1
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Aguirre L, Hendelman A, Hutton SF, McCandlish DM, Lippman ZB. Idiosyncratic and dose-dependent epistasis drives variation in tomato fruit size. Science 2023; 382:315-320. [PMID: 37856609 PMCID: PMC10602613 DOI: 10.1126/science.adi5222] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Accepted: 09/06/2023] [Indexed: 10/21/2023]
Abstract
Epistasis between genes is traditionally studied with mutations that eliminate protein activity, but most natural genetic variation is in cis-regulatory DNA and influences gene expression and function quantitatively. In this study, we used natural and engineered cis-regulatory alleles in a plant stem-cell circuit to systematically evaluate epistatic relationships controlling tomato fruit size. Combining a promoter allelic series with two other loci, we collected over 30,000 phenotypic data points from 46 genotypes to quantify how allele strength transforms epistasis. We revealed a saturating dose-dependent relationship but also allele-specific idiosyncratic interactions, including between alleles driving a step change in fruit size during domestication. Our approach and findings expose an underexplored dimension of epistasis, in which cis-regulatory allelic diversity within gene regulatory networks elicits nonlinear, unpredictable interactions that shape phenotypes.
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Affiliation(s)
- Lyndsey Aguirre
- Cold Spring Harbor Laboratory, School of Biological Sciences, Cold Spring Harbor, NY, USA
| | - Anat Hendelman
- Cold Spring Harbor Laboratory; Cold Spring Harbor, NY, USA
| | - Samuel F. Hutton
- Gulf Coast Research and Education Center, University of Florida, Wimauma, FL, USA
| | | | - Zachary B. Lippman
- Cold Spring Harbor Laboratory, School of Biological Sciences, Cold Spring Harbor, NY, USA
- Cold Spring Harbor Laboratory; Cold Spring Harbor, NY, USA
- Howard Hughes Medical Institute, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA
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2
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Liu H, Cui P, Zhang B, Zhu J, Liu C, Li Q. Binding of the transcription factor MYC2-like to the ABRE of the OsCYP2 promoter enhances salt tolerance in Oryza sativa. PLoS One 2022; 17:e0276075. [PMID: 36240213 PMCID: PMC9565382 DOI: 10.1371/journal.pone.0276075] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2022] [Accepted: 09/28/2022] [Indexed: 11/05/2022] Open
Abstract
Cyclophilins, a type of peptidyl-prolyl cis-trans isomerase, function as important molecular chaperones in a series of biological processes. However, the expression pattern and signal transduction pathway of cyclophilins are still unclear. Here, we showed that the promoter of OsCYP2 could function as a tissue-specific promoter by GUS staining. Moreover, we found that the promoter sequence contained not only core elements but also inducible elements. Then, the ABA-responsive element was used for cDNA library screening, and the transcription factor MYC2-like was identified by a yeast one-hybrid assay and confirmed through an electrophoretic mobility shift assay. Furthermore, the relative expression showed that MYC2-like was induced by abscisic acid. In addition, MYC2-like overexpression enhanced salt tolerance in transformants and partially restored the cyp2-RNAi line. In summary, we explored a novel transcriptional signal mediated by MYC2-like, a potential regulator of salt stress-related physiological processes in rice.
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Affiliation(s)
- Hongbo Liu
- Key Laboratory for Quality Improvement of Agricultural Products of Zhejiang Province, College of Advanced Agricultural Sciences, Zhejiang A & F University, Hangzhou, China
- * E-mail:
| | - Peng Cui
- Key Laboratory for Quality Improvement of Agricultural Products of Zhejiang Province, College of Advanced Agricultural Sciences, Zhejiang A & F University, Hangzhou, China
| | - Bingxin Zhang
- Key Laboratory for Quality Improvement of Agricultural Products of Zhejiang Province, College of Advanced Agricultural Sciences, Zhejiang A & F University, Hangzhou, China
| | - Jinbo Zhu
- Key Laboratory for Quality Improvement of Agricultural Products of Zhejiang Province, College of Advanced Agricultural Sciences, Zhejiang A & F University, Hangzhou, China
| | - Cui Liu
- Key Laboratory for Quality Improvement of Agricultural Products of Zhejiang Province, College of Advanced Agricultural Sciences, Zhejiang A & F University, Hangzhou, China
| | - Qingyang Li
- Key Laboratory for Quality Improvement of Agricultural Products of Zhejiang Province, College of Advanced Agricultural Sciences, Zhejiang A & F University, Hangzhou, China
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3
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Song X, Meng X, Guo H, Cheng Q, Jing Y, Chen M, Liu G, Wang B, Wang Y, Li J, Yu H. Targeting a gene regulatory element enhances rice grain yield by decoupling panicle number and size. Nat Biotechnol 2022; 40:1403-1411. [PMID: 35449414 DOI: 10.1038/s41587-022-01281-7] [Citation(s) in RCA: 104] [Impact Index Per Article: 52.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Accepted: 03/14/2022] [Indexed: 12/13/2022]
Abstract
Crop genetic improvement requires balancing complex tradeoffs caused by gene pleiotropy and linkage drags, as exemplified by IPA1 (Ideal Plant Architecture 1), a typical pleiotropic gene in rice that increases grains per panicle but reduces tillers. In this study, we identified a 54-base pair cis-regulatory region in IPA1 via a tiling-deletion-based CRISPR-Cas9 screen that, when deleted, resolves the tradeoff between grains per panicle and tiller number, leading to substantially enhanced grain yield per plant. Mechanistic studies revealed that the deleted fragment is a target site for the transcription factor An-1 to repress IPA1 expression in panicles and roots. Targeting gene regulatory regions should help dissect tradeoff effects and provide a rich source of targets for breeding complementary beneficial traits.
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Affiliation(s)
- Xiaoguang Song
- State Key Laboratory of Plant Genomics and National Center for Plant Gene Research, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing, China
| | - Xiangbing Meng
- State Key Laboratory of Plant Genomics and National Center for Plant Gene Research, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing, China
| | - Hongyan Guo
- State Key Laboratory of Plant Genomics and National Center for Plant Gene Research, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing, China
| | - Qiao Cheng
- State Key Laboratory of Plant Genomics and National Center for Plant Gene Research, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Yanhui Jing
- State Key Laboratory of Plant Genomics and National Center for Plant Gene Research, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing, China
| | - Mingjiang Chen
- State Key Laboratory of Plant Genomics and National Center for Plant Gene Research, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing, China
| | - Guifu Liu
- State Key Laboratory of Plant Genomics and National Center for Plant Gene Research, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing, China
| | - Bing Wang
- State Key Laboratory of Plant Genomics and National Center for Plant Gene Research, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing, China
| | - Yonghong Wang
- State Key Laboratory of Plant Genomics and National Center for Plant Gene Research, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing, China.,University of Chinese Academy of Sciences, Beijing, China.,College of Life Sciences, Shandong Agricultural University, Tai'an, China
| | - Jiayang Li
- State Key Laboratory of Plant Genomics and National Center for Plant Gene Research, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing, China.,University of Chinese Academy of Sciences, Beijing, China.,Hainan Yazhou Bay Seed Laboratory, Sanya, China
| | - Hong Yu
- State Key Laboratory of Plant Genomics and National Center for Plant Gene Research, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing, China. .,University of Chinese Academy of Sciences, Beijing, China.
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4
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Paredes O, Morales JA, Mendizabal AP, Romo-Vázquez R. Metacode: One code to rule them all. Biosystems 2021; 208:104486. [PMID: 34274462 DOI: 10.1016/j.biosystems.2021.104486] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Revised: 07/07/2021] [Accepted: 07/09/2021] [Indexed: 12/13/2022]
Abstract
The code of codes or metacode is a microcosm where biological layers, as well as their codes, interact together allowing the continuity of information flow in organisms by increasing biological entities' complexity. Through this novel organic code, biological systems scale towards niches with higher informatic freedom building structures that increase the entropy in the universe. Code biology has developed a novel informational framework where biological entities strive themselves through the information flow carried out through organic codes consisting of two molecular or functional landscapes intertwined through arbitrary linkages via an adaptor whose nature is autonomous from molecular determinism. Here we will integrate genomic and epigenomic codes according to the evidence released in ENCODE (phase 3), psychENCODE and GTEx project, outlining the principles of the metacode, to address the continuous nature of biological systems and their inter-layered information flow. This novel complex metacode maps from very constrained sets of elements (i.e., regulation sites modulating gene expression) to new ones with greater freedom of decoding (i.e., a continuous cell phenotypic space). This leads to a new domain in code biology where biological systems are informatic attractors that navigate an energy metaspace through a complexity-noise balance, stalling in emergent niches where organic codes take meaning.
