cell and Chemical Biology, Leiden University Medical Center, Leiden, the Netherlands.
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13
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Roy Chowdhury N, Gurevich V, Shamay M. KSHV genome harbors both constitutive and lytically induced enhancers. J Virol 2024; 98:e0017924. [PMID: 38695538 PMCID: PMC11237633 DOI: 10.1128/jvi.00179-24] [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: 01/30/2024] [Accepted: 04/03/2024] [Indexed: 06/14/2024] Open
Abstract
Kaposi's sarcoma-associated herpesvirus (KSHV) belongs to the gamma-herpesvirus family and is a well-known human oncogenic virus. In infected cells, the viral genome of 165 kbp is circular DNA wrapped in chromatin. The tight control of gene expression is critical for latency, the transition into the lytic phase, and the development of viral-associated malignancies. Distal cis-regulatory elements, such as enhancers and silencers, can regulate gene expression in a position- and orientation-independent manner. Open chromatin is another characteristic feature of enhancers. To systematically search for enhancers, we cloned all the open chromatin regions in the KSHV genome downstream of the luciferase gene and tested their enhancer activity in infected and uninfected cells. A silencer was detected upstream of the latency-associated nuclear antigen promoter. Two constitutive enhancers were identified in the K12p-OriLyt-R and ORF29 Intron regions, where ORF29 Intron is a tissue-specific enhancer. The following promoters: OriLyt-L, PANp, ALTp, and the terminal repeats (TRs) acted as lytically induced enhancers. The expression of the replication and transcription activator (RTA), the master regulator of the lytic cycle, was sufficient to induce the activity of lytic enhancers in uninfected cells. We propose that the TRs that span about 24 kbp region serve as a "viral super-enhancer" that integrates the repressive effect of the latency-associated nuclear antigen (LANA) with the activating effect of RTA. Utilizing CRISPR activation and interference techniques, we determined the connections between these enhancers and their regulated genes. The silencer and enhancers described here provide an additional layer to the complex gene regulation of herpesviruses.IMPORTANCEIn this study, we performed a systematic functional assay to identify cis-regulatory elements within the genome of the oncogenic herpesvirus, Kaposi's sarcoma-associated herpesvirus (KSHV). Similar to other herpesviruses, KSHV presents both latent and lytic phases. Therefore, our assays were performed in uninfected cells, during latent infection, and under lytic conditions. We identified two constitutive enhancers, one of which seems to be a tissue-specific enhancer. In addition, four lytically induced enhancers, which are all responsive to the replication and transcription activator (RTA), were identified. Furthermore, a silencer was identified between the major latency promoter and the lytic gene locus. Utilizing CRISPR activation and interference techniques, we determined the connections between these enhancers and their regulated genes. The terminal repeats, spanning a region of about 24 kbp, seem like a "viral super-enhancer" that integrates the repressive effect of the latency-associated nuclear antigen (LANA) with the activating effect of RTA to regulate latency to lytic transition.
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Affiliation(s)
- Nilabja Roy Chowdhury
- Daniella Lee Casper Laboratory in Viral Oncology, Azrieli Faculty of Medicine, Bar-Ilan University, Safed, Israel
| | - Vyacheslav Gurevich
- Daniella Lee Casper Laboratory in Viral Oncology, Azrieli Faculty of Medicine, Bar-Ilan University, Safed, Israel
| | - Meir Shamay
- Daniella Lee Casper Laboratory in Viral Oncology, Azrieli Faculty of Medicine, Bar-Ilan University, Safed, Israel
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14
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Delihas N. Evolution of a Human-Specific De Novo Open Reading Frame and Its Linked Transcriptional Silencer. Int J Mol Sci 2024; 25:3924. [PMID: 38612733 PMCID: PMC11011693 DOI: 10.3390/ijms25073924] [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: 02/27/2024] [Revised: 03/23/2024] [Accepted: 03/26/2024] [Indexed: 04/14/2024] Open
Abstract
In the human genome, two short open reading frames (ORFs) separated by a transcriptional silencer and a small intervening sequence stem from the gene SMIM45. The two ORFs show different translational characteristics, and they also show divergent patterns of evolutionary development. The studies presented here describe the evolution of the components of SMIM45. One ORF consists of an ultra-conserved 68 amino acid (aa) sequence, whose origins can be traced beyond the evolutionary age of divergence of the elephant shark, ~462 MYA. The silencer also has ancient origins, but it has a complex and divergent pattern of evolutionary formation, as it overlaps both at the 68 aa ORF and the intervening sequence. The other ORF consists of 107 aa. It develops during primate evolution but is found to originate de novo from an ancestral non-coding genomic region with root origins within the Afrothere clade of placental mammals, whose evolutionary age of divergence is ~99 MYA. The formation of the complete 107 aa ORF during primate evolution is outlined, whereby sequence development is found to occur through biased mutations, with disruptive random mutations that also occur but lead to a dead-end. The 107 aa ORF is of particular significance, as there is evidence to suggest it is a protein that may function in human brain development. Its evolutionary formation presents a view of a human-specific ORF and its linked silencer that were predetermined in non-primate ancestral species. The genomic position of the silencer offers interesting possibilities for the regulation of transcription of the 107 aa ORF. A hypothesis is presented with respect to possible spatiotemporal expression of the 107 aa ORF in embryonic tissues.
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Affiliation(s)
- Nicholas Delihas
- Department of Microbiology and Immunology, Renaissance School of Medicine, Stony Brook University, Stony Brook, NY 11794, USA
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15
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Merrill CB, Titos I, Pabon MA, Montgomery AB, Rodan AR, Rothenfluh A. Iterative assay for transposase-accessible chromatin by sequencing to isolate functionally relevant neuronal subtypes. SCIENCE ADVANCES 2024; 10:eadi4393. [PMID: 38536919 PMCID: PMC10971406 DOI: 10.1126/sciadv.adi4393] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Accepted: 02/21/2024] [Indexed: 04/18/2024]
Abstract
The Drosophila brain contains tens of thousands of distinct cell types. Thousands of different transgenic lines reproducibly target specific neuron subsets, yet most still express in several cell types. Furthermore, most lines were developed without a priori knowledge of where the transgenes would be expressed. To aid in the development of cell type-specific tools for neuronal identification and manipulation, we developed an iterative assay for transposase-accessible chromatin (ATAC) approach. Open chromatin regions (OCRs) enriched in neurons, compared to whole bodies, drove transgene expression preferentially in subsets of neurons. A second round of ATAC-seq from these specific neuron subsets revealed additional enriched OCR2s that further restricted transgene expression within the chosen neuron subset. This approach allows for continued refinement of transgene expression, and we used it to identify neurons relevant for sleep behavior. Furthermore, this approach is widely applicable to other cell types and to other organisms.
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Affiliation(s)
- Collin B. Merrill
- Department of Psychiatry, Huntsman Mental Health Institute, University of Utah, Salt Lake City, UT 84108, USA
| | - Iris Titos
- Department of Psychiatry, Huntsman Mental Health Institute, University of Utah, Salt Lake City, UT 84108, USA
| | - Miguel A. Pabon
- Molecular Medicine Program, University of Utah, Salt Lake City, UT 84112, USA
| | | | - Aylin R. Rodan
- Molecular Medicine Program, University of Utah, Salt Lake City, UT 84112, USA
- Division of Nephrology and Hypertension, Department of Internal Medicine, University of Utah, Salt Lake City, UT 84132, USA
- Department of Human Genetics, University of Utah, Salt Lake City, UT 84112, USA
- Medical Service, Veterans Affairs Salt Lake City Health Care System, Salt Lake City, UT, USA
| | - Adrian Rothenfluh
- Department of Psychiatry, Huntsman Mental Health Institute, University of Utah, Salt Lake City, UT 84108, USA
- Molecular Medicine Program, University of Utah, Salt Lake City, UT 84112, USA
- Department of Human Genetics, University of Utah, Salt Lake City, UT 84112, USA
- Department of Neurobiology, University of Utah, Salt Lake City, UT 84112, USA
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16
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Shepherdson JL, Friedman RZ, Zheng Y, Sun C, Oh IY, Granas DM, Cohen BA, Chen S, White MA. Pathogenic variants in CRX have distinct cis-regulatory effects on enhancers and silencers in photoreceptors. Genome Res 2024; 34:243-255. [PMID: 38355306 PMCID: PMC10984388 DOI: 10.1101/gr.278133.123] [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: 05/27/2023] [Accepted: 02/01/2024] [Indexed: 02/16/2024]
Abstract
Dozens of variants in the gene for the homeodomain transcription factor (TF) cone-rod homeobox (CRX) are linked with human blinding diseases that vary in their severity and age of onset. How different variants in this single TF alter its function in ways that lead to a range of phenotypes is unclear. We characterized the effects of human disease-causing variants on CRX cis-regulatory function by deploying massively parallel reporter assays (MPRAs) in mouse retina explants carrying knock-ins of two variants, one in the DNA-binding domain (p.R90W) and the other in the transcriptional effector domain (p.E168d2). The degree of reporter gene dysregulation in these mutant Crx retinas corresponds with their phenotypic severity. The two variants affect similar sets of enhancers, and p.E168d2 has distinct effects on silencers. Cis-regulatory elements (CREs) near cone photoreceptor genes are enriched for silencers that are derepressed in the presence of p.E168d2. Chromatin environments of CRX-bound loci are partially predictive of episomal MPRA activity, and distal elements whose accessibility increases later in retinal development are enriched for CREs with silencer activity. We identified a set of potentially pleiotropic regulatory elements that convert from silencers to enhancers in retinas that lack a functional CRX effector domain. Our findings show that phenotypically distinct variants in different domains of CRX have partially overlapping effects on its cis-regulatory function, leading to misregulation of similar sets of enhancers while having a qualitatively different impact on silencers.
