201
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Lancho O, Herranz D. The MYC Enhancer-ome: Long-Range Transcriptional Regulation of MYC in Cancer. Trends Cancer 2018; 4:810-822. [PMID: 30470303 DOI: 10.1016/j.trecan.2018.10.003] [Citation(s) in RCA: 102] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2018] [Revised: 10/04/2018] [Accepted: 10/05/2018] [Indexed: 12/20/2022]
Abstract
MYC is one of the most important oncogenes in cancer. Indeed, MYC is upregulated in 50-60% of all tumors. MYC overexpression can be achieved through a variety of mechanisms, including gene duplications, chromosomal translocations, or somatic mutations leading to increased MYC stability. However, recent studies have identified numerous tissue-specific noncoding enhancers of MYC that play major roles in cancer, highlighting long-range transcriptional regulation of MYC as a critical novel mechanism leading to MYC hyperactivation and as a potential target for new therapeutic strategies in the near future. Here we summarize the regions and mechanisms involved in the long-range transcriptional regulation of MYC, underscoring the relevance of MYC enhancers both in normal physiological development and in MYC-driven cancer initiation and progression.
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Affiliation(s)
- Olga Lancho
- Rutgers Cancer Institute of New Jersey, Rutgers University, New Brunswick, NJ, USA
| | - Daniel Herranz
- Rutgers Cancer Institute of New Jersey, Rutgers University, New Brunswick, NJ, USA; Department of Pharmacology, Robert Wood Johnson Medical School, Rutgers University, Piscataway, NJ, USA.
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202
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Zoller B, Little SC, Gregor T. Diverse Spatial Expression Patterns Emerge from Unified Kinetics of Transcriptional Bursting. Cell 2018; 175:835-847.e25. [PMID: 30340044 PMCID: PMC6779125 DOI: 10.1016/j.cell.2018.09.056] [Citation(s) in RCA: 93] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Revised: 07/02/2018] [Accepted: 09/26/2018] [Indexed: 01/14/2023]
Abstract
How transcriptional bursting relates to gene regulation is a central question that has persisted for more than a decade. Here, we measure nascent transcriptional activity in early Drosophila embryos and characterize the variability in absolute activity levels across expression boundaries. We demonstrate that boundary formation follows a common transcription principle: a single control parameter determines the distribution of transcriptional activity, regardless of gene identity, boundary position, or enhancer-promoter architecture. We infer the underlying bursting kinetics and identify the key regulatory parameter as the fraction of time a gene is in a transcriptionally active state. Unexpectedly, both the rate of polymerase initiation and the switching rates are tightly constrained across all expression levels, predicting synchronous patterning outcomes at all positions in the embryo. These results point to a shared simplicity underlying the apparently complex transcriptional processes of early embryonic patterning and indicate a path to general rules in transcriptional regulation.
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Affiliation(s)
- Benjamin Zoller
- Joseph Henry Laboratories of Physics and the Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA
| | - Shawn C Little
- Department of Molecular Biology and Howard Hughes Medical Institute, Princeton University, Princeton, NJ 08544, USA; Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, 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, Institut Pasteur, 75015 Paris, France.
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203
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Yeung J, Naef F. Rhythms of the Genome: Circadian Dynamics from Chromatin Topology, Tissue-Specific Gene Expression, to Behavior. Trends Genet 2018; 34:915-926. [PMID: 30309754 DOI: 10.1016/j.tig.2018.09.005] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2018] [Revised: 08/31/2018] [Accepted: 09/10/2018] [Indexed: 11/18/2022]
Abstract
Circadian rhythms in physiology and behavior evolved to resonate with daily cycles in the external environment. In mammals, organs orchestrate temporal physiology over the 24-h day, which requires extensive gene expression rhythms targeted to the right tissue. Although a core set of gene products oscillates across virtually all cell types, gene expression profiling across tissues over the 24-h day showed that rhythmic gene expression programs are tissue specific. We highlight recent progress in uncovering how the circadian clock interweaves with tissue-specific gene regulatory networks involving functions such as xenobiotic metabolism, glucose homeostasis, and sleep. This progress hinges on not only comprehensive experimental approaches but also computational methods for multivariate analysis of periodic functional genomics data. We emphasize dynamic chromatin interactions as a novel regulatory layer underlying circadian gene transcription, core clock functions, and ultimately behavior. Finally, we discuss perspectives on extending the knowledge of the circadian clock in animals to human chronobiology.
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Affiliation(s)
- Jake Yeung
- The Institute of Bioengineering (IBI), School of Life Sciences, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Felix Naef
- The Institute of Bioengineering (IBI), School of Life Sciences, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland.
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204
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Haberle V, Stark A. Eukaryotic core promoters and the functional basis of transcription initiation. Nat Rev Mol Cell Biol 2018; 19:621-637. [PMID: 29946135 PMCID: PMC6205604 DOI: 10.1038/s41580-018-0028-8] [Citation(s) in RCA: 447] [Impact Index Per Article: 63.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
RNA polymerase II (Pol II) core promoters are specialized DNA sequences at transcription start sites of protein-coding and non-coding genes that support the assembly of the transcription machinery and transcription initiation. They enable the highly regulated transcription of genes by selectively integrating regulatory cues from distal enhancers and their associated regulatory proteins. In this Review, we discuss the defining properties of gene core promoters, including their sequence features, chromatin architecture and transcription initiation patterns. We provide an overview of molecular mechanisms underlying the function and regulation of core promoters and their emerging functional diversity, which defines distinct transcription programmes. On the basis of the established properties of gene core promoters, we discuss transcription start sites within enhancers and integrate recent results obtained from dedicated functional assays to propose a functional model of transcription initiation. This model can explain the nature and function of transcription initiation at gene starts and at enhancers and can explain the different roles of core promoters, of Pol II and its associated factors and of the activating cues provided by enhancers and the transcription factors and cofactors they recruit.
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Affiliation(s)
- Vanja Haberle
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), Vienna, Austria
| | - Alexander Stark
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), Vienna, Austria.
- Medical University of Vienna, Vienna Biocenter (VBC), Vienna, Austria.
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205
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Brown JM, Roberts NA, Graham B, Waithe D, Lagerholm C, Telenius JM, De Ornellas S, Oudelaar AM, Scott C, Szczerbal I, Babbs C, Kassouf MT, Hughes JR, Higgs DR, Buckle VJ. A tissue-specific self-interacting chromatin domain forms independently of enhancer-promoter interactions. Nat Commun 2018; 9:3849. [PMID: 30242161 PMCID: PMC6155075 DOI: 10.1038/s41467-018-06248-4] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Accepted: 08/24/2018] [Indexed: 11/08/2022] Open
Abstract
Self-interacting chromatin domains encompass genes and their cis-regulatory elements; however, the three-dimensional form a domain takes, whether this relies on enhancer-promoter interactions, and the processes necessary to mediate the formation and maintenance of such domains, remain unclear. To examine these questions, here we use a combination of high-resolution chromosome conformation capture, a non-denaturing form of fluorescence in situ hybridisation and super-resolution imaging to study a 70 kb domain encompassing the mouse α-globin regulatory locus. We show that this region forms an erythroid-specific, decompacted, self-interacting domain, delimited by frequently apposed CTCF/cohesin binding sites early in terminal erythroid differentiation, and does not require transcriptional elongation for maintenance of the domain structure. Formation of this domain does not rely on interactions between the α-globin genes and their major enhancers, suggesting a transcription-independent mechanism for establishment of the domain. However, absence of the major enhancers does alter internal domain interactions. Formation of a loop domain therefore appears to be a mechanistic process that occurs irrespective of the specific interactions within.
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Affiliation(s)
- Jill M Brown
- MRC Molecular Haematology Unit, MRC Weatherall Institute of Molecular Medicine, Oxford University, Oxford, OX3 9DS, UK
| | - Nigel A Roberts
- MRC Molecular Haematology Unit, MRC Weatherall Institute of Molecular Medicine, Oxford University, Oxford, OX3 9DS, UK
| | - Bryony Graham
- MRC Molecular Haematology Unit, MRC Weatherall Institute of Molecular Medicine, Oxford University, Oxford, OX3 9DS, UK
| | - Dominic Waithe
- Wolfson Imaging Centre Oxford, MRC Weatherall Institute of Molecular Medicine, Oxford, OX3 9DS, UK
| | - Christoffer Lagerholm
- Wolfson Imaging Centre Oxford, MRC Weatherall Institute of Molecular Medicine, Oxford, OX3 9DS, UK
| | - Jelena M Telenius
- MRC Molecular Haematology Unit, MRC Weatherall Institute of Molecular Medicine, Oxford University, Oxford, OX3 9DS, UK
| | - Sara De Ornellas
- MRC Molecular Haematology Unit, MRC Weatherall Institute of Molecular Medicine, Oxford University, Oxford, OX3 9DS, UK
| | - A Marieke Oudelaar
- MRC Molecular Haematology Unit, MRC Weatherall Institute of Molecular Medicine, Oxford University, Oxford, OX3 9DS, UK
| | - Caroline Scott
- MRC Molecular Haematology Unit, MRC Weatherall Institute of Molecular Medicine, Oxford University, Oxford, OX3 9DS, UK
| | - Izabela Szczerbal
- MRC Molecular Haematology Unit, MRC Weatherall Institute of Molecular Medicine, Oxford University, Oxford, OX3 9DS, UK
- Department of Genetics and Animal Breeding, Poznan University of Life Sciences, Wolynska 33, 60-637 Poznan, Poland
| | - Christian Babbs
- MRC Molecular Haematology Unit, MRC Weatherall Institute of Molecular Medicine, Oxford University, Oxford, OX3 9DS, UK
| | - Mira T Kassouf
- MRC Molecular Haematology Unit, MRC Weatherall Institute of Molecular Medicine, Oxford University, Oxford, OX3 9DS, UK
| | - Jim R Hughes
- MRC Molecular Haematology Unit, MRC Weatherall Institute of Molecular Medicine, Oxford University, Oxford, OX3 9DS, UK
| | - Douglas R Higgs
- MRC Molecular Haematology Unit, MRC Weatherall Institute of Molecular Medicine, Oxford University, Oxford, OX3 9DS, UK
| | - Veronica J Buckle
- MRC Molecular Haematology Unit, MRC Weatherall Institute of Molecular Medicine, Oxford University, Oxford, OX3 9DS, UK.
