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Ryan GE, Farley EK. Functional genomic approaches to elucidate the role of enhancers during development. WILEY INTERDISCIPLINARY REVIEWS. SYSTEMS BIOLOGY AND MEDICINE 2020; 12:e1467. [PMID: 31808313 PMCID: PMC7027484 DOI: 10.1002/wsbm.1467] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Revised: 10/02/2019] [Accepted: 10/11/2019] [Indexed: 12/22/2022]
Abstract
Successful development depends on the precise tissue-specific regulation of genes by enhancers, genetic elements that act as switches to control when and where genes are expressed. Because enhancers are critical for development, and the majority of disease-associated mutations reside within enhancers, it is essential to understand which sequences within enhancers are important for function. Advances in sequencing technology have enabled the rapid generation of genomic data that predict putative active enhancers, but functionally validating these sequences at scale remains a fundamental challenge. Herein, we discuss the power of genome-wide strategies used to identify candidate enhancers, and also highlight limitations and misconceptions that have arisen from these data. We discuss the use of massively parallel reporter assays to test enhancers for function at scale. We also review recent advances in our ability to study gene regulation during development, including CRISPR-based tools to manipulate genomes and single-cell transcriptomics to finely map gene expression. Finally, we look ahead to a synthesis of complementary genomic approaches that will advance our understanding of enhancer function during development. This article is categorized under: Physiology > Mammalian Physiology in Health and Disease Developmental Biology > Developmental Processes in Health and Disease Laboratory Methods and Technologies > Genetic/Genomic Methods.
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Affiliation(s)
- Genevieve E. Ryan
- Department of MedicineUniversity of CaliforniaSan DiegoCalifornia
- Division of Biological Sciences, Department of MedicineUniversity of CaliforniaSan DiegoCalifornia
| | - Emma K. Farley
- Department of MedicineUniversity of CaliforniaSan DiegoCalifornia
- Division of Biological Sciences, Department of MedicineUniversity of CaliforniaSan DiegoCalifornia
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102
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Di Gregorio A. The notochord gene regulatory network in chordate evolution: Conservation and divergence from Ciona to vertebrates. Curr Top Dev Biol 2020; 139:325-374. [PMID: 32450965 DOI: 10.1016/bs.ctdb.2020.01.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The notochord is a structure required for support and patterning of all chordate embryos, from sea squirts to humans. An increasing amount of information on notochord development and on the molecular strategies that ensure its proper morphogenesis has been gleaned through studies in the sea squirt Ciona. This invertebrate chordate offers a fortunate combination of experimental advantages, ranging from translucent, fast-developing embryos to a compact genome and impressive biomolecular resources. These assets have enabled the rapid identification of numerous notochord genes and cis-regulatory regions, and provide a rather unique opportunity to reconstruct the gene regulatory network that controls the formation of this developmental and evolutionary chordate landmark. This chapter summarizes the morphogenetic milestones that punctuate notochord formation in Ciona, their molecular effectors, and the current knowledge of the gene regulatory network that ensures the accurate spatial and temporal orchestration of these processes.
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Affiliation(s)
- Anna Di Gregorio
- Department of Basic Science and Craniofacial Biology, New York University College of Dentistry, New York, NY, United States.
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103
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Korkmaz G, Manber Z, Lopes R, Prekovic S, Schuurman K, Kim Y, Teunissen H, Flach K, Wit ED, Galli GG, Zwart W, Elkon R, Agami R. A CRISPR-Cas9 screen identifies essential CTCF anchor sites for estrogen receptor-driven breast cancer cell proliferation. Nucleic Acids Res 2019; 47:9557-9572. [PMID: 31372638 PMCID: PMC6765117 DOI: 10.1093/nar/gkz675] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Revised: 07/11/2019] [Accepted: 07/24/2019] [Indexed: 01/07/2023] Open
Abstract
Estrogen receptor α (ERα) is an enhancer activating transcription factor, a key driver of breast cancer and a main target for cancer therapy. ERα-mediated gene regulation requires proper chromatin-conformation to facilitate interactions between ERα-bound enhancers and their target promoters. A major determinant of chromatin structure is the CCCTC-binding factor (CTCF), that dimerizes and together with cohesin stabilizes chromatin loops and forms the boundaries of topologically associated domains. However, whether CTCF-binding elements (CBEs) are essential for ERα-driven cell proliferation is unknown. To address this question in a global manner, we implemented a CRISPR-based functional genetic screen targeting CBEs located in the vicinity of ERα-bound enhancers. We identified four functional CBEs and demonstrated the role of one of them in inducing chromatin conformation changes in favor of activation of PREX1, a key ERα target gene in breast cancer. Indeed, high PREX1 expression is a bona-fide marker of ERα-dependency in cell lines, and is associated with good outcome after anti-hormonal treatment. Altogether, our data show that distinct CTCF-mediated chromatin structures are required for ERα- driven breast cancer cell proliferation.
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Affiliation(s)
- Gozde Korkmaz
- Division of Oncogenomics, Oncode Institute, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, The Netherlands
| | - Zohar Manber
- Department of Human Genetics, Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
| | - Rui Lopes
- Division of Oncogenomics, Oncode Institute, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, The Netherlands
| | - Stefan Prekovic
- Division of Oncogenomics, Oncode Institute, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, The Netherlands
| | - Karianne Schuurman
- Division of Oncogenomics, Oncode Institute, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, The Netherlands
| | - Yongsoo Kim
- Division of Oncogenomics, Oncode Institute, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, The Netherlands
| | - Hans Teunissen
- Division of Gene Regulation, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, The Netherlands
| | - Koen Flach
- Division of Gene Regulation, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, The Netherlands
| | - Elzo de Wit
- Division of Gene Regulation, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, The Netherlands
| | - Giorgio G Galli
- Disease area Oncology, Novartis Institute for Biomedical Research, CH-4002 Basel, Switzerland
| | - Wilbert Zwart
- Division of Oncogenomics, Oncode Institute, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, The Netherlands.,Laboratory of Chemical Biology and Institute for Complex Molecular Systems, Department of Biomedical Engineering, Eindhoven University of Technology, PO Box 513, 5600MB, Eindhoven, The Netherlands
| | - Ran Elkon
- Department of Human Genetics, Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
| | - Reuven Agami
- Division of Oncogenomics, Oncode Institute, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, The Netherlands.,Erasmus MC, Rotterdam University, Doctor Molewaterplein 40, 3015 GD Rotterdam, The Netherlands
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104
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Xie S, Armendariz D, Zhou P, Duan J, Hon GC. Global Analysis of Enhancer Targets Reveals Convergent Enhancer-Driven Regulatory Modules. Cell Rep 2019; 29:2570-2578.e5. [PMID: 31775028 PMCID: PMC6904118 DOI: 10.1016/j.celrep.2019.10.073] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Revised: 09/15/2019] [Accepted: 10/17/2019] [Indexed: 12/30/2022] Open
Abstract
Single-cell screens enable high-throughput functional assessment of enhancers in their endogenous genomic context. However, the design of current studies limits their application to identifying the primary gene targets of enhancers. Here, we improve the experimental and computational parameters of single-cell enhancer screens to identify the secondary gene targets of enhancers. Our analysis of >500 putative enhancers in K562 cells reveals an interwoven enhancer-driven gene regulatory network. We find that enhancers from distinct genomic loci converge to modulate the expression of common sub-modules, including the α- and β-globin loci, by directly regulating transcription factors. Our analysis suggests that several genetic variants associated with myeloid blood cell traits alter the activity of a distal enhancer of MYB (~140 kb away), with downstream consequences on hemoglobin genes expression and cell state. These data have implications for the understanding of enhancer-associated traits and emphasize the flexibility of controlling transcriptional systems by modifying enhancer activity. Xie et al. apply improved strategies for single-cell screens to identify an enhancer-driven transcriptional regulatory network in K562 cells. They demonstrate that the same group of genes can be indirectly regulated by enhancers from distinct genomic loci. These data have implications for the understanding of enhancer-associated traits.
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Affiliation(s)
- Shiqi Xie
- Cecil H. and Ida Green Center for Reproductive Biology Sciences, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; Department of Obstetrics and Gynecology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; Lyda Hill Department of Bioinformatics, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Daniel Armendariz
- Cecil H. and Ida Green Center for Reproductive Biology Sciences, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; Department of Obstetrics and Gynecology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; Lyda Hill Department of Bioinformatics, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Pei Zhou
- Cecil H. and Ida Green Center for Reproductive Biology Sciences, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; Department of Obstetrics and Gynecology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; Lyda Hill Department of Bioinformatics, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Jialei Duan
- Cecil H. and Ida Green Center for Reproductive Biology Sciences, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; Department of Obstetrics and Gynecology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; Lyda Hill Department of Bioinformatics, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Gary C Hon
- Cecil H. and Ida Green Center for Reproductive Biology Sciences, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; Department of Obstetrics and Gynecology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; Lyda Hill Department of Bioinformatics, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
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105
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Rice G, Rebeiz M. Evolution: How Many Phenotypes Do Regulatory Mutations Affect? Curr Biol 2019; 29:R21-R23. [PMID: 30620910 DOI: 10.1016/j.cub.2018.11.027] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Mutations in gene regulatory regions are thought to play an important role in the evolution of morphological structures. This is largely due to their minimal pleiotropic effects, limiting their impact to one particular body part. A recent study finds that one such regulatory mutation may affect two particular morphological structures.
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Affiliation(s)
- Gavin Rice
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - Mark Rebeiz
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, USA.
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106
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Ordoñez R, Martínez-Calle N, Agirre X, Prosper F. DNA Methylation of Enhancer Elements in Myeloid Neoplasms: Think Outside the Promoters? Cancers (Basel) 2019; 11:cancers11101424. [PMID: 31554341 PMCID: PMC6827153 DOI: 10.3390/cancers11101424] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Revised: 09/15/2019] [Accepted: 09/18/2019] [Indexed: 12/19/2022] Open
Abstract
Gene regulation through DNA methylation is a well described phenomenon that has a prominent role in physiological and pathological cell-states. This epigenetic modification is usually grouped in regions denominated CpG islands, which frequently co-localize with gene promoters, silencing the transcription of those genes. Recent genome-wide DNA methylation studies have challenged this paradigm, demonstrating that DNA methylation of regulatory regions outside promoters is able to influence cell-type specific gene expression programs under physiologic or pathologic conditions. Coupling genome-wide DNA methylation assays with histone mark annotation has allowed for the identification of specific epigenomic changes that affect enhancer regulatory regions, revealing an additional layer of complexity to the epigenetic regulation of gene expression. In this review, we summarize the novel evidence for the molecular and biological regulation of DNA methylation in enhancer regions and the dynamism of these changes contributing to the fine-tuning of gene expression. We also analyze the contribution of enhancer DNA methylation on the expression of relevant genes in acute myeloid leukemia and chronic myeloproliferative neoplasms. The characterization of the aberrant enhancer DNA methylation provides not only a novel pathogenic mechanism for different tumors but also highlights novel potential therapeutic targets for myeloid derived neoplasms.
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Affiliation(s)
- Raquel Ordoñez
- Área de Hemato-Oncología, Centro de Investigación Médica Aplicada, IDISNA, Universidad de Navarra, Avenida Pío XII-55, 31008 Pamplona, Spain
- Centro de Investigación Biomédica en Red de Cáncer (CIBERONC), 28029 Madrid, Spain
| | - Nicolás Martínez-Calle
- Área de Hemato-Oncología, Centro de Investigación Médica Aplicada, IDISNA, Universidad de Navarra, Avenida Pío XII-55, 31008 Pamplona, Spain
- Centro de Investigación Biomédica en Red de Cáncer (CIBERONC), 28029 Madrid, Spain
| | - Xabier Agirre
- Área de Hemato-Oncología, Centro de Investigación Médica Aplicada, IDISNA, Universidad de Navarra, Avenida Pío XII-55, 31008 Pamplona, Spain.
- Centro de Investigación Biomédica en Red de Cáncer (CIBERONC), 28029 Madrid, Spain.
| | - Felipe Prosper
- Área de Hemato-Oncología, Centro de Investigación Médica Aplicada, IDISNA, Universidad de Navarra, Avenida Pío XII-55, 31008 Pamplona, Spain.
- Centro de Investigación Biomédica en Red de Cáncer (CIBERONC), 28029 Madrid, Spain.
- Departamento de Hematología, Clínica Universidad de Navarra, Universidad de Navarra, Avenida Pío XII-36, 31008 Pamplona, Spain.
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107
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QTL mapping of rat blood pressure loci on RNO1 within a homologous region linked to human hypertension on HSA15. PLoS One 2019; 14:e0221658. [PMID: 31442284 PMCID: PMC6707578 DOI: 10.1371/journal.pone.0221658] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2019] [Accepted: 08/12/2019] [Indexed: 11/21/2022] Open
Abstract
Fine-mapping of regions linked to the inheritance of hypertension is accomplished by genetic dissection of blood pressure quantitative trait loci (BP QTLs) in rats. The goal of the current study was to further fine-map two genomic regions on rat chromosome 1 with opposing blood pressure effects (BP QTL1b1 and BP QTL1b1a), the homologous region of which on human chromosome 15 harbors BP QTLs. Two new substrains were constructed and studied from the previously reported BP QTL1b1, one having significantly lower systolic BP by 17 mmHg than that of the salt-sensitive (S) rat (P = 0.007). The new limits of BP QTL1b1 were between 134.09 Mb and 135.40 Mb with a 43% improvement from the previous 2.31 Mb to the current 1.31 Mb interval containing 4 protein-coding genes (Rgma, Chd2, Fam174b, and St8sia2), 2 predicted miRNAs, and 4 lncRNAs. One new substrain was constructed and studied from the previously reported BPQTL1b1a having a significantly higher systolic BP by 22 mmHg (P = 0.006) than that of the S rat. The new limits of BPQTL1b1a were between 133.53 Mb and 134.52 Mb with a 32% improvement from the previous1.45 Mb to the current 990.21 Kb interval containing 1 protein-coding gene, Mctp2, and a lncRNA. The congenic segments of these two BP QTLs overlapped between 134.09 Mb and 134.52 Mb. No exonic variants were detected in any of the genes. These findings reiterate complexity of genetic regulation of BP within QTL regions, where elements beyond protein-coding sequences could be factors in controlling BP.