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Affiliation(s)
- James L Shepherdson
- Department of Genetics, Washington University School of Medicine in St. Louis, St. Louis, Missouri 63110, USA
- Edison Family Center for Genome Sciences & Systems Biology, Washington University School of Medicine in St. Louis, St. Louis, Missouri 63110, USA
| | - Ryan Z Friedman
- Department of Genetics, Washington University School of Medicine in St. Louis, St. Louis, Missouri 63110, USA
- Edison Family Center for Genome Sciences & Systems Biology, Washington University School of Medicine in St. Louis, St. Louis, Missouri 63110, USA
| | - Yiqiao Zheng
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine in St. Louis, St. Louis, Missouri 63110, USA
| | - Chi Sun
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine in St. Louis, St. Louis, Missouri 63110, USA
| | - Inez Y Oh
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine in St. Louis, St. Louis, Missouri 63110, USA
| | - David M Granas
- Department of Genetics, Washington University School of Medicine in St. Louis, St. Louis, Missouri 63110, USA
- Edison Family Center for Genome Sciences & Systems Biology, Washington University School of Medicine in St. Louis, St. Louis, Missouri 63110, USA
| | - Barak A Cohen
- Department of Genetics, Washington University School of Medicine in St. Louis, St. Louis, Missouri 63110, USA
- Edison Family Center for Genome Sciences & Systems Biology, Washington University School of Medicine in St. Louis, St. Louis, Missouri 63110, USA
| | - Shiming Chen
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine in St. Louis, St. Louis, Missouri 63110, USA;
- Department of Developmental Biology, Washington University School of Medicine in St. Louis, St. Louis, Missouri 63110, USA
| | - Michael A White
- Department of Genetics, Washington University School of Medicine in St. Louis, St. Louis, Missouri 63110, USA;
- Edison Family Center for Genome Sciences & Systems Biology, Washington University School of Medicine in St. Louis, St. Louis, Missouri 63110, USA
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17
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Ando K, Ou J, Thompson JD, Welsby J, Bangru S, Shen J, Wei X, Diao Y, Poss KD. A screen for regeneration-associated silencer regulatory elements in zebrafish. Dev Cell 2024; 59:676-691.e5. [PMID: 38290519 PMCID: PMC10939760 DOI: 10.1016/j.devcel.2024.01.004] [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: 06/24/2023] [Revised: 11/03/2023] [Accepted: 01/08/2024] [Indexed: 02/01/2024]
Abstract
Regeneration involves gene expression changes explained in part by context-dependent recruitment of transcriptional activators to distal enhancers. Silencers that engage repressive transcriptional complexes are less studied than enhancers and more technically challenging to validate, but they potentially have profound biological importance for regeneration. Here, we identified candidate silencers through a screening process that examined the ability of DNA sequences to limit injury-induced gene expression in larval zebrafish after fin amputation. A short sequence (s1) on chromosome 5 near several genes that reduce expression during adult fin regeneration could suppress promoter activity in stable transgenic lines and diminish nearby gene expression in knockin lines. High-resolution analysis of chromatin organization identified physical associations of s1 with gene promoters occurring preferentially during fin regeneration, and genomic deletion of s1 elevated the expression of these genes after fin amputation. Our study provides methods to identify "tissue regeneration silencer elements" (TRSEs) with the potential to reduce unnecessary or deleterious gene expression during regeneration.
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Affiliation(s)
- Kazunori Ando
- Duke Regeneration Center and Department of Cell Biology, Duke University School of Medicine, Durham, NC 27710, USA
| | - Jianhong Ou
- Duke Regeneration Center and Department of Cell Biology, Duke University School of Medicine, Durham, NC 27710, USA
| | - John D Thompson
- Duke Regeneration Center and Department of Cell Biology, Duke University School of Medicine, Durham, NC 27710, USA
| | - John Welsby
- Duke Regeneration Center and Department of Cell Biology, Duke University School of Medicine, Durham, NC 27710, USA
| | - Sushant Bangru
- Duke Regeneration Center and Department of Cell Biology, Duke University School of Medicine, Durham, NC 27710, USA
| | - Jingwen Shen
- Duke Regeneration Center and Department of Cell Biology, Duke University School of Medicine, Durham, NC 27710, USA
| | - Xiaolin Wei
- Duke Regeneration Center and Department of Cell Biology, Duke University School of Medicine, Durham, NC 27710, USA
| | - Yarui Diao
- Duke Regeneration Center and Department of Cell Biology, Duke University School of Medicine, Durham, NC 27710, USA
| | - Kenneth D Poss
- Duke Regeneration Center and Department of Cell Biology, Duke University School of Medicine, Durham, NC 27710, USA.
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18
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Lim B, Domsch K, Mall M, Lohmann I. Canalizing cell fate by transcriptional repression. Mol Syst Biol 2024; 20:144-161. [PMID: 38302581 PMCID: PMC10912439 DOI: 10.1038/s44320-024-00014-z] [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: 09/19/2023] [Revised: 11/28/2023] [Accepted: 12/15/2023] [Indexed: 02/03/2024] Open
Abstract
Precision in the establishment and maintenance of cellular identities is crucial for the development of multicellular organisms and requires tight regulation of gene expression. While extensive research has focused on understanding cell type-specific gene activation, the complex mechanisms underlying the transcriptional repression of alternative fates are not fully understood. Here, we provide an overview of the repressive mechanisms involved in cell fate regulation. We discuss the molecular machinery responsible for suppressing alternative fates and highlight the crucial role of sequence-specific transcription factors (TFs) in this process. Depletion of these TFs can result in unwanted gene expression and increased cellular plasticity. We suggest that these TFs recruit cell type-specific repressive complexes to their cis-regulatory elements, enabling them to modulate chromatin accessibility in a context-dependent manner. This modulation effectively suppresses master regulators of alternative fate programs and their downstream targets. The modularity and dynamic behavior of these repressive complexes enables a limited number of repressors to canalize and maintain major and minor cell fate decisions at different stages of development.
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Affiliation(s)
- Bryce Lim
- Cell Fate Engineering and Disease Modeling Group, German Cancer Research Center (DKFZ) and DKFZ-ZMBH Alliance, 69120, Heidelberg, Germany
- HITBR Hector Institute for Translational Brain Research gGmbH, 69120, Heidelberg, Germany
- Central Institute of Mental Health, Medical Faculty Mannheim, Heidelberg University, 68159, Mannheim, Germany
| | - Katrin Domsch
- Heidelberg University, Centre for Organismal Studies (COS) Heidelberg, Department of Developmental Biology and Cell Networks - Cluster of Excellence, Heidelberg, Germany
| | - Moritz Mall
- Cell Fate Engineering and Disease Modeling Group, German Cancer Research Center (DKFZ) and DKFZ-ZMBH Alliance, 69120, Heidelberg, Germany.
- HITBR Hector Institute for Translational Brain Research gGmbH, 69120, Heidelberg, Germany.
- Central Institute of Mental Health, Medical Faculty Mannheim, Heidelberg University, 68159, Mannheim, Germany.
| | - Ingrid Lohmann
- Heidelberg University, Centre for Organismal Studies (COS) Heidelberg, Department of Developmental Biology and Cell Networks - Cluster of Excellence, Heidelberg, Germany.
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19
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Tendolkar A, Mazo-Vargas A, Livraghi L, Hanly JJ, Van Horne KC, Gilbert LE, Martin A. Cis-regulatory modes of Ultrabithorax inactivation in butterfly forewings. eLife 2024; 12:RP90846. [PMID: 38261357 PMCID: PMC10945631 DOI: 10.7554/elife.90846] [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] [Indexed: 01/24/2024] Open
Abstract
Hox gene clusters encode transcription factors that drive regional specialization during animal development: for example the Hox factor Ubx is expressed in the insect metathoracic (T3) wing appendages and differentiates them from T2 mesothoracic identities. Hox transcriptional regulation requires silencing activities that prevent spurious activation and regulatory crosstalks in the wrong tissues, but this has seldom been studied in insects other than Drosophila, which shows a derived Hox dislocation into two genomic clusters that disjoined Antennapedia (Antp) and Ultrabithorax (Ubx). Here, we investigated how Ubx is restricted to the hindwing in butterflies, amidst a contiguous Hox cluster. By analysing Hi-C and ATAC-seq data in the butterfly Junonia coenia, we show that a Topologically Associated Domain (TAD) maintains a hindwing-enriched profile of chromatin opening around Ubx. This TAD is bordered by a Boundary Element (BE) that separates it from a region of joined wing activity around the Antp locus. CRISPR mutational perturbation of this BE releases ectopic Ubx expression in forewings, inducing homeotic clones with hindwing identities. Further mutational interrogation of two non-coding RNA encoding regions and one putative cis-regulatory module within the Ubx TAD cause rare homeotic transformations in both directions, indicating the presence of both activating and repressing chromatin features. We also describe a series of spontaneous forewing homeotic phenotypes obtained in Heliconius butterflies, and discuss their possible mutational basis. By leveraging the extensive wing specialization found in butterflies, our initial exploration of Ubx regulation demonstrates the existence of silencing and insulating sequences that prevent its spurious expression in forewings.