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206
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Promoter-mediated diversification of transcriptional bursting dynamics following gene duplication. Proc Natl Acad Sci U S A 2018; 115:8364-8369. [PMID: 30061408 DOI: 10.1073/pnas.1800943115] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
During the evolution of gene families, functional diversification of proteins often follows gene duplication. However, many gene families expand while preserving protein sequence. Why do cells maintain multiple copies of the same gene? Here we have addressed this question for an actin family with 17 genes encoding an identical protein. The genes have divergent flanking regions and are scattered throughout the genome. Surprisingly, almost the entire family showed similar developmental expression profiles, with their expression also strongly coupled in single cells. Using live cell imaging, we show that differences in gene expression were apparent over shorter timescales, with family members displaying different transcriptional bursting dynamics. Strong "bursty" behaviors contrasted steady, more continuous activity, indicating different regulatory inputs to individual actin genes. To determine the sources of these different dynamic behaviors, we reciprocally exchanged the upstream regulatory regions of gene family members. This revealed that dynamic transcriptional behavior is directly instructed by upstream sequence, rather than features specific to genomic context. A residual minor contribution of genomic context modulates the gene OFF rate. Our data suggest promoter diversification following gene duplication could expand the range of stimuli that regulate the expression of essential genes. These observations contextualize the significance of transcriptional bursting.
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207
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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: 318] [Impact Index Per Article: 45.4] [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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208
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Abstract
Single-cell analyses have revealed a tremendous variety among cells in the abundance and chemical composition of RNA. Much of this heterogeneity is due to alternative splicing by the spliceosome. Little is known about how many of the resulting isoforms are biologically functional or just provide noise with little to no impact. The dynamic nature of the spliceosome provides numerous opportunities for regulation but is also the source of stochastic fluctuations. We discuss possible origins of splicing stochasticity, the experimental approaches for studying heterogeneity in isoforms, and the potential biological significance of noisy splicing in development and disease.
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Affiliation(s)
- Yihan Wan
- Laboratory of Receptor Biology and Gene Expression, Center for Cancer Research, National Cancer Institute, Bethesda, MD, 20892, USA
| | - Daniel R Larson
- Laboratory of Receptor Biology and Gene Expression, Center for Cancer Research, National Cancer Institute, Bethesda, MD, 20892, USA.
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209
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Nicolas D, Zoller B, Suter DM, Naef F. Modulation of transcriptional burst frequency by histone acetylation. Proc Natl Acad Sci U S A 2018; 115:7153-7158. [PMID: 29915087 PMCID: PMC6142243 DOI: 10.1073/pnas.1722330115] [Citation(s) in RCA: 100] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Many mammalian genes are transcribed during short bursts of variable frequencies and sizes that substantially contribute to cell-to-cell variability. However, which molecular mechanisms determine bursting properties remains unclear. To probe putative mechanisms, we combined temporal analysis of transcription along the circadian cycle with multiple genomic reporter integrations, using both short-lived luciferase live microscopy and single-molecule RNA-FISH. Using the Bmal1 circadian promoter as our model, we observed that rhythmic transcription resulted predominantly from variations in burst frequency, while the genomic position changed the burst size. Thus, burst frequency and size independently modulated Bmal1 transcription. We then found that promoter histone-acetylation level covaried with burst frequency, being greatest at peak expression and lowest at trough expression, while remaining unaffected by the genomic location. In addition, specific deletions of ROR-responsive elements led to constitutively elevated histone acetylation and burst frequency. We then investigated the suggested link between histone acetylation and burst frequency by dCas9p300-targeted modulation of histone acetylation, revealing that acetylation levels influence burst frequency more than burst size. The correlation between acetylation levels at the promoter and burst frequency was also observed in endogenous circadian genes and in embryonic stem cell fate genes. Thus, our data suggest that histone acetylation-mediated control of transcription burst frequency is a common mechanism to control mammalian gene expression.
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Affiliation(s)
- Damien Nicolas
- Institute of Bioengineering, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, Lausanne CH-1015, Switzerland
| | - Benjamin Zoller
- Institute of Bioengineering, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, Lausanne CH-1015, Switzerland
| | - David M Suter
- Institute of Bioengineering, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, Lausanne CH-1015, Switzerland
| | - Felix Naef
- Institute of Bioengineering, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, Lausanne CH-1015, Switzerland
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210
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Limi S, Senecal A, Coleman R, Lopez-Jones M, Guo P, Polumbo C, Singer RH, Skoultchi AI, Cvekl A. Transcriptional burst fraction and size dynamics during lens fiber cell differentiation and detailed insights into the denucleation process. J Biol Chem 2018; 293:13176-13190. [PMID: 29959226 DOI: 10.1074/jbc.ra118.001927] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Revised: 06/11/2018] [Indexed: 01/05/2023] Open
Abstract
Genes are transcribed in irregular pulses of activity termed transcriptional bursts. Cellular differentiation requires coordinated gene expression; however, it is unknown whether the burst fraction (i.e. the number of active phases of transcription) or size/intensity (the number of RNA molecules produced within a burst) changes during cell differentiation. In the ocular lens, the positions of lens fiber cells correlate precisely with their differentiation status, and the most advanced cells degrade their nuclei. Here, we examined the transcriptional parameters of the β-actin and lens differentiation-specific α-, β-, and γ-crystallin genes by RNA fluorescent in situ hybridization (FISH) in the lenses of embryonic day (E) E12.5, E14.5, and E16.5 mouse embryos and newborns. We found that cellular differentiation dramatically alters the burst fraction in synchronized waves across the lens fiber cell compartment with less dramatic changes in burst intensity. Surprisingly, we observed nascent transcription of multiple genes in nuclei just before nuclear destruction. Nuclear condensation was accompanied by transfer of nuclear proteins, including histone and nonhistone proteins, to the cytoplasm. Although lens-specific deletion of the chromatin remodeler SWI/SNF-related matrix-associated actin-dependent regulator of chromatin subfamily A member 5 (Smarca5/Snf2h) interfered with denucleation, persisting nuclei remained transcriptionally competent and exhibited changes in both burst intensity and fraction depending on the gene examined. Our results uncover the mechanisms of nascent transcriptional control during differentiation and chromatin remodeling, confirm the burst fraction as the major factor adjusting gene expression levels, and reveal transcriptional competence of fiber cell nuclei even as they approach disintegration.
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Affiliation(s)
| | | | | | | | | | | | - Robert H Singer
- Anatomy and Structural Biology.,Cell Biology.,Neuroscience, and
| | | | - Ales Cvekl
- From the Departments of Genetics, .,Ophthalmology and Visual Sciences, Albert Einstein College of Medicine, Bronx, New York 10461
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211
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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: 59] [Impact Index Per Article: 8.4] [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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212
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A Caenorhabditis elegans protein with a PRDM9-like SET domain localizes to chromatin-associated foci and promotes spermatocyte gene expression, sperm production and fertility. PLoS Genet 2018; 14:e1007295. [PMID: 29702639 PMCID: PMC5942854 DOI: 10.1371/journal.pgen.1007295] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2017] [Revised: 05/09/2018] [Accepted: 03/06/2018] [Indexed: 11/19/2022] Open
Abstract
To better understand the tissue-specific regulation of chromatin state in cell-fate determination and animal development, we defined the tissue-specific expression of all 36 C. elegans presumptive lysine methyltransferase (KMT) genes using single-molecule fluorescence in situ hybridization (smFISH). Most KMTs were expressed in only one or two tissues. The germline was the tissue with the broadest KMT expression. We found that the germline-expressed C. elegans protein SET-17, which has a SET domain similar to that of the PRDM9 and PRDM7 SET-domain proteins, promotes fertility by regulating gene expression in primary spermatocytes. SET-17 drives the transcription of spermatocyte-specific genes from four genomic clusters to promote spermatid development. SET-17 is concentrated in stable chromatin-associated nuclear foci at actively transcribed msp (major sperm protein) gene clusters, which we term msp locus bodies. Our results reveal the function of a PRDM9/7-family SET-domain protein in spermatocyte transcription. We propose that the spatial intranuclear organization of chromatin factors might be a conserved mechanism in tissue-specific control of transcription.
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213
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Heritable, Allele-Specific Chromosomal Looping between Tandem Promoters Specifies Promoter Usage of SHC1. Mol Cell Biol 2018; 38:MCB.00658-17. [PMID: 29440311 DOI: 10.1128/mcb.00658-17] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Accepted: 02/08/2018] [Indexed: 11/20/2022] Open
Abstract
One-half of the genes in the human genome contain alternative promoters, some of which generate products with opposing functions. Aberrant silencing or activation of such alternative promoters is associated with multiple diseases, including cancer, but little is known regarding the molecular mechanisms that control alternative promoter choice. The SHC1 gene encodes p46Shc/p52Shc and p66Shc, proteins oppositely regulating anchorage-independent growth that are produced by transcription initiated from the upstream and downstream tandem promoters of SHC1, respectively. Here we demonstrate that activation of these promoters is mutually exclusive on separate alleles in single primary endothelial cells in a heritable fashion, ensuring expression of both transcripts by the cell. Peripheral blood lymphocytes that do not transcribe p66Shc transcribed p52Shc biallelically. This distinct monoallelic transcription pattern is established by allele-specific chromosomal looping between tandem promoters, which silences the upstream promoter. Our results reveal a new mechanism to control alternative promoter usage through higher-order chromatin structure.
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214
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Nicolas D, Phillips NE, Naef F. What shapes eukaryotic transcriptional bursting? MOLECULAR BIOSYSTEMS 2018; 13:1280-1290. [PMID: 28573295 DOI: 10.1039/c7mb00154a] [Citation(s) in RCA: 79] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Isogenic cells in a common environment present a large degree of heterogeneity in gene expression. Part of this variability is attributed to transcriptional bursting: the stochastic activation and inactivation of promoters that leads to the discontinuous production of mRNA. The diversity in bursting patterns displayed by different genes suggests the existence of a connection between bursting and gene regulation. Experimental strategies such as single-molecule RNA FISH, MS2-GFP or short-lived protein reporters allow the quantification of transcriptional bursting and the comparison of bursting kinetics between conditions, allowing therefore the identification of molecular mechanisms modulating transcriptional bursting. In this review we recapitulate the impact on transcriptional bursting of different molecular aspects of transcription such as the chromatin environment, nucleosome occupancy, histone modifications, the number and affinity of regulatory elements, DNA looping and transcription factor availability. More specifically, we examine their role in tuning the burst size or the burst frequency. While some molecular mechanisms involved in transcription such as histone marks can affect every aspect of bursting, others predominantly influence the burst size (e.g. the number and affinity of cis-regulatory elements) or frequency (e.g. transcription factor availability).
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Affiliation(s)
- Damien Nicolas
- The Institute of Bioengineering, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland.