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Affiliation(s)
- Omar Paredes
- Computer Sciences Department, CUCEI, Universidad de Guadalajara, Mexico
| | | | - Adriana P Mendizabal
- Molecular Biology Laboratory, Farmacobiology Department, CUCEI, Universidad de Guadalajara, Mexico
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5
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Xiao JY, Hafner A, Boettiger AN. How subtle changes in 3D structure can create large changes in transcription. eLife 2021; 10:e64320. [PMID: 34240703 PMCID: PMC8352591 DOI: 10.7554/elife.64320] [Citation(s) in RCA: 66] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2020] [Accepted: 06/25/2021] [Indexed: 12/17/2022] Open
Abstract
Animal genomes are organized into topologically associated domains (TADs). TADs are thought to contribute to gene regulation by facilitating enhancer-promoter (E-P) contacts within a TAD and preventing these contacts across TAD borders. However, the absolute difference in contact frequency across TAD boundaries is usually less than 2-fold, even though disruptions of TAD borders can change gene expression by 10-fold. Existing models fail to explain this hypersensitive response. Here, we propose a futile cycle model of enhancer-mediated regulation that can exhibit hypersensitivity through bistability and hysteresis. Consistent with recent experiments, this regulation does not exhibit strong correlation between E-P contact and promoter activity, even though regulation occurs through contact. Through mathematical analysis and stochastic simulation, we show that this system can create an illusion of E-P biochemical specificity and explain the importance of weak TAD boundaries. It also offers a mechanism to reconcile apparently contradictory results from recent global TAD disruption with local TAD boundary deletion experiments. Together, these analyses advance our understanding of cis-regulatory contacts in controlling gene expression and suggest new experimental directions.
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Affiliation(s)
| | - Antonina Hafner
- Department of Developmental Biology, Stanford UniversityStanfordUnited States
| | - Alistair N Boettiger
- Program in Biophysics, Stanford UniversityStanfordUnited States
- Department of Developmental Biology, Stanford UniversityStanfordUnited States
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6
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Espinola SM, Götz M, Bellec M, Messina O, Fiche JB, Houbron C, Dejean M, Reim I, Cardozo Gizzi AM, Lagha M, Nollmann M. Cis-regulatory chromatin loops arise before TADs and gene activation, and are independent of cell fate during early Drosophila development. Nat Genet 2021; 53:477-486. [PMID: 33795867 DOI: 10.1038/s41588-021-00816-z] [Citation(s) in RCA: 81] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Accepted: 02/09/2021] [Indexed: 12/15/2022]
Abstract
Acquisition of cell fate is thought to rely on the specific interaction of remote cis-regulatory modules (CRMs), for example, enhancers and target promoters. However, the precise interplay between chromatin structure and gene expression is still unclear, particularly within multicellular developing organisms. In the present study, we employ Hi-M, a single-cell spatial genomics approach, to detect CRM-promoter looping interactions within topologically associating domains (TADs) during early Drosophila development. By comparing cis-regulatory loops in alternate cell types, we show that physical proximity does not necessarily instruct transcriptional states. Moreover, multi-way analyses reveal that multiple CRMs spatially coalesce to form hubs. Loops and CRM hubs are established early during development, before the emergence of TADs. Moreover, CRM hubs are formed, in part, via the action of the pioneer transcription factor Zelda and precede transcriptional activation. Our approach provides insight into the role of CRM-promoter interactions in defining transcriptional states, as well as distinct cell types.
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Affiliation(s)
- Sergio Martin Espinola
- Centre de Biologie Structurale, CNRS UMR 5048, INSERM U1054, Univ Montpellier, Montpellier, France
| | - Markus Götz
- Centre de Biologie Structurale, CNRS UMR 5048, INSERM U1054, Univ Montpellier, Montpellier, France
| | | | - Olivier Messina
- Centre de Biologie Structurale, CNRS UMR 5048, INSERM U1054, Univ Montpellier, Montpellier, France.,IGMM, CNRS, Univ Montpellier, Montpellier, France
| | - Jean-Bernard Fiche
- Centre de Biologie Structurale, CNRS UMR 5048, INSERM U1054, Univ Montpellier, Montpellier, France
| | - Christophe Houbron
- Centre de Biologie Structurale, CNRS UMR 5048, INSERM U1054, Univ Montpellier, Montpellier, France
| | | | - Ingolf Reim
- Department of Biology, Friedrich-Alexander University of Erlangen-Nürnberg, Erlangen, Germany
| | - Andrés M Cardozo Gizzi
- Centro de Investigación en Medicina Traslacional Severo Amuchastegui, Instituto Universitario de Ciencias Biomédicas de Córdoba, Consejo Nacional de Investigaciones Científicas y Técnicas, Córdoba, Argentina
| | - Mounia Lagha
- IGMM, CNRS, Univ Montpellier, Montpellier, France.
| | - Marcelo Nollmann
- Centre de Biologie Structurale, CNRS UMR 5048, INSERM U1054, Univ Montpellier, Montpellier, France.
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7
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Hendelman A, Zebell S, Rodriguez-Leal D, Dukler N, Robitaille G, Wu X, Kostyun J, Tal L, Wang P, Bartlett ME, Eshed Y, Efroni I, Lippman ZB. Conserved pleiotropy of an ancient plant homeobox gene uncovered by cis-regulatory dissection. Cell 2021; 184:1724-1739.e16. [PMID: 33667348 DOI: 10.1016/j.cell.2021.02.001] [Citation(s) in RCA: 102] [Impact Index Per Article: 34.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Revised: 01/03/2021] [Accepted: 02/01/2021] [Indexed: 01/09/2023]
Abstract
Divergence of gene function is a hallmark of evolution, but assessing functional divergence over deep time is not trivial. The few alleles available for cross-species studies often fail to expose the entire functional spectrum of genes, potentially obscuring deeply conserved pleiotropic roles. Here, we explore the functional divergence of WUSCHEL HOMEOBOX9 (WOX9), suggested to have species-specific roles in embryo and inflorescence development. Using a cis-regulatory editing drive system, we generate a comprehensive allelic series in tomato, which revealed hidden pleiotropic roles for WOX9. Analysis of accessible chromatin and conserved cis-regulatory sequences identifies the regions responsible for this pleiotropic activity, the functions of which are conserved in groundcherry, a tomato relative. Mimicking these alleles in Arabidopsis, distantly related to tomato and groundcherry, reveals new inflorescence phenotypes, exposing a deeply conserved pleiotropy. We suggest that targeted cis-regulatory mutations can uncover conserved gene functions and reduce undesirable effects in crop improvement.
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Affiliation(s)
- Anat Hendelman
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA
| | - Sophia Zebell
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA; Howard Hughes Medical Institute, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA
| | | | - Noah Dukler
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA
| | - Gina Robitaille
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA; Howard Hughes Medical Institute, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA
| | - Xuelin Wu
- The Salk Institute for Biological Research, San Diego, CA, USA
| | - Jamie Kostyun
- Biology Department, University of Massachusetts Amherst, Amherst, MA, USA
| | - Lior Tal
- Department of Plant and Environmental Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Peipei Wang
- Institute of Plant Sciences and Genetics in Agriculture, The Robert H. Smith Faculty of Agriculture, The Hebrew University, Rehovot, Israel
| | | | - Yuval Eshed
- Department of Plant and Environmental Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Idan Efroni
- Institute of Plant Sciences and Genetics in Agriculture, The Robert H. Smith Faculty of Agriculture, The Hebrew University, Rehovot, Israel.
| | - Zachary B Lippman
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA; Howard Hughes Medical Institute, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA.
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8
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Oberhofer G, Ivy T, Hay BA. Gene drive and resilience through renewal with next generation Cleave and Rescue selfish genetic elements. Proc Natl Acad Sci U S A 2020; 117:9013-9021. [PMID: 32245808 PMCID: PMC7183144 DOI: 10.1073/pnas.1921698117] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Gene drive-based strategies for modifying populations face the problem that genes encoding cargo and the drive mechanism are subject to separation, mutational inactivation, and loss of efficacy. Resilience, an ability to respond to these eventualities in ways that restore population modification with functional genes, is needed for long-term success. Here, we show that resilience can be achieved through cycles of population modification with "Cleave and Rescue" (ClvR) selfish genetic elements. ClvR comprises a DNA sequence-modifying enzyme such as Cas9/gRNAs that disrupts endogenous versions of an essential gene and a recoded version of the essential gene resistant to cleavage. ClvR spreads by creating conditions in which those lacking ClvR die because they lack functional versions of the essential gene. Cycles of modification can, in principle, be carried out if two ClvR elements targeting different essential genes are located at the same genomic position, and one of them, ClvRn+1, carries a Rescue transgene from an earlier element, ClvRnClvRn+1 should spread within a population of ClvRn, while also bringing about a decrease in its frequency. To test this hypothesis, we first show that multiple ClvRs, each targeting a different essential gene, function when located at a common chromosomal position in Drosophila We then show that when several of these also carry the Rescue from a different ClvR, they spread to transgene fixation in populations fixed for the latter and at its expense. Therefore, genetic modifications of populations can be overwritten with new content, providing an ongoing point of control.