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Affiliation(s)
- Amruta Tendolkar
- Department of Biological Sciences, The George Washington UniversityWashington, DCUnited States
| | - Anyi Mazo-Vargas
- Department of Biological Sciences, The George Washington UniversityWashington, DCUnited States
| | - Luca Livraghi
- Department of Biological Sciences, The George Washington UniversityWashington, DCUnited States
| | - Joseph J Hanly
- Department of Biological Sciences, The George Washington UniversityWashington, DCUnited States
- Smithsonian Tropical Research InstitutePanama CityPanama
| | - Kelsey C Van Horne
- Department of Biological Sciences, The George Washington UniversityWashington, DCUnited States
| | - Lawrence E Gilbert
- Department of Integrative Biology, University of Texas – AustinAustinUnited States
| | - Arnaud Martin
- Department of Biological Sciences, The George Washington UniversityWashington, DCUnited States
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20
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Qiu K, Vu D, Wang L, Bookstaver A, Dinh TN, Goldfarb AN, Tenen DG, Trinh BQ. Chromatin structure and 3D architecture define differential functions of PU.1 cis regulatory elements in human blood cell lineages. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.01.573782. [PMID: 38260486 PMCID: PMC10802337 DOI: 10.1101/2024.01.01.573782] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
The precise spatio-temporal expression of the hematopoietic ETS transcription factor PU.1 that determines the hematopoietic cell fates is tightly regulated at the chromatin level. However, it remains elusive as to how chromatin signatures are linked to this dynamic expression pattern of PU.1 across blood cell lineages. Here we performed an unbiased and in-depth analysis of the relationship between human PU.1 expression, the presence of trans-acting factors, and 3D architecture at various cis-regulatory elements (CRE) proximal to the PU.1 locus. We identified multiple novel CREs at the upstream region of the gene following an integrative inspection for conserved DNA elements at the chromatin-accessible regions in primary human blood lineages. We showed that a subset of CREs localize within a 10 kb-wide cluster that exhibits that exhibit molecular features of a myeloid-specific super-enhancer involved in mediating PU.1 autoregulation, including open chromatin, unmethylated DNA, histone enhancer marks, transcription of enhancer RNAs, and occupancy of the PU.1 protein itself. Importantly, we revealed the presence of common 35-kb-wide CTCF-bound insulated neighborhood that contains the CRE cluster, forming the chromatin territory for lineage-specific and CRE-mediated chromatin interactions. These include functional CRE-promoter interactions in myeloid and B cells but not in erythroid and T cells. Our findings also provide mechanistic insights into the interplay between dynamic chromatin structure and 3D architecture in defining certain CREs as enhancers or silencers in chromatin regulation of PU.1 expression. The study lays the groundwork for further examination of PU.1 CREs as well as epigenetic regulation in malignant hematopoiesis.
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21
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Shepherdson JL, Friedman RZ, Zheng Y, Sun C, Oh IY, Granas DM, Cohen BA, Chen S, White MA. Pathogenic variants in Crx have distinct cis-regulatory effects on enhancers and silencers in photoreceptors. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.27.542576. [PMID: 37292699 PMCID: PMC10245955 DOI: 10.1101/2023.05.27.542576] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Dozens of variants in the photoreceptor-specific transcription factor (TF) CRX are linked with human blinding diseases that vary in their severity and age of onset. It is unclear how different variants in this single TF alter its function in ways that lead to a range of phenotypes. We examined the effects of human disease-causing variants on CRX cis-regulatory function by deploying massively parallel reporter assays (MPRAs) in live mouse retinas carrying knock-ins of two variants, one in the DNA binding domain (p.R90W) and the other in the transcriptional effector domain (p.E168d2). The degree of reporter gene dysregulation caused by the variants corresponds with their phenotypic severity. The two variants affect similar sets of enhancers, while p.E168d2 has stronger effects on silencers. Cis-regulatory elements (CREs) near cone photoreceptor genes are enriched for silencers that are de-repressed in the presence of p.E168d2. Chromatin environments of CRX-bound loci were partially predictive of episomal MPRA activity, and silencers were notably enriched among distal elements whose accessibility increases later in retinal development. We identified a set of potentially pleiotropic regulatory elements that convert from silencers to enhancers in retinas that lack a functional CRX effector domain. Our findings show that phenotypically distinct variants in different domains of CRX have partially overlapping effects on its cis-regulatory function, leading to misregulation of similar sets of enhancers, while having a qualitatively different impact on silencers.
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Affiliation(s)
- James L. Shepherdson
- Department of Genetics
- Edison Family Center for Genome Sciences & Systems Biology
| | - Ryan Z. Friedman
- Department of Genetics
- Edison Family Center for Genome Sciences & Systems Biology
| | | | - Chi Sun
- Department of Ophthalmology and Visual Sciences
| | - Inez Y. Oh
- Department of Ophthalmology and Visual Sciences
| | - David M. Granas
- Department of Genetics
- Edison Family Center for Genome Sciences & Systems Biology
| | - Barak A. Cohen
- Department of Genetics
- Edison Family Center for Genome Sciences & Systems Biology
| | - Shiming Chen
- Department of Ophthalmology and Visual Sciences
- Department of Developmental Biology, Washington University School of Medicine in St. Louis, St. Louis, MO 63110
| | - Michael A. White
- Department of Genetics
- Edison Family Center for Genome Sciences & Systems Biology
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22
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Edrei Y, Levy R, Kaye D, Marom A, Radlwimmer B, Hellman A. Methylation-directed regulatory networks determine enhancing and silencing of mutation disease driver genes and explain inter-patient expression variation. Genome Biol 2023; 24:264. [PMID: 38012713 PMCID: PMC10683314 DOI: 10.1186/s13059-023-03094-6] [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: 05/23/2022] [Accepted: 10/23/2023] [Indexed: 11/29/2023] Open
Abstract
BACKGROUND Common diseases manifest differentially between patients, but the genetic origin of this variation remains unclear. To explore possible involvement of gene transcriptional-variation, we produce a DNA methylation-oriented, driver-gene-wide dataset of regulatory elements in human glioblastomas and study their effect on inter-patient gene expression variation. RESULTS In 175 of 177 analyzed gene regulatory domains, transcriptional enhancers and silencers are intermixed. Under experimental conditions, DNA methylation induces enhancers to alter their enhancing effects or convert into silencers, while silencers are affected inversely. High-resolution mapping of the association between DNA methylation and gene expression in intact genomes reveals methylation-related regulatory units (average size = 915.1 base-pairs). Upon increased methylation of these units, their target-genes either increased or decreased in expression. Gene-enhancing and silencing units constitute cis-regulatory networks of genes. Mathematical modeling of the networks highlights indicative methylation sites, which signified the effect of key regulatory units, and add up to make the overall transcriptional effect of the network. Methylation variation in these sites effectively describe inter-patient expression variation and, compared with DNA sequence-alterations, appears as a major contributor of gene-expression variation among glioblastoma patients. CONCLUSIONS We describe complex cis-regulatory networks, which determine gene expression by summing the effects of positive and negative transcriptional inputs. In these networks, DNA methylation induces both enhancing and silencing effects, depending on the context. The revealed mechanism sheds light on the regulatory role of DNA methylation, explains inter-individual gene-expression variation, and opens the way for monitoring the driving forces behind deferential courses of cancer and other diseases.
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Affiliation(s)
- Yifat Edrei
- Department of Developmental Biology and Cancer Research, The Institute for Medical Research Israel-Canada (IMRIC), The Hebrew University-Hadassah Medical School, 9112102, Jerusalem, Israel
| | - Revital Levy
- Department of Developmental Biology and Cancer Research, The Institute for Medical Research Israel-Canada (IMRIC), The Hebrew University-Hadassah Medical School, 9112102, Jerusalem, Israel
| | - Daniel Kaye
- Department of Developmental Biology and Cancer Research, The Institute for Medical Research Israel-Canada (IMRIC), The Hebrew University-Hadassah Medical School, 9112102, Jerusalem, Israel
| | - Anat Marom
- Department of Developmental Biology and Cancer Research, The Institute for Medical Research Israel-Canada (IMRIC), The Hebrew University-Hadassah Medical School, 9112102, Jerusalem, Israel
| | - Bernhard Radlwimmer
- Division of Molecular Genetics, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Asaf Hellman
- Department of Developmental Biology and Cancer Research, The Institute for Medical Research Israel-Canada (IMRIC), The Hebrew University-Hadassah Medical School, 9112102, Jerusalem, Israel.
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23
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Milevskiy MJ, Coughlan HD, Kane SR, Johanson TM, Kordafshari S, Chan WF, Tsai M, Surgenor E, Wilcox S, Allan RS, Chen Y, Lindeman GJ, Smyth GK, Visvader JE. Three-dimensional genome architecture coordinates key regulators of lineage specification in mammary epithelial cells. CELL GENOMICS 2023; 3:100424. [PMID: 38020976 PMCID: PMC10667557 DOI: 10.1016/j.xgen.2023.100424] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Revised: 06/20/2023] [Accepted: 09/20/2023] [Indexed: 12/01/2023]
Abstract
Although lineage-specific genes have been identified in the mammary gland, little is known about the contribution of the 3D genome organization to gene regulation in the epithelium. Here, we describe the chromatin landscape of the three major epithelial subsets through integration of long- and short-range chromatin interactions, accessibility, histone modifications, and gene expression. While basal genes display exquisite lineage specificity via distal enhancers, luminal-specific genes show widespread promoter priming in basal cells. Cell specificity in luminal progenitors is largely mediated through extensive chromatin interactions with super-enhancers in gene-body regions in addition to interactions with polycomb silencer elements. Moreover, lineage-specific transcription factors appear to be controlled through cell-specific chromatin interactivity. Finally, chromatin accessibility rather than interactivity emerged as a defining feature of the activation of quiescent basal stem cells. This work provides a comprehensive resource for understanding the role of higher-order chromatin interactions in cell-fate specification and differentiation in the adult mouse mammary gland.