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215
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Mermet J, Yeung J, Hurni C, Mauvoisin D, Gustafson K, Jouffe C, Nicolas D, Emmenegger Y, Gobet C, Franken P, Gachon F, Naef F. Clock-dependent chromatin topology modulates circadian transcription and behavior. Genes Dev 2018; 32:347-358. [PMID: 29572261 PMCID: PMC5900709 DOI: 10.1101/gad.312397.118] [Citation(s) in RCA: 73] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Accepted: 03/02/2018] [Indexed: 12/27/2022]
Abstract
The circadian clock in animals orchestrates widespread oscillatory gene expression programs, which underlie 24-h rhythms in behavior and physiology. Several studies have shown the possible roles of transcription factors and chromatin marks in controlling cyclic gene expression. However, how daily active enhancers modulate rhythmic gene transcription in mammalian tissues is not known. Using circular chromosome conformation capture (4C) combined with sequencing (4C-seq), we discovered oscillatory promoter-enhancer interactions along the 24-h cycle in the mouse liver and kidney. Rhythms in chromatin interactions were abolished in arrhythmic Bmal1 knockout mice. Deleting a contacted intronic enhancer element in the Cryptochrome 1 (Cry1) gene was sufficient to compromise the rhythmic chromatin contacts in tissues. Moreover, the deletion reduced the daily dynamics of Cry1 transcriptional burst frequency and, remarkably, shortened the circadian period of locomotor activity rhythms. Our results establish oscillating and clock-controlled promoter-enhancer looping as a regulatory layer underlying circadian transcription and behavior.
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Affiliation(s)
- Jérôme Mermet
- School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Jake Yeung
- School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Clémence Hurni
- School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Daniel Mauvoisin
- School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Kyle Gustafson
- School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Céline Jouffe
- Nestle Institute of Health Sciences, CH-1015 Lausanne, Switzerland
| | - Damien Nicolas
- School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Yann Emmenegger
- Center for Integrative Genomics, University of Lausanne, CH-1015 Lausanne, Switzerland
| | - Cédric Gobet
- School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland.,Nestle Institute of Health Sciences, CH-1015 Lausanne, Switzerland
| | - Paul Franken
- Center for Integrative Genomics, University of Lausanne, CH-1015 Lausanne, Switzerland
| | - Frédéric Gachon
- School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland.,Nestle Institute of Health Sciences, CH-1015 Lausanne, Switzerland
| | - Félix Naef
- School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
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216
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Abstract
Tissue-specific transcription factors primarily act to define the phenotype of the cell. The power of a single transcription factor to alter cell fate is often minimal, as seen in gain-of-function analyses, but when multiple transcription factors cooperate synergistically it potentiates their ability to induce changes in cell fate. By contrast, transcription factor function is often dispensable in the maintenance of cell phenotype, as is evident in loss-of-function assays. Why does this phenomenon, commonly known as redundancy, occur? Here, I discuss the role that transcription factor networks play in collaboratively regulating stem cell fate and differentiation by providing multiple explanations for their functional redundancy.
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Affiliation(s)
- Hitoshi Niwa
- Department of Pluripotent Stem Cell Biology, Institute of Molecular Embryology and Genetics, Kumamoto University, 2-2-1 Honjo, Chuo-ku, Kumamoto 860-0811, Japan
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217
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Lim B. Imaging transcriptional dynamics. Curr Opin Biotechnol 2018; 52:49-55. [PMID: 29501816 DOI: 10.1016/j.copbio.2018.02.008] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Accepted: 02/11/2018] [Indexed: 01/02/2023]
Abstract
Recent advances in imaging techniques have enabled visualizations of nascent transcripts or individual protein molecules at high spatiotemporal resolution, revealing the complex nature of transcriptional regulation. Here, we highlight recent studies that have provided comprehensive insights to transcriptional dynamics using such quantitative imaging techniques. Specifically, they demonstrated that transcriptional activity is stochastic, and such transcriptional bursting is modulated by multiple components like chromatin environments, concentration of transcription factors, and enhancer-promoter interactions. Moreover, recent studies suggested that regulation of transcriptional activity is more complex than previously thought, by showing that transcription factors and RNA polymerases also move within the cell with distinct kinetics and sometimes form dynamic clusters to mediate transcriptional initiation.
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Affiliation(s)
- Bomyi Lim
- Department of Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, PA 19104, USA.
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218
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Li C, Cesbron F, Oehler M, Brunner M, Höfer T. Frequency Modulation of Transcriptional Bursting Enables Sensitive and Rapid Gene Regulation. Cell Syst 2018; 6:409-423.e11. [PMID: 29454937 DOI: 10.1016/j.cels.2018.01.012] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Revised: 11/16/2017] [Accepted: 01/11/2018] [Indexed: 01/17/2023]
Abstract
Gene regulation is a complex non-equilibrium process. Here, we show that quantitating the temporal regulation of key gene states (transcriptionally inactive, active, and refractory) provides a parsimonious framework for analyzing gene regulation. Our theory makes two non-intuitive predictions. First, for transcription factors (TFs) that regulate transcription burst frequency, as opposed to amplitude or duration, weak TF binding is sufficient to elicit strong transcriptional responses. Second, refractoriness of a gene after a transcription burst enables rapid responses to stimuli. We validate both predictions experimentally by exploiting the natural, optogenetic-like responsiveness of the Neurospora GATA-type TF White Collar Complex (WCC) to blue light. Further, we demonstrate that differential regulation of WCC target genes is caused by different gene activation rates, not different TF occupancy, and that these rates are tuned by both the core promoter and the distance between TF-binding site and core promoter. In total, our work demonstrates the relevance of a kinetic, non-equilibrium framework for understanding transcriptional regulation.
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Affiliation(s)
- Congxin Li
- Division of Theoretical Systems Biology, German Cancer Research Center (DKFZ), 69120 Heidelberg, Germany; Bioquant Center, Heidelberg University, 69120 Heidelberg, Germany
| | - François Cesbron
- Biochemistry Center, Heidelberg University, 69120 Heidelberg, Germany
| | - Michael Oehler
- Biochemistry Center, Heidelberg University, 69120 Heidelberg, Germany
| | - Michael Brunner
- Biochemistry Center, Heidelberg University, 69120 Heidelberg, Germany.
| | - Thomas Höfer
- Division of Theoretical Systems Biology, German Cancer Research Center (DKFZ), 69120 Heidelberg, Germany; Bioquant Center, Heidelberg University, 69120 Heidelberg, Germany.
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219
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Catarino RR, Stark A. Assessing sufficiency and necessity of enhancer activities for gene expression and the mechanisms of transcription activation. Genes Dev 2018; 32:202-223. [PMID: 29491135 PMCID: PMC5859963 DOI: 10.1101/gad.310367.117] [Citation(s) in RCA: 124] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Enhancers are important genomic regulatory elements directing cell type-specific transcription. They assume a key role during development and disease, and their identification and functional characterization have long been the focus of scientific interest. The advent of next-generation sequencing and clustered regularly interspaced short palindromic repeat (CRISPR)/Cas9-based genome editing has revolutionized the means by which we study enhancer biology. In this review, we cover recent developments in the prediction of enhancers based on chromatin characteristics and their identification by functional reporter assays and endogenous DNA perturbations. We discuss that the two latter approaches provide different and complementary insights, especially in assessing enhancer sufficiency and necessity for transcription activation. Furthermore, we discuss recent insights into mechanistic aspects of enhancer function, including findings about cofactor requirements and the role of post-translational histone modifications such as monomethylation of histone H3 Lys4 (H3K4me1). Finally, we survey how these approaches advance our understanding of transcription regulation with respect to promoter specificity and transcriptional bursting and provide an outlook covering open questions and promising developments.
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Affiliation(s)
- Rui R Catarino
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), 1030 Vienna, Austria
| | - Alexander Stark
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), 1030 Vienna, Austria
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220
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Patange S, Girvan M, Larson DR. Single-cell systems biology: probing the basic unit of information flow. ACTA ACUST UNITED AC 2017; 8:7-15. [PMID: 29552672 DOI: 10.1016/j.coisb.2017.11.011] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Gene expression varies across cells in a population or a tissue. This heterogeneity has come into sharp focus in recent years through developments in new imaging and sequencing technologies. However, our ability to measure variation has outpaced our ability to interpret it. Much of the variability may arise from random effects occurring in the processes of gene expression (transcription, RNA processing and decay, translation). The molecular basis of these effects is largely unknown. Likewise, a functional role of this variability in growth, differentiation and disease has only been elucidated in a few cases. In this review, we highlight recent experimental and theoretical advances for measuring and analyzing stochastic variation.
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Affiliation(s)
- Simona Patange
- Laboratory of Receptor Biology and Gene Expression, Center for Cancer Research, National Cancer Institute. Bethesda, MD 20892
- Institute for Physical Science and Technology, University of Maryland, College Park, MD
| | - Michelle Girvan
- Institute for Physical Science and Technology, University of Maryland, College Park, MD
- Department of Physics, University of Maryland. College Park, MD
| | - Daniel R Larson
- Laboratory of Receptor Biology and Gene Expression, Center for Cancer Research, National Cancer Institute. Bethesda, MD 20892
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221
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Tycko J, Van MV, Elowitz MB, Bintu L. Advancing towards a global mammalian gene regulation model through single-cell analysis and synthetic biology. CURRENT OPINION IN BIOMEDICAL ENGINEERING 2017. [DOI: 10.1016/j.cobme.2017.10.011] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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222
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Blinka S, Rao S. Nanog Expression in Embryonic Stem Cells - An Ideal Model System to Dissect Enhancer Function. Bioessays 2017; 39:10.1002/bies.201700086. [PMID: 28977693 PMCID: PMC5878941 DOI: 10.1002/bies.201700086] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2017] [Revised: 08/31/2017] [Indexed: 01/17/2023]
Abstract
Embryonic stem cells (ESCs) are derived from the preimplantation embryo and can differentiate into virtually any other cell type (termed pluripotency), which is governed by lineage specific transcriptions factors (TFs) binding to cis regulatory elements (CREs) to mediate changes in gene expression. The reliance on transcriptional regulation to maintain pluripotency makes ESCs a valuable model to study the role of distal CREs such as enhancers in modulating gene expression to affect cell fate decisions. This review will highlight recent advance on transcriptional enhancers, focusing on studies performed in ESCs. In addition, we argue that the Nanog locus, which encodes for an ESC-critical TF, is particularly informative because it contains multiple co-regulated genes and enhancers in close proximity to one another. The unique landscape at Nanog permits the study of ongoing questions including whether multiple enhancers function additively versus synergistically, determinants of gene specificity, and cell-to-cell variability in gene expression.
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Affiliation(s)
- Steven Blinka
- Department of Cell Biology, Neurobiology, and Anatomy, Medical College of Wisconsin, Milwaukee, WI 53226, USA
- Blood Research Institute, Blood Center of Wisconsin, 8733 West Watertown Plank Road, Milwaukee, WI 53226, USA
| | - Sridhar Rao
- Department of Cell Biology, Neurobiology, and Anatomy, Medical College of Wisconsin, Milwaukee, WI 53226, USA
- Blood Research Institute, Blood Center of Wisconsin, 8733 West Watertown Plank Road, Milwaukee, WI 53226, USA
- Department of Pediatrics, Medical College of Wisconsin, Milwaukee, WI 53226, USA
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223
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Bissiere S, Gasnier M, Alvarez YD, Plachta N. Cell Fate Decisions During Preimplantation Mammalian Development. Curr Top Dev Biol 2017; 128:37-58. [PMID: 29477170 DOI: 10.1016/bs.ctdb.2017.11.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
The early mouse embryo offers a phenomenal system to dissect how changes in the mechanisms controlling cell fate are integrated with morphogenetic events at the single-cell level. New technologies based on live imaging have enabled the discovery of dynamic changes in the regulation of single genes, transcription factors, and epigenetic mechanisms directing early cell fate decision in the early embryo. Here, we review recent progress in linking molecular dynamic events occurring at the level of the single cell in vivo, to some of the key morphogenetic changes regulating early mouse development.