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108
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Lewis MW, Li S, Franco HL. Transcriptional control by enhancers and enhancer RNAs. Transcription 2019; 10:171-186. [PMID: 31791217 PMCID: PMC6948965 DOI: 10.1080/21541264.2019.1695492] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Revised: 11/14/2019] [Accepted: 11/15/2019] [Indexed: 11/02/2022] Open
Abstract
The regulation of gene expression is a fundamental cellular process and its misregulation is a key component of disease. Enhancers are one of the most salient regulatory elements in the genome and help orchestrate proper spatiotemporal gene expression during development, in homeostasis, and in response to signaling. Notably, molecular aberrations at enhancers, such as translocations and single nucleotide polymorphisms, are emerging as an important source of human variation and susceptibility to disease. Herein we discuss emerging paradigms addressing how genes are regulated by enhancers, common features of active enhancers, and how non-coding enhancer RNAs (eRNAs) can direct gene expression programs that underlie cellular phenotypes. We survey the current evidence, which suggests that eRNAs can bind to transcription factors, mediate enhancer-promoter interactions, influence RNA Pol II elongation, and act as decoys for repressive cofactors. Furthermore, we discuss current methodologies for the identification of eRNAs and novel approaches to elucidate their functions.
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Affiliation(s)
- Michael W. Lewis
- The Lineberger Comprehensive Cancer Center, Department of Genetics, University of North Carolina, Chapel Hill, NC, USA
| | - Shen Li
- The Lineberger Comprehensive Cancer Center, Department of Genetics, University of North Carolina, Chapel Hill, NC, USA
| | - Hector L. Franco
- The Lineberger Comprehensive Cancer Center, Department of Genetics, University of North Carolina, Chapel Hill, NC, USA
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109
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Eres IE, Luo K, Hsiao CJ, Blake LE, Gilad Y. Reorganization of 3D genome structure may contribute to gene regulatory evolution in primates. PLoS Genet 2019; 15:e1008278. [PMID: 31323043 PMCID: PMC6668850 DOI: 10.1371/journal.pgen.1008278] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Revised: 07/31/2019] [Accepted: 06/28/2019] [Indexed: 12/22/2022] Open
Abstract
A growing body of evidence supports the notion that variation in gene regulation plays a crucial role in both speciation and adaptation. However, a comprehensive functional understanding of the mechanisms underlying regulatory evolution remains elusive. In primates, one of the crucial missing pieces of information towards a better understanding of regulatory evolution is a comparative annotation of interactions between distal regulatory elements and promoters. Chromatin conformation capture technologies have enabled genome-wide quantifications of such distal 3D interactions. However, relatively little comparative research in primates has been done using such technologies. To address this gap, we used Hi-C to characterize 3D chromatin interactions in induced pluripotent stem cells (iPSCs) from humans and chimpanzees. We also used RNA-seq to collect gene expression data from the same lines. We generally observed that lower-order, pairwise 3D genomic interactions are conserved in humans and chimpanzees, but higher order genomic structures, such as topologically associating domains (TADs), are not as conserved. Inter-species differences in 3D genomic interactions are often associated with gene expression differences between the species. To provide additional functional context to our observations, we considered previously published chromatin data from human stem cells. We found that inter-species differences in 3D genomic interactions, which are also associated with gene expression differences between the species, are enriched for both active and repressive marks. Overall, our data demonstrate that, as expected, an understanding of 3D genome reorganization is key to explaining regulatory evolution. The way in which a genome folds affects the regulation of gene expression. This is often due to loops in the three-dimensional structure that bring linearly distant genes and regulatory elements into close proximity. Most studies examining three-dimensional structure genome-wide are limited to a single species. In this study, we compared three-dimensional structure in the genomes of induced pluripotent stem cells from humans and chimpanzees. We collected gene expression data from the same samples, which allowed us to assess the contribution of three-dimensional chromatin conformation to gene regulatory evolution in primates. Our results demonstrate that gene expression differences between the species may often be mediated by differences in three-dimensional genomic interactions. Our data also suggest that large-scale chromatin structures (i.e. topologically associating domains, TADs) are not well conserved in their placement across species. We hope the analytical paradigms we present here could serve as a basis for future comparative studies of three-dimensional genome organization, elucidating the putative functional regulatory loci driving speciation.
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Affiliation(s)
- Ittai E. Eres
- Department of Human Genetics, University of Chicago, Chicago, Illinois, United States of America
| | - Kaixuan Luo
- Department of Human Genetics, University of Chicago, Chicago, Illinois, United States of America
| | - Chiaowen Joyce Hsiao
- Department of Human Genetics, University of Chicago, Chicago, Illinois, United States of America
| | - Lauren E. Blake
- Department of Human Genetics, University of Chicago, Chicago, Illinois, United States of America
| | - Yoav Gilad
- Department of Human Genetics, University of Chicago, Chicago, Illinois, United States of America
- Department of Medicine, University of Chicago, Chicago, Illinois, United States of America
- * E-mail:
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110
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Ghavi-Helm Y, Jankowski A, Meiers S, Viales RR, Korbel JO, Furlong EEM. Highly rearranged chromosomes reveal uncoupling between genome topology and gene expression. Nat Genet 2019; 51:1272-1282. [PMID: 31308546 PMCID: PMC7116017 DOI: 10.1038/s41588-019-0462-3] [Citation(s) in RCA: 211] [Impact Index Per Article: 42.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2018] [Accepted: 06/05/2019] [Indexed: 12/21/2022]
Abstract
Chromatin topology is intricately linked to gene expression, yet its functional requirement remains unclear. Here, we comprehensively assessed the interplay between genome topology and gene expression using highly rearranged chromosomes (balancers) spanning ~75% of the Drosophila genome. Using transheterozyte (balancer/wild-type) embryos, we measured allele-specific changes in topology and gene expression in cis, whilst minimizing trans effects. Through genome sequencing, we resolved eight large nested inversions, smaller inversions, duplications, and thousands of deletions. These extensive rearrangements caused many changes to chromatin topology, including long-range loops, TADs and promoter interactions, yet these are not predictive of changes in expression. Gene expression is generally not altered around inversion breakpoints, indicating that mis-appropriate enhancer-promoter activation is a rare event. Similarly, shuffling or fusing TADs, changing intra-TAD connections and disrupting long-range inter-TAD loops, does not alter expression for the majority of genes. Our results suggest that properties other than chromatin topology ensure productive enhancer-promoter interactions.
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Affiliation(s)
- Yad Ghavi-Helm
- European Molecular Biology Laboratory, Genome Biology Unit, Heidelberg, Germany. .,Institut de Génomique Fonctionnelle de Lyon, Univ Lyon, CNRS UMR 5242, Ecole Normale Supérieure de Lyon, Université Claude Bernard Lyon 1, Lyon, France.
| | | | - Sascha Meiers
- European Molecular Biology Laboratory, Genome Biology Unit, Heidelberg, Germany
| | - Rebecca R Viales
- European Molecular Biology Laboratory, Genome Biology Unit, Heidelberg, Germany
| | - Jan O Korbel
- European Molecular Biology Laboratory, Genome Biology Unit, Heidelberg, Germany.
| | - Eileen E M Furlong
- European Molecular Biology Laboratory, Genome Biology Unit, Heidelberg, Germany.
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111
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Park J, Estrada J, Johnson G, Vincent BJ, Ricci-Tam C, Bragdon MDJ, Shulgina Y, Cha A, Wunderlich Z, Gunawardena J, DePace AH. Dissecting the sharp response of a canonical developmental enhancer reveals multiple sources of cooperativity. eLife 2019; 8:e41266. [PMID: 31223115 PMCID: PMC6588347 DOI: 10.7554/elife.41266] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2018] [Accepted: 03/04/2019] [Indexed: 12/19/2022] Open
Abstract
Developmental enhancers integrate graded concentrations of transcription factors (TFs) to create sharp gene expression boundaries. Here we examine the hunchback P2 (HbP2) enhancer which drives a sharp expression pattern in the Drosophila blastoderm embryo in response to the transcriptional activator Bicoid (Bcd). We systematically interrogate cis and trans factors that influence the shape and position of expression driven by HbP2, and find that the prevailing model, based on pairwise cooperative binding of Bcd to HbP2 is not adequate. We demonstrate that other proteins, such as pioneer factors, Mediator and histone modifiers influence the shape and position of the HbP2 expression pattern. Comparing our results to theory reveals how higher-order cooperativity and energy expenditure impact boundary location and sharpness. Our results emphasize that the bacterial view of transcription regulation, where pairwise interactions between regulatory proteins dominate, must be reexamined in animals, where multiple molecular mechanisms collaborate to shape the gene regulatory function.
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Affiliation(s)
- Jeehae Park
- Department of Systems BiologyHarvard Medical SchoolBostonUnited States
| | - Javier Estrada
- Department of Systems BiologyHarvard Medical SchoolBostonUnited States
| | - Gemma Johnson
- Department of Systems BiologyHarvard Medical SchoolBostonUnited States
| | - Ben J Vincent
- Department of Systems BiologyHarvard Medical SchoolBostonUnited States
| | - Chiara Ricci-Tam
- Department of Systems BiologyHarvard Medical SchoolBostonUnited States
| | - Meghan DJ Bragdon
- Department of Systems BiologyHarvard Medical SchoolBostonUnited States
| | | | - Anna Cha
- Department of Systems BiologyHarvard Medical SchoolBostonUnited States
| | - Zeba Wunderlich
- Department of Systems BiologyHarvard Medical SchoolBostonUnited States
| | | | - Angela H DePace
- Department of Systems BiologyHarvard Medical SchoolBostonUnited States
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112
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Zemke NR, Gou D, Berk AJ. Dedifferentiation by adenovirus E1A due to inactivation of Hippo pathway effectors YAP and TAZ. Genes Dev 2019; 33:828-843. [PMID: 31171701 PMCID: PMC6601516 DOI: 10.1101/gad.324814.119] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Accepted: 04/26/2019] [Indexed: 01/09/2023]
Abstract
In this study, Zemke et al. show that E1A inactivates the Hippo pathway-regulated TEAD coactivators YAP and TAZ by causing their sequestration in the cytoplasm. Their findings suggest that YAP/TAZ function in a developmental checkpoint controlled by signaling from the actin cytoskeleton that prevents differentiation of a progenitor cell until it is in the correct cellular and tissue environment. Adenovirus transformed cells have a dedifferentiated phenotype. Eliminating E1A in transformed human embryonic kidney cells derepressed ∼2600 genes, generating a gene expression profile closely resembling mesenchymal stem cells (MSCs). This was associated with a dramatic change in cell morphology from one with scant cytoplasm and a globular nucleus to one with increased cytoplasm, extensive actin stress fibers, and actomyosin-dependent flattening against the substratum. E1A-induced hypoacetylation at histone H3 Lys27 and Lys18 (H3K27/18) was reversed. Most of the increase in H3K27/18ac was in enhancers near TEAD transcription factors bound by Hippo signaling-regulated coactivators YAP and TAZ. E1A causes YAP/TAZ cytoplasmic sequestration. After eliminating E1A, YAP/TAZ were transported into nuclei, where they associated with poised enhancers with DNA-bound TEAD4 and H3K4me1. This activation of YAP/TAZ required RHO family GTPase signaling and caused histone acetylation by p300/CBP, chromatin remodeling, and cohesin loading to establish MSC-associated enhancers and then superenhancers. Consistent results were also observed in primary rat embryo kidney cells, human fibroblasts, and human respiratory tract epithelial cells. These results together with earlier studies suggest that YAP/TAZ function in a developmental checkpoint controlled by signaling from the actin cytoskeleton that prevents differentiation of a progenitor cell until it is in the correct cellular and tissue environment.
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Affiliation(s)
- Nathan R Zemke
- Molecular Biology Institute, University of California at Los Angeles, Los Angeles, California 90095, USA
| | - Dawei Gou
- Molecular Biology Institute, University of California at Los Angeles, Los Angeles, California 90095, USA
| | - Arnold J Berk
- Molecular Biology Institute, University of California at Los Angeles, Los Angeles, California 90095, USA
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113
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Bao J, Li M, Liang S, Yang Y, Wu J, Zou Q, Fang S, Chen S, Guo L. Integrated high-throughput analysis identifies super enhancers associated with chemoresistance in SCLC. BMC Med Genomics 2019; 12:67. [PMID: 31118037 PMCID: PMC6532255 DOI: 10.1186/s12920-019-0520-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2018] [Accepted: 05/07/2019] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Chemoresistance is a primary clinical challenge for the management of small cell lung cancer. Additionally, transcriptional regulation by super enhancer (SE) has an important role in tumor evolution. The functions of SEs, a key class of noncoding DNA cis-regulatory elements, have been the subject of many recent studies in the field of cancer research. METHODS In this study, using chromatin immunoprecipitation-sequencing and RNA-sequencing (RNA-seq), we aimed to identify SEs associated with chemoresistance from H69AR cells. Through integrated bioinformatics analysis of the MEME chip, we predicted the master transcriptional factors (TFs) binding to SE sites and verified the relationships between TFs of SEs and drug resistance by RNA interference, cell counting kit 8 assays, quantitative real-time reverse transcription polymerase chain reaction. RESULTS In total, 108 SEs were screened from H69AR cells. When combining this analysis with RNA-seq data, 45 SEs were suggested to be closely related to drug resistance. Then, 12 master TFs were predicted to localize to regions of those SEs. Subsequently, we selected forkhead box P1 (FOXP1), interferon regulatory factor 1 (IRF1), and specificity protein 1 (SP1) to authenticate the functional relationships of master TFs with chemoresistance via SEs. CONCLUSIONS We screened out SEs involved with drug resistance and evaluated the functions of FOXP1, IRF1, and SP1 in chemoresistance. Our findings established a large group of SEs associated with drug resistance in small cell lung cancer, revealed the drug resistance mechanisms of SEs, and provided insights into the clinical applications of SEs.