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Affiliation(s)
- Michael J.G. Milevskiy
- ACRF Cancer Biology and Stem Cells Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC 3052, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, VIC 3010, Australia
| | - Hannah D. Coughlan
- Department of Medical Biology, The University of Melbourne, Parkville, VIC 3010, Australia
- Bioinformatics Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC 3052, Australia
| | - Serena R. Kane
- ACRF Cancer Biology and Stem Cells Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC 3052, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, VIC 3010, Australia
| | - Timothy M. Johanson
- Department of Medical Biology, The University of Melbourne, Parkville, VIC 3010, Australia
- Immunology Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC 3052, Australia
| | - Somayeh Kordafshari
- ACRF Cancer Biology and Stem Cells Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC 3052, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, VIC 3010, Australia
| | - Wing Fuk Chan
- Department of Medical Biology, The University of Melbourne, Parkville, VIC 3010, Australia
- Immunology Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC 3052, Australia
| | - Minhsuang Tsai
- ACRF Cancer Biology and Stem Cells Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC 3052, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, VIC 3010, Australia
| | - Elliot Surgenor
- ACRF Cancer Biology and Stem Cells Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC 3052, Australia
| | - Stephen Wilcox
- Advanced Technology and Biology Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC 3052, Australia
| | - Rhys S. Allan
- Department of Medical Biology, The University of Melbourne, Parkville, VIC 3010, Australia
- Immunology Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC 3052, Australia
| | - Yunshun Chen
- ACRF Cancer Biology and Stem Cells Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC 3052, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, VIC 3010, Australia
- Bioinformatics Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC 3052, Australia
| | - Geoffrey J. Lindeman
- ACRF Cancer Biology and Stem Cells Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC 3052, Australia
- Department of Medicine, Royal Melbourne Hospital, The University of Melbourne, Parkville, VIC 3010, Australia
- Parkville Familial Cancer Centre and Department of Medical Oncology, The Royal Melbourne Hospital and Peter MacCallum Cancer Centre, Parkville, VIC 3050, Australia
| | - Gordon K. Smyth
- Bioinformatics Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC 3052, Australia
- School of Mathematics and Statistics, The University of Melbourne, Parkville, VIC 3010, Australia
| | - Jane E. Visvader
- ACRF Cancer Biology and Stem Cells Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC 3052, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, VIC 3010, Australia
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24
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Mendieta JP, Sangra A, Yan H, Minow MAA, Schmitz RJ. Exploring plant cis-regulatory elements at single-cell resolution: overcoming biological and computational challenges to advance plant research. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2023; 115:1486-1499. [PMID: 37309871 PMCID: PMC10598807 DOI: 10.1111/tpj.16351] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Revised: 06/06/2023] [Accepted: 06/08/2023] [Indexed: 06/14/2023]
Abstract
Cis-regulatory elements (CREs) are important sequences for gene expression and for plant biological processes such as development, evolution, domestication, and stress response. However, studying CREs in plant genomes has been challenging. The totipotent nature of plant cells, coupled with the inability to maintain plant cell types in culture and the inherent technical challenges posed by the cell wall has limited our understanding of how plant cell types acquire and maintain their identities and respond to the environment via CRE usage. Advances in single-cell epigenomics have revolutionized the field of identifying cell-type-specific CREs. These new technologies have the potential to significantly advance our understanding of plant CRE biology, and shed light on how the regulatory genome gives rise to diverse plant phenomena. However, there are significant biological and computational challenges associated with analyzing single-cell epigenomic datasets. In this review, we discuss the historical and foundational underpinnings of plant single-cell research, challenges, and common pitfalls in the analysis of plant single-cell epigenomic data, and highlight biological challenges unique to plants. Additionally, we discuss how the application of single-cell epigenomic data in various contexts stands to transform our understanding of the importance of CREs in plant genomes.
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Affiliation(s)
| | - Ankush Sangra
- Department of Genetics, University of Georgia, Athens, 30602, Georgia, USA
| | - Haidong Yan
- Department of Genetics, University of Georgia, Athens, 30602, Georgia, USA
| | - Mark A A Minow
- Department of Genetics, University of Georgia, Athens, 30602, Georgia, USA
| | - Robert J Schmitz
- Department of Genetics, University of Georgia, Athens, 30602, Georgia, USA
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25
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Friedman RZ, Ramu A, Lichtarge S, Myers CA, Granas DM, Gause M, Corbo JC, Cohen BA, White MA. Active learning of enhancer and silencer regulatory grammar in photoreceptors. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.21.554146. [PMID: 37662358 PMCID: PMC10473580 DOI: 10.1101/2023.08.21.554146] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 09/05/2023]
Abstract
Cis-regulatory elements (CREs) direct gene expression in health and disease, and models that can accurately predict their activities from DNA sequences are crucial for biomedicine. Deep learning represents one emerging strategy to model the regulatory grammar that relates CRE sequence to function. However, these models require training data on a scale that exceeds the number of CREs in the genome. We address this problem using active machine learning to iteratively train models on multiple rounds of synthetic DNA sequences assayed in live mammalian retinas. During each round of training the model actively selects sequence perturbations to assay, thereby efficiently generating informative training data. We iteratively trained a model that predicts the activities of sequences containing binding motifs for the photoreceptor transcription factor Cone-rod homeobox (CRX) using an order of magnitude less training data than current approaches. The model's internal confidence estimates of its predictions are reliable guides for designing sequences with high activity. The model correctly identified critical sequence differences between active and inactive sequences with nearly identical transcription factor binding sites, and revealed order and spacing preferences for combinations of motifs. Our results establish active learning as an effective method to train accurate deep learning models of cis-regulatory function after exhausting naturally occurring training examples in the genome.
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Affiliation(s)
- Ryan Z. Friedman
- The Edison Family Center for Genome Sciences & Systems Biology, Washington University School of Medicine, Saint Louis, MO, 63110
- Department of Genetics, Washington University School of Medicine, Saint Louis, MO, 63110
| | - Avinash Ramu
- The Edison Family Center for Genome Sciences & Systems Biology, Washington University School of Medicine, Saint Louis, MO, 63110
- Department of Genetics, Washington University School of Medicine, Saint Louis, MO, 63110
| | - Sara Lichtarge
- The Edison Family Center for Genome Sciences & Systems Biology, Washington University School of Medicine, Saint Louis, MO, 63110
- Department of Genetics, Washington University School of Medicine, Saint Louis, MO, 63110
| | - Connie A. Myers
- Department of Pathology and Immunology, Washington University School of Medicine, Saint Louis, MO, 63110
| | - David M. Granas
- The Edison Family Center for Genome Sciences & Systems Biology, Washington University School of Medicine, Saint Louis, MO, 63110
- Department of Genetics, Washington University School of Medicine, Saint Louis, MO, 63110
| | - Maria Gause
- Department of Pathology and Immunology, Washington University School of Medicine, Saint Louis, MO, 63110
| | - Joseph C. Corbo
- Department of Pathology and Immunology, Washington University School of Medicine, Saint Louis, MO, 63110
| | - Barak A. Cohen
- The Edison Family Center for Genome Sciences & Systems Biology, Washington University School of Medicine, Saint Louis, MO, 63110
- Department of Genetics, Washington University School of Medicine, Saint Louis, MO, 63110
| | - Michael A. White
- The Edison Family Center for Genome Sciences & Systems Biology, Washington University School of Medicine, Saint Louis, MO, 63110
- Department of Genetics, Washington University School of Medicine, Saint Louis, MO, 63110
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26
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Chan B, Rubinstein M. Theory of chromatin organization maintained by active loop extrusion. Proc Natl Acad Sci U S A 2023; 120:e2222078120. [PMID: 37253009 PMCID: PMC10266055 DOI: 10.1073/pnas.2222078120] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2023] [Accepted: 04/13/2023] [Indexed: 06/01/2023] Open
Abstract
The active loop extrusion hypothesis proposes that chromatin threads through the cohesin protein complex into progressively larger loops until reaching specific boundary elements. We build upon this hypothesis and develop an analytical theory for active loop extrusion which predicts that loop formation probability is a nonmonotonic function of loop length and describes chromatin contact probabilities. We validate our model with Monte Carlo and hybrid Molecular Dynamics-Monte Carlo simulations and demonstrate that our theory recapitulates experimental chromatin conformation capture data. Our results support active loop extrusion as a mechanism for chromatin organization and provide an analytical description of chromatin organization that may be used to specifically modify chromatin contact probabilities.
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Affiliation(s)
- Brian Chan
- Department of Biomedical Engineering, Duke University, Durham, NC27708
| | - Michael Rubinstein
- Department of Biomedical Engineering, Duke University, Durham, NC27708
- Department of Mechanical Engineering and Materials Science, Duke University, Durham, NC27708
- Department of Chemistry, Duke University, Durham, NC27708
- Department of Physics, Duke University, Durham, NC27708
- Institute for Chemical Reaction Design and Discovery (World Premier International Research Center Initiative-ICReDD), Hokkaido University, Sapporo001-0021, Japan
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27
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Stefan K, Barski A. Cis-regulatory atlas of primary human CD4+ T cells. BMC Genomics 2023; 24:253. [PMID: 37170195 PMCID: PMC10173520 DOI: 10.1186/s12864-023-09288-3] [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: 12/30/2022] [Accepted: 03/31/2023] [Indexed: 05/13/2023] Open
Abstract
Cis-regulatory elements (CRE) are critical for coordinating gene expression programs that dictate cell-specific differentiation and homeostasis. Recently developed self-transcribing active regulatory region sequencing (STARR-Seq) has allowed for genome-wide annotation of functional CREs. Despite this, STARR-Seq assays are only employed in cell lines, in part, due to difficulties in delivering reporter constructs. Herein, we implemented and validated a STARR-Seq-based screen in human CD4+ T cells using a non-integrating lentiviral transduction system. Lenti-STARR-Seq is the first example of a genome-wide assay of CRE function in human primary cells, identifying thousands of functional enhancers and negative regulatory elements (NREs) in human CD4+ T cells. We find an unexpected difference in nucleosome organization between enhancers and NRE: enhancers are located between nucleosomes, whereas NRE are occupied by nucleosomes in their endogenous locations. We also describe chromatin modification, eRNA production, and transcription factor binding at both enhancers and NREs. Our findings support the idea of silencer repurposing as enhancers in alternate cell types. Collectively, these data suggest that Lenti-STARR-Seq is a successful approach for CRE screening in primary human cell types, and provides an atlas of functional CREs in human CD4+ T cells.
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Affiliation(s)
- Kurtis Stefan
- Division of Allergy & Immunology, Cincinnati Children's Hospital Medical Center, 3333 Burnet Avenue, MLC 7028, Cincinnati, OH, 45229-3026, USA
- Medical Scientist Training Program (MSTP), University of Cincinnati College of Medicine, Cincinnati, OH, 45267, USA
| | - Artem Barski
- Division of Allergy & Immunology, Cincinnati Children's Hospital Medical Center, 3333 Burnet Avenue, MLC 7028, Cincinnati, OH, 45229-3026, USA.