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Affiliation(s)
- Georg Oberhofer
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125
| | - Tobin Ivy
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125
| | - Bruce A Hay
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125;
- St John's College, University of Cambridge, CB2 1TP Cambridge, United Kingdom
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9
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Bangham CRM, Miura M, Kulkarni A, Matsuoka M. Regulation of Latency in the Human T Cell Leukemia Virus, HTLV-1. Annu Rev Virol 2019; 6:365-385. [PMID: 31283437 DOI: 10.1146/annurev-virology-092818-015501] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The human T cell leukemia virus persists in vivo in 103 to 106 clones of T lymphocytes that appear to survive for the lifetime of the host. The plus strand of the provirus is typically transcriptionally silent in freshly isolated lymphocytes, but the strong, persistently activated cytotoxic T lymphocyte (CTL) response to the viral antigens indicates that the virus is not constantly latent in vivo. There is now evidence that the plus strand is transcribed in intense intermittent bursts that are triggered by cellular stress, modulated by hypoxia and glycolysis, and inhibited by polycomb repressive complex 1 (PRC1). The minus-strand gene hbz is transcribed at a lower, more constant level but is silent in a proportion of infected cells at a given time. Viral genes in the sense and antisense strands of the provirus play different respective roles in latency and de novo infection: Expression of the plus-strand gene tax is essential for de novo infection, whereas hbz appears to facilitate survival of the infected T cell clone in vivo.
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Affiliation(s)
- Charles R M Bangham
- Division of Infectious Diseases, Department of Medicine, Imperial College London, London W2 1PG, United Kingdom;
| | - Michi Miura
- Division of Infectious Diseases, Department of Medicine, Imperial College London, London W2 1PG, United Kingdom;
| | - Anurag Kulkarni
- Division of Infectious Diseases, Department of Medicine, Imperial College London, London W2 1PG, United Kingdom;
| | - Masao Matsuoka
- Laboratory of Virus Control, Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto 606-8507, Japan.,Department of Hematology, Rheumatology and Infectious Diseases, Kumamoto University School of Medicine, Kumamoto 860-8556, Japan;
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10
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Alexander JM, Guan J, Li B, Maliskova L, Song M, Shen Y, Huang B, Lomvardas S, Weiner OD. Live-cell imaging reveals enhancer-dependent Sox2 transcription in the absence of enhancer proximity. eLife 2019; 8:e41769. [PMID: 31124784 PMCID: PMC6534382 DOI: 10.7554/elife.41769] [Citation(s) in RCA: 191] [Impact Index Per Article: 38.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Accepted: 05/08/2019] [Indexed: 12/13/2022] Open
Abstract
Enhancers are important regulatory elements that can control gene activity across vast genetic distances. However, the underlying nature of this regulation remains obscured because it has been difficult to observe in living cells. Here, we visualize the spatial organization and transcriptional output of the key pluripotency regulator Sox2 and its essential enhancer Sox2 Control Region (SCR) in living embryonic stem cells (ESCs). We find that Sox2 and SCR show no evidence of enhanced spatial proximity and that spatial dynamics of this pair is limited over tens of minutes. Sox2 transcription occurs in short, intermittent bursts in ESCs and, intriguingly, we find this activity demonstrates no association with enhancer proximity, suggesting that direct enhancer-promoter contacts do not drive contemporaneous Sox2 transcription. Our study establishes a framework for interrogation of enhancer function in living cells and supports an unexpected mechanism for enhancer control of Sox2 expression that uncouples transcription from enhancer proximity.
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Affiliation(s)
- Jeffrey M Alexander
- Cardiovascular Research InstituteUniversity of California, San FranciscoSan FranciscoUnited States
| | - Juan Guan
- Department of Pharmaceutical ChemistryUniversity of California, San FranciscoSan FranciscoUnited States
| | - Bingkun Li
- Institute for Human GeneticsUniversity of California, San FranciscoSan FranciscoUnited States
| | - Lenka Maliskova
- Institute for Human GeneticsUniversity of California, San FranciscoSan FranciscoUnited States
| | - Michael Song
- Institute for Human GeneticsUniversity of California, San FranciscoSan FranciscoUnited States
- Pharmaceutical Sciences and Pharmacogenomics Graduate ProgramUniversity of California, San FranciscoSan FranciscoUnited States
| | - Yin Shen
- Institute for Human GeneticsUniversity of California, San FranciscoSan FranciscoUnited States
- Pharmaceutical Sciences and Pharmacogenomics Graduate ProgramUniversity of California, San FranciscoSan FranciscoUnited States
- Department of NeurologyUniversity of California, San FranciscoSan FranciscoUnited States
| | - Bo Huang
- Department of Pharmaceutical ChemistryUniversity of California, San FranciscoSan FranciscoUnited States
- Department of Biochemistry and BiophysicsUniversity of California, San FranciscoSan FranciscoUnited States
- Chan Zuckerberg BiohubSan FranciscoUnited States
| | - Stavros Lomvardas
- Department of Biochemistry and Molecular BiophysicsColumbia UniversityNew York CityUnited States
- Mortimer B Zuckerman Mind Brain and Behavior InstituteColumbia UniversityNew York CityUnited States
| | - Orion D Weiner
- Cardiovascular Research InstituteUniversity of California, San FranciscoSan FranciscoUnited States
- Department of Biochemistry and BiophysicsUniversity of California, San FranciscoSan FranciscoUnited States
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11
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Richerson PJ. An integrated bayesian theory of phenotypic flexibility. Behav Processes 2019; 161:54-64. [DOI: 10.1016/j.beproc.2018.02.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Revised: 02/02/2018] [Accepted: 02/02/2018] [Indexed: 12/28/2022]
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12
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Zheng Y, Liu X. Review: Chromatin organization in plant and animal stem cell maintenance. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2019; 281:173-179. [PMID: 30824049 DOI: 10.1016/j.plantsci.2018.12.026] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Revised: 11/16/2018] [Accepted: 12/26/2018] [Indexed: 06/09/2023]
Abstract
Stem cells have self-renewal capacity and can differentiate into specialized cell types. Although the origin, form and differentiated destinations of stem cells differ between animals and plants, they are regulated by similar epigenetic mechanisms during differentiation. There is increasing evidence that the three-dimensional (3D) genome organization plays important roles in gene expression regulation during stem cell differentiation. In plant cells, however, studies related to chromatin interaction in gene expression regulation are just beginning and will be a hot topic in the future. In this review, we summarized the similarities of plant and animal stem cell niches and their function in stem cell maintenance, the roles of chromatin conformation changes in regulating gene expression and recent findings about chromatin organization in plant cells at genome-wide and loci-specific levels.
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Affiliation(s)
- Yan Zheng
- National Marine Data and Information Service, Tianjin 300100, China; Key Laboratory of Agricultural Water Resources, Hebei Laboratory of Agricultural Water-Saving, Center for Agricultural Resources Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, 286 Huaizhong Rd, Shijiazhuang, 050021 China
| | - Xigang Liu
- Key Laboratory of Agricultural Water Resources, Hebei Laboratory of Agricultural Water-Saving, Center for Agricultural Resources Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, 286 Huaizhong Rd, Shijiazhuang, 050021 China.
