1
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Fallacaro S, Mukherjee A, Turner MA, Garcia HG, Mir M. Transcription factor hubs exhibit gene-specific properties that tune expression. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2025:2025.04.07.647578. [PMID: 40291650 PMCID: PMC12026892 DOI: 10.1101/2025.04.07.647578] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/30/2025]
Abstract
The spatial and temporal control of gene expression relies on transcription factors binding to and occupying their target sites. Transcription factor hubs-localized, high-concentration microenvironments-promote transcription by facilitating binding and recruitment of transcriptional machinery and co-factors. Hubs are often thought to have emergent nucleus-wide properties depending on transcription factor nuclear concentrations and intrinsic, protein sequence-dependent properties. This global model does not account for gene-specific hub regulation. Using high-resolution lattice light-sheet microscopy in Drosophila embryos, we examined hubs formed by the morphogen transcription factor, Dorsal, at reporter genes with distinct enhancer compositions. We found that snail recruits long-lived, high-intensity hubs; sog exhibits shorter-lived, lower-intensity hubs; and hunchback , lacking Dorsal binding sites, shows only transient hub interactions. Hub intensity and interaction duration correlate with burst amplitude, RNAPII loading rate, and transcriptional output. These findings challenge the global view of hub formation and support a model where hub properties are locally tuned in a gene-specific manner to regulate transcriptional kinetics.
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2
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Liu S, Gomez-Alcala P, Leemans C, Glassford WJ, Melo LA, Lu XJ, Mann RS, Bussemaker HJ. Predicting the DNA binding specificity of transcription factor mutants using family-level biophysically interpretable machine learning. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2025:2024.01.24.577115. [PMID: 38352411 PMCID: PMC10862739 DOI: 10.1101/2024.01.24.577115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/20/2024]
Abstract
Sequence-specific interactions of transcription factors (TFs) with genomic DNA underlie many cellular processes. High-throughput in vitro binding assays coupled with machine learning have made it possible to accurately define such molecular recognition in a biophysically interpretable way for hundreds of TFs across many structural families, providing new avenues for predicting how the sequence preference of a TF is impacted by disease-associated mutations in its DNA binding domain. We developed a method based on a reference-free tetrahedral representation of variation in base preference within a given structural family that can be used to accurately predict the effect of mutations in the protein sequence of the TF. Using the basic helix-loop-helix (bHLH) and homeodomain families as test cases, our results demonstrate the feasibility of accurately predicting the shifts (ΔΔΔG/RT) in binding free energy associated with TF mutants by leveraging high-quality DNA binding models for sets of homologous wild-type TFs.
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Affiliation(s)
- Shaoxun Liu
- Department of Biological Sciences, Columbia University, New York, NY, USA
| | - Pilar Gomez-Alcala
- Department of Biological Sciences, Columbia University, New York, NY, USA
| | - Christ Leemans
- Department of Biological Sciences, Columbia University, New York, NY, USA
| | - William J. Glassford
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, USA
| | - Lucas A.N. Melo
- Department of Biological Sciences, Columbia University, New York, NY, USA
| | - Xiang-Jun Lu
- Department of Biological Sciences, Columbia University, New York, NY, USA
| | - Richard S. Mann
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, USA
- Department of Systems Biology, Columbia University, New York, NY, USA
| | - Harmen J. Bussemaker
- Department of Biological Sciences, Columbia University, New York, NY, USA
- Department of Systems Biology, Columbia University, New York, NY, USA
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3
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Pei G, Lyons H, Li P, Sabari BR. Transcription regulation by biomolecular condensates. Nat Rev Mol Cell Biol 2025; 26:213-236. [PMID: 39516712 DOI: 10.1038/s41580-024-00789-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/30/2024] [Indexed: 11/16/2024]
Abstract
Biomolecular condensates regulate transcription by dynamically compartmentalizing the transcription machinery. Classic models of transcription regulation focus on the recruitment and regulation of RNA polymerase II by the formation of complexes at the 1-10 nm length scale, which are driven by structured and stoichiometric interactions. These complexes are further organized into condensates at the 100-1,000 nm length scale, which are driven by dynamic multivalent interactions often involving domain-ligand pairs or intrinsically disordered regions. Regulation through condensate-mediated organization does not supersede the processes occurring at the 1-10 nm scale, but it provides regulatory mechanisms for promoting or preventing these processes in the crowded nuclear environment. Regulation of transcription by transcriptional condensates is involved in cell state transitions during animal and plant development, cell signalling and cellular responses to the environment. These condensate-mediated processes are dysregulated in developmental disorders, cancer and neurodegeneration. In this Review, we discuss the principles underlying the regulation of transcriptional condensates, their roles in physiology and their dysregulation in human diseases.