- Division of Human Genetics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, 45229-3026, USA.
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, 45267, USA.
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28
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Méndez-González ID, Williams TM, Rebeiz M. Changes in locus wide repression underlie the evolution of Drosophila abdominal pigmentation. PLoS Genet 2023; 19:e1010722. [PMID: 37134121 PMCID: PMC10184908 DOI: 10.1371/journal.pgen.1010722] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Revised: 05/15/2023] [Accepted: 03/28/2023] [Indexed: 05/04/2023] Open
Abstract
Changes in gene regulation represent an important path to generate developmental differences affecting anatomical traits. Interspecific divergence in gene expression often results from changes in transcription-stimulating enhancer elements. While gene repression is crucial for precise spatiotemporal expression patterns, the relative contribution of repressive transcriptional silencers to regulatory evolution remains to be addressed. Here, we show that the Drosophila pigmentation gene ebony has mainly evolved through changes in the spatial domains of silencers patterning its abdominal expression. By precisely editing the endogenous ebony locus of D. melanogaster, we demonstrate the requirement of two redundant abdominal enhancers and three silencers that repress the redundant enhancers in a patterned manner. We observe a role for changes in these silencers in every case of ebony evolution observed to date. Our findings suggest that negative regulation by silencers likely has an under-appreciated role in gene regulatory evolution.
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Affiliation(s)
- Iván D Méndez-González
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Thomas M Williams
- Department of Biology, University of Dayton, Dayton, Ohio, United States of America
| | - Mark Rebeiz
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
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29
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Vermunt MW, Luan J, Zhang Z, Thrasher AJ, Huang A, Saari MS, Khandros E, Beagrie RA, Zhang S, Vemulamada P, Brilleman M, Lee K, Yano JA, Giardine BM, Keller CA, Hardison RC, Blobel GA. Gene silencing dynamics are modulated by transiently active regulatory elements. Mol Cell 2023; 83:715-730.e6. [PMID: 36868189 PMCID: PMC10719944 DOI: 10.1016/j.molcel.2023.02.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Revised: 12/05/2022] [Accepted: 02/03/2023] [Indexed: 03/05/2023]
Abstract
Transcriptional enhancers have been extensively characterized, but cis-regulatory elements involved in acute gene repression have received less attention. Transcription factor GATA1 promotes erythroid differentiation by activating and repressing distinct gene sets. Here, we study the mechanism by which GATA1 silences the proliferative gene Kit during murine erythroid cell maturation and define stages from initial loss of activation to heterochromatinization. We find that GATA1 inactivates a potent upstream enhancer but concomitantly creates a discrete intronic regulatory region marked by H3K27ac, short noncoding RNAs, and de novo chromatin looping. This enhancer-like element forms transiently and serves to delay Kit silencing. The element is ultimately erased via the FOG1/NuRD deacetylase complex, as revealed by the study of a disease-associated GATA1 variant. Hence, regulatory sites can be self-limiting by dynamic co-factor usage. Genome-wide analyses across cell types and species uncover transiently active elements at numerous genes during repression, suggesting that modulation of silencing kinetics is widespread.
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Affiliation(s)
- Marit W Vermunt
- Division of Hematology, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA.
| | - Jing Luan
- Medical Scientist Training Program, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Zhe Zhang
- Department of Biomedical and Health Informatics, The Children's Hospital of Pennsylvania, Philadelphia, PA 19104, USA
| | - A Josephine Thrasher
- Division of Hematology, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Anran Huang
- Division of Hematology, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Megan S Saari
- Division of Hematology, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Eugene Khandros
- Division of Hematology, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Robert A Beagrie
- Chromatin and Disease Group, Wellcome Centre for Human Genetics, Oxford OX3 7BN, UK
| | - Shiping Zhang
- Department of Biomedical and Health Informatics, The Children's Hospital of Pennsylvania, Philadelphia, PA 19104, USA
| | - Pranay Vemulamada
- Division of Hematology, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Matilda Brilleman
- Division of Hematology, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Kiwon Lee
- Division of Hematology, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Jennifer A Yano
- Division of Hematology, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Belinda M Giardine
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, PA 16802, USA
| | - Cheryl A Keller
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, PA 16802, USA
| | - Ross C Hardison
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, PA 16802, USA
| | - Gerd A Blobel
- Division of Hematology, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA.
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30
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Mechanisms of Interaction between Enhancers and Promoters in Three Drosophila Model Systems. Int J Mol Sci 2023; 24:ijms24032855. [PMID: 36769179 PMCID: PMC9917889 DOI: 10.3390/ijms24032855] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Revised: 01/26/2023] [Accepted: 01/30/2023] [Indexed: 02/05/2023] Open
Abstract
In higher eukaryotes, the regulation of developmental gene expression is determined by enhancers, which are often located at a large distance from the promoters they regulate. Therefore, the architecture of chromosomes and the mechanisms that determine the functional interaction between enhancers and promoters are of decisive importance in the development of organisms. Mammals and the model animal Drosophila have homologous key architectural proteins and similar mechanisms in the organization of chromosome architecture. This review describes the current progress in understanding the mechanisms of the formation and regulation of long-range interactions between enhancers and promoters at three well-studied key regulatory loci in Drosophila.
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31
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Kim S, Wysocka J. Deciphering the multi-scale, quantitative cis-regulatory code. Mol Cell 2023; 83:373-392. [PMID: 36693380 PMCID: PMC9898153 DOI: 10.1016/j.molcel.2022.12.032] [Citation(s) in RCA: 116] [Impact Index Per Article: 58.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Revised: 12/29/2022] [Accepted: 12/30/2022] [Indexed: 01/24/2023]
Abstract
Uncovering the cis-regulatory code that governs when and how much each gene is transcribed in a given genome and cellular state remains a central goal of biology. Here, we discuss major layers of regulation that influence how transcriptional outputs are encoded by DNA sequence and cellular context. We first discuss how transcription factors bind specific DNA sequences in a dosage-dependent and cooperative manner and then proceed to the cofactors that facilitate transcription factor function and mediate the activity of modular cis-regulatory elements such as enhancers, silencers, and promoters. We then consider the complex and poorly understood interplay of these diverse elements within regulatory landscapes and its relationships with chromatin states and nuclear organization. We propose that a mechanistically informed, quantitative model of transcriptional regulation that integrates these multiple regulatory layers will be the key to ultimately cracking the cis-regulatory code.
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Affiliation(s)
- Seungsoo Kim
- Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, CA 94305, USA; Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA 94305, USA; Department of Developmental Biology, Stanford University School of Medicine, Stanford, CA 94305, USA; Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Joanna Wysocka
- Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, CA 94305, USA; Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA 94305, USA; Department of Developmental Biology, Stanford University School of Medicine, Stanford, CA 94305, USA; Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA.
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32
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Enhancer-promoter entanglement explains their transcriptional interdependence. Proc Natl Acad Sci U S A 2023; 120:e2216436120. [PMID: 36656865 PMCID: PMC9942820 DOI: 10.1073/pnas.2216436120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Enhancers not only activate target promoters to stimulate messenger RNA (mRNA) synthesis, but they themselves also undergo transcription to produce enhancer RNAs (eRNAs), the significance of which is not well understood. Transcription at the participating enhancer-promoter pair appears coordinated, but it is unclear why and how. Here, we employ cell-free transcription assays using constructs derived from the human GREB1 locus to demonstrate that transcription at an enhancer and its target promoter is interdependent. This interdependence is observable under conditions where direct enhancer-promoter contact (EPC) takes place. We demonstrate that transcription activation at a participating enhancer-promoter pair is dependent on i) the mutual availability of the enhancer and promoter, ii) the state of transcription at both the enhancer and promoter, iii) local abundance of both eRNA and mRNA, and iv) direct EPC. Our results suggest transcriptional interdependence between the enhancer and the promoter as the basis of their transcriptional concurrence and coordination throughout the genome. We propose a model where transcriptional concurrence, coordination and interdependence are possible if the participating enhancer and promoter are entangled in the form of EPC, reside in a proteinaceous bubble, and utilize shared transcriptional resources and regulatory inputs.
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33
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Mouri K, Dewey HB, Castro R, Berenzy D, Kales S, Tewhey R. Whole-genome functional characterization of RE1 silencers using a modified massively parallel reporter assay. CELL GENOMICS 2023; 3:100234. [PMID: 36777181 PMCID: PMC9903721 DOI: 10.1016/j.xgen.2022.100234] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Revised: 09/12/2022] [Accepted: 11/23/2022] [Indexed: 12/23/2022]
Abstract
Both upregulation and downregulation by cis-regulatory elements help modulate precise gene expression. However, our understanding of repressive elements is far more limited than activating elements. To address this gap, we characterized RE1, a group of transcriptional silencers bound by REST, at genome-wide scale using a modified massively parallel reporter assay (MPRAduo). MPRAduo empirically defined a minimal binding strength of REST (REST motif-intrinsic value [m-value]), above which cofactors colocalize and silence transcription. We identified 1,500 human variants that alter RE1 silencing and found that their effect sizes are predictable when they overlap with REST-binding sites above the m-value. Additionally, we demonstrate that non-canonical REST-binding motifs exhibit silencer function only if they precisely align half sites with specific spacer lengths. Our results show mechanistic insights into RE1, which allow us to predict its activity and effect of variants on RE1, providing a paradigm for performing genome-wide functional characterization of transcription-factor-binding sites.