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13
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de Bruijn S, Zhao T, Muiño JM, Schranz EM, Angenent GC, Kaufmann K. PISTILLATA paralogs in Tarenaya hassleriana have diverged in interaction specificity. BMC PLANT BIOLOGY 2018; 18:368. [PMID: 30577806 PMCID: PMC6303913 DOI: 10.1186/s12870-018-1574-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Accepted: 11/26/2018] [Indexed: 06/09/2023]
Abstract
BACKGROUND Floral organs are specified by MADS-domain transcription factors that act in a combinatorial manner, as summarized in the (A)BCE model. However, this evolutionarily conserved model is in contrast to a remarkable amount of morphological diversity in flowers. One of the mechanisms suggested to contribute to this diversity is duplication of floral MADS-domain transcription factors. Although gene duplication is often followed by loss of one of the copies, sometimes both copies are retained. If both copies are retained they will initially be redundant, providing freedom for one of the paralogs to change function. Here, we examine the evolutionary fate and functional consequences of a transposition event at the base of the Brassicales that resulted in the duplication of the floral regulator PISTILLATA (PI), using Tarenaya hassleriana (Cleomaceae) as a model system. RESULTS The transposition of a genomic region containing a PI gene led to two paralogs which are located at different positions in the genome. The original PI copy is syntenic in position with most angiosperms, whereas the transposed copy is syntenic with the PI genes in Brassicaceae. The two PI paralogs of T. hassleriana have very similar expression patterns. However, they may have diverged in function, as only one of these PI proteins was able to act heterologously in the first whorl of A. thaliana flowers. We also observed differences in protein complex formation between the two paralogs, and the two paralogs exhibit subtle differences in DNA-binding specificity. Sequence analysis indicates that most of the protein sequence divergence between the two T. hassleriana paralogs emerged in a common ancestor of the Cleomaceae and the Brassicaceae. CONCLUSIONS We found that the PI paralogs in T. hassleriana have similar expression patterns, but may have diverged at the level of protein function. Data suggest that most protein sequence divergence occurred rapidly, prior to the origin of the Brassicaceae and Cleomaceae. It is tempting to speculate that the interaction specificities of the Brassicaceae-specific PI proteins are different compared to the PI found in other angiosperms. This could lead to PI regulating partly different genes in the Brassicaceae, and ultimately might result in change floral in morphology.
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Affiliation(s)
- Suzanne de Bruijn
- Laboratory of Molecular Biology, Wageningen University, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands
- Bioscience, Wageningen Plant Research, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands
| | - Tao Zhao
- Biosystematics Group, Wageningen University, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands
| | - Jose M. Muiño
- Institute for Biology, Systems Biology of Gene Regulation, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Eric M. Schranz
- Biosystematics Group, Wageningen University, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands
| | - Gerco C. Angenent
- Laboratory of Molecular Biology, Wageningen University, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands
- Bioscience, Wageningen Plant Research, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands
| | - Kerstin Kaufmann
- Institute for Biology, Plant Cell and Molecular Biology, Humboldt-Universität zu Berlin, Philippstraße 13, 10115 Berlin, Germany
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14
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Melamed A, Yaguchi H, Miura M, Witkover A, Fitzgerald TW, Birney E, Bangham CR. The human leukemia virus HTLV-1 alters the structure and transcription of host chromatin in cis. eLife 2018; 7:36245. [PMID: 29941091 PMCID: PMC6019074 DOI: 10.7554/elife.36245] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Accepted: 06/07/2018] [Indexed: 12/29/2022] Open
Abstract
Chromatin looping controls gene expression by regulating promoter-enhancer contacts, the spread of epigenetic modifications, and the segregation of the genome into transcriptionally active and inactive compartments. We studied the impact on the structure and expression of host chromatin by the human retrovirus HTLV-1. We show that HTLV-1 disrupts host chromatin structure by forming loops between the provirus and the host genome; certain loops depend on the critical chromatin architectural protein CTCF, which we recently discovered binds to the HTLV-1 provirus. We show that the provirus causes two distinct patterns of abnormal transcription of the host genome in cis: bidirectional transcription in the host genome immediately flanking the provirus, and clone-specific transcription in cis at non-contiguous loci up to >300 kb from the integration site. We conclude that HTLV-1 causes insertional mutagenesis up to the megabase range in the host genome in >104 persistently-maintained HTLV-1+ T-cell clones in vivo.
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Affiliation(s)
- Anat Melamed
- Division of Infectious Diseases, Imperial College London, London, United Kingdom
| | - Hiroko Yaguchi
- Division of Infectious Diseases, Imperial College London, London, United Kingdom
| | - Michi Miura
- Division of Infectious Diseases, Imperial College London, London, United Kingdom
| | - Aviva Witkover
- Division of Infectious Diseases, Imperial College London, London, United Kingdom
| | - Tomas W Fitzgerald
- The European Bioinformatics Institute (EMBL-EBI), Cambridge, United Kingdom
| | - Ewan Birney
- The European Bioinformatics Institute (EMBL-EBI), Cambridge, United Kingdom
| | - Charles Rm Bangham
- Division of Infectious Diseases, Imperial College London, London, United Kingdom
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15
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Man J, Barnett P, Christoffels VM. Structure and function of the Nppa-Nppb cluster locus during heart development and disease. Cell Mol Life Sci 2018; 75:1435-1444. [PMID: 29302701 PMCID: PMC5852170 DOI: 10.1007/s00018-017-2737-0] [Citation(s) in RCA: 65] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2017] [Revised: 12/07/2017] [Accepted: 12/20/2017] [Indexed: 01/20/2023]
Abstract
Atrial natriuretic factor and brain natriuretic peptide are two important biomarkers in clinical cardiology. These two natriuretic peptide hormones are encoded by the paralogous genes Nppa and Nppb, which are evolutionary conserved. Both genes are predominantly expressed by the heart muscle during the embryonic and fetal stages, and in particular Nppa expression is strongly reduced in the ventricles after birth. Upon cardiac stress, Nppa and Nppb are strongly upregulated in the ventricular myocardium. Much is known about the molecular and physiological ques inducing Nppa and Nppb expression; however, the transcriptional regulatory mechanisms of the Nppa-Nppb cluster in vivo has proven to be quite complex and is not well understood. In this review, we will provide recent insights into the dynamic and complex regulation of Nppa and Nppb during heart development and hypertrophy, and the association of this gene cluster with the cardiomyocyte-intrinsic program of heart regeneration.
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Affiliation(s)
- Joyce Man
- Department of Medical Biology, Academic Medical Center, University of Amsterdam, Meibergdreef 15, 1105 AZ, Amsterdam, The Netherlands.
| | - Phil Barnett
- Department of Medical Biology, Academic Medical Center, University of Amsterdam, Meibergdreef 15, 1105 AZ, Amsterdam, The Netherlands
| | - Vincent M Christoffels
- Department of Medical Biology, Academic Medical Center, University of Amsterdam, Meibergdreef 15, 1105 AZ, Amsterdam, The Netherlands
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16
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Racko D, Benedetti F, Dorier J, Stasiak A. Transcription-induced supercoiling as the driving force of chromatin loop extrusion during formation of TADs in interphase chromosomes. Nucleic Acids Res 2018; 46:1648-1660. [PMID: 29140466 PMCID: PMC5829651 DOI: 10.1093/nar/gkx1123] [Citation(s) in RCA: 67] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Revised: 10/03/2017] [Accepted: 10/30/2017] [Indexed: 12/16/2022] Open
Abstract
Using molecular dynamics simulations, we show here that growing plectonemes resulting from transcription-induced supercoiling have the ability to actively push cohesin rings along chromatin fibres. The pushing direction is such that within each topologically associating domain (TAD) cohesin rings forming handcuffs move from the source of supercoiling, constituted by RNA polymerase with associated DNA topoisomerase TOP1, towards borders of TADs, where supercoiling is released by topoisomerase TOPIIB. Cohesin handcuffs are pushed by continuous flux of supercoiling that is generated by transcription and is then progressively released by action of TOPIIB located at TADs borders. Our model explains what can be the driving force of chromatin loop extrusion and how it can be ensured that loops grow quickly and in a good direction. In addition, the supercoiling-driven loop extrusion mechanism is consistent with earlier explanations proposing why TADs flanked by convergent CTCF binding sites form more stable chromatin loops than TADs flanked by divergent CTCF binding sites. We discuss the role of supercoiling in stimulating enhancer promoter contacts and propose that transcription of eRNA sends the first wave of supercoiling that can activate mRNA transcription in a given TAD.