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Affiliation(s)
- Gaofeng Pei
- State Key Laboratory of Membrane Biology, School of Life Sciences, Tsinghua University, Beijing, China
- Beijing Frontier Research Center for Biological Structure, School of Life Sciences, Tsinghua University, Beijing, China
- Tsinghua-Peking Center for Life Sciences, Beijing, China
| | - Heankel Lyons
- Laboratory of Nuclear Organization, Cecil H. and Ida Green Center for Reproductive Biology Sciences, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Pilong Li
- State Key Laboratory of Membrane Biology, School of Life Sciences, Tsinghua University, Beijing, China.
- Beijing Frontier Research Center for Biological Structure, School of Life Sciences, Tsinghua University, Beijing, China.
- Tsinghua-Peking Center for Life Sciences, Beijing, China.
| | - Benjamin R Sabari
- Laboratory of Nuclear Organization, Cecil H. and Ida Green Center for Reproductive Biology Sciences, University of Texas Southwestern Medical Center, Dallas, TX, USA.
- Division of Basic Research, Department of Obstetrics and Gynecology, University of Texas Southwestern Medical Center, Dallas, TX, USA.
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX, USA.
- Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA.
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4
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Ugolini M, Vastenhouw NL. The role of transcription bodies in gene expression: what embryos teach us. Biochem Soc Trans 2025; 53:BST20240599. [PMID: 39912709 DOI: 10.1042/bst20240599] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2024] [Revised: 01/22/2025] [Accepted: 01/24/2025] [Indexed: 02/07/2025]
Abstract
Transcription does not occur diffusely throughout the nucleus but is concentrated in specific areas. Areas of accumulated transcriptional machinery have been called clusters, hubs, or condensates, while transcriptionally active areas have been referred to as transcription factories or transcription bodies. Despite the widespread occurrence of transcription bodies, it has been difficult to study their assembly, function, and effect on gene expression. This review highlights the advantages of developmental model systems such as zebrafish and fruit fly embryos, in addressing these questions. We focus on three important discoveries that were made in embryos. (i) It had previously been suggested that, in transcription bodies, the different steps of the transcription process are organized in space. We explore how work in embryos has revealed that they can also be organized in time. In this case, transcription bodies mature from transcription factor clusters to elongating transcription bodies. This type of organization has important implications for transcription body function. (ii) The relevance of clustering for in vivo gene regulation has benefited greatly from studies in embryos. We discuss examples in which transcription bodies regulate developmental gene expression by compensating for low transcription factor concentrations and low-affinity enhancers. Finally, (iii) while accumulations of transcriptional machinery can facilitate transcription locally, work in embryos showed that transcription bodies can also sequester the transcriptional machinery, modulating the availability for activity at other sites. In brief, the reviewed literature highlights the properties of developmental model organisms that make them powerful systems for uncovering the form and function of transcription bodies.