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Affiliation(s)
- Jiarong Bao
- Department of Pathology, Zhujiang Hospital, Southern Medical University, 253 Gongye Road, Guangzhou, 510282, People's Republic of China
- Department of Pathology, The Fifth Affiliated Hospital, Southern Medical University, Guangzhou, 510900, People's Republic of China
| | - Man Li
- Department of Pathology, Zhujiang Hospital, Southern Medical University, 253 Gongye Road, Guangzhou, 510282, People's Republic of China
| | - Shumei Liang
- Department of Pathology, Zhujiang Hospital, Southern Medical University, 253 Gongye Road, Guangzhou, 510282, People's Republic of China
| | - Yunchu Yang
- Department of Pathology, Zhujiang Hospital, Southern Medical University, 253 Gongye Road, Guangzhou, 510282, People's Republic of China
| | - Jingfang Wu
- Department of Pathology, Zhujiang Hospital, Southern Medical University, 253 Gongye Road, Guangzhou, 510282, People's Republic of China
| | - Qingqing Zou
- Department of Oncology, The First Affiliated Hospital of Guangdong Pharmaceutical University, Guangzhou, 510080, People's Republic of China
| | - Shun Fang
- Department of Pathology, Zhujiang Hospital, Southern Medical University, 253 Gongye Road, Guangzhou, 510282, People's Republic of China
| | - Size Chen
- Department of Oncology, The First Affiliated Hospital of Guangdong Pharmaceutical University, Guangzhou, 510080, People's Republic of China.
| | - Linlang Guo
- Department of Pathology, Zhujiang Hospital, Southern Medical University, 253 Gongye Road, Guangzhou, 510282, People's Republic of China.
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114
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Identification and Conservation Analysis of Cis-Regulatory Elements in Pig Liver. Genes (Basel) 2019; 10:genes10050348. [PMID: 31067820 PMCID: PMC6562536 DOI: 10.3390/genes10050348] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Revised: 04/29/2019] [Accepted: 05/01/2019] [Indexed: 01/02/2023] Open
Abstract
The liver plays a key role in metabolism and affects pig production. However, the functional annotation of noncoding regions of the pig liver remains poorly understood. We revealed the landscape of cis-regulatory elements and their functional characterization in pig liver. We identified 102,373 cis-regulatory elements in the pig liver, including enhancers, promoters, super-enhancers, and broad H3K4me3 domains, and highlighted 26 core transcription regulatory factors in the pig liver as well. We found similarity of cis-regulatory elements among those of pigs, humans, and cattle. Despite the low proportion of functionally conserved enhancers (~30%) between pig and human liver tissue, ~78% of the pig liver enhancer orthologues sequence could play an enhancer role in other human tissues. Additionally, we observed that the ratio of consistent super-enhancer-associated genes was significantly higher than the ratio of functionally conserved super-enhancers. Approximately 54% of the core regulation factors driven by super-enhancers were consistent across the liver from these three species. Our pig liver annotation and functional characterization studies provide a system and resource for noncoding annotation for future gene regulatory studies in pigs. Furthermore, our study also showed the high level functional conservation of cis-regulatory elements in mammals; it also improved our understanding of regulation function of mammal cis-regulatory elements.
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115
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Torres-Ruiz R, Benítez-Burraco A, Martínez-Lage M, Rodríguez-Perales S, García-Bellido P. Functional characterization of two enhancers located downstream FOXP2. BMC MEDICAL GENETICS 2019; 20:65. [PMID: 31046704 PMCID: PMC6498672 DOI: 10.1186/s12881-019-0810-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/09/2019] [Accepted: 04/17/2019] [Indexed: 01/01/2023]
Abstract
BACKGROUND Mutations in the coding region of FOXP2 are known to cause speech and language impairment. However, it is not clear how dysregulation of the gene contributes to language deficit. Interestingly, microdeletions of the region downstream the gene have been associated with cognitive deficits. METHODS Here, we investigate changes in FOXP2 expression in the SK-N-MC neuroblastoma human cell line after deletion by CRISPR-Cas9 of two enhancers located downstream of the gene. RESULTS Deletion of any of these two functional enhancers downregulates FOXP2, but also upregulates the closest 3' gene MDFIC. Because this effect is not statistically significant in a HEK 293 cell line, derived from the human kidney, both enhancers might confer a tissue specific regulation to both genes. We have also found that the deletion of any of these enhancers downregulates six well-known FOXP2 target genes in the SK-N-MC cell line. CONCLUSIONS We expect these findings contribute to a deeper understanding of how FOXP2 and MDFIC are regulated to pace neuronal development supporting cognition, speech and language.
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Affiliation(s)
- Raúl Torres-Ruiz
- Molecular Cytogenetics Group, Centro Nacional Investigaciones Oncológicas (CNIO), Madrid, Spain
| | - Antonio Benítez-Burraco
- Department of Spanish, Linguistics, and Theory of Literature (Linguistics), University of Seville, Seville, Spain.
| | - Marta Martínez-Lage
- Molecular Cytogenetics Group, Centro Nacional Investigaciones Oncológicas (CNIO), Madrid, Spain
| | | | - Paloma García-Bellido
- Faculty of Modern Languages, University of Oxford, Oxford, UK.,Faculty of Linguistics, Philology and Phonetics, University of Oxford, Oxford, UK
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116
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Bashor CJ, Patel N, Choubey S, Beyzavi A, Kondev J, Collins JJ, Khalil AS. Complex signal processing in synthetic gene circuits using cooperative regulatory assemblies. Science 2019; 364:593-597. [PMID: 31000590 DOI: 10.1126/science.aau8287] [Citation(s) in RCA: 86] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2018] [Accepted: 04/03/2019] [Indexed: 12/21/2022]
Abstract
Eukaryotic genes are regulated by multivalent transcription factor complexes. Through cooperative self-assembly, these complexes perform nonlinear regulatory operations involved in cellular decision-making and signal processing. In this study, we apply this design principle to synthetic networks, testing whether engineered cooperative assemblies can program nonlinear gene circuit behavior in yeast. Using a model-guided approach, we show that specifying the strength and number of assembly subunits enables predictive tuning between linear and nonlinear regulatory responses for single- and multi-input circuits. We demonstrate that assemblies can be adjusted to control circuit dynamics. We harness this capability to engineer circuits that perform dynamic filtering, enabling frequency-dependent decoding in cell populations. Programmable cooperative assembly provides a versatile way to tune the nonlinearity of network connections, markedly expanding the engineerable behaviors available to synthetic circuits.
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Affiliation(s)
- Caleb J Bashor
- Department of Bioengineering, Rice University, Houston, TX 77030, USA
| | - Nikit Patel
- Department of Biomedical Engineering and Biological Design Center, Boston University, Boston, MA 02215, USA
| | - Sandeep Choubey
- Department of Physics, Brandeis University, Waltham, MA 02453, USA
| | - Ali Beyzavi
- Department of Mechanical Engineering, Boston University, Boston, MA 02215, USA
| | - Jané Kondev
- Department of Physics, Brandeis University, Waltham, MA 02453, USA
| | - James J Collins
- Institute for Medical Engineering and Science, Department of Biological Engineering, and Synthetic Biology Center, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.,Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA.,Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA 02115, USA
| | - Ahmad S Khalil
- Department of Biomedical Engineering and Biological Design Center, Boston University, Boston, MA 02215, USA. .,Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA 02115, USA
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117
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Zeeshan S, Xiong R, Liang BT, Ahmed Z. 100 Years of evolving gene-disease complexities and scientific debutants. Brief Bioinform 2019; 21:885-905. [PMID: 30972412 DOI: 10.1093/bib/bbz038] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Revised: 03/06/2019] [Accepted: 03/08/2019] [Indexed: 12/22/2022] Open
Abstract
It's been over 100 years since the word `gene' is around and progressively evolving in several scientific directions. Time-to-time technological advancements have heavily revolutionized the field of genomics, especially when it's about, e.g. triple code development, gene number proposition, genetic mapping, data banks, gene-disease maps, catalogs of human genes and genetic disorders, CRISPR/Cas9, big data and next generation sequencing, etc. In this manuscript, we present the progress of genomics from pea plant genetics to the human genome project and highlight the molecular, technical and computational developments. Studying genome and epigenome led to the fundamentals of development and progression of human diseases, which includes chromosomal, monogenic, multifactorial and mitochondrial diseases. World Health Organization has classified, standardized and maintained all human diseases, when many academic and commercial online systems are sharing information about genes and linking to associated diseases. To efficiently fathom the wealth of this biological data, there is a crucial need to generate appropriate gene annotation repositories and resources. Our focus has been how many gene-disease databases are available worldwide and which sources are authentic, timely updated and recommended for research and clinical purposes. In this manuscript, we have discussed and compared 43 such databases and bioinformatics applications, which enable users to connect, explore and, if possible, download gene-disease data.
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Affiliation(s)
- Saman Zeeshan
- The Jackson Laboratory for Genomic Medicine, 10 Discovery Drive, Farmington, CT, USA
| | - Ruoyun Xiong
- Department of Genetics and Genome Sciences, School of Medicine, University of Connecticut Health Center, Farmington Ave, Farmington, CT, USA
| | - Bruce T Liang
- Department of Genetics and Genome Sciences, School of Medicine, University of Connecticut Health Center, Farmington Ave, Farmington, CT, USA.,Pat and Jim Calhoun Cardiology Center, School of Medicine, University of Connecticut Health Center, Farmington Ave, Farmington, CT, USA
| | - Zeeshan Ahmed
- Department of Genetics and Genome Sciences, School of Medicine, University of Connecticut Health Center, Farmington Ave, Farmington, CT, USA
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118
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Wang F, Yang Q, Wu F, Zhang Y, Sun S, Wang X, Gui Y, Li Q. Identification of a 42-bp heart-specific enhancer of the notch1b gene in zebrafish embryos. Dev Dyn 2019; 248:426-436. [PMID: 30919514 DOI: 10.1002/dvdy.31] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2018] [Revised: 03/18/2019] [Accepted: 03/21/2019] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND NOTCH1 plays a key role in the differentiation of ventricles, and mutations are strongly associated with both sporadic and familial bicuspid aortic valves. However, few heart-specific enhancers have been identified to date. RESULTS In this study, we investigated evolutionary conserved regions (ECRs) that might act as potential enhancers within the region approximately 150-kb upstream and downstream of the NOTCH1 gene. Functional validation revealed that one 127-bp ECR located ~85-kb downstream of the NOTCH1 gene drives green fluorescent protein expression in the zebrafish embryo heart. Transcription factor (TF) prediction and core TF distribution analyses were performed to identify the core region. Dissection of ECR3 was performed to identify the 42-bp sequence, which is sufficient for heart-specific expression. In situ hybridization experiments showed that notch1b is expressed in the heart. Overexpression experiments in cells indicated that NKX2-5 is critical for enhancer activity. Mutation of the NKX-5 binding site significantly decreased reporter gene expression. Next, compared with the commonly used myocardium-labeled zebrafish transgenic strain Tg(cmlc2: mCherry), this 42-bp enhancer-labeled stable line mediated a similar expression pattern but with a smaller core region. CONCLUSION This study identified a 42-bp heart-specific enhancer near the NOTCH1 gene and further verified its functional targeting by NKX2-5.
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Affiliation(s)
- Feng Wang
- Translational Medical Center for Development and Disease, Institute of Pediatrics, Shanghai Key Laboratory of Birth Defect, Children's Hospital of Fudan University, Shanghai, China.,Cardiovascular Center, Children's Hospital of Fudan University, Shanghai, China
| | - Qian Yang
- Translational Medical Center for Development and Disease, Institute of Pediatrics, Shanghai Key Laboratory of Birth Defect, Children's Hospital of Fudan University, Shanghai, China.,Cardiovascular Center, Children's Hospital of Fudan University, Shanghai, China
| | - Fang Wu
- Translational Medical Center for Development and Disease, Institute of Pediatrics, Shanghai Key Laboratory of Birth Defect, Children's Hospital of Fudan University, Shanghai, China.,Cardiovascular Center, Children's Hospital of Fudan University, Shanghai, China
| | - Yawen Zhang
- Cardiovascular Center, Children's Hospital of Fudan University, Shanghai, China
| | - Shuna Sun
- Cardiovascular Center, Children's Hospital of Fudan University, Shanghai, China
| | - Xu Wang
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Fudan University, Shanghai, China
| | - Yonghao Gui
- Cardiovascular Center, Children's Hospital of Fudan University, Shanghai, China
| | - Qiang Li
- Translational Medical Center for Development and Disease, Institute of Pediatrics, Shanghai Key Laboratory of Birth Defect, Children's Hospital of Fudan University, Shanghai, China
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119
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Bozek M, Cortini R, Storti AE, Unnerstall U, Gaul U, Gompel N. ATAC-seq reveals regional differences in enhancer accessibility during the establishment of spatial coordinates in the Drosophila blastoderm. Genome Res 2019; 29:771-783. [PMID: 30962180 PMCID: PMC6499308 DOI: 10.1101/gr.242362.118] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Accepted: 03/26/2019] [Indexed: 12/21/2022]
Abstract
Establishment of spatial coordinates during Drosophila embryogenesis relies on differential regulatory activity of axis patterning enhancers. Concentration gradients of activator and repressor transcription factors (TFs) provide positional information to each enhancer, which in turn promotes transcription of a target gene in a specific spatial pattern. However, the interplay between an enhancer regulatory activity and its accessibility as determined by local chromatin organization is not well understood. We profiled chromatin accessibility with ATAC-seq in narrow, genetically tagged domains along the antero-posterior axis in the Drosophila blastoderm. We demonstrate that one-quarter of the accessible genome displays significant regional variation in its ATAC-seq signal immediately after zygotic genome activation. Axis patterning enhancers are enriched among the most variable intervals, and their accessibility changes correlate with their regulatory activity. In an embryonic domain where an enhancer receives a net activating TF input and promotes transcription, it displays elevated accessibility in comparison to a domain where it receives a net repressive input. We propose that differential accessibility is a signature of patterning cis-regulatory elements in the Drosophila blastoderm and discuss potential mechanisms by which accessibility of enhancers may be modulated by activator and repressor TFs.