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Affiliation(s)
- Dusan Racko
- Center for Integrative Genomics, University of Lausanne, 1015-Lausanne, Switzerland
- SIB Swiss Institute of Bioinformatics, 1015-Lausanne, Switzerland
- Polymer Institute of the Slovak Academy of Sciences, 842 36 Bratislava, Slovakia
| | - Fabrizio Benedetti
- Center for Integrative Genomics, University of Lausanne, 1015-Lausanne, Switzerland
- Vital-IT, SIB Swiss Institute of Bioinformatics, 1015-Lausanne, Switzerland
| | - Julien Dorier
- Center for Integrative Genomics, University of Lausanne, 1015-Lausanne, Switzerland
- Vital-IT, SIB Swiss Institute of Bioinformatics, 1015-Lausanne, Switzerland
| | - Andrzej Stasiak
- Center for Integrative Genomics, University of Lausanne, 1015-Lausanne, Switzerland
- SIB Swiss Institute of Bioinformatics, 1015-Lausanne, Switzerland
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17
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Rodríguez-Leal D, Lemmon ZH, Man J, Bartlett ME, Lippman ZB. Engineering Quantitative Trait Variation for Crop Improvement by Genome Editing. Cell 2017; 171:470-480.e8. [PMID: 28919077 DOI: 10.1016/j.cell.2017.08.030] [Citation(s) in RCA: 552] [Impact Index Per Article: 78.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2017] [Revised: 07/30/2017] [Accepted: 08/17/2017] [Indexed: 12/18/2022]
Abstract
Major advances in crop yields are needed in the coming decades. However, plant breeding is currently limited by incremental improvements in quantitative traits that often rely on laborious selection of rare naturally occurring mutations in gene-regulatory regions. Here, we demonstrate that CRISPR/Cas9 genome editing of promoters generates diverse cis-regulatory alleles that provide beneficial quantitative variation for breeding. We devised a simple genetic scheme, which exploits trans-generational heritability of Cas9 activity in heterozygous loss-of-function mutant backgrounds, to rapidly evaluate the phenotypic impact of numerous promoter variants for genes regulating three major productivity traits in tomato: fruit size, inflorescence branching, and plant architecture. Our approach allows immediate selection and fixation of novel alleles in transgene-free plants and fine manipulation of yield components. Beyond a platform to enhance variation for diverse agricultural traits, our findings provide a foundation for dissecting complex relationships between gene-regulatory changes and control of quantitative traits.
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Affiliation(s)
| | - Zachary H Lemmon
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA
| | - Jarrett Man
- Biology Department, University of Massachusetts Amherst, Amherst, MA 01003, USA
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18
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Appel E, Weissmann S, Salzberg Y, Orlovsky K, Negreanu V, Tsoory M, Raanan C, Feldmesser E, Bernstein Y, Wolstein O, Levanon D, Groner Y. An ensemble of regulatory elements controls Runx3 spatiotemporal expression in subsets of dorsal root ganglia proprioceptive neurons. Genes Dev 2017; 30:2607-2622. [PMID: 28007784 PMCID: PMC5204353 DOI: 10.1101/gad.291484.116] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2016] [Accepted: 11/16/2016] [Indexed: 12/11/2022]
Abstract
Appel et al. defined the genomic transcription unit encompassing regulatory elements (REs) that mediate the tissue-specific expression of Runx3. Then, using transgenic mice expressing BAC reporters spanning the Runx3 locus, they discovered three REs that cross-talk with promoter-2 (P2) to drive TrkC neuron-specific Runx3 transcription. The Runx3 transcription factor is essential for development and diversification of the dorsal root ganglia (DRGs) TrkC sensory neurons. In Runx3-deficient mice, developing TrkC neurons fail to extend central and peripheral afferents, leading to cell death and disruption of the stretch reflex circuit, resulting in severe limb ataxia. Despite its central role, the mechanisms underlying the spatiotemporal expression specificities of Runx3 in TrkC neurons were largely unknown. Here we first defined the genomic transcription unit encompassing regulatory elements (REs) that mediate the tissue-specific expression of Runx3. Using transgenic mice expressing BAC reporters spanning the Runx3 locus, we discovered three REs—dubbed R1, R2, and R3—that cross-talk with promoter-2 (P2) to drive TrkC neuron-specific Runx3 transcription. Deletion of single or multiple elements either in the BAC transgenics or by CRISPR/Cas9-mediated endogenous ablation established the REs’ ability to promote and/or repress Runx3 expression in developing sensory neurons. Our analysis reveals that an intricate combinatorial interplay among the three REs governs Runx3 expression in distinct subtypes of TrkC neurons while concomitantly extinguishing its expression in non-TrkC neurons. These findings provide insights into the mechanism regulating cell type-specific expression and subtype diversification of TrkC neurons in developing DRGs.
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Affiliation(s)
- Elena Appel
- Department of Molecular Genetics, The Weizmann Institute of Science, Rehovot, 7610001, Israel
| | - Sarit Weissmann
- Department of Molecular Genetics, The Weizmann Institute of Science, Rehovot, 7610001, Israel
| | - Yehuda Salzberg
- Department of Molecular Genetics, The Weizmann Institute of Science, Rehovot, 7610001, Israel.,Department of Biomolecular Sciences, The Weizmann Institute of Science, Rehovot, 7610001, Israel
| | - Kira Orlovsky
- Department of Molecular Genetics, The Weizmann Institute of Science, Rehovot, 7610001, Israel
| | - Varda Negreanu
- Department of Molecular Genetics, The Weizmann Institute of Science, Rehovot, 7610001, Israel
| | - Michael Tsoory
- Department of Veterinary Resources, The Weizmann Institute of Science, Rehovot, 7610001, Israel
| | - Calanit Raanan
- Department of Veterinary Resources, The Weizmann Institute of Science, Rehovot, 7610001, Israel
| | - Ester Feldmesser
- Life Science Core Facilities, The Weizmann Institute of Science, Rehovot, 7610001, Israel
| | - Yael Bernstein
- Department of Molecular Genetics, The Weizmann Institute of Science, Rehovot, 7610001, Israel
| | - Orit Wolstein
- Department of Molecular Genetics, The Weizmann Institute of Science, Rehovot, 7610001, Israel
| | - Ditsa Levanon
- Department of Molecular Genetics, The Weizmann Institute of Science, Rehovot, 7610001, Israel
| | - Yoram Groner
- Department of Molecular Genetics, The Weizmann Institute of Science, Rehovot, 7610001, Israel
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19
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Abstract
The first animals evolved from an unknown single-celled ancestor in the Precambrian period. Recently, the identification and characterization of the genomic and cellular traits of the protists most closely related to animals have shed light on the origin of animals. Comparisons of animals with these unicellular relatives allow us to reconstruct the first evolutionary steps towards animal multicellularity. Here, we review the results of these investigations and discuss their implications for understanding the earliest stages of animal evolution, including the origin of metazoan genes and genome function.
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20
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Maeso I, Acemel RD, Gómez-Skarmeta JL. Cis-regulatory landscapes in development and evolution. Curr Opin Genet Dev 2016; 43:17-22. [PMID: 27842294 DOI: 10.1016/j.gde.2016.10.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2016] [Accepted: 10/17/2016] [Indexed: 10/20/2022]
Abstract
The recent advances in our understanding of the 3D organization of the chromatin together with an almost unlimited ability to detect cis-regulatory elements genome-wide using different biochemical signatures has provided us with an unprecedented power to study gene regulation. It is now possible to profile the complete regulatory apparatus controlling the spatio-temporal expression of any given gene, the so-called gene Regulatory Landscapes (RLs). Here we review several studies over the last two years demonstrating the functional consequences of altering RL structure in development, disease and evolution. These works clearly show that a deep understanding of transcriptional regulation is no longer conceivable without considering the 3D modular organization of animal genomes.
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Affiliation(s)
- Ignacio Maeso
- Centro Andaluz de Biología del Desarrollo (CABD), Consejo Superior de Investigaciones Científicas/Universidad Pablo de Olavide, Carretera de Utrera Km1, Seville, Spain.
| | - Rafael D Acemel
- Centro Andaluz de Biología del Desarrollo (CABD), Consejo Superior de Investigaciones Científicas/Universidad Pablo de Olavide, Carretera de Utrera Km1, Seville, Spain
| | - José Luis Gómez-Skarmeta
- Centro Andaluz de Biología del Desarrollo (CABD), Consejo Superior de Investigaciones Científicas/Universidad Pablo de Olavide, Carretera de Utrera Km1, Seville, Spain.
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21
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Abstract
Enhancer elements function as the logic gates of the genetic regulatory circuitry. One of their most important functions is the integration of extracellular signals with intracellular cell fate information to generate cell type-specific transcriptional responses. Mutations occurring in cancer often misregulate enhancers that normally control the signal-dependent expression of growth-related genes. This misregulation can result from trans-acting mechanisms, such as activation of the transcription factors or epigenetic regulators that control enhancer activity, or can be caused in cis by direct mutations that alter the activity of the enhancer or its target gene specificity. These processes can generate tumour type-specific super-enhancers and establish a 'locked' gene regulatory state that drives the uncontrolled proliferation of cancer cells. Here, we review the role of enhancers in cancer, and their potential as therapeutic targets.