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Affiliation(s)
- Martino Ugolini
- Center for Integrative Genomics (CIG), University of Lausanne (UNIL), Lausanne, Switzerland
| | - Nadine L Vastenhouw
- Center for Integrative Genomics (CIG), University of Lausanne (UNIL), Lausanne, Switzerland
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5
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Munshi R, Ling J, Ryabichko S, Wieschaus EF, Gregor T. Transcription factor clusters as information transfer agents. SCIENCE ADVANCES 2025; 11:eadp3251. [PMID: 39742495 DOI: 10.1126/sciadv.adp3251] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2024] [Accepted: 11/21/2024] [Indexed: 01/03/2025]
Abstract
Deciphering how genes interpret information from transcription factor (TF) concentrations within the cell nucleus remains a fundamental question in gene regulation. Recent advancements have revealed the heterogeneous distribution of TF molecules, posing challenges to precisely decoding concentration signals. Using high-resolution single-cell imaging of the fluorescently tagged TF Bicoid in living Drosophila embryos, we show that Bicoid accumulation in submicrometer clusters preserves the spatial information of the maternal Bicoid gradient. These clusters provide precise spatial cues through intensity, size, and frequency. We further discover that Bicoid target genes colocalize with these clusters in an enhancer-binding affinity-dependent manner. Our modeling suggests that clustering offers a faster sensing mechanism for global nuclear concentrations than freely diffusing TF molecules detected by simple enhancers.
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Affiliation(s)
- Rahul Munshi
- Joseph Henry Laboratories of Physics, Princeton University, Princeton, NJ 08544, USA
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA
| | - Jia Ling
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA
| | - Sergey Ryabichko
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA
| | - Eric F Wieschaus
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA
- Department of Molecular Biology and Howard Hughes Medical Institute, Princeton University, Princeton, NJ 08544, USA
| | - Thomas Gregor
- Joseph Henry Laboratories of Physics, Princeton University, Princeton, NJ 08544, USA
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA
- Department of Stem Cell and Developmental Biology, CNRS UMR3738 Paris Cité, Institut Pasteur, 25 rue du Docteur Roux, 75015 Paris, France
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6
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Berrocal A, Lammers NC, Garcia HG, Eisen MB. Unified bursting strategies in ectopic and endogenous even-skipped expression patterns. eLife 2024; 12:RP88671. [PMID: 39651963 PMCID: PMC11627552 DOI: 10.7554/elife.88671] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2024] Open
Abstract
Transcription often occurs in bursts as gene promoters switch stochastically between active and inactive states. Enhancers can dictate transcriptional activity in animal development through the modulation of burst frequency, duration, or amplitude. Previous studies observed that different enhancers can achieve a wide range of transcriptional outputs through the same strategies of bursting control. For example, in Berrocal et al., 2020, we showed that despite responding to different transcription factors, all even-skipped enhancers increase transcription by upregulating burst frequency and amplitude while burst duration remains largely constant. These shared bursting strategies suggest that a unified molecular mechanism constraints how enhancers modulate transcriptional output. Alternatively, different enhancers could have converged on the same bursting control strategy because of natural selection favoring one of these particular strategies. To distinguish between these two scenarios, we compared transcriptional bursting between endogenous and ectopic gene expression patterns. Because enhancers act under different regulatory inputs in ectopic patterns, dissimilar bursting control strategies between endogenous and ectopic patterns would suggest that enhancers adapted their bursting strategies to their trans-regulatory environment. Here, we generated ectopic even-skipped transcription patterns in fruit fly embryos and discovered that bursting strategies remain consistent in endogenous and ectopic even-skipped expression. These results provide evidence for a unified molecular mechanism shaping even-skipped bursting strategies and serve as a starting point to uncover the realm of strategies employed by other enhancers.