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Affiliation(s)
| | | | | | | | - Susan Kales
- The Jackson Laboratory, Bar Harbor, ME 04609, USA
| | - Ryan Tewhey
- The Jackson Laboratory, Bar Harbor, ME 04609, USA
- Graduate School of Biomedical Sciences and Engineering, University of Maine, Orono, ME, USA
- Graduate School of Biomedical Sciences, Tufts University School of Medicine, Boston, MA, USA
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Preissl S, Gaulton KJ, Ren B. Characterizing cis-regulatory elements using single-cell epigenomics. Nat Rev Genet 2023; 24:21-43. [PMID: 35840754 PMCID: PMC9771884 DOI: 10.1038/s41576-022-00509-1] [Citation(s) in RCA: 103] [Impact Index Per Article: 51.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/24/2022] [Indexed: 12/24/2022]
Abstract
Cell type-specific gene expression patterns and dynamics during development or in disease are controlled by cis-regulatory elements (CREs), such as promoters and enhancers. Distinct classes of CREs can be characterized by their epigenomic features, including DNA methylation, chromatin accessibility, combinations of histone modifications and conformation of local chromatin. Tremendous progress has been made in cataloguing CREs in the human genome using bulk transcriptomic and epigenomic methods. However, single-cell epigenomic and multi-omic technologies have the potential to provide deeper insight into cell type-specific gene regulatory programmes as well as into how they change during development, in response to environmental cues and through disease pathogenesis. Here, we highlight recent advances in single-cell epigenomic methods and analytical tools and discuss their readiness for human tissue profiling.
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Affiliation(s)
- Sebastian Preissl
- Center for Epigenomics, University of California San Diego, La Jolla, CA, USA.
- Institute of Experimental and Clinical Pharmacology and Toxicology, Faculty of Medicine, University of Freiburg, Freiburg, Germany.
| | - Kyle J Gaulton
- Department of Paediatrics, Paediatric Diabetes Research Center, University of California San Diego, La Jolla, CA, USA.
| | - Bing Ren
- Center for Epigenomics, University of California San Diego, La Jolla, CA, USA.
- Department of Cellular and Molecular Medicine, University of California San Diego, School of Medicine, La Jolla, CA, USA.
- Ludwig Institute for Cancer Research, La Jolla, CA, USA.
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Lohia R, Fox N, Gillis J. A global high-density chromatin interaction network reveals functional long-range and trans-chromosomal relationships. Genome Biol 2022; 23:238. [PMID: 36352464 PMCID: PMC9647974 DOI: 10.1186/s13059-022-02790-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2022] [Accepted: 10/10/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Chromatin contacts are essential for gene-expression regulation; however, obtaining a high-resolution genome-wide chromatin contact map is still prohibitively expensive owing to large genome sizes and the quadratic scale of pairwise data. Chromosome conformation capture (3C)-based methods such as Hi-C have been extensively used to obtain chromatin contacts. However, since the sparsity of these maps increases with an increase in genomic distance between contacts, long-range or trans-chromatin contacts are especially challenging to sample. RESULTS Here, we create a high-density reference genome-wide chromatin contact map using a meta-analytic approach. We integrate 3600 human, 6700 mouse, and 500 fly Hi-C experiments to create species-specific meta-Hi-C chromatin contact maps with 304 billion, 193 billion, and 19 billion contacts in respective species. We validate that meta-Hi-C contact maps are uniquely powered to capture functional chromatin contacts in both cis and trans. We find that while individual dataset Hi-C networks are largely unable to predict any long-range coexpression (median 0.54 AUC), meta-Hi-C networks perform comparably in both cis and trans (0.65 AUC vs 0.64 AUC). Similarly, for long-range expression quantitative trait loci (eQTL), meta-Hi-C contacts outperform all individual Hi-C experiments, providing an improvement over the conventionally used linear genomic distance-based association. Assessing between species, we find patterns of chromatin contact conservation in both cis and trans and strong associations with coexpression even in species for which Hi-C data is lacking. CONCLUSIONS We have generated an integrated chromatin interaction network which complements a large number of methodological and analytic approaches focused on improved specificity or interpretation. This high-depth "super-experiment" is surprisingly powerful in capturing long-range functional relationships of chromatin interactions, which are now able to predict coexpression, eQTLs, and cross-species relationships. The meta-Hi-C networks are available at https://labshare.cshl.edu/shares/gillislab/resource/HiC/ .
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Affiliation(s)
- Ruchi Lohia
- Stanley Institute for Cognitive Genomics, Cold Spring Harbor Laboratory, Cold Spring Harbor, USA
| | - Nathan Fox
- Stanley Institute for Cognitive Genomics, Cold Spring Harbor Laboratory, Cold Spring Harbor, USA
| | - Jesse Gillis
- Stanley Institute for Cognitive Genomics, Cold Spring Harbor Laboratory, Cold Spring Harbor, USA
- Department of Physiology and Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Canada
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36
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Pang B, van Weerd JH, Hamoen FL, Snyder MP. Identification of non-coding silencer elements and their regulation of gene expression. Nat Rev Mol Cell Biol 2022; 24:383-395. [DOI: 10.1038/s41580-022-00549-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/29/2022] [Indexed: 11/09/2022]
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Xu J, Pratt HE, Moore JE, Gerstein MB, Weng Z. Building integrative functional maps of gene regulation. Hum Mol Genet 2022; 31:R114-R122. [PMID: 36083269 PMCID: PMC9585680 DOI: 10.1093/hmg/ddac195] [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: 07/17/2022] [Revised: 08/03/2022] [Accepted: 08/09/2022] [Indexed: 11/13/2022] Open
Abstract
Every cell in the human body inherits a copy of the same genetic information. The three billion base pairs of DNA in the human genome, and the roughly 50 000 coding and non-coding genes they contain, must thus encode all the complexity of human development and cell and tissue type diversity. Differences in gene regulation, or the modulation of gene expression, enable individual cells to interpret the genome differently to carry out their specific functions. Here we discuss recent and ongoing efforts to build gene regulatory maps, which aim to characterize the regulatory roles of all sequences in a genome. Many researchers and consortia have identified such regulatory elements using functional assays and evolutionary analyses; we discuss the results, strengths and shortcomings of their approaches. We also discuss new techniques the field can leverage and emerging challenges it will face while striving to build gene regulatory maps of ever-increasing resolution and comprehensiveness.
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Affiliation(s)
- Jinrui Xu
- Program in Computational Biology and Bioinformatics, Yale University, New Haven, CT 06520, USA
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA
| | - Henry E Pratt
- Program in Bioinformatics and Integrative Biology, UMass Chan Medical School, Worcester, MA 01605, USA
| | - Jill E Moore
- Program in Bioinformatics and Integrative Biology, UMass Chan Medical School, Worcester, MA 01605, USA
| | - Mark B Gerstein
- Program in Computational Biology and Bioinformatics, Yale University, New Haven, CT 06520, USA
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA
- Department of Computer Science, Yale University, New Haven, CT 06520, USA
- Department of Statistics and Data Science, Yale University, New Haven, CT 06520, USA
| | - Zhiping Weng
- Program in Bioinformatics and Integrative Biology, UMass Chan Medical School, Worcester, MA 01605, USA
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Zheng M, Guo T, Yang B, Zhang Z, Huang L. Origin, evolution, and tissue-specific functions of the porcine repetitive element 1. Genet Sel Evol 2022; 54:54. [PMID: 35896967 PMCID: PMC9327148 DOI: 10.1186/s12711-022-00745-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Accepted: 07/04/2022] [Indexed: 11/17/2022] Open
Abstract
Background The porcine repetitive element 1 (PRE1) is the most abundant short interspersed nuclear element (SINE) in the Sus scrofa genome and it has been suggested that some PRE1 can have regulatory functions. The million copies of PRE1 in the porcine genome have accumulated abundant CpG dinucleotides and unique structural variations, such as direct repeats and patterns of sequence degeneration. The aims of this study were to analyse these structural variations to trace the origin and evolutionary pattern of PRE1 and to investigate potential methylation-related functions of PRE1 based on methylation patterns of PRE1 CpG dinucleotides in different tissues. Results We investigated the evolutionary trajectory of PRE1 and found that PRE1 originated from the ancestral CHRS-S1 family through three main successive partial duplications. We found that the partial duplications and deletions of PRE1 were likely due to RNA splicing events during retrotransposition. Functionally, correlation analysis showed that the methylation levels of 103 and 261 proximal PRE1 were, respectively, negatively and positively correlated with the expression levels of neighboring genes (Spearman correlation, P < 0.01). Further epigenomic analysis revealed that, in the testis, demethylation of proximal PRE1 in the HORMAD1 and HACD3 genes had tissue-specific enhancer and promoter functions, while in the muscle, methylation of proximal PRE1 repeats in the TCEA3 gene had an enhancer function. Conclusions The characteristic sequences of PRE1 reflect unique patterns of origin and evolution and provide a structural basis for diverse regulatory functions. Supplementary Information The online version contains supplementary material available at 10.1186/s12711-022-00745-3.
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Affiliation(s)
- Min Zheng
- State Key Laboratory for Pig Genetic Improvement and Production Technology, Jiangxi Agricultural University, Nanchang, China.
| | - Tianfu Guo
- State Key Laboratory for Pig Genetic Improvement and Production Technology, Jiangxi Agricultural University, Nanchang, China
| | - Bin Yang
- State Key Laboratory for Pig Genetic Improvement and Production Technology, Jiangxi Agricultural University, Nanchang, China
| | - Zhiyan Zhang
- State Key Laboratory for Pig Genetic Improvement and Production Technology, Jiangxi Agricultural University, Nanchang, China.
| | - Lusheng Huang
- State Key Laboratory for Pig Genetic Improvement and Production Technology, Jiangxi Agricultural University, Nanchang, China.