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Affiliation(s)
- Inderpreet Sur
- Division of Functional Genomics and Systems Biology, Department of Medical Biochemistry and Biophysics, and Department of Biosciences and Nutrition, Karolinska Institutet, Stockholm SE-171 77, Sweden
| | - Jussi Taipale
- Division of Functional Genomics and Systems Biology, Department of Medical Biochemistry and Biophysics, and Department of Biosciences and Nutrition, Karolinska Institutet, Stockholm SE-171 77, Sweden
- Genome-Scale Biology Program, University of Helsinki, Biomedicum, PO Box 63, Helsinki 00014, Finland
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22
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Dekker J, Mirny L. The 3D Genome as Moderator of Chromosomal Communication. Cell 2016; 164:1110-1121. [PMID: 26967279 PMCID: PMC4788811 DOI: 10.1016/j.cell.2016.02.007] [Citation(s) in RCA: 592] [Impact Index Per Article: 74.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2016] [Revised: 01/22/2016] [Accepted: 02/01/2016] [Indexed: 02/07/2023]
Abstract
Proper expression of genes requires communication with their regulatory elements that can be located elsewhere along the chromosome. The physics of chromatin fibers imposes a range of constraints on such communication. The molecular and biophysical mechanisms by which chromosomal communication is established, or prevented, have become a topic of intense study, and important roles for the spatial organization of chromosomes are being discovered. Here we present a view of the interphase 3D genome characterized by extensive physical compartmentalization and insulation on the one hand and facilitated long-range interactions on the other. We propose the existence of topological machines dedicated to set up and to exploit a 3D genome organization to both promote and censor communication along and between chromosomes.
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Affiliation(s)
- Job Dekker
- Howard Hughes Medical Institute, Program in Systems Biology, Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, 368 Plantation Street, Worcester, MA, 01605-0103, USA.
| | - Leonid Mirny
- Institute for Medical Engineering and Science and Department of Physics, Massachusetts Institute of Technology, 77 Massachusetts Avenue, E25-526C, Cambridge, MA 02139, USA.
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23
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Deschamps J. Birth and upgrowth of the Hox topological domains during evolution. Nat Genet 2016; 48:227-8. [PMID: 26906681 DOI: 10.1038/ng.3514] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The recently discovered chromatin compartments called topologically associating domains (TADs) are essential for the three-dimensional organization of regulatory interactions driving gene expression. A new study documents the emergence of a TAD flanking the amphioxus Hox cluster, prefiguring the vertebrate anterior Hox TAD and preceding the appearance of the concurring posterior Hox TAD.
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Affiliation(s)
- Jacqueline Deschamps
- Hubrecht Institute, Developmental Biology and Stem Cell Research, Utrecht, the Netherlands
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24
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Visualizing the HoxD Gene Cluster at the Nanoscale Level. COLD SPRING HARBOR SYMPOSIA ON QUANTITATIVE BIOLOGY 2016; 80:9-16. [PMID: 26767994 DOI: 10.1101/sqb.2015.80.027177] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Transcription of HoxD cluster genes in limbs is coordinated by two topologically associating domains (TADs), neighboring the cluster and containing various enhancers. Here, we use a combination of microscopy approaches and chromosome conformation capture to assess the structural changes occurring in this global architecture in various functional states. We observed that despite their spatial juxtaposition, the TADs are consistently kept as distinct three-dimensional units. Hox genes located at their boundary can show significant spatial segregation over long distances, suggesting that physical elongation of the HoxD cluster occurs. The use of superresolution imaging (STORM [stochastic optical reconstruction microscopy]) revealed that the gene cluster can be in an either compact or elongated shape. The latter configuration is observed in transcriptionally active tissue and in embryonic stem cells, consistent with chromosome conformation capture results. Such morphological changes at HoxD in developing digits seem to be associated with its position at the boundary between two TADs and support the idea that chromatin dynamics is important in the establishment of transcriptional activity.
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25
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Joo JY, Schaukowitch K, Farbiak L, Kilaru G, Kim TK. Stimulus-specific combinatorial functionality of neuronal c-fos enhancers. Nat Neurosci 2015; 19:75-83. [PMID: 26595656 PMCID: PMC4696896 DOI: 10.1038/nn.4170] [Citation(s) in RCA: 166] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Accepted: 10/09/2015] [Indexed: 12/16/2022]
Abstract
The c-fos gene is induced by a broad range of stimuli, and has been commonly used as a reliable marker for neural activity. Its induction mechanism and available reporter mouse lines are exclusively based on the c-fos promoter activity. Here, we demonstrate that multiple enhancers surrounding the c-fos gene are critical for ensuring robust c-fos response to various stimuli. Membrane depolarization, brain-derived neurotrophic factor (BDNF), and Forskolin activate distinct subsets of the enhancers to induce c-fos transcription in neurons, suggesting that stimulus-specific combinatorial activation of multiple enhancers underlies the broad inducibility of the c-fos gene. Accordingly, the functional requirement of key transcription factors varies depending on the type of stimulation. Combinatorial enhancer activation also occurs in the brain. Providing a comprehensive picture of the c-fos induction mechanism beyond the minimal promoter, our study should help in understanding the physiological nature of c-fos induction in relation to neural activity and plasticity.
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Affiliation(s)
- Jae-Yeol Joo
- Department of Neuroscience, The University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Katie Schaukowitch
- Department of Neuroscience, The University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Lukas Farbiak
- Department of Neuroscience, The University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Gokhul Kilaru
- Department of Neuroscience, The University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Tae-Kyung Kim
- Department of Neuroscience, The University of Texas Southwestern Medical Center, Dallas, Texas, USA
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26
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Remeseiro S, Hörnblad A, Spitz F. Gene regulation during development in the light of topologically associating domains. WILEY INTERDISCIPLINARY REVIEWS-DEVELOPMENTAL BIOLOGY 2015; 5:169-85. [PMID: 26558551 DOI: 10.1002/wdev.218] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2015] [Revised: 08/31/2015] [Accepted: 09/15/2015] [Indexed: 01/20/2023]
Abstract
During embryonic development, complex transcriptional programs govern the precision of gene expression. Many key developmental genes are regulated via cis-regulatory elements that are located far away in the linear genome. How sequences located hundreds of kilobases away from a promoter can influence its activity has been the subject of numerous speculations, which all underline the importance of the 3D-organization of the genome. The recent advent of chromosome conformation capture techniques has put into focus the subdivision of the genome into topologically associating domains (TADs). TADs may influence regulatory activities on multiple levels. The relative invariance of TAD limits across cell types suggests that they may form fixed structural domains that could facilitate and/or confine long-range regulatory interactions. However, most recent studies suggest that interactions within TADs are more variable and dynamic than initially described. Hence, different models are emerging regarding how TADs shape the complex 3D conformations, and thereafter influence the networks of cis-interactions that govern gene expression during development. For further resources related to this article, please visit the WIREs website.
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Affiliation(s)
- Silvia Remeseiro
- Developmental Biology Unit, European Molecular Biology Laboratory (EMBL), Heidelberg, Germany
| | - Andreas Hörnblad
- Developmental Biology Unit, European Molecular Biology Laboratory (EMBL), Heidelberg, Germany
| | - François Spitz
- Developmental Biology Unit, European Molecular Biology Laboratory (EMBL), Heidelberg, Germany
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27
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Nanoscale spatial organization of the HoxD gene cluster in distinct transcriptional states. Proc Natl Acad Sci U S A 2015; 112:13964-9. [PMID: 26504220 DOI: 10.1073/pnas.1517972112] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Chromatin condensation plays an important role in the regulation of gene expression. Recently, it was shown that the transcriptional activation of Hoxd genes during vertebrate digit development involves modifications in 3D interactions within and around the HoxD gene cluster. This reorganization follows a global transition from one set of regulatory contacts to another, between two topologically associating domains (TADs) located on either side of the HoxD locus. Here, we use 3D DNA FISH to assess the spatial organization of chromatin at and around the HoxD gene cluster and report that although the two TADs are tightly associated, they appear as spatially distinct units. We measured the relative position of genes within the cluster and found that they segregate over long distances, suggesting that a physical elongation of the HoxD cluster can occur. We analyzed this possibility by super-resolution imaging (STORM) and found that tissues with distinct transcriptional activity exhibit differing degrees of elongation. We also observed that the morphological change of the HoxD cluster in developing digits is associated with its position at the boundary between the two TADs. Such variations in the fine-scale architecture of the gene cluster suggest causal links among its spatial configuration, transcriptional activation, and the flanking chromatin context.