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Affiliation(s)
- Marta Bozek
- Ludwig-Maximilians-Universität München, Department Biochemie, Genzentrum, 81377 München, Germany
| | - Roberto Cortini
- Ludwig-Maximilians-Universität München, Department Biochemie, Genzentrum, 81377 München, Germany
| | - Andrea Ennio Storti
- Ludwig-Maximilians-Universität München, Department Biochemie, Genzentrum, 81377 München, Germany
| | - Ulrich Unnerstall
- Ludwig-Maximilians-Universität München, Department Biochemie, Genzentrum, 81377 München, Germany
| | - Ulrike Gaul
- Ludwig-Maximilians-Universität München, Department Biochemie, Genzentrum, 81377 München, Germany
| | - Nicolas Gompel
- Ludwig-Maximilians Universität München, Fakultät für Biologie, Biozentrum, 82152 Planegg-Martinsried, Germany
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120
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Fernandez-Valverde SL, Aguilera F, Ramos-Díaz RA. Inference of Developmental Gene Regulatory Networks Beyond Classical Model Systems: New Approaches in the Post-genomic Era. Integr Comp Biol 2019; 58:640-653. [PMID: 29917089 DOI: 10.1093/icb/icy061] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The advent of high-throughput sequencing (HTS) technologies has revolutionized the way we understand the transformation of genetic information into morphological traits. Elucidating the network of interactions between genes that govern cell differentiation through development is one of the core challenges in genome research. These networks are known as developmental gene regulatory networks (dGRNs) and consist largely of the functional linkage between developmental control genes, cis-regulatory modules, and differentiation genes, which generate spatially and temporally refined patterns of gene expression. Over the last 20 years, great advances have been made in determining these gene interactions mainly in classical model systems, including human, mouse, sea urchin, fruit fly, and worm. This has brought about a radical transformation in the fields of developmental biology and evolutionary biology, allowing the generation of high-resolution gene regulatory maps to analyze cell differentiation during animal development. Such maps have enabled the identification of gene regulatory circuits and have led to the development of network inference methods that can recapitulate the differentiation of specific cell-types or developmental stages. In contrast, dGRN research in non-classical model systems has been limited to the identification of developmental control genes via the candidate gene approach and the characterization of their spatiotemporal expression patterns, as well as to the discovery of cis-regulatory modules via patterns of sequence conservation and/or predicted transcription-factor binding sites. However, thanks to the continuous advances in HTS technologies, this scenario is rapidly changing. Here, we give a historical overview on the architecture and elucidation of the dGRNs. Subsequently, we summarize the approaches available to unravel these regulatory networks, highlighting the vast range of possibilities of integrating multiple technical advances and theoretical approaches to expand our understanding on the global gene regulation during animal development in non-classical model systems. Such new knowledge will not only lead to greater insights into the evolution of molecular mechanisms underlying cell identity and animal body plans, but also into the evolution of morphological key innovations in animals.
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Affiliation(s)
- Selene L Fernandez-Valverde
- CONACYT, Unidad de Genómica Avanzada, Laboratorio Nacional de Genómica para la Biodiversidad (Langebio), Centro de Investigación y de Estudios Avanzados del IPN, Irapuato, Guanajuato, Mexico
| | - Felipe Aguilera
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Biológicas, Universidad de Concepción, Chile
| | - René Alexander Ramos-Díaz
- CONACYT, Unidad de Genómica Avanzada, Laboratorio Nacional de Genómica para la Biodiversidad (Langebio), Centro de Investigación y de Estudios Avanzados del IPN, Irapuato, Guanajuato, Mexico
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121
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Colbran LL, Chen L, Capra JA. Sequence Characteristics Distinguish Transcribed Enhancers from Promoters and Predict Their Breadth of Activity. Genetics 2019; 211:1205-1217. [PMID: 30696717 PMCID: PMC6456323 DOI: 10.1534/genetics.118.301895] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2018] [Accepted: 01/27/2019] [Indexed: 01/08/2023] Open
Abstract
Enhancers and promoters both regulate gene expression by recruiting transcription factors (TFs); however, the degree to which enhancer vs. promoter activity is due to differences in their sequences or to genomic context is the subject of ongoing debate. We examined this question by analyzing the sequences of thousands of transcribed enhancers and promoters from hundreds of cellular contexts previously identified by cap analysis of gene expression. Support vector machine classifiers trained on counts of all possible 6-bp-long sequences (6-mers) were able to accurately distinguish promoters from enhancers and distinguish their breadth of activity across tissues. Classifiers trained to predict enhancer activity also performed well when applied to promoter prediction tasks, but promoter-trained classifiers performed poorly on enhancers. This suggests that the learned sequence patterns predictive of enhancer activity generalize to promoters, but not vice versa. Our classifiers also indicate that there are functionally relevant differences in enhancer and promoter GC content beyond the influence of CpG islands. Furthermore, sequences characteristic of broad promoter or broad enhancer activity matched different TFs, with predicted ETS- and RFX-binding sites indicative of promoters, and AP-1 sites indicative of enhancers. Finally, we evaluated the ability of our models to distinguish enhancers and promoters defined by histone modifications. Separating these classes was substantially more difficult, and this difference may contribute to ongoing debates about the similarity of enhancers and promoters. In summary, our results suggest that high-confidence transcribed enhancers and promoters can largely be distinguished based on biologically relevant sequence properties.
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Affiliation(s)
- Laura L Colbran
- Vanderbilt Genetics Institute, Vanderbilt University, Nashville, Tennessee 37235
| | - Ling Chen
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee 37235
| | - John A Capra
- Vanderbilt Genetics Institute, Vanderbilt University, Nashville, Tennessee 37235
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee 37235
- Center for Structural Biology, Departments of Biomedical Informatics and Computer Science, Vanderbilt University, Nashville, Tennessee 37235
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122
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Redundant and Cryptic Enhancer Activities of the Drosophila yellow Gene. Genetics 2019; 212:343-360. [PMID: 30842209 DOI: 10.1534/genetics.119.301985] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Accepted: 02/25/2019] [Indexed: 11/18/2022] Open
Abstract
Cis-regulatory sequences known as enhancers play a key role in regulating gene expression. Evolutionary changes in these DNA sequences contribute to phenotypic evolution. The Drosophila yellow gene, which is required for pigmentation, has emerged as a model system for understanding how cis-regulatory sequences evolve, providing some of the most detailed insights available into how activities of orthologous enhancers have diverged between species. Here, we examine the evolution of yellow cis-regulatory sequences on a broader scale, by comparing the distribution and function of yellow enhancer activities throughout the 5' intergenic and intronic sequences of Drosophila melanogaster, D. pseudoobscura, and D. willistoni We find that cis-regulatory sequences driving expression in a particular tissue are not as modular as previously described, but rather have many redundant and cryptic enhancer activities distributed throughout the regions surveyed. Interestingly, cryptic enhancer activities of sequences from one species often drove patterns of expression observed in other species, suggesting that the frequent evolutionary changes in yellow expression observed among Drosophila species may be facilitated by gaining and losing repression of preexisting cis-regulatory sequences.
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123
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Carlin AF, Shresta S. Genome-wide approaches to unravelling host-virus interactions in Dengue and Zika infections. Curr Opin Virol 2019; 34:29-38. [PMID: 30576956 PMCID: PMC6476700 DOI: 10.1016/j.coviro.2018.11.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Revised: 11/08/2018] [Accepted: 11/30/2018] [Indexed: 12/16/2022]
Abstract
Genomics approaches are increasingly utilized to probe host-viral interactions and identify mechanisms of viral pathogenesis and host-subversion. Here we review recent studies that utilize Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)-Cas9 screens, transcriptomics and epigenomics to gain insight into Dengue and Zika virus infections in humans. We discuss the benefits and limitations of recently utilized techniques that separate virally infected cells from neighboring uninfected cells to identify the mechanisms by which these viruses regulate host responses. We conclude by discussing how these approaches can best advance our understanding of Dengue and Zika virus pathogenesis in humans.
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Affiliation(s)
- Aaron F Carlin
- Department of Medicine, School of Medicine, University of California, San Diego, La Jolla, CA, United States.
| | - Sujan Shresta
- Department of Medicine, School of Medicine, University of California, San Diego, La Jolla, CA, United States; Division of Inflammation Biology, La Jolla Institute for Immunology, La Jolla, CA, United States.
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124
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Petkova MD, Tkačik G, Bialek W, Wieschaus EF, Gregor T. Optimal Decoding of Cellular Identities in a Genetic Network. Cell 2019; 176:844-855.e15. [PMID: 30712870 DOI: 10.1016/j.cell.2019.01.007] [Citation(s) in RCA: 83] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Revised: 11/04/2018] [Accepted: 01/02/2019] [Indexed: 11/24/2022]
Abstract
In developing organisms, spatially prescribed cell identities are thought to be determined by the expression levels of multiple genes. Quantitative tests of this idea, however, require a theoretical framework capable of exposing the rules and precision of cell specification over developmental time. We use the gap gene network in the early fly embryo as an example to show how expression levels of the four gap genes can be jointly decoded into an optimal specification of position with 1% accuracy. The decoder correctly predicts, with no free parameters, the dynamics of pair-rule expression patterns at different developmental time points and in various mutant backgrounds. Precise cellular identities are thus available at the earliest stages of development, contrasting the prevailing view of positional information being slowly refined across successive layers of the patterning network. Our results suggest that developmental enhancers closely approximate a mathematically optimal decoding strategy.
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Affiliation(s)
- Mariela D Petkova
- Joseph Henry Laboratories of Physics and the Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA; Program in Biophysics, Harvard University, Cambridge, MA 02138, USA
| | - Gašper Tkačik
- Institute of Science and Technology Austria, Am Campus 1, 3400 Klosterneuburg, Austria
| | - William Bialek
- Joseph Henry Laboratories of Physics and the Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA
| | - Eric F Wieschaus
- Department of Molecular Biology and Howard Hughes Medical Institute, Princeton University, Princeton, NJ 08544, USA
| | - Thomas Gregor
- Joseph Henry Laboratories of Physics and the Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA; Department of Developmental and Stem Cell Biology, UMR3738, Institut Pasteur, 75015 Paris, France.
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125
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Fonseca GJ, Tao J, Westin EM, Duttke SH, Spann NJ, Strid T, Shen Z, Stender JD, Sakai M, Link VM, Benner C, Glass CK. Diverse motif ensembles specify non-redundant DNA binding activities of AP-1 family members in macrophages. Nat Commun 2019; 10:414. [PMID: 30679424 PMCID: PMC6345992 DOI: 10.1038/s41467-018-08236-0] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2018] [Accepted: 12/13/2018] [Indexed: 02/08/2023] Open
Abstract
Mechanisms by which members of the AP-1 family of transcription factors play non-redundant biological roles despite recognizing the same DNA sequence remain poorly understood. To address this question, here we investigate the molecular functions and genome-wide DNA binding patterns of AP-1 family members in primary and immortalized mouse macrophages. ChIP-sequencing shows overlapping and distinct binding profiles for each factor that were remodeled following TLR4 ligation. Development of a machine learning approach that jointly weighs hundreds of DNA recognition elements yields dozens of motifs predicted to drive factor-specific binding profiles. Machine learning-based predictions are confirmed by analysis of the effects of mutations in genetically diverse mice and by loss of function experiments. These findings provide evidence that non-redundant genomic locations of different AP-1 family members in macrophages largely result from collaborative interactions with diverse, locus-specific ensembles of transcription factors and suggest a general mechanism for encoding functional specificities of their common recognition motif.