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Affiliation(s)
| | - Maxime Gasnier
- Institute of Molecular and Cell Biology, A*STAR, Singapore, Singapore
| | - Yanina D Alvarez
- Institute of Molecular and Cell Biology, A*STAR, Singapore, Singapore; Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Conicet, Buenos Aires, Argentina
| | - Nicolas Plachta
- Institute of Molecular and Cell Biology, A*STAR, Singapore, Singapore; National University of Singapore, Singapore, Singapore.
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224
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Bentovim L, Harden TT, DePace AH. Transcriptional precision and accuracy in development: from measurements to models and mechanisms. Development 2017; 144:3855-3866. [PMID: 29089359 PMCID: PMC5702068 DOI: 10.1242/dev.146563] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
During development, genes are transcribed at specific times, locations and levels. In recent years, the emergence of quantitative tools has significantly advanced our ability to measure transcription with high spatiotemporal resolution in vivo. Here, we highlight recent studies that have used these tools to characterize transcription during development, and discuss the mechanisms that contribute to the precision and accuracy of the timing, location and level of transcription. We attempt to disentangle the discrepancies in how physicists and biologists use the term ‘precision' to facilitate interactions using a common language. We also highlight selected examples in which the coupling of mathematical modeling with experimental approaches has provided important mechanistic insights, and call for a more expansive use of mathematical modeling to exploit the wealth of quantitative data and advance our understanding of animal transcription. Summary: This Review highlights how high-resolution quantitative tools and theoretical models have formed our current view of the mechanisms determining precision and accuracy in the timing, location and level of transcription in the Drosophila embryo.
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Affiliation(s)
- Lital Bentovim
- Department of Systems Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Timothy T Harden
- Department of Systems Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Angela H DePace
- Department of Systems Biology, Harvard Medical School, Boston, MA 02115, USA
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225
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Andrey G, Mundlos S. The three-dimensional genome: regulating gene expression during pluripotency and development. Development 2017; 144:3646-3658. [PMID: 29042476 DOI: 10.1242/dev.148304] [Citation(s) in RCA: 82] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The precise expression of genes in time and space during embryogenesis is largely influenced by communication between enhancers and promoters, which is propagated and governed by the physical proximity of these elements in the nucleus. Here, we review how chromatin domains organize the genome by guiding enhancers to their target genes thereby preventing non-specific interactions with other neighboring regions. We also discuss the dynamics of chromatin interactions between enhancers and promoters, as well as the consequent changes in gene expression, that occur in pluripotent cells and during development. Finally, we evaluate how genomic changes such as deletions, inversions and duplications affect 3D chromatin configuration overall and lead to ectopic enhancer-promoter contacts, and thus gene misexpression, which can contribute to abnormal development and disease.
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Affiliation(s)
- Guillaume Andrey
- Max Planck Institute for Molecular Genetics, RG Development & Disease, 14195 Berlin, Germany
| | - Stefan Mundlos
- Max Planck Institute for Molecular Genetics, RG Development & Disease, 14195 Berlin, Germany .,Institute for Medical and Human Genetics, Charité Universitätsmedizin Berlin, Augustenburger Platz 1, 13353 Berlin, Germany
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226
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Huang L, Liu P, Yuan Z, Zhou T, Yu J. The free-energy cost of interaction between DNA loops. Sci Rep 2017; 7:12610. [PMID: 28974770 PMCID: PMC5626758 DOI: 10.1038/s41598-017-12765-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Accepted: 09/14/2017] [Indexed: 12/03/2022] Open
Abstract
From the viewpoint of thermodynamics, the formation of DNA loops and the interaction between them, which are all non-equilibrium processes, result in the change of free energy, affecting gene expression and further cell-to-cell variability as observed experimentally. However, how these processes dissipate free energy remains largely unclear. Here, by analyzing a mechanic model that maps three fundamental topologies of two interacting DNA loops into a 4-state model of gene transcription, we first show that a longer DNA loop needs more mean free energy consumption. Then, independent of the type of interacting two DNA loops (nested, side-by-side or alternating), the promotion between them always consumes less mean free energy whereas the suppression dissipates more mean free energy. More interestingly, we find that in contrast to the mechanism of direct looping between promoter and enhancer, the facilitated-tracking mechanism dissipates less mean free energy but enhances the mean mRNA expression, justifying the facilitated-tracking hypothesis, a long-standing debate in biology. Based on minimal energy principle, we thus speculate that organisms would utilize the mechanisms of loop-loop promotion and facilitated tracking to survive in complex environments. Our studies provide insights into the understanding of gene expression regulation mechanism from the view of energy consumption.
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Affiliation(s)
- Lifang Huang
- Research Centre of Applied Mathematics, Guangzhou University, Guangzhou, 510006, P.R. China
- School of Statistics and Mathematics, Guangdong University of Finance & Economics, Guangzhou, 510275, P.R. China
| | - Peijiang Liu
- School of Statistics and Mathematics, Guangdong University of Finance & Economics, Guangzhou, 510275, P.R. China
| | - Zhanjiang Yuan
- Guangdong Province Key Laboratory of Computational Science, School of Mathematics and Computational Science, Sun Yat-Sen University, Guangzhou, 510275, P.R. China
| | - Tianshou Zhou
- Guangdong Province Key Laboratory of Computational Science, School of Mathematics and Computational Science, Sun Yat-Sen University, Guangzhou, 510275, P.R. China.
| | - Jianshe Yu
- Research Centre of Applied Mathematics, Guangzhou University, Guangzhou, 510006, P.R. China.
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227
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Transcriptional Output Transiently Spikes Upon Mitotic Exit. Sci Rep 2017; 7:12607. [PMID: 28974707 PMCID: PMC5626720 DOI: 10.1038/s41598-017-12723-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2017] [Accepted: 09/14/2017] [Indexed: 12/11/2022] Open
Abstract
The pulsatile nature of gene activity has recently emerged as a general property of the transcriptional process. It has been shown that the frequency and amplitude of transcriptional bursts can be subjected to extrinsic regulation. Here we have investigated if these parameters were constant throughout the cell cycle using the single molecule RNA FISH technique. We found evidence of transcriptional spikes upon mitotic exit in three different human cell lines. Recording of cell growth prior to hybridization and immuno-RNA FISH analysis revealed that these spikes were short-lived and subsided before completion of cytokinesis. The transient post-mitotic increase in transcriptional output was found to be the result of cells displaying a higher number of active alleles and/or an increased number of nascent transcripts per active allele, indicating that both the burst fraction and the amplitude of individual bursts can be increased upon mitotic exit. Our results further suggest that distinct regulatory mechanisms are at work shortly after mitotic exit and during the rest of interphase. We speculate that transcriptional spikes are associated with chromatin decondensation, a hallmark of post-mitotic cells that might alter the dynamics of transcriptional regulators and effectors.
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228
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Hendy O, Campbell J, Weissman JD, Larson DR, Singer DS. Differential context-specific impact of individual core promoter elements on transcriptional dynamics. Mol Biol Cell 2017; 28:3360-3370. [PMID: 28931597 PMCID: PMC5687036 DOI: 10.1091/mbc.e17-06-0408] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2017] [Revised: 08/23/2017] [Accepted: 09/11/2017] [Indexed: 11/11/2022] Open
Abstract
The roles of individual core promoter elements in transcriptional dynamics of MHC class I gene expression were determined by smFISH in primary B-cells. The elements individually modulated transcriptional bursting, differentially contributing to burst size or burst frequency, to enable combinatorial fine-tuning of the level of transcription. Eukaryotic transcription occurs in bursts that vary in size and frequency, but the contribution of individual core promoter elements to transcriptional bursting is not known. Here we analyze the relative contributions to bursting of the individual core promoter elements—CCAAT, TATAA-like, Sp1BS, and Inr—of an MHC class I gene in primary B-cells during both basal and activated transcription. The TATAA-like, Sp1BS, and Inr elements all function as negative regulators of transcription, and each was found to contribute differentially to the overall bursting pattern of the promoter during basal transcription. Whereas the Sp1BS element regulates burst size, the Inr element regulates burst frequency. The TATAA-like element contributes to both. Surprisingly, each element has a distinct role in bursting during transcriptional activation by γ-interferon. The CCAAT element does not contribute significantly to the constitutive transcriptional dynamics of primary B-cells, but modulates both burst size and frequency in response to γ-interferon activation. The ability of core promoter elements to modulate transcriptional bursting individually allows combinatorial fine-tuning of the level of MHC class I gene expression in response to intrinsic and extrinsic signals.
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Affiliation(s)
- Oliver Hendy
- Experimental Immunology Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892
| | - John Campbell
- Experimental Immunology Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892
| | - Jocelyn D Weissman
- Experimental Immunology Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892
| | - Daniel R Larson
- Laboratory of Receptor Biology and Gene Expression, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892
| | - Dinah S Singer
- Experimental Immunology Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892
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229
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Huang P, Keller CA, Giardine B, Grevet JD, Davies JOJ, Hughes JR, Kurita R, Nakamura Y, Hardison RC, Blobel GA. Comparative analysis of three-dimensional chromosomal architecture identifies a novel fetal hemoglobin regulatory element. Genes Dev 2017; 31:1704-1713. [PMID: 28916711 PMCID: PMC5647940 DOI: 10.1101/gad.303461.117] [Citation(s) in RCA: 98] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2017] [Accepted: 08/21/2017] [Indexed: 01/04/2023]
Abstract
In this study, Huang et al. compared the chromosomal architectures of fetal and adult human erythroblasts and found that, globally, chromatin structures and compartments A/B are highly similar at both developmental stages. Their results uncover a new critical regulatory region as a potential target for therapeutic genome editing for hemoglobinopathies and highlight the power of chromosome conformation analysis in discovering new cis control elements. Chromatin structure is tightly intertwined with transcription regulation. Here we compared the chromosomal architectures of fetal and adult human erythroblasts and found that, globally, chromatin structures and compartments A/B are highly similar at both developmental stages. At a finer scale, we detected distinct folding patterns at the developmentally controlled β-globin locus. Specifically, new fetal stage-specific contacts were uncovered between a region separating the fetal (γ) and adult (δ and β) globin genes (encompassing the HBBP1 and BGLT3 noncoding genes) and two distal chromosomal sites (HS5 and 3′HS1) that flank the locus. In contrast, in adult cells, the HBBP1–BGLT3 region contacts the embryonic ε-globin gene, physically separating the fetal globin genes from the enhancer (locus control region [LCR]). Deletion of the HBBP1 region in adult cells alters contact landscapes in ways more closely resembling those of fetal cells, including increased LCR–γ-globin contacts. These changes are accompanied by strong increases in γ-globin transcription. Notably, the effects of HBBP1 removal on chromatin architecture and gene expression closely mimic those of deleting the fetal globin repressor BCL11A, implicating BCL11A in the function of the HBBP1 region. Our results uncover a new critical regulatory region as a potential target for therapeutic genome editing for hemoglobinopathies and highlight the power of chromosome conformation analysis in discovering new cis control elements.