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Affiliation(s)
- Augusto Berrocal
- Department of Molecular & Cell Biology, University of California at BerkeleyBerkeleyUnited States
| | - Nicholas C Lammers
- Biophysics Graduate Group, University of California at BerkeleyBerkeleyUnited States
| | - Hernan G Garcia
- Department of Molecular & Cell Biology, University of California at BerkeleyBerkeleyUnited States
- Biophysics Graduate Group, University of California at BerkeleyBerkeleyUnited States
- Department of Physics, University of California at BerkeleyBerkeleyUnited States
- California Institute for Quantitative Biosciences (QB3), University of California at BerkeleyBerkeleyUnited States
- Chan Zuckerberg Biohub–San FranciscoSan FranciscoUnited States
| | - Michael B Eisen
- Department of Molecular & Cell Biology, University of California at BerkeleyBerkeleyUnited States
- Biophysics Graduate Group, University of California at BerkeleyBerkeleyUnited States
- California Institute for Quantitative Biosciences (QB3), University of California at BerkeleyBerkeleyUnited States
- Howard Hughes Medical Institute, University of California at BerkeleyBerkeleyUnited States
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7
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Fallacaro S, Mukherjee A, Ratchasanmuang P, Zinski J, Haloush YI, Shankta K, Mir M. A fine kinetic balance of interactions directs transcription factor hubs to genes. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.16.589811. [PMID: 38659757 PMCID: PMC11042322 DOI: 10.1101/2024.04.16.589811] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/26/2024]
Abstract
Eukaryotic gene regulation relies on the binding of sequence-specific transcription factors (TFs). TFs bind chromatin transiently yet occupy their target sites by forming high-local concentration microenvironments (hubs and condensates) that increase the frequency of binding. Despite their ubiquity, such microenvironments are difficult to study in endogenous contexts due to technical limitations. Here, we use live embryo light-sheet imaging, single-molecule tracking, and genomics to overcome these limitations and investigate how hubs are localized to target genes to drive TF occupancy and transcription. By examining mutants of a hub-forming TF, Zelda, in Drosophila embryos, we find that hub formation propensity, spatial distributions, and temporal stabilities are differentially regulated by DNA binding and disordered protein domains. We show that hub localization to genomic targets is driven by a finely-tuned kinetic balance of interactions between proteins and chromatin, and hubs can be redirected to new genomic sites when this balance is perturbed.
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Affiliation(s)
- Samantha Fallacaro
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania; Philadelphia, PA 19104, USA
- Center for Computational and Genomic Medicine, Children’s Hospital of Philadelphia; Philadelphia, PA 19104, USA
- Developmental, Stem Cell, and Regenerative Biology Graduate Group, Perelman School of Medicine; Philadelphia, PA 19104, USA
| | - Apratim Mukherjee
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania; Philadelphia, PA 19104, USA
- Center for Computational and Genomic Medicine, Children’s Hospital of Philadelphia; Philadelphia, PA 19104, USA
| | - Puttachai Ratchasanmuang
- Center for Computational and Genomic Medicine, Children’s Hospital of Philadelphia; Philadelphia, PA 19104, USA
- Howard Hughes Medical Institute, Children’s Hospital of Philadelphia; Philadelphia, PA 19104, USA
| | - Joseph Zinski
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania; Philadelphia, PA 19104, USA
- Center for Computational and Genomic Medicine, Children’s Hospital of Philadelphia; Philadelphia, PA 19104, USA
| | - Yara I Haloush
- Center for Computational and Genomic Medicine, Children’s Hospital of Philadelphia; Philadelphia, PA 19104, USA
| | - Kareena Shankta
- Center for Computational and Genomic Medicine, Children’s Hospital of Philadelphia; Philadelphia, PA 19104, USA
- Roy and Diana Vagelos Program in Life Sciences and Management, University of Pennsylvania; Philadelphia, PA 19104, USA
| | - Mustafa Mir
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania; Philadelphia, PA 19104, USA
- Center for Computational and Genomic Medicine, Children’s Hospital of Philadelphia; Philadelphia, PA 19104, USA
- Howard Hughes Medical Institute, Children’s Hospital of Philadelphia; Philadelphia, PA 19104, USA
- Epigenetics Institute, University of Pennsylvania Perelman School of Medicine; Philadelphia, PA 19104, USA
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8
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Kribelbauer-Swietek JF, Pushkarev O, Gardeux V, Faltejskova K, Russeil J, van Mierlo G, Deplancke B. Context transcription factors establish cooperative environments and mediate enhancer communication. Nat Genet 2024; 56:2199-2212. [PMID: 39363017 PMCID: PMC11525195 DOI: 10.1038/s41588-024-01892-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Accepted: 08/01/2024] [Indexed: 10/05/2024]
Abstract
Many enhancers control gene expression by assembling regulatory factor clusters, also referred to as condensates. This process is vital for facilitating enhancer communication and establishing cellular identity. However, how DNA sequence and transcription factor (TF) binding instruct the formation of high regulatory factor environments remains poorly understood. Here we developed a new approach leveraging enhancer-centric chromatin accessibility quantitative trait loci (caQTLs) to nominate regulatory factor clusters genome-wide. By analyzing TF-binding signatures within the context of caQTLs and comparing episomal versus endogenous enhancer activities, we discovered a class of regulators, 'context-only' TFs, that amplify the activity of cell type-specific caQTL-binding TFs, that is, 'context-initiator' TFs. Similar to super-enhancers, enhancers enriched for context-only TF-binding sites display high coactivator binding and sensitivity to bromodomain-inhibiting molecules. We further show that binding sites for context-only and context-initiator TFs underlie enhancer coordination, providing a mechanistic rationale for how a loose TF syntax confers regulatory specificity.