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Affiliation(s)
- Gregory J Fonseca
- Department of Cellular and Molecular Medicine, School of Medicine, University of California San Diego, La Jolla, CA, 92037, USA
| | - Jenhan Tao
- Department of Cellular and Molecular Medicine, School of Medicine, University of California San Diego, La Jolla, CA, 92037, USA
| | - Emma M Westin
- Department of Cellular and Molecular Medicine, School of Medicine, University of California San Diego, La Jolla, CA, 92037, USA
| | - Sascha H Duttke
- Department of Medicine, School of Medicine, University of California San Diego, La Jolla, CA, 92037, USA
| | - Nathanael J Spann
- Department of Cellular and Molecular Medicine, School of Medicine, University of California San Diego, La Jolla, CA, 92037, USA
| | - Tobias Strid
- Department of Cellular and Molecular Medicine, School of Medicine, University of California San Diego, La Jolla, CA, 92037, USA
| | - Zeyang Shen
- Department of Bioengineering, Jacobs School of Engineering, University of California San Diego, La Jolla, CA, 92037, USA
| | - Joshua D Stender
- Department of Cellular and Molecular Medicine, School of Medicine, University of California San Diego, La Jolla, CA, 92037, USA
| | - Mashito Sakai
- Department of Cellular and Molecular Medicine, School of Medicine, University of California San Diego, La Jolla, CA, 92037, USA
| | - Verena M Link
- Faculty of Biology, Division of Evolutionary Biology, Ludwig-Maximilian University of Munich, Munich, 80539, Germany
| | - Christopher Benner
- Department of Medicine, School of Medicine, University of California San Diego, La Jolla, CA, 92037, USA
| | - Christopher K Glass
- Department of Cellular and Molecular Medicine, School of Medicine, University of California San Diego, La Jolla, CA, 92037, USA.
- Department of Medicine, School of Medicine, University of California San Diego, La Jolla, CA, 92037, USA.
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126
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Hoyer JS, Pruneda‐Paz JL, Breton G, Hassert MA, Holcomb EE, Fowler H, Bauer KM, Mreen J, Kay SA, Carrington JC. Functional dissection of the ARGONAUTE7 promoter. PLANT DIRECT 2019; 3:e00102. [PMID: 31245750 PMCID: PMC6508778 DOI: 10.1002/pld3.102] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Revised: 10/29/2018] [Accepted: 11/09/2018] [Indexed: 05/27/2023]
Abstract
ARGONAUTES are the central effector proteins of RNA silencing which bind target transcripts in a small RNA-guided manner. Arabidopsis thaliana has 10 ARGONAUTE (AGO) genes, with specialized roles in RNA-directed DNA methylation, post-transcriptional gene silencing, and antiviral defense. To better understand specialization among AGO genes at the level of transcriptional regulation we tested a library of 1497 transcription factors for binding to the promoters of AGO1,AGO10, and AGO7 using yeast 1-hybrid assays. A ranked list of candidate DNA-binding TFs revealed binding of the AGO7 promoter by a number of proteins in two families: the miR156-regulated SPL family and the miR319-regulated TCP family, both of which have roles in developmental timing and leaf morphology. Possible functions for SPL and TCP binding are unclear: we showed that these binding sites are not required for the polar expression pattern of AGO7, nor for the function of AGO7 in leaf shape. Normal AGO7 transcription levels and function appear to depend instead on an adjacent 124-bp region. Progress in understanding the structure of this promoter may aid efforts to understand how the conserved AGO7-triggered TAS3 pathway functions in timing and polarity.
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Affiliation(s)
- J. Steen Hoyer
- Donald Danforth Plant Science CenterSt. LouisMissouri
- Computational and Systems Biology ProgramWashington UniversitySt. LouisMissouri
| | - Jose L. Pruneda‐Paz
- Division of Biological Sciences and Center for ChronobiologyUniversity of California San DiegoLa JollaCalifornia
| | - Ghislain Breton
- Division of Biological Sciences and Center for ChronobiologyUniversity of California San DiegoLa JollaCalifornia
- Department of Integrative Biology and PharmacologyMcGovern Medical SchoolHoustonTexas
| | | | | | - Halley Fowler
- Donald Danforth Plant Science CenterSt. LouisMissouri
| | | | - Jacob Mreen
- Donald Danforth Plant Science CenterSt. LouisMissouri
| | - Steve A. Kay
- Division of Biological Sciences and Center for ChronobiologyUniversity of California San DiegoLa JollaCalifornia
- Department of NeurologyUniversity of Southern CaliforniaLos AngelesCalifornia
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127
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Cai Z, Cui Y, Tan Z, Zhang G, Tan Z, Zhang X, Peng Y. RAEdb: a database of enhancers identified by high-throughput reporter assays. Database (Oxford) 2019; 2019:5280307. [PMID: 30624654 PMCID: PMC6323319 DOI: 10.1093/database/bay140] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2018] [Revised: 11/07/2018] [Accepted: 12/09/2018] [Indexed: 02/01/2023]
Abstract
High-throughput reporter assays have been recently developed to directly and quantitatively assess enhancer activity for thousands of regulatory elements. However, there is still no database to collect these enhancers. We developed RAEdb, the first database to collect enhancers identified by high-throughput reporter assays. RAEdb includes 538 320 enhancers derived from eight studies, most of which were from six human cell lines. An activity score was assigned to each enhancer based on reporter assays. Based on these enhancers, 7658 epromoters (promoters with enhancer activity) were identified and stored in the database. RAEdb provides two ways of searches: the first is to search studies by species and cell line; the other is to search enhancers or epromoters by position, activity score, sequence and gene. RAEdb also provides a genome browser to query, visualize and compare enhancers. All data in RAEdb is freely available for download.
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Affiliation(s)
- Zena Cai
- College of Biology, Hunan University, Changsha, China
| | - Ya Cui
- Key Laboratory of RNA Biology, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
- University of the Chinese Academy of Sciences, Beijing, China
| | - Zhiying Tan
- College of Computer Science and Electronic Engineering, Hunan University, Changsha, China
| | - Gaihua Zhang
- College of Life Sciences, Hunan Normal University, Changsha, China
| | - Zhongyang Tan
- College of Biology, Hunan University, Changsha, China
| | - Xinlei Zhang
- Suzhou Geneworks Biotechnology Co., Ltd., Suzhou, China
| | - Yousong Peng
- College of Biology, Hunan University, Changsha, China
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128
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Urban EA, Johnston RJ. Buffering and Amplifying Transcriptional Noise During Cell Fate Specification. Front Genet 2018; 9:591. [PMID: 30555516 PMCID: PMC6282114 DOI: 10.3389/fgene.2018.00591] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2018] [Accepted: 11/15/2018] [Indexed: 11/29/2022] Open
Abstract
The molecular processes that drive gene transcription are inherently noisy. This noise often manifests in the form of transcriptional bursts, producing fluctuations in gene activity over time. During cell fate specification, this noise is often buffered to ensure reproducible developmental outcomes. However, sometimes noise is utilized as a “bet-hedging” mechanism to diversify functional roles across a population of cells. Studies of bacteria, yeast, and cultured cells have provided insights into the nature and roles of noise in transcription, yet we are only beginning to understand the mechanisms by which noise influences the development of multicellular organisms. Here we discuss the sources of transcriptional noise and the mechanisms that either buffer noise to drive reproducible fate choices or amplify noise to randomly specify fates.
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Affiliation(s)
- Elizabeth A Urban
- Department of Biology, Johns Hopkins University, Baltimore, MD, United States
| | - Robert J Johnston
- Department of Biology, Johns Hopkins University, Baltimore, MD, United States
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129
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CUEDC1 is a primary target of ERα essential for the growth of breast cancer cells. Cancer Lett 2018; 436:87-95. [DOI: 10.1016/j.canlet.2018.08.018] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2018] [Revised: 08/14/2018] [Accepted: 08/16/2018] [Indexed: 01/31/2023]
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130
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From pattern to process: studies at the interface of gene regulatory networks, morphogenesis, and evolution. Curr Opin Genet Dev 2018; 51:103-110. [PMID: 30278289 DOI: 10.1016/j.gde.2018.08.004] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Revised: 08/17/2018] [Accepted: 08/25/2018] [Indexed: 12/12/2022]
Abstract
The development of anatomical structures is complex, beginning with patterning of gene expression by multiple gene regulatory networks (GRNs). These networks ultimately regulate the activity of effector molecules, which in turn alter cellular behavior during development. Together these processes biomechanically produce the three-dimensional shape that the anatomical structure adopts over time. However, the interfaces between these processes are often overlooked and also include counter-intuitive feedback mechanisms. In this review, we examine each step in this extraordinarily complex process and explore how evolutionary developmental biology model systems, such as butterfly scales, vertebrate teeth, and the Drosophila dorsal appendage offer a complementary approach to expose the multifactorial integration of genetics and morphogenesis from an alternative perspective.
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131
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Peng Y, Zhang Y. Enhancer and super-enhancer: Positive regulators in gene transcription. Animal Model Exp Med 2018; 1:169-179. [PMID: 30891562 PMCID: PMC6388056 DOI: 10.1002/ame2.12032] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2018] [Revised: 07/19/2018] [Accepted: 07/31/2018] [Indexed: 12/23/2022] Open
Abstract
Enhancer is a positive regulator for spatiotemporal development in eukaryotes. As a cluster, super-enhancer is closely related to cell identity- and fate-determined processes. Both of them function tightly depending on their targeted transcription factors, cofactors, and genes through distal genomic interactions. They have been recognized as critical components and played positive roles in transcriptional regulatory network or factory. Recent advances of next-generation sequencing have dramatically expanded our ability and knowledge to interrogate the molecular mechanism of enhancer and super-enhancer for transcription. Here, we review the history, importance, advances and challenges on enhancer and super-enhancer field. This will benefit our understanding of their function mechanism for transcription underlying precise gene expression.
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Affiliation(s)
- Yanling Peng
- Animal Functional Genomics GroupAgricultural Genomics Institute at ShenzhenChinese Academy of Agricultural SciencesShenzhenChina
| | - Yubo Zhang
- Animal Functional Genomics GroupAgricultural Genomics Institute at ShenzhenChinese Academy of Agricultural SciencesShenzhenChina
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132
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Cheng D, Cheng T, Yang X, Zhang Q, Fu J, Feng T, Gong J, Xia Q. The genome-wide transcriptional regulatory landscape of ecdysone in the silkworm. Epigenetics Chromatin 2018; 11:48. [PMID: 30149809 PMCID: PMC6109983 DOI: 10.1186/s13072-018-0216-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Accepted: 08/10/2018] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND The silkworm, Bombyx mori, a typical representative of metamorphic insects, is of great agricultural and economic importance. The steroid hormone ecdysone (20-hydroxyecdysone, 20E) is the central regulator of insect developmental transitions, and its nuclear receptors are crucial for numerous biological processes, including reproduction, metabolism, and immunity. However, genome-wide DNA regulatory elements and the ecdysone receptor (EcR) that control these programs of gene expression are not well defined. RESULTS In this study, we investigated the alterations in three types of histone modification in silkworm embryonic cells treated with 20E by chromatin immunoprecipitation sequencing (ChIP-seq). We identified enhancers using histone modifications and derived genome-wide ecdysone-dependent enhancer activity maps in the silkworm. We found enhancers enriched for monomethylation of histone H3 Lys4 (H3K4me1) that showed dynamic changes in acetylation of histone H3 Lys27 (H3K27ac) after 20E treatment and functioned to regulate the transcription of specific genes. EcR regulated transcription by binding not only to proximal promoters but also to the distal enhancers of target genes. Moreover, only 52.65% EcR peaks contained ecdysone response element (EcRE) motif, suggesting that EcR regulates the expression of target genes not only by binding directly to EcRE, but also by binding with other transcription factor. CONCLUSIONS Our findings provide novel insights into the complex regulatory landscape of hormone-responsive cell activity and a basis for understanding the complex transcriptional regulatory processes of ecdysone.
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Affiliation(s)
- Dong Cheng
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, 400715, China
| | - Tingcai Cheng
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, 400715, China. .,Chongqing Engineering and Technology Research Center for Novel Silk Materials, Southwest University, 2, Tiansheng Road, Beibei, Chongqing, 400715, China.
| | - Xi Yang
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, 400715, China
| | - Quan Zhang
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, 400715, China
| | - Jianfeng Fu
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, 400715, China
| | - Tieshan Feng
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, 400715, China
| | - Jiao Gong
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, 400715, China
| | - Qingyou Xia
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, 400715, China.,Chongqing Engineering and Technology Research Center for Novel Silk Materials, Southwest University, 2, Tiansheng Road, Beibei, Chongqing, 400715, China
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133
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Newcomb S, Voutev R, Jory A, Delker RK, Slattery M, Mann RS. cis-regulatory architecture of a short-range EGFR organizing center in the Drosophila melanogaster leg. PLoS Genet 2018; 14:e1007568. [PMID: 30142157 PMCID: PMC6147608 DOI: 10.1371/journal.pgen.1007568] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Revised: 09/20/2018] [Accepted: 07/16/2018] [Indexed: 12/19/2022] Open
Abstract
We characterized the establishment of an Epidermal Growth Factor Receptor (EGFR) organizing center (EOC) during leg development in Drosophila melanogaster. Initial EGFR activation occurs in the center of leg discs by expression of the EGFR ligand Vn and the EGFR ligand-processing protease Rho, each through single enhancers, vnE and rhoE, that integrate inputs from Wg, Dpp, Dll and Sp1. Deletion of vnE and rhoE eliminates vn and rho expression in the center of the leg imaginal discs, respectively. Animals with deletions of both vnE and rhoE (but not individually) show distal but not medial leg truncations, suggesting that the distal source of EGFR ligands acts at short-range to only specify distal-most fates, and that multiple additional ‘ring’ enhancers are responsible for medial fates. Further, based on the cis-regulatory logic of vnE and rhoE we identified many additional leg enhancers, suggesting that this logic is broadly used by many genes during Drosophila limb development. The EGFR signaling pathway plays a major role in innumerable developmental processes in all animals and its deregulation leads to different types of cancer, as well as many other developmental diseases in humans. Here we explored the integration of inputs from the Wnt- and TGF-beta signaling pathways and the leg-specifying transcription factors Distal-less and Sp1 at enhancer elements of EGFR ligands. These enhancers trigger a specific EGFR-dependent developmental output in the fly leg that is limited to specifying distal-most fates. Our findings suggest that activation of the EGFR pathway during fly leg development occurs through the activation of multiple EGFR ligand enhancers that are active at different positions along the proximo-distal axis. Similar enhancer elements are likely to control EGFR activation in humans as well. Such DNA elements might be ‘hot spots’ that cause formation of EGFR-dependent tumors if mutations in them occur. Thus, understanding the molecular characteristics of such DNA elements could facilitate the detection and treatment of cancer.