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Affiliation(s)
- Peng Huang
- Division of Hematology, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania 19104, USA
| | - Cheryl A Keller
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - Belinda Giardine
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - Jeremy D Grevet
- Division of Hematology, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania 19104, USA.,Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - James O J Davies
- Medical Research Council (MRC) Molecular Hematology Unit, Weatherall Institute of Molecular Medicine, Oxford University, Oxford OX3 9DS, United Kingdom
| | - Jim R Hughes
- Medical Research Council (MRC) Molecular Hematology Unit, Weatherall Institute of Molecular Medicine, Oxford University, Oxford OX3 9DS, United Kingdom
| | - Ryo Kurita
- Research and Development Department, Central Blood Institute, Blood Service Headquarters, Japanese Red Cross Society, Koto-ku, Tokyo 135-8521, Japan
| | - Yukio Nakamura
- Cell Engineering Division, RIKEN BioResource Center, Tsukuba, Ibaraki 305-0074, Japan
| | - Ross C Hardison
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - Gerd A Blobel
- Division of Hematology, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania 19104, USA.,Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
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230
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Soler-Oliva ME, Guerrero-Martínez JA, Bachetti V, Reyes JC. Analysis of the relationship between coexpression domains and chromatin 3D organization. PLoS Comput Biol 2017; 13:e1005708. [PMID: 28902867 PMCID: PMC5612749 DOI: 10.1371/journal.pcbi.1005708] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2017] [Revised: 09/25/2017] [Accepted: 08/03/2017] [Indexed: 01/08/2023] Open
Abstract
Gene order is not random in eukaryotic chromosomes, and co-regulated genes tend to be clustered. The mechanisms that determine co-regulation of large regions of the genome and its connection with chromatin three-dimensional (3D) organization are still unclear however. Here we have adapted a recently described method for identifying chromatin topologically associating domains (TADs) to identify coexpression domains (which we term “CODs”). Using human normal breast and breast cancer RNA-seq data, we have identified approximately 500 CODs. CODs in the normal and breast cancer genomes share similar characteristics but differ in their gene composition. COD genes have a greater tendency to be coexpressed with genes that reside in other CODs than with non-COD genes. Such inter-COD coexpression is maintained over large chromosomal distances in the normal genome but is partially lost in the cancer genome. Analyzing the relationship between CODs and chromatin 3D organization using Hi-C contact data, we find that CODs do not correspond to TADs. In fact, intra-TAD gene coexpression is the same as random for most chromosomes. However, the contact profile is similar between gene pairs that reside either in the same COD or in coexpressed CODs. These data indicate that co-regulated genes in the genome present similar patterns of contacts irrespective of the frequency of physical chromatin contacts between them. Prokaryotic operons normally comprise functionally related genes whose expression is coordinated. Even though operons do not exist in most eukaryotes, results from the last fifteen years indicate that gene order is nonetheless not random in eukaryotes, and that coexpressed genes tend to be grouped in the genome. We identify here about 500 coexpression domain (CODs) in normal breast tissue. Interestingly, we find that genes within CODs often are coexpressed with other genes that reside in other CODs placed very far away in the same chromosome, which is indicative of long-range inter-COD co-regulation. Furthermore, we find that coexpressed genes within CODs or within co-regulated CODs display similar three-dimensional chromatin contacts, suggesting a spatial coordination of CODs.
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Affiliation(s)
- María E. Soler-Oliva
- Centro Andaluz de Biología Molecular y Medicina Regenerativa-CABIMER, Consejo Superior de Investigaciones Científicas-Universidad de Sevilla-Universidad Pablo de Olavide (CSIC-USE-UPO), Sevilla, Spain
| | - José A. Guerrero-Martínez
- Centro Andaluz de Biología Molecular y Medicina Regenerativa-CABIMER, Consejo Superior de Investigaciones Científicas-Universidad de Sevilla-Universidad Pablo de Olavide (CSIC-USE-UPO), Sevilla, Spain
| | - Valentina Bachetti
- Centro Andaluz de Biología Molecular y Medicina Regenerativa-CABIMER, Consejo Superior de Investigaciones Científicas-Universidad de Sevilla-Universidad Pablo de Olavide (CSIC-USE-UPO), Sevilla, Spain
| | - José C. Reyes
- Centro Andaluz de Biología Molecular y Medicina Regenerativa-CABIMER, Consejo Superior de Investigaciones Científicas-Universidad de Sevilla-Universidad Pablo de Olavide (CSIC-USE-UPO), Sevilla, Spain
- * E-mail:
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231
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Siersbæk R, Madsen JGS, Javierre BM, Nielsen R, Bagge EK, Cairns J, Wingett SW, Traynor S, Spivakov M, Fraser P, Mandrup S. Dynamic Rewiring of Promoter-Anchored Chromatin Loops during Adipocyte Differentiation. Mol Cell 2017; 66:420-435.e5. [PMID: 28475875 DOI: 10.1016/j.molcel.2017.04.010] [Citation(s) in RCA: 166] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2016] [Revised: 03/06/2017] [Accepted: 04/11/2017] [Indexed: 01/08/2023]
Abstract
Interactions between transcriptional promoters and their distal regulatory elements play an important role in transcriptional regulation; however, the extent to which these interactions are subject to rapid modulations in response to signals is unknown. Here, we use promoter capture Hi-C to demonstrate a rapid reorganization of promoter-anchored chromatin loops within 4 hr after inducing differentiation of 3T3-L1 preadipocytes. The establishment of new promoter-enhancer loops is tightly coupled to activation of poised (histone H3 lysine 4 mono- and dimethylated) enhancers, as evidenced by the acquisition of histone H3 lysine 27 acetylation and the binding of MED1, SMC1, and P300 proteins to these regions, as well as to activation of target genes. Intriguingly, formation of loops connecting activated enhancers and promoters is also associated with extensive recruitment of corepressors such as NCoR and HDACs, indicating that this class of coregulators may play a previously unrecognized role during enhancer activation.
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Affiliation(s)
- Rasmus Siersbæk
- University of Southern Denmark, Campusvej 55, 5230 Odense M, Denmark
| | | | | | - Ronni Nielsen
- University of Southern Denmark, Campusvej 55, 5230 Odense M, Denmark
| | | | - Jonathan Cairns
- Nuclear Dynamics Programme, Babraham Institute, Cambridge CB22 3AT, UK
| | - Steven William Wingett
- Nuclear Dynamics Programme, Babraham Institute, Cambridge CB22 3AT, UK; Bioinformatics Group, Babraham Institute, Cambridge CB22 3AT, UK
| | - Sofie Traynor
- University of Southern Denmark, Campusvej 55, 5230 Odense M, Denmark
| | - Mikhail Spivakov
- Nuclear Dynamics Programme, Babraham Institute, Cambridge CB22 3AT, UK
| | - Peter Fraser
- Nuclear Dynamics Programme, Babraham Institute, Cambridge CB22 3AT, UK; Department of Biological Science, Florida State University, Tallahassee, FL 32306, USA.
| | - Susanne Mandrup
- University of Southern Denmark, Campusvej 55, 5230 Odense M, Denmark.
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232
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Symmons O, Raj A. What's Luck Got to Do with It: Single Cells, Multiple Fates, and Biological Nondeterminism. Mol Cell 2017; 62:788-802. [PMID: 27259209 DOI: 10.1016/j.molcel.2016.05.023] [Citation(s) in RCA: 138] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
The field of single-cell biology has morphed from a philosophical digression at its inception, to a playground for quantitative biologists, to a major area of biomedical research. The last several years have witnessed an explosion of new technologies, allowing us to apply even more of the modern molecular biology toolkit to single cells. Conceptual progress, however, has been comparatively slow. Here, we provide a framework for classifying both the origins of the differences between individual cells and the consequences of those differences. We discuss how the concept of "random" differences is context dependent, and propose that rigorous definitions of inputs and outputs may bring clarity to the discussion. We also categorize ways in which probabilistic behavior may influence cellular function, highlighting studies that point to exciting future directions in the field.
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Affiliation(s)
- Orsolya Symmons
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA 19104, USA.
| | - Arjun Raj
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA 19104, USA.
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233
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Barr KA, Reinitz J. A sequence level model of an intact locus predicts the location and function of nonadditive enhancers. PLoS One 2017; 12:e0180861. [PMID: 28715438 PMCID: PMC5513433 DOI: 10.1371/journal.pone.0180861] [Citation(s) in RCA: 10] [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: 11/07/2016] [Accepted: 06/22/2017] [Indexed: 01/24/2023] Open
Abstract
Metazoan gene expression is controlled through the action of long stretches of noncoding DNA that contain enhancers-shorter sequences responsible for controlling a single aspect of a gene's expression pattern. Models built on thermodynamics have shown how enhancers interpret protein concentration in order to determine specific levels of gene expression, but the emergent regulatory logic of a complete regulatory locus shows qualitative and quantitative differences from isolated enhancers. Such differences may arise from steric competition limiting the quantity of DNA that can simultaneously influence the transcription machinery. We incorporated this competition into a mechanistic model of gene regulation, generated efficient algorithms for this computation, and applied it to the regulation of Drosophila even-skipped (eve). This model finds the location of enhancers and identifies which factors control the boundaries of eve expression. This model predicts a new enhancer that, when assayed in vivo, drives expression in a non-eve pattern. Incorporation of chromatin accessibility eliminates this inconsistency.