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28
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Bartman CR, Blobel GA. Perturbing Chromatin Structure to Understand Mechanisms of Gene Expression. COLD SPRING HARBOR SYMPOSIA ON QUANTITATIVE BIOLOGY 2015; 80:207-12. [PMID: 26370411 DOI: 10.1101/sqb.2015.80.027359] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The study of nuclear structure falls between the fields of cell biology and molecular biology and draws on techniques from both fields. In recent years, many exciting advances have been made in these areas, including single-molecule and superresolution imaging and the development of chromosome conformation capture (3C)-based technologies, which have brought the advent of genome-wide analysis of chromatin structure and contacts. However, many questions remain as to the function of nuclear structures, in particular their influence on transcription. Here we describe studies that have directly manipulated nuclear architecture at various levels and thus have clarified the causal influence of structure on transcription. We will also highlight open questions in the field, most notably regarding our understanding of the dynamics and variability in nuclear structure and its influence on gene expression.
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Affiliation(s)
- Caroline R Bartman
- Division of Hematology, Children's Hospital of Pennsylvania, Philadelphia, Pennsylvania 19104 Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Gerd A Blobel
- Division of Hematology, Children's Hospital of Pennsylvania, Philadelphia, Pennsylvania 19104 Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104
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Stein C, Bardet AF, Roma G, Bergling S, Clay I, Ruchti A, Agarinis C, Schmelzle T, Bouwmeester T, Schübeler D, Bauer A. YAP1 Exerts Its Transcriptional Control via TEAD-Mediated Activation of Enhancers. PLoS Genet 2015; 11:e1005465. [PMID: 26295846 PMCID: PMC4546604 DOI: 10.1371/journal.pgen.1005465] [Citation(s) in RCA: 278] [Impact Index Per Article: 30.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2015] [Accepted: 07/23/2015] [Indexed: 12/30/2022] Open
Abstract
YAP1 is a major effector of the Hippo pathway and a well-established oncogene. Elevated YAP1 activity due to mutations in Hippo pathway components or YAP1 amplification is observed in several types of human cancers. Here we investigated its genomic binding landscape in YAP1-activated cancer cells, as well as in non-transformed cells. We demonstrate that TEAD transcription factors mediate YAP1 chromatin-binding genome-wide, further explaining their dominant role as primary mediators of YAP1-transcriptional activity. Moreover, we show that YAP1 largely exerts its transcriptional control via distal enhancers that are marked by H3K27 acetylation and that YAP1 is necessary for this chromatin mark at bound enhancers and the activity of the associated genes. This work establishes YAP1-mediated transcriptional regulation at distal enhancers and provides an expanded set of target genes resulting in a fundamental source to study YAP1 function in a normal and cancer setting. The YAP1/Hippo signaling pathway is a key regulator of organ size and tissue homeostasis, and its dysregulation is linked to cancer development. Elevated activity of YAP1, a transcriptional coactivator and well-established oncogene has been reported to occur in human cancers. Comprehensive identification of YAP1 regulated genes and its mode of action will be of high importance to uncover YAP1 biology that could be exploited for a therapeutic intervention. To this end, we performed genome-wide analyses to identify YAP1 occupied sites in cancer cell lines representing different YAP1/Hippo pathway tumor etiologies and in non-transformed fibroblasts. Our data demonstrate that YAP1 activity is mediated predominantly via TEAD transcription factors supporting the importance of TEADs as main mediators of YAP1-coactivator activity. We further show that YAP1 and TEAD1 exert their transcriptional control via binding to enhancers, leading to characteristic chromatin changes and distal activation of genes. By linking enhancers to genes, we provide a list of novel YAP1 target genes in an oncogenic setting that we show can readily be exploited in tumor classification and provides a foundation for further investigations.
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Affiliation(s)
- Claudia Stein
- Developmental and Molecular Pathways, Novartis Institutes for Biomedical Research, Novartis Pharma AG, Basel, Switzerland
| | - Anaïs Flore Bardet
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
| | - Guglielmo Roma
- Developmental and Molecular Pathways, Novartis Institutes for Biomedical Research, Novartis Pharma AG, Basel, Switzerland
| | - Sebastian Bergling
- Developmental and Molecular Pathways, Novartis Institutes for Biomedical Research, Novartis Pharma AG, Basel, Switzerland
| | - Ieuan Clay
- Developmental and Molecular Pathways, Novartis Institutes for Biomedical Research, Novartis Pharma AG, Basel, Switzerland
| | - Alexandra Ruchti
- Developmental and Molecular Pathways, Novartis Institutes for Biomedical Research, Novartis Pharma AG, Basel, Switzerland
| | - Claudia Agarinis
- Developmental and Molecular Pathways, Novartis Institutes for Biomedical Research, Novartis Pharma AG, Basel, Switzerland
| | - Tobias Schmelzle
- Oncology, Novartis Institutes for Biomedical Research, Novartis Pharma AG, Basel, Switzerland
| | - Tewis Bouwmeester
- Developmental and Molecular Pathways, Novartis Institutes for Biomedical Research, Novartis Pharma AG, Basel, Switzerland
| | - Dirk Schübeler
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
- University of Basel, Faculty of Sciences, Basel, Switzerland
- * E-mail: (DS); (AB)
| | - Andreas Bauer
- Developmental and Molecular Pathways, Novartis Institutes for Biomedical Research, Novartis Pharma AG, Basel, Switzerland
- * E-mail: (DS); (AB)
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30
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Using transgenic reporter assays to functionally characterize enhancers in animals. Genomics 2015; 106:185-192. [PMID: 26072435 DOI: 10.1016/j.ygeno.2015.06.007] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2015] [Revised: 05/11/2015] [Accepted: 06/09/2015] [Indexed: 11/21/2022]
Abstract
Enhancers or cis-regulatory modules play an instructive role in regulating gene expression during animal development and in response to the environment. Despite their importance, we only have an incomplete map of enhancers in the genome and our understanding of the mechanisms governing their function is still limited. Recent advances in genomics provided powerful tools to generate genome-wide maps of potential enhancers. However, most of these methods are based on indirect measures of enhancer activity and have to be followed by functional testing. Animal transgenesis has been a valuable method to functionally test and characterize enhancers in vivo. In this review I discuss how different transgenic strategies are utilized to characterize enhancers in model organisms focusing on studies in Drosophila and mouse. I will further discuss recent large-scale transgenic efforts to systematically identify and catalog enhancers as well as highlight the challenges and future directions in the field.
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31
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Erokhin M, Vassetzky Y, Georgiev P, Chetverina D. Eukaryotic enhancers: common features, regulation, and participation in diseases. Cell Mol Life Sci 2015; 72:2361-75. [PMID: 25715743 PMCID: PMC11114076 DOI: 10.1007/s00018-015-1871-9] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2014] [Revised: 02/07/2015] [Accepted: 02/20/2015] [Indexed: 01/01/2023]
Abstract
Enhancers are positive DNA regulatory sequences controlling temporal and tissue-specific gene expression. These elements act independently of their orientation and distance relative to the promoters of target genes. Enhancers act through a variety of transcription factors that ensure their correct match with target promoters and consequent gene activation. There is a growing body of evidence on association of enhancers with transcription factors, co-activators, histone chromatin marks, and lncRNAs. Alterations in enhancers lead to misregulation of gene expression, causing a number of human diseases. In this review, we focus on the common characteristics of enhancers required for transcription stimulation.