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Keränen SVE, Villahoz-Baleta A, Bruno AE, Halfon MS. REDfly: An Integrated Knowledgebase for Insect Regulatory Genomics. INSECTS 2022; 13:618. [PMID: 35886794 PMCID: PMC9323752 DOI: 10.3390/insects13070618] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/16/2022] [Revised: 07/01/2022] [Accepted: 07/06/2022] [Indexed: 11/29/2022]
Abstract
We provide here an updated description of the REDfly (Regulatory Element Database for Fly) database of transcriptional regulatory elements, a unique resource that provides regulatory annotation for the genome of Drosophila and other insects. The genomic sequences regulating insect gene expression-transcriptional cis-regulatory modules (CRMs, e.g., "enhancers") and transcription factor binding sites (TFBSs)-are not currently curated by any other major database resources. However, knowledge of such sequences is important, as CRMs play critical roles with respect to disease as well as normal development, phenotypic variation, and evolution. Characterized CRMs also provide useful tools for both basic and applied research, including developing methods for insect control. REDfly, which is the most detailed existing platform for metazoan regulatory-element annotation, includes over 40,000 experimentally verified CRMs and TFBSs along with their DNA sequences, their associated genes, and the expression patterns they direct. Here, we briefly describe REDfly's contents and data model, with an emphasis on the new features implemented since 2020. We then provide an illustrated walk-through of several common REDfly search use cases.
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Affiliation(s)
| | - Angel Villahoz-Baleta
- Center for Computational Research, State University of New York at Buffalo, Buffalo, NY 14203, USA; (A.V.-B.); (A.E.B.)
- New York State Center of Excellence in Bioinformatics and Life Sciences, State University of New York at Buffalo, Buffalo, NY 14203, USA
| | - Andrew E. Bruno
- Center for Computational Research, State University of New York at Buffalo, Buffalo, NY 14203, USA; (A.V.-B.); (A.E.B.)
- New York State Center of Excellence in Bioinformatics and Life Sciences, State University of New York at Buffalo, Buffalo, NY 14203, USA
| | - Marc S. Halfon
- New York State Center of Excellence in Bioinformatics and Life Sciences, State University of New York at Buffalo, Buffalo, NY 14203, USA
- Department of Biochemistry, State University of New York at Buffalo, Buffalo, NY 14203, USA
- Department of Biomedical Informatics, State University of New York at Buffalo, Buffalo, NY 14203, USA
- Department of Biological Sciences, State University of New York at Buffalo, Buffalo, NY 14203, USA
- Department of Molecular and Cellular Biology and Program in Cancer Genetics, Roswell Park Cancer Institute, Buffalo, NY 14263, USA
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Boldyreva LV, Andreyeva EN, Pindyurin AV. Position Effect Variegation: Role of the Local Chromatin Context in Gene Expression Regulation. Mol Biol 2022. [DOI: 10.1134/s0026893322030049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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41
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Interplay between regulatory elements and chromatin topology in cellular lineage determination. Trends Genet 2022; 38:1048-1061. [DOI: 10.1016/j.tig.2022.05.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Revised: 05/02/2022] [Accepted: 05/12/2022] [Indexed: 11/16/2022]
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Sun DA, Bredeson JV, Bruce HS, Patel NH. Identification and classification of cis-regulatory elements in the amphipod crustacean Parhyale hawaiensis. Development 2022; 149:275484. [PMID: 35608283 DOI: 10.1242/dev.200793] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Accepted: 04/21/2022] [Indexed: 12/13/2022]
Abstract
Emerging research organisms enable the study of biology that cannot be addressed using classical 'model' organisms. New data resources can accelerate research in such animals. Here, we present new functional genomic resources for the amphipod crustacean Parhyale hawaiensis, facilitating the exploration of gene regulatory evolution using this emerging research organism. We use Omni-ATAC-seq to identify accessible chromatin genome-wide across a broad time course of Parhyale embryonic development. This time course encompasses many major morphological events, including segmentation, body regionalization, gut morphogenesis and limb development. In addition, we use short- and long-read RNA-seq to generate an improved Parhyale genome annotation, enabling deeper classification of identified regulatory elements. We discover differential accessibility, predict nucleosome positioning, infer transcription factor binding, cluster peaks based on accessibility dynamics, classify biological functions and correlate gene expression with accessibility. Using a Minos transposase reporter system, we demonstrate the potential to identify novel regulatory elements using this approach. This work provides a platform for the identification of novel developmental regulatory elements in Parhyale, and offers a framework for performing such experiments in other emerging research organisms.
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Affiliation(s)
- Dennis A Sun
- Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720, USA
| | - Jessen V Bredeson
- Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720, USA
| | | | - Nipam H Patel
- Marine Biological Laboratory, Woods Hole, MA 02543, USA.,Department of Organismal Biology and Anatomy, University of Chicago, Chicago, IL 60637, USA
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Mulero Hernández J, Fernández-Breis JT. Analysis of the landscape of human enhancer sequences in biological databases. Comput Struct Biotechnol J 2022; 20:2728-2744. [PMID: 35685360 PMCID: PMC9168495 DOI: 10.1016/j.csbj.2022.05.045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Revised: 05/20/2022] [Accepted: 05/21/2022] [Indexed: 12/01/2022] Open
Abstract
The process of gene regulation extends as a network in which both genetic sequences and proteins are involved. The levels of regulation and the mechanisms involved are multiple. Transcription is the main control mechanism for most genes, being the downstream steps responsible for refining the transcription patterns. In turn, gene transcription is mainly controlled by regulatory events that occur at promoters and enhancers. Several studies are focused on analyzing the contribution of enhancers in the development of diseases and their possible use as therapeutic targets. The study of regulatory elements has advanced rapidly in recent years with the development and use of next generation sequencing techniques. All this information has generated a large volume of information that has been transferred to a growing number of public repositories that store this information. In this article, we analyze the content of those public repositories that contain information about human enhancers with the aim of detecting whether the knowledge generated by scientific research is contained in those databases in a way that could be computationally exploited. The analysis will be based on three main aspects identified in the literature: types of enhancers, type of evidence about the enhancers, and methods for detecting enhancer-promoter interactions. Our results show that no single database facilitates the optimal exploitation of enhancer data, most types of enhancers are not represented in the databases and there is need for a standardized model for enhancers. We have identified major gaps and challenges for the computational exploitation of enhancer data.
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Affiliation(s)
- Juan Mulero Hernández
- Dept. Informática y Sistemas, Universidad de Murcia, CEIR Campus Mare Nostrum, IMIB-Arrixaca, Spain
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44
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Merrill CB, Montgomery AB, Pabon MA, Shabalin AA, Rodan AR, Rothenfluh A. Harnessing changes in open chromatin determined by ATAC-seq to generate insulin-responsive reporter constructs. BMC Genomics 2022; 23:399. [PMID: 35614386 PMCID: PMC9134605 DOI: 10.1186/s12864-022-08637-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2021] [Accepted: 05/12/2022] [Indexed: 01/07/2023] Open
Abstract
BACKGROUND Gene regulation is critical for proper cellular function. Next-generation sequencing technology has revealed the presence of regulatory networks that regulate gene expression and essential cellular functions. Studies investigating the epigenome have begun to uncover the complex mechanisms regulating transcription. Assay for transposase-accessible chromatin by sequencing (ATAC-seq) is quickly becoming the assay of choice for many epigenomic investigations. However, whether intervention-mediated changes in accessible chromatin determined by ATAC-seq can be harnessed to generate intervention-inducible reporter constructs has not been systematically assayed. RESULTS We used the insulin signaling pathway as a model to investigate chromatin regions and gene expression changes using ATAC- and RNA-seq in insulin-treated Drosophila S2 cells. We found correlations between ATAC- and RNA-seq data, especially when stratifying differentially-accessible chromatin regions by annotated feature type. In particular, our data demonstrated a weak but significant correlation between chromatin regions annotated to enhancers (1-2 kb from the transcription start site) and downstream gene expression. We cloned candidate enhancer regions upstream of luciferase and demonstrate insulin-inducibility of several of these reporters. CONCLUSIONS Insulin-induced chromatin accessibility determined by ATAC-seq reveals enhancer regions that drive insulin-inducible reporter gene expression.
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Affiliation(s)
- Collin B Merrill
- Department of Psychiatry, Huntsman Mental Health Institute, University of Utah, Salt Lake City, UT, 84108, USA.
| | - Austin B Montgomery
- Molecular Medicine Program, University of Utah, Salt Lake City, UT, 84112, USA
| | - Miguel A Pabon
- Molecular Medicine Program, University of Utah, Salt Lake City, UT, 84112, USA
| | - Andrey A Shabalin
- Department of Psychiatry, Huntsman Mental Health Institute, University of Utah, Salt Lake City, UT, 84108, USA
| | - Aylin R Rodan
- Molecular Medicine Program, University of Utah, Salt Lake City, UT, 84112, USA
- Division of Nephrology, Department of Internal Medicine, University of Utah, Salt Lake City, UT, 84112, USA
- Department of Human Genetics, University of Utah, Salt Lake City, UT, 84112, USA
| | - Adrian Rothenfluh
- Department of Psychiatry, Huntsman Mental Health Institute, University of Utah, Salt Lake City, UT, 84108, USA.
- Molecular Medicine Program, University of Utah, Salt Lake City, UT, 84112, USA.
- Department of Human Genetics, University of Utah, Salt Lake City, UT, 84112, USA.
- Department of Neurobiology, University of Utah, Salt Lake City, UT, 84112, USA.
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Long-Distance Repression by Human Silencers: Chromatin Interactions and Phase Separation in Silencers. Cells 2022; 11:cells11091560. [PMID: 35563864 PMCID: PMC9101175 DOI: 10.3390/cells11091560] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Revised: 05/01/2022] [Accepted: 05/02/2022] [Indexed: 12/12/2022] Open
Abstract
Three-dimensional genome organization represents an additional layer in the epigenetic regulation of gene expression. Active transcription controlled by enhancers or super-enhancers has been extensively studied. Enhancers or super-enhancers can recruit activators or co-activators to activate target gene expression through long-range chromatin interactions. Chromatin interactions and phase separation play important roles in terms of enhancer or super-enhancer functioning. Silencers are another major type of cis-regulatory element that can mediate gene regulation by turning off or reducing gene expression. However, compared to active transcription, silencer studies are still in their infancy. This review covers the current knowledge of human silencers, especially the roles of chromatin interactions and phase separation in silencers. This review also proposes future directions for human silencer studies.