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Affiliation(s)
- Kenneth A. Barr
- Committee on Genetics, Genomics, and Systems Biology, University of Chicago, Chicago, Illinois, United States of America
| | - John Reinitz
- Committee on Genetics, Genomics, and Systems Biology, University of Chicago, Chicago, Illinois, United States of America
- Department of Statistics, University of Chicago, Chicago, Illinois, United States of America
- Department of Ecology and Evolution, University of Chicago, Chicago, Illinois, United States of America
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, Illinois, United States of America
- Institute for Genomics and Systems Biology, University of Chicago, Chicago, Illinois, United States of America
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234
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Arnal JF, Lenfant F, Metivier R, Flouriot G, Henrion D, Adlanmerini M, Fontaine C, Gourdy P, Chambon P, Katzenellenbogen B, Katzenellenbogen J. Membrane and Nuclear Estrogen Receptor Alpha Actions: From Tissue Specificity to Medical Implications. Physiol Rev 2017; 97:1045-1087. [DOI: 10.1152/physrev.00024.2016] [Citation(s) in RCA: 284] [Impact Index Per Article: 35.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Revised: 12/19/2016] [Accepted: 01/18/2017] [Indexed: 12/22/2022] Open
Abstract
Estrogen receptor alpha (ERα) has been recognized now for several decades as playing a key role in reproduction and exerting functions in numerous nonreproductive tissues. In this review, we attempt to summarize the in vitro studies that are the basis of our current understanding of the mechanisms of action of ERα as a nuclear receptor and the key roles played by its two activation functions (AFs) in its transcriptional activities. We then depict the consequences of the selective inactivation of these AFs in mouse models, focusing on the prominent roles played by ERα in the reproductive tract and in the vascular system. Evidence has accumulated over the two last decades that ERα is also associated with the plasma membrane and activates non-nuclear signaling from this site. These rapid/nongenomic/membrane-initiated steroid signals (MISS) have been characterized in a variety of cell lines, and in particular in endothelial cells. The development of selective pharmacological tools that specifically activate MISS and the generation of mice expressing an ERα protein impeded for membrane localization have begun to unravel the physiological role of MISS in vivo. Finally, we discuss novel perspectives for the design of tissue-selective ER modulators based on the integration of the physiological and pathophysiological roles of MISS actions of estrogens.
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Affiliation(s)
- Jean-Francois Arnal
- I2MC, Institut National de la Santé et de la Recherche Médicale (INSERM) U 1048, Université de Toulouse 3 and CHU de Toulouse, Toulouse, France; Equipe SP@RTE UMR 6290 CNRS, Institut de Genétique et Développement de Rennes, Université de Rennes 1, Campus de Beaulieu, Rennes, France; Université de Rennes 1, Institut de Recherche en Santé, Environnement et Travail (Irest–INSERM UMR 1085), Equipe TREC, Rennes, France; Unité Mixte de Recherche 6214, Centre National de la Recherche Scientifique, Angers,
| | - Françoise Lenfant
- I2MC, Institut National de la Santé et de la Recherche Médicale (INSERM) U 1048, Université de Toulouse 3 and CHU de Toulouse, Toulouse, France; Equipe SP@RTE UMR 6290 CNRS, Institut de Genétique et Développement de Rennes, Université de Rennes 1, Campus de Beaulieu, Rennes, France; Université de Rennes 1, Institut de Recherche en Santé, Environnement et Travail (Irest–INSERM UMR 1085), Equipe TREC, Rennes, France; Unité Mixte de Recherche 6214, Centre National de la Recherche Scientifique, Angers,
| | - Raphaël Metivier
- I2MC, Institut National de la Santé et de la Recherche Médicale (INSERM) U 1048, Université de Toulouse 3 and CHU de Toulouse, Toulouse, France; Equipe SP@RTE UMR 6290 CNRS, Institut de Genétique et Développement de Rennes, Université de Rennes 1, Campus de Beaulieu, Rennes, France; Université de Rennes 1, Institut de Recherche en Santé, Environnement et Travail (Irest–INSERM UMR 1085), Equipe TREC, Rennes, France; Unité Mixte de Recherche 6214, Centre National de la Recherche Scientifique, Angers,
| | - Gilles Flouriot
- I2MC, Institut National de la Santé et de la Recherche Médicale (INSERM) U 1048, Université de Toulouse 3 and CHU de Toulouse, Toulouse, France; Equipe SP@RTE UMR 6290 CNRS, Institut de Genétique et Développement de Rennes, Université de Rennes 1, Campus de Beaulieu, Rennes, France; Université de Rennes 1, Institut de Recherche en Santé, Environnement et Travail (Irest–INSERM UMR 1085), Equipe TREC, Rennes, France; Unité Mixte de Recherche 6214, Centre National de la Recherche Scientifique, Angers,
| | - Daniel Henrion
- I2MC, Institut National de la Santé et de la Recherche Médicale (INSERM) U 1048, Université de Toulouse 3 and CHU de Toulouse, Toulouse, France; Equipe SP@RTE UMR 6290 CNRS, Institut de Genétique et Développement de Rennes, Université de Rennes 1, Campus de Beaulieu, Rennes, France; Université de Rennes 1, Institut de Recherche en Santé, Environnement et Travail (Irest–INSERM UMR 1085), Equipe TREC, Rennes, France; Unité Mixte de Recherche 6214, Centre National de la Recherche Scientifique, Angers,
| | - Marine Adlanmerini
- I2MC, Institut National de la Santé et de la Recherche Médicale (INSERM) U 1048, Université de Toulouse 3 and CHU de Toulouse, Toulouse, France; Equipe SP@RTE UMR 6290 CNRS, Institut de Genétique et Développement de Rennes, Université de Rennes 1, Campus de Beaulieu, Rennes, France; Université de Rennes 1, Institut de Recherche en Santé, Environnement et Travail (Irest–INSERM UMR 1085), Equipe TREC, Rennes, France; Unité Mixte de Recherche 6214, Centre National de la Recherche Scientifique, Angers,
| | - Coralie Fontaine
- I2MC, Institut National de la Santé et de la Recherche Médicale (INSERM) U 1048, Université de Toulouse 3 and CHU de Toulouse, Toulouse, France; Equipe SP@RTE UMR 6290 CNRS, Institut de Genétique et Développement de Rennes, Université de Rennes 1, Campus de Beaulieu, Rennes, France; Université de Rennes 1, Institut de Recherche en Santé, Environnement et Travail (Irest–INSERM UMR 1085), Equipe TREC, Rennes, France; Unité Mixte de Recherche 6214, Centre National de la Recherche Scientifique, Angers,
| | - Pierre Gourdy
- I2MC, Institut National de la Santé et de la Recherche Médicale (INSERM) U 1048, Université de Toulouse 3 and CHU de Toulouse, Toulouse, France; Equipe SP@RTE UMR 6290 CNRS, Institut de Genétique et Développement de Rennes, Université de Rennes 1, Campus de Beaulieu, Rennes, France; Université de Rennes 1, Institut de Recherche en Santé, Environnement et Travail (Irest–INSERM UMR 1085), Equipe TREC, Rennes, France; Unité Mixte de Recherche 6214, Centre National de la Recherche Scientifique, Angers,
| | - Pierre Chambon
- I2MC, Institut National de la Santé et de la Recherche Médicale (INSERM) U 1048, Université de Toulouse 3 and CHU de Toulouse, Toulouse, France; Equipe SP@RTE UMR 6290 CNRS, Institut de Genétique et Développement de Rennes, Université de Rennes 1, Campus de Beaulieu, Rennes, France; Université de Rennes 1, Institut de Recherche en Santé, Environnement et Travail (Irest–INSERM UMR 1085), Equipe TREC, Rennes, France; Unité Mixte de Recherche 6214, Centre National de la Recherche Scientifique, Angers,
| | - Benita Katzenellenbogen
- I2MC, Institut National de la Santé et de la Recherche Médicale (INSERM) U 1048, Université de Toulouse 3 and CHU de Toulouse, Toulouse, France; Equipe SP@RTE UMR 6290 CNRS, Institut de Genétique et Développement de Rennes, Université de Rennes 1, Campus de Beaulieu, Rennes, France; Université de Rennes 1, Institut de Recherche en Santé, Environnement et Travail (Irest–INSERM UMR 1085), Equipe TREC, Rennes, France; Unité Mixte de Recherche 6214, Centre National de la Recherche Scientifique, Angers,
| | - John Katzenellenbogen
- I2MC, Institut National de la Santé et de la Recherche Médicale (INSERM) U 1048, Université de Toulouse 3 and CHU de Toulouse, Toulouse, France; Equipe SP@RTE UMR 6290 CNRS, Institut de Genétique et Développement de Rennes, Université de Rennes 1, Campus de Beaulieu, Rennes, France; Université de Rennes 1, Institut de Recherche en Santé, Environnement et Travail (Irest–INSERM UMR 1085), Equipe TREC, Rennes, France; Unité Mixte de Recherche 6214, Centre National de la Recherche Scientifique, Angers,
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235
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Mll3 and Mll4 Facilitate Enhancer RNA Synthesis and Transcription from Promoters Independently of H3K4 Monomethylation. Mol Cell 2017; 66:568-576.e4. [PMID: 28483418 DOI: 10.1016/j.molcel.2017.04.018] [Citation(s) in RCA: 277] [Impact Index Per Article: 34.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2017] [Revised: 03/30/2017] [Accepted: 04/25/2017] [Indexed: 01/24/2023]
Abstract
Monomethylation of histone H3 at lysine 4 (H3K4me1) and acetylation of histone H3 at lysine 27 (H3K27ac) are correlated with transcriptionally engaged enhancer elements, but the functional impact of these modifications on enhancer activity is not well understood. Here we used CRISPR/Cas9 genome editing to separate catalytic activity-dependent and independent functions of Mll3 (Kmt2c) and Mll4 (Kmt2d, Mll2), the major enhancer H3K4 monomethyltransferases. Loss of H3K4me1 from enhancers in Mll3/4 catalytically deficient cells causes partial reduction of H3K27ac, but has surprisingly minor effects on transcription from either enhancers or promoters. In contrast, loss of Mll3/4 proteins leads to strong depletion of enhancer Pol II occupancy and eRNA synthesis, concomitant with downregulation of target genes. Interestingly, downregulated genes exhibit reduced polymerase levels in gene bodies, but not at promoters, suggestive of pause-release defects. Altogether, our results suggest that enhancer H3K4me1 provides only a minor contribution to the long-range coactivator function of Mll3/4.
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236
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Jiang Y, Zhang NR, Li M. SCALE: modeling allele-specific gene expression by single-cell RNA sequencing. Genome Biol 2017; 18:74. [PMID: 28446220 PMCID: PMC5407026 DOI: 10.1186/s13059-017-1200-8] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2017] [Accepted: 03/24/2017] [Indexed: 12/13/2022] Open
Abstract
Allele-specific expression is traditionally studied by bulk RNA sequencing, which measures average expression across cells. Single-cell RNA sequencing allows the comparison of expression distribution between the two alleles of a diploid organism and the characterization of allele-specific bursting. Here, we propose SCALE to analyze genome-wide allele-specific bursting, with adjustment of technical variability. SCALE detects genes exhibiting allelic differences in bursting parameters and genes whose alleles burst non-independently. We apply SCALE to mouse blastocyst and human fibroblast cells and find that cis control in gene expression overwhelmingly manifests as differences in burst frequency.
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Affiliation(s)
- Yuchao Jiang
- Genomics and Computational Biology Graduate Program, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Nancy R Zhang
- Department of Statistics, The Wharton School, University of Pennsylvania, Philadelphia, PA, 19104, USA.
| | - Mingyao Li
- Department of Biostatistics and Epidemiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA.