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Affiliation(s)
- Maksim Erokhin
- Department of the Control of Genetic Processes, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov St., Moscow, 119334 Russia
- LIA 1066, Laboratoire Franco-Russe de recherche en oncologie, 119334 Moscow, Russia
| | - Yegor Vassetzky
- LIA 1066, Laboratoire Franco-Russe de recherche en oncologie, 119334 Moscow, Russia
- UMR8126, Université Paris-Sud, CNRS, Institut de cancérologie Gustave Roussy, 94805 Villejuif, France
| | - Pavel Georgiev
- Department of the Control of Genetic Processes, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov St., Moscow, 119334 Russia
- LIA 1066, Laboratoire Franco-Russe de recherche en oncologie, 119334 Moscow, Russia
| | - Darya Chetverina
- Department of the Control of Genetic Processes, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov St., Moscow, 119334 Russia
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32
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Bhatia S, Gordon CT, Foster RG, Melin L, Abadie V, Baujat G, Vazquez MP, Amiel J, Lyonnet S, van Heyningen V, Kleinjan DA. Functional assessment of disease-associated regulatory variants in vivo using a versatile dual colour transgenesis strategy in zebrafish. PLoS Genet 2015; 11:e1005193. [PMID: 26030420 PMCID: PMC4452300 DOI: 10.1371/journal.pgen.1005193] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2014] [Accepted: 04/02/2015] [Indexed: 11/26/2022] Open
Abstract
Disruption of gene regulation by sequence variation in non-coding regions of the genome is now recognised as a significant cause of human disease and disease susceptibility. Sequence variants in cis-regulatory elements (CREs), the primary determinants of spatio-temporal gene regulation, can alter transcription factor binding sites. While technological advances have led to easy identification of disease-associated CRE variants, robust methods for discerning functional CRE variants from background variation are lacking. Here we describe an efficient dual-colour reporter transgenesis approach in zebrafish, simultaneously allowing detailed in vivo comparison of spatio-temporal differences in regulatory activity between putative CRE variants and assessment of altered transcription factor binding potential of the variant. We validate the method on known disease-associated elements regulating SHH, PAX6 and IRF6 and subsequently characterise novel, ultra-long-range SOX9 enhancers implicated in the craniofacial abnormality Pierre Robin Sequence. The method provides a highly cost-effective, fast and robust approach for simultaneously unravelling in a single assay whether, where and when in embryonic development a disease-associated CRE-variant is affecting its regulatory function. Cis-regulatory elements (CREs) play a vital role in gene regulation by providing spatial and temporal specificity to the expression of their target genes. Understanding how these regions of the genome work is of vital importance for human health as it has been demonstrated that genetic changes in these regions can result in incorrect gene expression, leading to a variety of human diseases. Functional characterization of putative CREs and the effects of mutations on their activity is currently a major bottleneck in many studies towards understanding the causes and mechanisms of disease and disease susceptibility. We describe a robust in-vivo approach using dual-colour reporter transgenesis in zebrafish for unambiguous assessment of the effects of disease-associated CRE mutations on CRE activity during the entire time-course of embryonic development. The highly efficient, cost-effective and modular design of the assay allows rapid analysis of several CRE-variants in parallel. We illustrate the robustness of our approach using examples of CRE-variants associated with a broad spectrum of genetic diseases including brain, limb, eye and jaw disorders. In a single assay the method can address where and when in development the CRE variant affects its activity, what potential target genes are misregulated by the change and what upstream trans-acting factors are likely to mediate this effect.
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Affiliation(s)
- Shipra Bhatia
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, United Kingdom
- * E-mail: (SB); (VvH); (DAK)
| | - Christopher T. Gordon
- INSERM U781, Hôpital Necker-Enfants Malades and Université Paris Descartes-Sorbonne Paris Cité, Institute Imagine, Paris, France
| | - Robert G. Foster
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, United Kingdom
| | - Lucie Melin
- INSERM U781, Hôpital Necker-Enfants Malades and Université Paris Descartes-Sorbonne Paris Cité, Institute Imagine, Paris, France
| | - Véronique Abadie
- Service de Pédiatrie Générale, Université Paris Descartes, Hôpital Necker-Enfants Malades, Paris, France
| | - Geneviève Baujat
- Departement de Génétique, Hôpital Necker-Enfants Malades, AP-HP, Paris France
| | - Marie-Paule Vazquez
- Service de Chirurgie Maxillo-Faciale et Plastique, CRMR des Malformations de la Face et de la Cavité Buccale, Hôpital Necker-Enfants Malades, Paris, France
| | - Jeanne Amiel
- INSERM U781, Hôpital Necker-Enfants Malades and Université Paris Descartes-Sorbonne Paris Cité, Institute Imagine, Paris, France
- Departement de Génétique, Hôpital Necker-Enfants Malades, AP-HP, Paris France
| | - Stanislas Lyonnet
- INSERM U781, Hôpital Necker-Enfants Malades and Université Paris Descartes-Sorbonne Paris Cité, Institute Imagine, Paris, France
- Departement de Génétique, Hôpital Necker-Enfants Malades, AP-HP, Paris France
| | - Veronica van Heyningen
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, United Kingdom
- * E-mail: (SB); (VvH); (DAK)
| | - Dirk A. Kleinjan
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, United Kingdom
- * E-mail: (SB); (VvH); (DAK)
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33
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Structure, function and evolution of topologically associating domains (TADs) at HOX loci. FEBS Lett 2015; 589:2869-76. [PMID: 25913784 DOI: 10.1016/j.febslet.2015.04.024] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2015] [Revised: 04/16/2015] [Accepted: 04/17/2015] [Indexed: 11/24/2022]
Abstract
Hox genes encode transcription factors necessary for patterning the major developing anterior to posterior embryonic axis. In addition, during vertebrate evolution, various subsets of this gene family were co-opted along with the emergence of novel body structures, such as the limbs or the external genitalia. The morphogenesis of these axial structures thus relies in part upon the precisely controlled transcription of specific Hox genes, a mechanism involving multiple long-range enhancers. Recently, it was reported that such regulatory mechanisms were largely shared between different developing tissues, though with some specificities, suggesting the recruitment of ancestral regulatory modalities from one tissue to another. The analysis of chromatin architectures at HoxD and HoxA loci revealed the existence of two flanking topologically associating domains (TADs), precisely encompassing the adjacent regulatory landscapes. Here, we discuss the function of these TADs in the control of Hox gene regulation and we speculate about their capacity to serve as structural frameworks for the emergence of novel enhancers. In this view, TADs may have been used as genomic niches to evolve pleiotropic regulations found at many developmental loci.
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34
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Abstract
Transcriptional regulation of thousands of genes instructs complex morphogenetic and molecular events for heart development. Cardiac transcription factors choreograph gene expression at each stage of differentiation by interacting with cofactors, including chromatin-modifying enzymes, and by binding to a constellation of regulatory DNA elements. Here, we present salient examples relevant to cardiovascular development and heart disease, and review techniques that can sharpen our understanding of cardiovascular biology. We discuss the interplay between cardiac transcription factors, cis-regulatory elements, and chromatin as dynamic regulatory networks, to orchestrate sequential deployment of the cardiac gene expression program.
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Affiliation(s)
- Irfan S Kathiriya
- From the Gladstone Institute of Cardiovascular Disease and the Roddenberry Center for Stem Cell Biology and Medicine at Gladstone, San Francisco, CA (I.S.K., E.P.N., B.G.B.); and Department of Anesthesia and Perioperative Care (I.S.K.), Department of Pediatrics (B.G.B.), Cardiovascular Research Institute (B.G.B.), and Institute for Regeneration Medicine (B.G.B.), University of California, San Francisco.
| | - Elphège P Nora
- From the Gladstone Institute of Cardiovascular Disease and the Roddenberry Center for Stem Cell Biology and Medicine at Gladstone, San Francisco, CA (I.S.K., E.P.N., B.G.B.); and Department of Anesthesia and Perioperative Care (I.S.K.), Department of Pediatrics (B.G.B.), Cardiovascular Research Institute (B.G.B.), and Institute for Regeneration Medicine (B.G.B.), University of California, San Francisco.
| | - Benoit G Bruneau
- From the Gladstone Institute of Cardiovascular Disease and the Roddenberry Center for Stem Cell Biology and Medicine at Gladstone, San Francisco, CA (I.S.K., E.P.N., B.G.B.); and Department of Anesthesia and Perioperative Care (I.S.K.), Department of Pediatrics (B.G.B.), Cardiovascular Research Institute (B.G.B.), and Institute for Regeneration Medicine (B.G.B.), University of California, San Francisco.
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35
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Lajoie BR, Dekker J, Kaplan N. The Hitchhiker's guide to Hi-C analysis: practical guidelines. Methods 2014; 72:65-75. [PMID: 25448293 DOI: 10.1016/j.ymeth.2014.10.031] [Citation(s) in RCA: 218] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2014] [Revised: 10/28/2014] [Accepted: 10/30/2014] [Indexed: 12/13/2022] Open
Abstract
Over the last decade, development and application of a set of molecular genomic approaches based on the chromosome conformation capture method (3C), combined with increasingly powerful imaging approaches, have enabled high resolution and genome-wide analysis of the spatial organization of chromosomes. The aim of this paper is to provide guidelines for analyzing and interpreting data obtained with genome-wide 3C methods such as Hi-C and 3C-seq that rely on deep sequencing to detect and quantify pairwise chromatin interactions.
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Affiliation(s)
- Bryan R Lajoie
- Program in Systems Biology, Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, 368 Plantation Street, Worcester, MA 01605-0103, USA.
| | - Job Dekker
- Program in Systems Biology, Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, 368 Plantation Street, Worcester, MA 01605-0103, USA.
| | - Noam Kaplan
- Program in Systems Biology, Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, 368 Plantation Street, Worcester, MA 01605-0103, USA.
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