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Affiliation(s)
- Susan Newcomb
- Department of Biological Sciences, Columbia University, New York, NY, United States of America
| | - Roumen Voutev
- Department of Biochemistry and Molecular Biophysics and Department of Systems Biology, Columbia University, New York, NY, United States of America
- * E-mail: (RV); (RSM)
| | - Aurelie Jory
- Department of Biochemistry and Molecular Biophysics and Department of Systems Biology, Columbia University, New York, NY, United States of America
| | - Rebecca K. Delker
- Department of Biochemistry and Molecular Biophysics and Department of Systems Biology, Columbia University, New York, NY, United States of America
| | - Matthew Slattery
- Department of Biochemistry and Molecular Biophysics and Department of Systems Biology, Columbia University, New York, NY, United States of America
| | - Richard S. Mann
- Department of Biochemistry and Molecular Biophysics and Department of Systems Biology, Columbia University, New York, NY, United States of America
- * E-mail: (RV); (RSM)
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134
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Rahnamoun H, Hong J, Sun Z, Lee J, Lu H, Lauberth SM. Mutant p53 regulates enhancer-associated H3K4 monomethylation through interactions with the methyltransferase MLL4. J Biol Chem 2018; 293:13234-13246. [PMID: 29954944 PMCID: PMC6109924 DOI: 10.1074/jbc.ra118.003387] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2018] [Revised: 06/17/2018] [Indexed: 01/18/2023] Open
Abstract
Monomethylation of histone H3 lysine 4 (H3K4me1) is enriched at enhancers that are primed for activation and the levels of this histone mark are frequently altered in various human cancers. Yet, how alterations in H3K4me1 are established and the consequences of these epigenetic changes in tumorigenesis are not well understood. Using ChIP-Seq in human colon cancer cells, we demonstrate that mutant p53 depletion results in decreased H3K4me1 levels at active enhancers that reveal a striking colocalization of mutant p53 and the H3K4 monomethyltransferase MLL4 following chronic tumor necrosis factor alpha (TNFα) signaling. We further reveal that mutant p53 forms physiological associations and direct interactions with MLL4 and promotes the enhancer binding of MLL4, which is required for TNFα-inducible H3K4me1 and histone H3 lysine 27 acetylation (H3K27ac) levels, enhancer-derived transcript (eRNA) synthesis, and mutant p53-dependent target gene activation. Complementary in vitro studies with recombinant chromatin and purified proteins demonstrate that binding of the MLL3/4 complex and H3K4me1 deposition is enhanced by mutant p53 and p300-mediated acetylation, which in turn reflects a MLL3/4-dependent enhancement of mutant p53 and p300-dependent transcriptional activation. Collectively, our findings establish a mechanism in which mutant p53 cooperates with MLL4 to regulate aberrant enhancer activity and tumor-promoting gene expression in response to chronic immune signaling.
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Affiliation(s)
- Homa Rahnamoun
- From the Section of Molecular Biology, University of California, San Diego, La Jolla, California 92093
| | - Juyeong Hong
- From the Section of Molecular Biology, University of California, San Diego, La Jolla, California 92093
| | - Zhengxi Sun
- From the Section of Molecular Biology, University of California, San Diego, La Jolla, California 92093
| | - Jihoon Lee
- From the Section of Molecular Biology, University of California, San Diego, La Jolla, California 92093
| | - Hanbin Lu
- From the Section of Molecular Biology, University of California, San Diego, La Jolla, California 92093
| | - Shannon M Lauberth
- From the Section of Molecular Biology, University of California, San Diego, La Jolla, California 92093
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135
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Han R, Li L, Ugalde AP, Tal A, Manber Z, Barbera EP, Chiara VD, Elkon R, Agami R. Functional CRISPR screen identifies AP1-associated enhancer regulating FOXF1 to modulate oncogene-induced senescence. Genome Biol 2018; 19:118. [PMID: 30119690 PMCID: PMC6097335 DOI: 10.1186/s13059-018-1494-1] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Accepted: 07/27/2018] [Indexed: 01/02/2023] Open
Abstract
BACKGROUND Functional characterization of non-coding elements in the human genome is a major genomic challenge and the maturation of genome-editing technologies is revolutionizing our ability to achieve this task. Oncogene-induced senescence, a cellular state of irreversible proliferation arrest that is enforced following excessive oncogenic activity, is a major barrier against cancer transformation; therefore, bypassing oncogene-induced senescence is a critical step in tumorigenesis. Here, we aim at further identification of enhancer elements that are required for the establishment of this state. RESULTS We first apply genome-wide profiling of enhancer-RNAs (eRNAs) to systematically identify enhancers that are activated upon oncogenic stress. DNA motif analysis of these enhancers indicates AP-1 as a major regulator of the transcriptional program induced by oncogene-induced senescence. We thus constructed a CRISPR-Cas9 sgRNA library designed to target senescence-induced enhancers that are putatively regulated by AP-1 and used it in a functional screen. We identify a critical enhancer that we name EnhAP1-OIS1 and validate that mutating the AP-1 binding site within this element results in oncogene-induced senescence bypass. Furthermore, we identify FOXF1 as the gene regulated by this enhancer and demonstrate that FOXF1 mediates EnhAP1-OIS1 effect on the senescence phenotype. CONCLUSIONS Our study elucidates a novel cascade mediated by AP-1 and FOXF1 that regulates oncogene-induced senescence and further demonstrates the power of CRISPR-based functional genomic screens in deciphering the function of non-coding regulatory elements in the genome.
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Affiliation(s)
- Ruiqi Han
- Division of Oncogenomics, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, The Netherlands
- Oncode Institute, Amsterdam, The Netherlands
| | - Li Li
- Division of Oncogenomics, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, The Netherlands
- Oncode Institute, Amsterdam, The Netherlands
| | - Alejandro Piñeiro Ugalde
- Division of Oncogenomics, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, The Netherlands
| | - Arieh Tal
- Division of Oncogenomics, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, The Netherlands
| | - Zohar Manber
- Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, 69978 Tel Aviv, Israel
| | - Eric Pinto Barbera
- Division of Oncogenomics, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, The Netherlands
- Oncode Institute, Amsterdam, The Netherlands
| | - Veronica Della Chiara
- Division of Oncogenomics, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, The Netherlands
| | - Ran Elkon
- Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, 69978 Tel Aviv, Israel
| | - Reuven Agami
- Division of Oncogenomics, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, The Netherlands
- Department of Genetics, Erasmus University Medical Center, Wytemaweg 80, 3015 CN Rotterdam, The Netherlands
- Oncode Institute, Amsterdam, The Netherlands
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136
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Klein JC, Keith A, Agarwal V, Durham T, Shendure J. Functional characterization of enhancer evolution in the primate lineage. Genome Biol 2018; 19:99. [PMID: 30045748 PMCID: PMC6060477 DOI: 10.1186/s13059-018-1473-6] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Accepted: 07/05/2018] [Indexed: 11/21/2022] Open
Abstract
BACKGROUND Enhancers play an important role in morphological evolution and speciation by controlling the spatiotemporal expression of genes. Previous efforts to understand the evolution of enhancers in primates have typically studied many enhancers at low resolution, or single enhancers at high resolution. Although comparative genomic studies reveal large-scale turnover of enhancers, a specific understanding of the molecular steps by which mammalian or primate enhancers evolve remains elusive. RESULTS We identified candidate hominoid-specific liver enhancers from H3K27ac ChIP-seq data. After locating orthologs in 11 primates spanning around 40 million years, we synthesized all orthologs as well as computational reconstructions of 9 ancestral sequences for 348 active tiles of 233 putative enhancers. We concurrently tested all sequences for regulatory activity with STARR-seq in HepG2 cells. We observe groups of enhancer tiles with coherent trajectories, most of which can be potentially explained by a single gain or loss-of-activity event per tile. We quantify the correlation between the number of mutations along a branch and the magnitude of change in functional activity. Finally, we identify 84 mutations that correlate with functional changes; these are enriched for cytosine deamination events within CpGs. CONCLUSIONS We characterized the evolutionary-functional trajectories of hundreds of liver enhancers throughout the primate phylogeny. We observe subsets of regulatory sequences that appear to have gained or lost activity. We use these data to quantify the relationship between sequence and functional divergence, and to identify CpG deamination as a potentially important force in driving changes in enhancer activity during primate evolution.
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Affiliation(s)
- Jason C Klein
- Department of Genome Sciences, University of Washington, Seattle, WA, 98195, USA.
| | - Aidan Keith
- Department of Genome Sciences, University of Washington, Seattle, WA, 98195, USA
| | - Vikram Agarwal
- Department of Genome Sciences, University of Washington, Seattle, WA, 98195, USA
| | - Timothy Durham
- Department of Genome Sciences, University of Washington, Seattle, WA, 98195, USA
| | - Jay Shendure
- Department of Genome Sciences, University of Washington, Seattle, WA, 98195, USA.
- Howard Hughes Medical Institute, University of Washington, Seattle, WA, 98195, USA.
- Brotman Baty Institute for Precision Medicine, Seattle, WA, 98195-8047, USA.
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137
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Dynamic interplay between enhancer-promoter topology and gene activity. Nat Genet 2018; 50:1296-1303. [PMID: 30038397 PMCID: PMC6119122 DOI: 10.1038/s41588-018-0175-z] [Citation(s) in RCA: 282] [Impact Index Per Article: 47.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2017] [Accepted: 06/12/2018] [Indexed: 11/08/2022]
Abstract
A long-standing question in gene regulation is how remote enhancers communicate with their target promoters, and specifically how chromatin topology dynamically relates to gene activation. Here, we combine genome editing and multi-color live imaging to simultaneously visualize physical enhancer-promoter interaction and transcription at the single-cell level in Drosophila embryos. By examining transcriptional activation of a reporter by the endogenous even-skipped enhancers, which are located 150 kb away, we identify three distinct topological conformation states and measure their transition kinetics. We show that sustained proximity of the enhancer to its target is required for activation. Transcription in turn affects the three-dimensional topology as it enhances the temporal stability of the proximal conformation and is associated with further spatial compaction. Furthermore, the facilitated long-range activation results in transcriptional competition at the locus, causing corresponding developmental defects. Our approach offers quantitative insight into the spatial and temporal determinants of long-range gene regulation and their implications for cellular fates.
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138
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Tsai PF, Dell'Orso S, Rodriguez J, Vivanco KO, Ko KD, Jiang K, Juan AH, Sarshad AA, Vian L, Tran M, Wangsa D, Wang AH, Perovanovic J, Anastasakis D, Ralston E, Ried T, Sun HW, Hafner M, Larson DR, Sartorelli V. A Muscle-Specific Enhancer RNA Mediates Cohesin Recruitment and Regulates Transcription In trans. Mol Cell 2018; 71:129-141.e8. [PMID: 29979962 PMCID: PMC6082425 DOI: 10.1016/j.molcel.2018.06.008] [Citation(s) in RCA: 106] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Revised: 04/19/2018] [Accepted: 06/01/2018] [Indexed: 12/16/2022]
Abstract
The enhancer regions of the myogenic master regulator MyoD give rise to at least two enhancer RNAs. Core enhancer eRNA (CEeRNA) regulates transcription of the adjacent MyoD gene, whereas DRReRNA affects expression of Myogenin in trans. We found that DRReRNA is recruited at the Myogenin locus, where it colocalizes with Myogenin nascent transcripts. DRReRNA associates with the cohesin complex, and this association correlates with its transactivating properties. Despite being expressed in undifferentiated cells, cohesin is not loaded on Myogenin until the cells start expressing DRReRNA, which is then required for cohesin chromatin recruitment and maintenance. Functionally, depletion of either cohesin or DRReRNA reduces chromatin accessibility, prevents Myogenin activation, and hinders muscle cell differentiation. Thus, DRReRNA ensures spatially appropriate cohesin loading in trans to regulate gene expression.