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237
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Xie S, Duan J, Li B, Zhou P, Hon GC. Multiplexed Engineering and Analysis of Combinatorial Enhancer Activity in Single Cells. Mol Cell 2017; 66:285-299.e5. [PMID: 28416141 DOI: 10.1016/j.molcel.2017.03.007] [Citation(s) in RCA: 239] [Impact Index Per Article: 29.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Revised: 01/18/2017] [Accepted: 03/07/2017] [Indexed: 12/25/2022]
Abstract
The study of enhancers has been hampered by the scarcity of methods to systematically quantify their endogenous activity. We develop Mosaic-seq to systematically perturb enhancers and measure their endogenous activities at single-cell resolution. Mosaic-seq uses a CRISPR barcoding system to jointly measure a cell's transcriptome and its sgRNA modulators, thus quantifying the effects of dCas9-KRAB-mediated enhancer repression in single cells. Applying Mosaic-seq to 71 constituent enhancers from 15 super-enhancers, our analysis of 51,448 sgRNA-induced transcriptomes finds that only a small number of constituents are major effectors of target gene expression. Binding of p300 and RNAPII are key features of these constituents. We determine two key parameters of enhancer activity in single cells: their penetrance in a population and their contribution to expression in these cells. Through combinatorial interrogation, we find that simultaneous repression of multiple weak constituents can alter super-enhancer activity in a manner greatly exceeding repression of individual constituents.
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Affiliation(s)
- Shiqi Xie
- Laboratory of Regulatory Genomics, Cecil H. and Ida Green Center for Reproductive Biology Sciences, Division of Basic Reproductive Biology Research, Department of Obstetrics and Gynecology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Jialei Duan
- Laboratory of Regulatory Genomics, Cecil H. and Ida Green Center for Reproductive Biology Sciences, Division of Basic Reproductive Biology Research, Department of Obstetrics and Gynecology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Boxun Li
- Laboratory of Regulatory Genomics, Cecil H. and Ida Green Center for Reproductive Biology Sciences, Division of Basic Reproductive Biology Research, Department of Obstetrics and Gynecology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Pei Zhou
- Laboratory of Regulatory Genomics, Cecil H. and Ida Green Center for Reproductive Biology Sciences, Division of Basic Reproductive Biology Research, Department of Obstetrics and Gynecology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Gary C Hon
- Laboratory of Regulatory Genomics, Cecil H. and Ida Green Center for Reproductive Biology Sciences, Division of Basic Reproductive Biology Research, Department of Obstetrics and Gynecology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
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238
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Freire-Pritchett P, Schoenfelder S, Várnai C, Wingett SW, Cairns J, Collier AJ, García-Vílchez R, Furlan-Magaril M, Osborne CS, Fraser P, Rugg-Gunn PJ, Spivakov M. Global reorganisation of cis-regulatory units upon lineage commitment of human embryonic stem cells. eLife 2017; 6:e21926. [PMID: 28332981 PMCID: PMC5407860 DOI: 10.7554/elife.21926] [Citation(s) in RCA: 101] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Accepted: 03/22/2017] [Indexed: 12/19/2022] Open
Abstract
Long-range cis-regulatory elements such as enhancers coordinate cell-specific transcriptional programmes by engaging in DNA looping interactions with target promoters. Deciphering the interplay between the promoter connectivity and activity of cis-regulatory elements during lineage commitment is crucial for understanding developmental transcriptional control. Here, we use Promoter Capture Hi-C to generate a high-resolution atlas of chromosomal interactions involving ~22,000 gene promoters in human pluripotent and lineage-committed cells, identifying putative target genes for known and predicted enhancer elements. We reveal extensive dynamics of cis-regulatory contacts upon lineage commitment, including the acquisition and loss of promoter interactions. This spatial rewiring occurs preferentially with predicted changes in the activity of cis-regulatory elements and is associated with changes in target gene expression. Our results provide a global and integrated view of promoter interactome dynamics during lineage commitment of human pluripotent cells.
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Affiliation(s)
| | | | - Csilla Várnai
- Nuclear Dynamics Programme, Babraham Institute, Cambridge, United Kingdom
| | - Steven W Wingett
- Nuclear Dynamics Programme, Babraham Institute, Cambridge, United Kingdom
| | - Jonathan Cairns
- Nuclear Dynamics Programme, Babraham Institute, Cambridge, United Kingdom
| | - Amanda J Collier
- Epigenetics Programme, Babraham Institute, Cambridge, United Kingdom
- Wellcome Trust – Medical Research Council Cambridge Stem Cell Institute, University of Cambridge, Cambridge, United Kingdom
| | | | | | - Cameron S Osborne
- Department of Genetics and Molecular Medicine, King's College London School of Medicine, London, United Kingdom
| | - Peter Fraser
- Nuclear Dynamics Programme, Babraham Institute, Cambridge, United Kingdom
| | - Peter J Rugg-Gunn
- Epigenetics Programme, Babraham Institute, Cambridge, United Kingdom
- Wellcome Trust – Medical Research Council Cambridge Stem Cell Institute, University of Cambridge, Cambridge, United Kingdom
| | - Mikhail Spivakov
- Nuclear Dynamics Programme, Babraham Institute, Cambridge, United Kingdom
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239
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De Gobbi M, Brazel AJ, Sharpe JA, Sloane-Stanley JA, Smith AJ, Wood WG, Vernimmen D. Enhancer deletion generates cellular phenotypic diversity due to bimodal gene expression. Blood Cells Mol Dis 2017; 64:10-12. [PMID: 28292728 DOI: 10.1016/j.bcmd.2017.02.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Accepted: 02/25/2017] [Indexed: 11/26/2022]
Affiliation(s)
- Marco De Gobbi
- University of Torino, Department of Clinical and Biological Sciences, AOU San Luigi Gonzaga, Orbassano 10043, Torino, Italy
| | - Ailbhe J Brazel
- The Roslin Institute, Developmental Biology Division, University of Edinburgh, Easter Bush, Midlothian EH25 9RG, UK
| | - Jacqueline A Sharpe
- MRC Molecular Haematology Unit, Weatherall Institute for Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DS, United Kingdom
| | - Jacqueline A Sloane-Stanley
- MRC Molecular Haematology Unit, Weatherall Institute for Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DS, United Kingdom
| | - Andrew J Smith
- MRC Molecular Haematology Unit, Weatherall Institute for Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DS, United Kingdom
| | - William G Wood
- MRC Molecular Haematology Unit, Weatherall Institute for Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DS, United Kingdom
| | - Douglas Vernimmen
- The Roslin Institute, Developmental Biology Division, University of Edinburgh, Easter Bush, Midlothian EH25 9RG, UK.
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240
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Mermet J, Yeung J, Naef F. Systems Chronobiology: Global Analysis of Gene Regulation in a 24-Hour Periodic World. Cold Spring Harb Perspect Biol 2017; 9:cshperspect.a028720. [PMID: 27920039 DOI: 10.1101/cshperspect.a028720] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Mammals have evolved an internal timing system, the circadian clock, which synchronizes physiology and behavior to the daily light and dark cycles of the Earth. The master clock, located in the suprachiasmatic nucleus (SCN) of the brain, takes fluctuating light input from the retina and synchronizes other tissues to the same internal rhythm. The molecular clocks that drive these circadian rhythms are ticking in nearly all cells in the body. Efforts in systems chronobiology are now being directed at understanding, on a comprehensive scale, how the circadian clock controls different layers of gene regulation to provide robust timing cues at the cellular and tissue level. In this review, we introduce some basic concepts underlying periodicity of gene regulation, and then highlight recent genome-wide investigations on the propagation of rhythms across multiple regulatory layers in mammals, all the way from chromatin conformation to protein accumulation.
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Affiliation(s)
- Jérôme Mermet
- Institute of Bioengineering, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
| | - Jake Yeung
- Institute of Bioengineering, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
| | - Felix Naef
- Institute of Bioengineering, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
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241
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Zhao ZW, White MD, Bissiere S, Levi V, Plachta N. Quantitative imaging of mammalian transcriptional dynamics: from single cells to whole embryos. BMC Biol 2016; 14:115. [PMID: 28010727 PMCID: PMC5180410 DOI: 10.1186/s12915-016-0331-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Probing dynamic processes occurring within the cell nucleus at the quantitative level has long been a challenge in mammalian biology. Advances in bio-imaging techniques over the past decade have enabled us to directly visualize nuclear processes in situ with unprecedented spatial and temporal resolution and single-molecule sensitivity. Here, using transcription as our primary focus, we survey recent imaging studies that specifically emphasize the quantitative understanding of nuclear dynamics in both time and space. These analyses not only inform on previously hidden physical parameters and mechanistic details, but also reveal a hierarchical organizational landscape for coordinating a wide range of transcriptional processes shared by mammalian systems of varying complexity, from single cells to whole embryos.
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Affiliation(s)
- Ziqing W Zhao
- Institute of Molecular and Cell Biology, Agency for Science, Technology and Research (A*STAR), 61 Biopolis Drive, Singapore, 138673, Singapore
| | - Melanie D White
- Institute of Molecular and Cell Biology, Agency for Science, Technology and Research (A*STAR), 61 Biopolis Drive, Singapore, 138673, Singapore
| | - Stephanie Bissiere
- Institute of Molecular and Cell Biology, Agency for Science, Technology and Research (A*STAR), 61 Biopolis Drive, Singapore, 138673, Singapore
| | - Valeria Levi
- Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Conicet, Buenos Aires, C1428EHA, Argentina
| | - Nicolas Plachta
- Institute of Molecular and Cell Biology, Agency for Science, Technology and Research (A*STAR), 61 Biopolis Drive, Singapore, 138673, Singapore.
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242
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Yang MG, West AE. Editing the Neuronal Genome: a CRISPR View of Chromatin Regulation in Neuronal Development, Function, and Plasticity. THE YALE JOURNAL OF BIOLOGY AND MEDICINE 2016; 89:457-470. [PMID: 28018138 PMCID: PMC5168825] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The dynamic orchestration of gene expression is crucial for the proper differentiation, function, and adaptation of cells. In the brain, transcriptional regulation underlies the incredible diversity of neuronal cell types and contributes to the ability of neurons to adapt their function to the environment. Recently, novel methods for genome and epigenome editing have begun to revolutionize our understanding of gene regulatory mechanisms. In particular, the clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9 system has proven to be a particularly accessible and adaptable technique for genome engineering. Here, we review the use of CRISPR/Cas9 in neurobiology and discuss how these studies have advanced understanding of nervous system development and plasticity. We cover four especially salient applications of CRISPR/Cas9: testing the consequences of enhancer mutations, tagging genes and gene products for visualization in live cells, directly activating or repressing enhancers in vivo, and manipulating the epigenome. In each case, we summarize findings from recent studies and discuss evolving adaptations of the method.