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Martinez-Ara M, Comoglio F, van Arensbergen J, van Steensel B. Systematic analysis of intrinsic enhancer-promoter compatibility in the mouse genome. Mol Cell 2022; 82:2519-2531.e6. [PMID: 35594855 PMCID: PMC9278412 DOI: 10.1016/j.molcel.2022.04.009] [Citation(s) in RCA: 58] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Revised: 02/17/2022] [Accepted: 04/05/2022] [Indexed: 12/12/2022]
Affiliation(s)
- Miguel Martinez-Ara
- Division of Gene Regulation and Oncode Institute, Netherlands Cancer Institute, 1066 CX Amsterdam, the Netherlands
| | - Federico Comoglio
- Division of Gene Regulation and Oncode Institute, Netherlands Cancer Institute, 1066 CX Amsterdam, the Netherlands
| | - Joris van Arensbergen
- Division of Gene Regulation and Oncode Institute, Netherlands Cancer Institute, 1066 CX Amsterdam, the Netherlands
| | - Bas van Steensel
- Division of Gene Regulation and Oncode Institute, Netherlands Cancer Institute, 1066 CX Amsterdam, the Netherlands.
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Boyling A, Perez-Siles G, Kennerson ML. Structural Variation at a Disease Mutation Hotspot: Strategies to Investigate Gene Regulation and the 3D Genome. Front Genet 2022; 13:842860. [PMID: 35401663 PMCID: PMC8990796 DOI: 10.3389/fgene.2022.842860] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2021] [Accepted: 02/21/2022] [Indexed: 12/18/2022] Open
Abstract
A rare form of X-linked Charcot-Marie-Tooth neuropathy, CMTX3, is caused by an interchromosomal insertion occurring at chromosome Xq27.1. Interestingly, eight other disease phenotypes have been associated with insertions (or insertion-deletions) occurring at the same genetic locus. To date, the pathogenic mechanism underlying most of these diseases remains unsolved, although local gene dysregulation has clearly been implicated in at least two phenotypes. The challenges of accessing disease-relevant tissue and modelling these complex genomic rearrangements has led to this research impasse. We argue that recent technological advancements can overcome many of these challenges, particularly induced pluripotent stem cells (iPSC) and their capacity to provide access to patient-derived disease-relevant tissue. However, to date these valuable tools have not been utilized to investigate the disease-associated insertions at chromosome Xq27.1. Therefore, using CMTX3 as a reference disease, we propose an experimental approach that can be used to explore these complex mutations, as well as similar structural variants located elsewhere in the genome. The mutational hotspot at Xq27.1 is a valuable disease paradigm with the potential to improve our understanding of the pathogenic consequences of complex structural variation, and more broadly, refine our knowledge of the multifaceted process of long-range gene regulation. Intergenic structural variation is a critically understudied class of mutation, although it is likely to contribute significantly to unsolved genetic disease.
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Affiliation(s)
- Alexandra Boyling
- Northcott Neuroscience Laboratory, ANZAC Research Institute, Sydney, NSW, Australia
- Sydney Medical School, University of Sydney, Sydney, NSW, Australia
- *Correspondence: Alexandra Boyling, ; Marina L. Kennerson,
| | - Gonzalo Perez-Siles
- Northcott Neuroscience Laboratory, ANZAC Research Institute, Sydney, NSW, Australia
- Sydney Medical School, University of Sydney, Sydney, NSW, Australia
| | - Marina L. Kennerson
- Northcott Neuroscience Laboratory, ANZAC Research Institute, Sydney, NSW, Australia
- Sydney Medical School, University of Sydney, Sydney, NSW, Australia
- Molecular Medicine Laboratory, Concord Repatriation General Hospital, Sydney, NSW, Australia
- *Correspondence: Alexandra Boyling, ; Marina L. Kennerson,
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Akiyama N, Sato S, Tanaka KM, Sakai T, Takahashi A. The role of the epidermis enhancer element in positive and negative transcriptional regulation of ebony in Drosophila melanogaster. G3 (BETHESDA, MD.) 2022; 12:jkac010. [PMID: 35100378 PMCID: PMC8895987 DOI: 10.1093/g3journal/jkac010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Accepted: 01/06/2022] [Indexed: 11/15/2022]
Abstract
The spatiotemporal regulation of gene expression is essential to ensure robust phenotypic outcomes. Pigmentation patterns in Drosophila are determined by pigments biosynthesized in the developing epidermis and the cis-regulatory elements of the genes involved in this process are well-characterized. Here, we report that the known primary epidermal enhancer is dispensable for the transcriptional activation of ebony (involved in light-colored pigment synthesis) in the developing epidermis of Drosophila melanogaster. The evidence was obtained by introducing an approximately 1 kbp deletion at the primary epidermal enhancer by genome editing. The effect of the primary epidermal enhancer deletion on pigmentation and on the endogenous expression pattern of a mCherry-fused ebony allele was examined in the abdomen. The expression levels of the mCherry-fused ebony in the primary epidermal enhancer-deleted strains were slightly higher than that of the control strain, indicating that the sequences outside the primary epidermal enhancer have an ability to drive an expression of this gene in the epidermis. Interestingly, the primary epidermal enhancer deletion resulted in a derepression of this gene in the dorsal midline of the abdominal tergites, where dark pigmentation is present in the wild-type individuals. This indicated that the primary epidermal enhancer fragment contains a silencer. Furthermore, the endogenous expression pattern of ebony in the 2 additional strains with partially deleted primary epidermal enhancer revealed that the silencer resides within a 351-bp fragment in the 5' portion of the primary epidermal enhancer. These results demonstrated that deletion assays combined with reporter assays are highly effective in detecting the presence of positively and negatively regulating sequences within and outside the focal cis-regulatory elements.
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Affiliation(s)
- Noriyoshi Akiyama
- Department of Biological Sciences, Tokyo Metropolitan University, Hachioji 192-0397, Japan
| | - Shoma Sato
- Department of Biological Sciences, Tokyo Metropolitan University, Hachioji 192-0397, Japan
| | - Kentaro M Tanaka
- Department of Biological Sciences, Tokyo Metropolitan University, Hachioji 192-0397, Japan
| | - Takaomi Sakai
- Department of Biological Sciences, Tokyo Metropolitan University, Hachioji 192-0397, Japan
| | - Aya Takahashi
- Department of Biological Sciences, Tokyo Metropolitan University, Hachioji 192-0397, Japan
- Research Center for Genomics and Bioinformatics, Tokyo Metropolitan University, Hachioji 192-0397, Japan
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Luecke D, Rice G, Kopp A. Sex-specific evolution of a Drosophila sensory system via interacting cis- and trans-regulatory changes. Evol Dev 2022; 24:37-60. [PMID: 35239254 PMCID: PMC9179014 DOI: 10.1111/ede.12398] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Revised: 01/20/2022] [Accepted: 01/25/2022] [Indexed: 12/13/2022]
Abstract
The evolution of gene expression via cis-regulatory changes is well established as a major driver of phenotypic evolution. However, relatively little is known about the influence of enhancer architecture and intergenic interactions on regulatory evolution. We address this question by examining chemosensory system evolution in Drosophila. Drosophila prolongata males show a massively increased number of chemosensory bristles compared to females and males of sibling species. This increase is driven by sex-specific transformation of ancestrally mechanosensory organs. Consistent with this phenotype, the Pox neuro transcription factor (Poxn), which specifies chemosensory bristle identity, shows expanded expression in D. prolongata males. Poxn expression is controlled by nonadditive interactions among widely dispersed enhancers. Although some D. prolongata Poxn enhancers show increased activity, the additive component of this increase is slight, suggesting that most changes in Poxn expression are due to epistatic interactions between Poxn enhancers and trans-regulatory factors. Indeed, the expansion of D. prolongata Poxn enhancer activity is only observed in cells that express doublesex (dsx), the gene that controls sexual differentiation in Drosophila and also shows increased expression in D. prolongata males due to cis-regulatory changes. Although expanded dsx expression may contribute to increased activity of D. prolongata Poxn enhancers, this interaction is not sufficient to explain the full expansion of Poxn expression, suggesting that cis-trans interactions between Poxn, dsx, and additional unknown genes are necessary to produce the derived D. prolongata phenotype. Overall, our results demonstrate the importance of epistatic gene interactions for evolution, particularly when pivotal genes have complex regulatory architecture.
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Affiliation(s)
- David Luecke
- Department of Evolution and Ecology, University of California – Davis,Current Address: Department of Integrative Biology, Michigan State University
| | - Gavin Rice
- Department of Evolution and Ecology, University of California – Davis,Current Address: Department of Biological Sciences, University of Pittsburgh
| | - Artyom Kopp
- Department of Evolution and Ecology, University of California – Davis
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Galouzis CC, Furlong EEM. Regulating specificity in enhancer-promoter communication. Curr Opin Cell Biol 2022; 75:102065. [PMID: 35240372 DOI: 10.1016/j.ceb.2022.01.010] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Revised: 01/23/2022] [Accepted: 01/25/2022] [Indexed: 12/14/2022]
Abstract
Enhancers are cis-regulatory elements that can activate transcription remotely to regulate a specific pattern of a gene's expression. Genes typically have many enhancers that are often intermingled in the loci of other genes. To regulate expression, enhancers must therefore activate their correct promoter while ignoring others that may be in closer linear proximity. In this review, we discuss mechanisms by which enhancers engage with promoters, including recent findings on the role of cohesin and the Mediator complex, and how this specificity in enhancer-promoter communication is encoded. Genetic dissection of model loci, in addition to more recent findings using genome-wide approaches, highlight the core promoter sequence, its accessibility, cofactor-promoter preference, in addition to the surrounding genomic context, as key components.
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Affiliation(s)
| | - Eileen E M Furlong
- European Molecular Biology Laboratory (EMBL), Genome Biology Unit, D-69117, Heidelberg, Germany.
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