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Affiliation(s)
- Pei-Fang Tsai
- Laboratory of Muscle Stem Cells and Gene Regulation, National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS), NIH, Bethesda, MD 20892, USA
| | - Stefania Dell'Orso
- High-Throughput Sequencing Unit, National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS), NIH, Bethesda, MD 20892, USA
| | - Joseph Rodriguez
- Laboratory of Receptor Biology and Gene Expression, National Cancer Institute, NIH, Bethesda, MD 20892, USA
| | - Karinna O Vivanco
- Laboratory of Muscle Stem Cells and Gene Regulation, National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS), NIH, Bethesda, MD 20892, USA
| | - Kyung-Dae Ko
- Laboratory of Muscle Stem Cells and Gene Regulation, National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS), NIH, Bethesda, MD 20892, USA
| | - Kan Jiang
- Biodata Mining and Discovery Section, NIAMS, NIH, Bethesda, MD 20892, USA
| | - Aster H Juan
- Laboratory of Muscle Stem Cells and Gene Regulation, National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS), NIH, Bethesda, MD 20892, USA
| | - Aishe A Sarshad
- Laboratory of Muscle Stem Cells and Gene Regulation, National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS), NIH, Bethesda, MD 20892, USA
| | - Laura Vian
- Translational Immunology Section, NIAMS, NIH, Bethesda, MD 20892, USA
| | - Michelle Tran
- Light Imaging Section, NIAMS, NIH, Bethesda, MD 20892, USA
| | - Darawalee Wangsa
- Genetics Branch, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD 20892, USA
| | - A Hongjun Wang
- Laboratory of Muscle Stem Cells and Gene Regulation, National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS), NIH, Bethesda, MD 20892, USA
| | - Jelena Perovanovic
- Laboratory of Muscle Stem Cells and Gene Regulation, National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS), NIH, Bethesda, MD 20892, USA
| | - Dimitrios Anastasakis
- Laboratory of Muscle Stem Cells and Gene Regulation, National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS), NIH, Bethesda, MD 20892, USA
| | - Evelyn Ralston
- Light Imaging Section, NIAMS, NIH, Bethesda, MD 20892, USA
| | - Thomas Ried
- Genetics Branch, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD 20892, USA
| | - Hong-Wei Sun
- Biodata Mining and Discovery Section, NIAMS, NIH, Bethesda, MD 20892, USA
| | - Markus Hafner
- Laboratory of Muscle Stem Cells and Gene Regulation, National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS), NIH, Bethesda, MD 20892, USA
| | - Daniel R Larson
- Laboratory of Receptor Biology and Gene Expression, National Cancer Institute, NIH, Bethesda, MD 20892, USA
| | - Vittorio Sartorelli
- Laboratory of Muscle Stem Cells and Gene Regulation, National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS), NIH, Bethesda, MD 20892, USA.
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139
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Link VM, Duttke SH, Chun HB, Holtman IR, Westin E, Hoeksema MA, Abe Y, Skola D, Romanoski CE, Tao J, Fonseca GJ, Troutman TD, Spann NJ, Strid T, Sakai M, Yu M, Hu R, Fang R, Metzler D, Ren B, Glass CK. Analysis of Genetically Diverse Macrophages Reveals Local and Domain-wide Mechanisms that Control Transcription Factor Binding and Function. Cell 2018; 173:1796-1809.e17. [PMID: 29779944 PMCID: PMC6003872 DOI: 10.1016/j.cell.2018.04.018] [Citation(s) in RCA: 119] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2018] [Revised: 04/06/2018] [Accepted: 04/13/2018] [Indexed: 12/22/2022]
Abstract
Non-coding genetic variation is a major driver of phenotypic diversity and allows the investigation of mechanisms that control gene expression. Here, we systematically investigated the effects of >50 million variations from five strains of mice on mRNA, nascent transcription, transcription start sites, and transcription factor binding in resting and activated macrophages. We observed substantial differences associated with distinct molecular pathways. Evaluating genetic variation provided evidence for roles of ∼100 TFs in shaping lineage-determining factor binding. Unexpectedly, a substantial fraction of strain-specific factor binding could not be explained by local mutations. Integration of genomic features with chromatin interaction data provided evidence for hundreds of connected cis-regulatory domains associated with differences in transcription factor binding and gene expression. This system and the >250 datasets establish a substantial new resource for investigation of how genetic variation affects cellular phenotypes.
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Affiliation(s)
- Verena M Link
- Department of Cellular and Molecular Medicine, School of Medicine, University of California, San Diego, La Jolla, CA, USA; Faculty of Biology, Division of Evolutionary Biology, Ludwig-Maximilian University of Munich, Munich, Germany
| | - Sascha H Duttke
- Department of Cellular and Molecular Medicine, School of Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Hyun B Chun
- Department of Cellular and Molecular Medicine, School of Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Inge R Holtman
- Department of Cellular and Molecular Medicine, School of Medicine, University of California, San Diego, La Jolla, CA, USA; Department of Neuroscience, Section Medical Physiology, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands
| | - Emma Westin
- Department of Cellular and Molecular Medicine, School of Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Marten A Hoeksema
- Department of Cellular and Molecular Medicine, School of Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Yohei Abe
- Department of Cellular and Molecular Medicine, School of Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Dylan Skola
- Department of Cellular and Molecular Medicine, School of Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Casey E Romanoski
- Department of Cellular and Molecular Medicine, University of Arizona, Tucson, AZ, USA
| | - Jenhan Tao
- Department of Cellular and Molecular Medicine, School of Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Gregory J Fonseca
- Department of Cellular and Molecular Medicine, School of Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Ty D Troutman
- Department of Cellular and Molecular Medicine, School of Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Nathanael J Spann
- Department of Cellular and Molecular Medicine, School of Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Tobias Strid
- Department of Cellular and Molecular Medicine, School of Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Mashito Sakai
- Department of Cellular and Molecular Medicine, School of Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Miao Yu
- Ludwig Institute for Cancer Research, La Jolla, CA, USA
| | - Rong Hu
- Ludwig Institute for Cancer Research, La Jolla, CA, USA
| | - Rongxin Fang
- Ludwig Institute for Cancer Research, La Jolla, CA, USA
| | - Dirk Metzler
- Faculty of Biology, Division of Evolutionary Biology, Ludwig-Maximilian University of Munich, Munich, Germany
| | - Bing Ren
- Department of Cellular and Molecular Medicine, School of Medicine, University of California, San Diego, La Jolla, CA, USA; Ludwig Institute for Cancer Research, La Jolla, CA, USA
| | - Christopher K Glass
- Department of Cellular and Molecular Medicine, School of Medicine, University of California, San Diego, La Jolla, CA, USA; Department of Medicine, University of California, San Diego, La Jolla, CA, USA.
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140
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Ding M, Liu Y, Liao X, Zhan H, Liu Y, Huang W. Enhancer RNAs (eRNAs): New Insights into Gene Transcription and Disease Treatment. J Cancer 2018; 9:2334-2340. [PMID: 30026829 PMCID: PMC6036709 DOI: 10.7150/jca.25829] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Accepted: 03/30/2018] [Indexed: 12/23/2022] Open
Abstract
Enhancers are cis-acting elements that have the ability to increase the expression of target genes. Recent studies have shown that enhancers can act as transcriptional units for the production of enhancer RNAs (eRNAs), which are hallmarks of activity enhancers and are involved in the regulation of gene transcription. The in-depth study of eRNAs is of great significance for us to better understand enhancer function and transcriptional regulation in various diseases. Therefore, eRNAs may be a potential therapeutic target for diseases. Here, we review the current knowledge of the characteristics of eRNAs, the molecular mechanisms of eRNAs action, as well as diseases related to dysregulation of eRNAs.
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Affiliation(s)
- Mengting Ding
- Department of Urology, Shenzhen Second People's Hospital, the First Affiliated Hospital of Shenzhen University, Clinical Medicine College of Anhui Medical University, Shenzhen 518000, Guangdong, China.,Anhui Medical University, Hefei 230032, Anhui Province, China
| | - Yuhan Liu
- Department of Urology, Shenzhen Second People's Hospital, the First Affiliated Hospital of Shenzhen University, Clinical Medicine College of Anhui Medical University, Shenzhen 518000, Guangdong, China.,Department of Urology, Shenzhen Second People's Hospital, the First Affiliated Hospital of Shenzhen University, Shenzhen 518000, China
| | - Xinhui Liao
- Department of Urology, Shenzhen Second People's Hospital, the First Affiliated Hospital of Shenzhen University, Shenzhen 518000, China
| | - Hengji Zhan
- Department of Urology, Shenzhen Second People's Hospital, the First Affiliated Hospital of Shenzhen University, Clinical Medicine College of Anhui Medical University, Shenzhen 518000, Guangdong, China.,Department of Urology, Shenzhen Second People's Hospital, the First Affiliated Hospital of Shenzhen University, Shenzhen 518000, China
| | - Yuchen Liu
- Department of Urology, Shenzhen Second People's Hospital, the First Affiliated Hospital of Shenzhen University, Shenzhen 518000, China
| | - Weiren Huang
- Department of Urology, Shenzhen Second People's Hospital, the First Affiliated Hospital of Shenzhen University, Shenzhen 518000, China
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141
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Shin HY. Targeting Super-Enhancers for Disease Treatment and Diagnosis. Mol Cells 2018; 41:506-514. [PMID: 29754476 PMCID: PMC6030247 DOI: 10.14348/molcells.2018.2297] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2017] [Revised: 04/06/2018] [Accepted: 04/12/2018] [Indexed: 01/05/2023] Open
Abstract
The transcriptional regulation of genes determines the fate of animal cell differentiation and subsequent organ development. With the recent progress in genome-wide technologies, the genomic landscapes of enhancers have been broadly explored in mammalian genomes, which led to the discovery of novel specific subsets of enhancers, termed super-enhancers. Super-enhancers are large clusters of enhancers covering the long region of regulatory DNA and are densely occupied by transcription factors, active histone marks, and co-activators. Accumulating evidence points to the critical role that super-enhancers play in cell type-specific development and differentiation, as well as in the development of various diseases. Here, I provide a comprehensive description of the optimal approach for identifying functional units of super-enhancers and their unique chromatin features in normal development and in diseases, including cancers. I also review the recent updated knowledge on novel approaches of targeting super-enhancers for the treatment of specific diseases, such as small-molecule inhibitors and potential gene therapy. This review will provide perspectives on using super-enhancers as biomarkers to develop novel disease diagnostic tools and establish new directions in clinical therapeutic strategies.
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Affiliation(s)
- Ha Youn Shin
- Department of Biomedical Science and Engineering, Konkuk University, Seoul 05029,
Korea
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142
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Kelley DR, Reshef YA, Bileschi M, Belanger D, McLean CY, Snoek J. Sequential regulatory activity prediction across chromosomes with convolutional neural networks. Genome Res 2018; 28:739-750. [PMID: 29588361 PMCID: PMC5932613 DOI: 10.1101/gr.227819.117] [Citation(s) in RCA: 231] [Impact Index Per Article: 38.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Accepted: 03/23/2018] [Indexed: 01/10/2023]
Abstract
Models for predicting phenotypic outcomes from genotypes have important applications to understanding genomic function and improving human health. Here, we develop a machine-learning system to predict cell-type-specific epigenetic and transcriptional profiles in large mammalian genomes from DNA sequence alone. By use of convolutional neural networks, this system identifies promoters and distal regulatory elements and synthesizes their content to make effective gene expression predictions. We show that model predictions for the influence of genomic variants on gene expression align well to causal variants underlying eQTLs in human populations and can be useful for generating mechanistic hypotheses to enable fine mapping of disease loci.
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Affiliation(s)
| | - Yakir A Reshef
- Department of Computer Science, Harvard University, Cambridge, Massachusetts 02138, USA
| | | | | | | | - Jasper Snoek
- Google Brain, Cambridge, Massachusetts 02142, USA
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143
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Mitra S, Biswas A, Narlikar L. DIVERSITY in binding, regulation, and evolution revealed from high-throughput ChIP. PLoS Comput Biol 2018; 14:e1006090. [PMID: 29684008 PMCID: PMC5933800 DOI: 10.1371/journal.pcbi.1006090] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2017] [Revised: 05/03/2018] [Accepted: 03/14/2018] [Indexed: 12/27/2022] Open
Abstract
Genome-wide in vivo protein-DNA interactions are routinely mapped using high-throughput chromatin immunoprecipitation (ChIP). ChIP-reported regions are typically investigated for enriched sequence-motifs, which are likely to model the DNA-binding specificity of the profiled protein and/or of co-occurring proteins. However, simple enrichment analyses can miss insights into the binding-activity of the protein. Note that ChIP reports regions making direct contact with the protein as well as those binding through intermediaries. For example, consider a ChIP experiment targeting protein X, which binds DNA at its cognate sites, but simultaneously interacts with four other proteins. Each of these proteins also binds to its own specific cognate sites along distant parts of the genome, a scenario consistent with the current view of transcriptional hubs and chromatin loops. Since ChIP will pull down all X-associated regions, the final reported data will be a union of five distinct sets of regions, each containing binding sites of one of the five proteins, respectively. Characterizing all five different motifs and the corresponding sets is important to interpret the ChIP experiment and ultimately, the role of X in regulation. We present diversity which attempts exactly this: it partitions the data so that each partition can be characterized with its own de novo motif. Diversity uses a Bayesian approach to identify the optimal number of motifs and the associated partitions, which together explain the entire dataset. This is in contrast to standard motif finders, which report motifs individually enriched in the data, but do not necessarily explain all reported regions. We show that the different motifs and associated regions identified by diversity give insights into the various complexes that may be forming along the chromatin, something that has so far not been attempted from ChIP data. Webserver at http://diversity.ncl.res.in/; standalone (Mac OS X/Linux) from https://github.com/NarlikarLab/DIVERSITY/releases/tag/v1.0.0. A high-throughput chromatin immunoprecipitation (ChIP) experiment identifies genomic regions bound by a protein in vivo. Current motif-discovery approaches seek an enriched motif signature in the reported regions, which they can attribute to the protein’s binding preferences. However, Diversity models the fact that since a ChIP experiment pulls down regions participating in all complexes involving the profiled protein, the reported regions are in all likelihood, a collection of different types of protein-DNA contacts. Diversity asks a different question: what sequence component caused a specific region to be reported in a ChIP experiment? The answer, in combination with additional data such as sequence conservation, SNPs, chromatin structure, downstream gene-expression, etc. can yield insights into the diverse regulatory mechanisms at play. The added benefits of a webserver and a standalone parallel version make diversity a practical tool for discovering new biology from ChIP experiments.