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Affiliation(s)
| | - Anne E. West
- Anne West, Department of Neurobiology, DUMC Box 3209, 311 Research Drive, Bryan Research 301D, Durham, NC 27710, Phone: 919-681-1909, Fax: 919-668-4431,
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243
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Soltani M, Singh A. Effects of cell-cycle-dependent expression on random fluctuations in protein levels. ROYAL SOCIETY OPEN SCIENCE 2016; 3:160578. [PMID: 28083102 PMCID: PMC5210684 DOI: 10.1098/rsos.160578] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Accepted: 11/10/2016] [Indexed: 06/06/2023]
Abstract
Expression of many genes varies as a cell transitions through different cell-cycle stages. How coupling between stochastic expression and cell cycle impacts cell-to-cell variability (noise) in the level of protein is not well understood. We analyse a model where a stable protein is synthesized in random bursts, and the frequency with which bursts occur varies within the cell cycle. Formulae quantifying the extent of fluctuations in the protein copy number are derived and decomposed into components arising from the cell cycle and stochastic processes. The latter stochastic component represents contributions from bursty expression and errors incurred during partitioning of molecules between daughter cells. These formulae reveal an interesting trade-off: cell-cycle dependencies that amplify the noise contribution from bursty expression also attenuate the contribution from partitioning errors. We investigate the existence of optimum strategies for coupling expression to the cell cycle that minimize the stochastic component. Intriguingly, results show that a zero production rate throughout the cell cycle, with expression only occurring just before cell division, minimizes noise from bursty expression for a fixed mean protein level. By contrast, the optimal strategy in the case of partitioning errors is to make the protein just after cell division. We provide examples of regulatory proteins that are expressed only towards the end of the cell cycle, and argue that such strategies enhance robustness of cell-cycle decisions to the intrinsic stochasticity of gene expression.
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Affiliation(s)
- Mohammad Soltani
- Department of Electrical and Computer Engineering, University of Delaware, Newark, DE, USA
| | - Abhyudai Singh
- Department of Electrical and Computer Engineering, University of Delaware, Newark, DE, USA
- Department of Mathematical Sciences, University of Delaware, Newark, DE, USA
- Department of Biomedical Engineering, University of Delaware, Newark, DE, USA
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244
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Long HK, Prescott SL, Wysocka J. Ever-Changing Landscapes: Transcriptional Enhancers in Development and Evolution. Cell 2016; 167:1170-1187. [PMID: 27863239 PMCID: PMC5123704 DOI: 10.1016/j.cell.2016.09.018] [Citation(s) in RCA: 626] [Impact Index Per Article: 69.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2016] [Revised: 08/24/2016] [Accepted: 09/07/2016] [Indexed: 12/27/2022]
Abstract
A class of cis-regulatory elements, called enhancers, play a central role in orchestrating spatiotemporally precise gene-expression programs during development. Consequently, divergence in enhancer sequence and activity is thought to be an important mediator of inter- and intra-species phenotypic variation. Here, we give an overview of emerging principles of enhancer function, current models of enhancer architecture, genomic substrates from which enhancers emerge during evolution, and the influence of three-dimensional genome organization on long-range gene regulation. We discuss intricate relationships between distinct elements within complex regulatory landscapes and consider their potential impact on specificity and robustness of transcriptional regulation.
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Affiliation(s)
- Hannah K Long
- Department of Chemical and Systems Biology, Stanford School of Medicine, Stanford University, Stanford, CA 94305, USA; Institute of Stem Cell Biology and Regenerative Medicine, Stanford School of Medicine, Stanford University, Stanford, CA 94305, USA
| | - Sara L Prescott
- Department of Chemical and Systems Biology, Stanford School of Medicine, Stanford University, Stanford, CA 94305, USA; Department of Developmental Biology, Stanford School of Medicine, Stanford University, Stanford, CA 94305, USA
| | - Joanna Wysocka
- Department of Chemical and Systems Biology, Stanford School of Medicine, Stanford University, Stanford, CA 94305, USA; Institute of Stem Cell Biology and Regenerative Medicine, Stanford School of Medicine, Stanford University, Stanford, CA 94305, USA; Department of Developmental Biology, Stanford School of Medicine, Stanford University, Stanford, CA 94305, USA; Howard Hughes Medical Institute, Stanford School of Medicine, Stanford University, Stanford, CA 94305, USA.
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245
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Zabidi MA, Stark A. Regulatory Enhancer-Core-Promoter Communication via Transcription Factors and Cofactors. Trends Genet 2016; 32:801-814. [PMID: 27816209 DOI: 10.1016/j.tig.2016.10.003] [Citation(s) in RCA: 149] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2016] [Revised: 10/08/2016] [Accepted: 10/10/2016] [Indexed: 01/20/2023]
Abstract
Gene expression is regulated by genomic enhancers that recruit transcription factors and cofactors to activate transcription from target core promoters. Over the past years, thousands of enhancers and core promoters in animal genomes have been annotated, and we have learned much about the domain structure in which regulatory genomes are organized in animals. Enhancer-core-promoter targeting occurs at several levels, including regulatory domains, DNA accessibility, and sequence-encoded core-promoter specificities that are likely mediated by different regulatory proteins. We review here current knowledge about enhancer-core-promoter targeting, regulatory communication between enhancers and core promoters, and the protein factors involved. We conclude with an outlook on open questions that we find particularly interesting and that will likely lead to additional insights in the upcoming years.
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Affiliation(s)
- Muhammad A Zabidi
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), Dr. Bohr-Gasse 7, 1030 Vienna, Austria
| | - Alexander Stark
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), Dr. Bohr-Gasse 7, 1030 Vienna, Austria.
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246
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Abstract
A recent study visualizes nascent RNAs in live Drosophila embryos to establish a connection between enhancer strength and the frequency of transcriptional bursts. Interestingly, one enhancer can simultaneously activate two core promoters, challenging models of enhancer-core-promoter communication via direct protein-protein contacts.
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Affiliation(s)
- Felix Muerdter
- Research Institute of Molecular Pathology, Vienna Biocenter, Dr. Bohr-Gasse 7, 1030 Vienna, Austria
| | - Alexander Stark
- Research Institute of Molecular Pathology, Vienna Biocenter, Dr. Bohr-Gasse 7, 1030 Vienna, Austria.
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247
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Cico A, Andrieu-Soler C, Soler E. Enhancers and their dynamics during hematopoietic differentiation and emerging strategies for therapeutic action. FEBS Lett 2016; 590:4084-4104. [DOI: 10.1002/1873-3468.12424] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2016] [Revised: 09/08/2016] [Accepted: 09/12/2016] [Indexed: 12/18/2022]
Affiliation(s)
- Alba Cico
- Inserm UMR967, CEA/DRF/iRCM; Fontenay-aux-Roses France
| | - Charlotte Andrieu-Soler
- Inserm UMR967, CEA/DRF/iRCM; Fontenay-aux-Roses France
- CNRS; Institute of Molecular Genetics (IGMM); Montpellier France
| | - Eric Soler
- Inserm UMR967, CEA/DRF/iRCM; Fontenay-aux-Roses France
- CNRS; Institute of Molecular Genetics (IGMM); Montpellier France
- Laboratory of Excellence GR-Ex; Paris France
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248
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Swain A, Misulovin Z, Pherson M, Gause M, Mihindukulasuriya K, Rickels RA, Shilatifard A, Dorsett D. Drosophila TDP-43 RNA-Binding Protein Facilitates Association of Sister Chromatid Cohesion Proteins with Genes, Enhancers and Polycomb Response Elements. PLoS Genet 2016; 12:e1006331. [PMID: 27662615 PMCID: PMC5035082 DOI: 10.1371/journal.pgen.1006331] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2016] [Accepted: 08/30/2016] [Indexed: 12/22/2022] Open
Abstract
The cohesin protein complex mediates sister chromatid cohesion and participates in transcriptional control of genes that regulate growth and development. Substantial reduction of cohesin activity alters transcription of many genes without disrupting chromosome segregation. Drosophila Nipped-B protein loads cohesin onto chromosomes, and together Nipped-B and cohesin occupy essentially all active transcriptional enhancers and a large fraction of active genes. It is unknown why some active genes bind high levels of cohesin and some do not. Here we show that the TBPH and Lark RNA-binding proteins influence association of Nipped-B and cohesin with genes and gene regulatory sequences. In vitro, TBPH and Lark proteins specifically bind RNAs produced by genes occupied by Nipped-B and cohesin. By genomic chromatin immunoprecipitation these RNA-binding proteins also bind to chromosomes at cohesin-binding genes, enhancers, and Polycomb response elements (PREs). RNAi depletion reveals that TBPH facilitates association of Nipped-B and cohesin with genes and regulatory sequences. Lark reduces binding of Nipped-B and cohesin at many promoters and aids their association with several large enhancers. Conversely, Nipped-B facilitates TBPH and Lark association with genes and regulatory sequences, and interacts with TBPH and Lark in affinity chromatography and immunoprecipitation experiments. Blocking transcription does not ablate binding of Nipped-B and the RNA-binding proteins to chromosomes, indicating transcription is not required to maintain binding once established. These findings demonstrate that RNA-binding proteins help govern association of sister chromatid cohesion proteins with genes and enhancers.
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Affiliation(s)
- Amanda Swain
- Edward A. Doisy Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, Saint Louis, Missouri, United States of America
| | - Ziva Misulovin
- Edward A. Doisy Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, Saint Louis, Missouri, United States of America
| | - Michelle Pherson
- Edward A. Doisy Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, Saint Louis, Missouri, United States of America
| | - Maria Gause
- Edward A. Doisy Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, Saint Louis, Missouri, United States of America
| | - Kathie Mihindukulasuriya
- Edward A. Doisy Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, Saint Louis, Missouri, United States of America
| | - Ryan A Rickels
- Department of Biochemistry and Molecular Genetics, Northwestern Feinberg School of Medicine, Chicago, Illinois, United States of America
| | - Ali Shilatifard
- Department of Biochemistry and Molecular Genetics, Northwestern Feinberg School of Medicine, Chicago, Illinois, United States of America
| | - Dale Dorsett
- Edward A. Doisy Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, Saint Louis, Missouri, United States of America
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249
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Abstract
The production of a single mRNA is the result of many sequential steps, from docking of transcription factors to polymerase initiation, elongation, splicing, and, finally, termination. Much of our knowledge about the fundamentals of RNA synthesis and processing come from ensemble in vitro biochemical measurements. Single-molecule approaches are very much in this same reductionist tradition but offer exquisite sensitivity in space and time along with the ability to observe heterogeneous behavior and actually manipulate macromolecules. These techniques can also be applied in vivo, allowing one to address questions in living cells that were previously restricted to reconstituted systems. In this review, we examine the unique insights that single-molecule techniques have yielded on the mechanisms of gene expression.
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Affiliation(s)
- Huimin Chen
- Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Daniel R Larson
- Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892, USA
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