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Affiliation(s)
- Sneha Mitra
- Department of Chemical Engineering, CSIR-National Chemical Laboratory, Pune, India
| | - Anushua Biswas
- Department of Chemical Engineering, CSIR-National Chemical Laboratory, Pune, India
| | - Leelavati Narlikar
- Department of Chemical Engineering, CSIR-National Chemical Laboratory, Pune, India
- * E-mail:
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144
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Gu B, Swigut T, Spencley A, Bauer MR, Chung M, Meyer T, Wysocka J. Transcription-coupled changes in nuclear mobility of mammalian cis-regulatory elements. Science 2018; 359:1050-1055. [PMID: 29371426 PMCID: PMC6590518 DOI: 10.1126/science.aao3136] [Citation(s) in RCA: 237] [Impact Index Per Article: 39.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2017] [Accepted: 01/16/2018] [Indexed: 12/15/2022]
Abstract
To achieve guide RNA (gRNA) multiplexing and an efficient delivery of tens of distinct gRNAs into single cells, we developed a molecular assembly strategy termed chimeric array of gRNA oligonucleotides (CARGO). We coupled CARGO with dCas9 (catalytically dead Cas9) imaging to quantitatively measure the movement of enhancers and promoters that undergo differentiation-associated activity changes in live embryonic stem cells. Whereas all examined functional elements exhibited subdiffusive behavior, their relative mobility increased concurrently with transcriptional activation. Furthermore, acute perturbation of RNA polymerase II activity can reverse these activity-linked increases in loci mobility. Through quantitative CARGO-dCas9 imaging, we provide direct measurements of cis-regulatory element dynamics in living cells and distinct cellular and activity states and uncover an intrinsic connection between cis-regulatory element mobility and transcription.
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Affiliation(s)
- Bo Gu
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Tomek Swigut
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Andrew Spencley
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
- Cancer Biology Program, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Matthew R Bauer
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Mingyu Chung
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Tobias Meyer
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Joanna Wysocka
- 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
- Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, CA 94305, USA
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145
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Yan J, Chen SAA, Local A, Liu T, Qiu Y, Dorighi KM, Preissl S, Rivera CM, Wang C, Ye Z, Ge K, Hu M, Wysocka J, Ren B. Histone H3 lysine 4 monomethylation modulates long-range chromatin interactions at enhancers. Cell Res 2018; 28:204-220. [PMID: 29313530 PMCID: PMC5799818 DOI: 10.1038/cr.2018.1] [Citation(s) in RCA: 90] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2017] [Revised: 04/05/2017] [Accepted: 11/14/2017] [Indexed: 12/22/2022] Open
Abstract
Long-range chromatin interactions between enhancers and promoters are essential for transcription of many developmentally controlled genes in mammals and other metazoans. Currently, the exact mechanisms that connect distal enhancers to their specific target promoters remain to be fully elucidated. Here, we show that the enhancer-specific histone H3 lysine 4 monomethylation (H3K4me1) and the histone methyltransferases MLL3 and MLL4 (MLL3/4) play an active role in this process. We demonstrate that in differentiating mouse embryonic stem cells, MLL3/4-dependent deposition of H3K4me1 at enhancers correlates with increased levels of chromatin interactions, whereas loss of this histone modification leads to reduced levels of chromatin interactions and defects in gene activation during differentiation. H3K4me1 facilitates recruitment of the Cohesin complex, a known regulator of chromatin organization, to chromatin in vitro and in vivo, providing a potential mechanism for MLL3/4 to promote chromatin interactions between enhancers and promoters. Taken together, our results support a role for MLL3/4-dependent H3K4me1 in orchestrating long-range chromatin interactions at enhancers in mammalian cells.
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Affiliation(s)
- Jian Yan
- Ludwig Institute for Cancer Research, 9500 Gilman Dr., La Jolla, CA 92093, USA
- Department of Medical Biochemistry and Biophysics, Division of Functional Genomics and Systems Biology, Karolinska Institutet, 171 65 Stockholm, Sweden
| | - Shi-An A Chen
- Ludwig Institute for Cancer Research, 9500 Gilman Dr., La Jolla, CA 92093, USA
| | - Andrea Local
- Ludwig Institute for Cancer Research, 9500 Gilman Dr., La Jolla, CA 92093, USA
- Current address: Aptose Biosciences Inc., 3550 General Atomics Ct, San Diego, CA 92122, USA
| | - Tristin Liu
- Ludwig Institute for Cancer Research, 9500 Gilman Dr., La Jolla, CA 92093, USA
| | - Yunjiang Qiu
- Ludwig Institute for Cancer Research, 9500 Gilman Dr., La Jolla, CA 92093, USA
| | - Kristel M Dorighi
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Sebastian Preissl
- Ludwig Institute for Cancer Research, 9500 Gilman Dr., La Jolla, CA 92093, USA
| | - Chloe M Rivera
- Ludwig Institute for Cancer Research, 9500 Gilman Dr., La Jolla, CA 92093, USA
| | - Chaochen Wang
- Laboratory of Endocrinology and Receptor Biology, National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Bethesda, MD 20892, USA
| | - Zhen Ye
- Ludwig Institute for Cancer Research, 9500 Gilman Dr., La Jolla, CA 92093, USA
| | - Kai Ge
- Laboratory of Endocrinology and Receptor Biology, National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Bethesda, MD 20892, USA
| | - Ming Hu
- Department of Quantitative Health Sciences, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH 44195, USA
| | - Joanna Wysocka
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Bing Ren
- Ludwig Institute for Cancer Research, 9500 Gilman Dr., La Jolla, CA 92093, USA
- Department of Cellular and Molecular Medicine, University of California San Diego, School of Medicine, Institute of Genomic Medicine, 9500 Gilman Dr., La Jolla, CA 92093, USA
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146
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Henriques T, Scruggs BS, Inouye MO, Muse GW, Williams LH, Burkholder AB, Lavender CA, Fargo DC, Adelman K. Widespread transcriptional pausing and elongation control at enhancers. Genes Dev 2018; 32:26-41. [PMID: 29378787 PMCID: PMC5828392 DOI: 10.1101/gad.309351.117] [Citation(s) in RCA: 226] [Impact Index Per Article: 37.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Accepted: 12/21/2017] [Indexed: 02/07/2023]
Abstract
In this study, Henriques et al. demonstrate that transcription is a nearly universal feature of enhancers in Drosophila and mammalian cells and that nascent RNA sequencing strategies are optimal for identification of both enhancers and superenhancers. Their findings provide insights into the unique characteristics of superenhancers, which stimulate high-level gene expression through rapid pause release; interestingly, this property renders associated genes resistant to loss of factors that stabilize paused RNAPII. Regulation by gene-distal enhancers is critical for cell type-specific and condition-specific patterns of gene expression. Thus, to understand the basis of gene activity in a given cell type or tissue, we must identify the precise locations of enhancers and functionally characterize their behaviors. Here, we demonstrate that transcription is a nearly universal feature of enhancers in Drosophila and mammalian cells and that nascent RNA sequencing strategies are optimal for identification of both enhancers and superenhancers. We dissect the mechanisms governing enhancer transcription and discover remarkable similarities to transcription at protein-coding genes. We show that RNA polymerase II (RNAPII) undergoes regulated pausing and release at enhancers. However, as compared with mRNA genes, RNAPII at enhancers is less stable and more prone to early termination. Furthermore, we found that the level of histone H3 Lys4 (H3K4) methylation at enhancers corresponds to transcriptional activity such that highly active enhancers display H3K4 trimethylation rather than the H3K4 monomethylation considered a hallmark of enhancers. Finally, our work provides insights into the unique characteristics of superenhancers, which stimulate high-level gene expression through rapid pause release; interestingly, this property renders associated genes resistant to the loss of factors that stabilize paused RNAPII.
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Affiliation(s)
- Telmo Henriques
- Epigenetics and Stem Cell Biology Laboratory, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina 27709, USA.,Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Benjamin S Scruggs
- Epigenetics and Stem Cell Biology Laboratory, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina 27709, USA
| | - Michiko O Inouye
- Epigenetics and Stem Cell Biology Laboratory, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina 27709, USA.,Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Ginger W Muse
- Epigenetics and Stem Cell Biology Laboratory, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina 27709, USA
| | - Lucy H Williams
- Epigenetics and Stem Cell Biology Laboratory, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina 27709, USA
| | - Adam B Burkholder
- Center for Integrative Bioinformatics, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina 27709, USA
| | - Christopher A Lavender
- Center for Integrative Bioinformatics, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina 27709, USA
| | - David C Fargo
- Center for Integrative Bioinformatics, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina 27709, USA
| | - Karen Adelman
- Epigenetics and Stem Cell Biology Laboratory, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina 27709, USA.,Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115, USA
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147
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Worley MI, Alexander LA, Hariharan IK. CtBP impedes JNK- and Upd/STAT-driven cell fate misspecifications in regenerating Drosophila imaginal discs. eLife 2018; 7:30391. [PMID: 29372681 PMCID: PMC5823544 DOI: 10.7554/elife.30391] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Accepted: 01/19/2018] [Indexed: 12/27/2022] Open
Abstract
Regeneration following tissue damage often necessitates a mechanism for cellular re-programming, so that surviving cells can give rise to all cell types originally found in the damaged tissue. This process, if unchecked, can also generate cell types that are inappropriate for a given location. We conducted a screen for genes that negatively regulate the frequency of notum-to-wing transformations following genetic ablation and regeneration of the wing pouch, from which we identified mutations in the transcriptional co-repressor C-terminal Binding Protein (CtBP). When CtBP function is reduced, ablation of the pouch can activate the JNK/AP-1 and JAK/STAT pathways in the notum to destabilize cell fates. Ectopic expression of Wingless and Dilp8 precede the formation of the ectopic pouch, which is subsequently generated by recruitment of both anterior and posterior cells near the compartment boundary. Thus, CtBP stabilizes cell fates following damage by opposing the destabilizing effects of the JNK/AP-1 and JAK/STAT pathways.
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Affiliation(s)
- Melanie I Worley
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States
| | - Larissa A Alexander
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States
| | - Iswar K Hariharan
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States
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148
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Abstract
We developed a predictive, stable, and interpretable tool: the iterative random forest algorithm (iRF). iRF discovers high-order interactions among biomolecules with the same order of computational cost as random forests. We demonstrate the efficacy of iRF by finding known and promising interactions among biomolecules, of up to fifth and sixth order, in two data examples in transcriptional regulation and alternative splicing. Genomics has revolutionized biology, enabling the interrogation of whole transcriptomes, genome-wide binding sites for proteins, and many other molecular processes. However, individual genomic assays measure elements that interact in vivo as components of larger molecular machines. Understanding how these high-order interactions drive gene expression presents a substantial statistical challenge. Building on random forests (RFs) and random intersection trees (RITs) and through extensive, biologically inspired simulations, we developed the iterative random forest algorithm (iRF). iRF trains a feature-weighted ensemble of decision trees to detect stable, high-order interactions with the same order of computational cost as the RF. We demonstrate the utility of iRF for high-order interaction discovery in two prediction problems: enhancer activity in the early Drosophila embryo and alternative splicing of primary transcripts in human-derived cell lines. In Drosophila, among the 20 pairwise transcription factor interactions iRF identifies as stable (returned in more than half of bootstrap replicates), 80% have been previously reported as physical interactions. Moreover, third-order interactions, e.g., between Zelda (Zld), Giant (Gt), and Twist (Twi), suggest high-order relationships that are candidates for follow-up experiments. In human-derived cells, iRF rediscovered a central role of H3K36me3 in chromatin-mediated splicing regulation and identified interesting fifth- and sixth-order interactions, indicative of multivalent nucleosomes with specific roles in splicing regulation. By decoupling the order of interactions from the computational cost of identification, iRF opens additional avenues of inquiry into the molecular mechanisms underlying genome biology.
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149
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Roeske MJ, Camino EM, Grover S, Rebeiz M, Williams TM. Cis-regulatory evolution integrated the Bric-à-brac transcription factors into a novel fruit fly gene regulatory network. eLife 2018; 7. [PMID: 29297463 PMCID: PMC5752203 DOI: 10.7554/elife.32273] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2017] [Accepted: 12/19/2017] [Indexed: 11/13/2022] Open
Abstract
Gene expression evolution through gene regulatory network (GRN) changes has gained appreciation as a driver of morphological evolution. However, understanding how GRNs evolve is hampered by finding relevant cis-regulatory element (CRE) mutations, and interpreting the protein-DNA interactions they alter. We investigated evolutionary changes in the duplicated Bric-à-brac (Bab) transcription factors and a key Bab target gene in a GRN underlying the novel dimorphic pigmentation of D. melanogaster and its relatives. It has remained uncertain how Bab was integrated within the pigmentation GRN. Here, we show that the ancestral transcription factor activity of Bab gained a role in sculpting sex-specific pigmentation through the evolution of binding sites in a CRE of the pigment-promoting yellow gene. This work demonstrates how a new trait can evolve by incorporating existing transcription factors into a GRN through CRE evolution, an evolutionary path likely to predominate newly evolved functions of transcription factors.
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Affiliation(s)
- Maxwell J Roeske
- Department of Biology, University of Dayton, Dayton, United States
| | - Eric M Camino
- Department of Biology, University of Dayton, Dayton, United States
| | - Sumant Grover
- Department of Biology, University of Dayton, Dayton, United States
| | - Mark Rebeiz
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, United States
| | - Thomas Michael Williams
- Department of Biology, University of Dayton, Dayton, United States.,Center for Tissue Regeneration and Engineering at Dayton, University of Dayton, Dayton, United States
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150
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Maguire JE, Pandey A, Wu Y, Di Gregorio A. Investigating Evolutionarily Conserved Molecular Mechanisms Controlling Gene Expression in the Notochord. TRANSGENIC ASCIDIANS 2018. [DOI: 10.1007/978-981-10-7545-2_8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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