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Affiliation(s)
- Judith F Kribelbauer-Swietek
- Laboratory of Systems Biology and Genetics, Institute of Bioengineering, School of Life Sciences, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland.
- Swiss Institute of Bioinformatics, Lausanne, Switzerland.
| | - Olga Pushkarev
- Laboratory of Systems Biology and Genetics, Institute of Bioengineering, School of Life Sciences, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
- Swiss Institute of Bioinformatics, Lausanne, Switzerland
| | - Vincent Gardeux
- Laboratory of Systems Biology and Genetics, Institute of Bioengineering, School of Life Sciences, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
- Swiss Institute of Bioinformatics, Lausanne, Switzerland
| | - Katerina Faltejskova
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Prague, Czech Republic
- Computer Science Institute, Faculty of Mathematics and Physics, Charles University, Prague, Czech Republic
| | - Julie Russeil
- Laboratory of Systems Biology and Genetics, Institute of Bioengineering, School of Life Sciences, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Guido van Mierlo
- Laboratory of Systems Biology and Genetics, Institute of Bioengineering, School of Life Sciences, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
- Swiss Institute of Bioinformatics, Lausanne, Switzerland
| | - Bart Deplancke
- Laboratory of Systems Biology and Genetics, Institute of Bioengineering, School of Life Sciences, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland.
- Swiss Institute of Bioinformatics, Lausanne, Switzerland.
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9
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Kawasaki K, Fukaya T. Regulatory landscape of enhancer-mediated transcriptional activation. Trends Cell Biol 2024; 34:826-837. [PMID: 38355349 DOI: 10.1016/j.tcb.2024.01.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Revised: 12/21/2023] [Accepted: 01/22/2024] [Indexed: 02/16/2024]
Abstract
Enhancers are noncoding regulatory elements that instruct spatial and temporal specificity of gene transcription in response to a variety of intrinsic and extrinsic signals during development. Although it has long been postulated that enhancers physically interact with target promoters through the formation of stable loops, recent studies have changed this static view: sequence-specific transcription factors (TFs) and coactivators are dynamically recruited to enhancers and assemble so-called transcription hubs. Dynamic assembly of transcription hubs appears to serve as a key scaffold to integrate regulatory information encoded by surrounding genome and biophysical properties of transcription machineries. In this review, we outline emerging new models of transcriptional regulation by enhancers and discuss future perspectives.
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Affiliation(s)
- Koji Kawasaki
- Laboratory of Transcription Dynamics, Research Center for Biological Visualization, Institute for Quantitative Biosciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-0032, Japan
| | - Takashi Fukaya
- Laboratory of Transcription Dynamics, Research Center for Biological Visualization, Institute for Quantitative Biosciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-0032, Japan; Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-0032, Japan.
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10
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Munshi R. How Transcription Factor Clusters Shape the Transcriptional Landscape. Biomolecules 2024; 14:875. [PMID: 39062589 PMCID: PMC11274464 DOI: 10.3390/biom14070875] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2024] [Revised: 07/14/2024] [Accepted: 07/16/2024] [Indexed: 07/28/2024] Open
Abstract
In eukaryotic cells, gene transcription typically occurs in discrete periods of promoter activity, interspersed with intervals of inactivity. This pattern deviates from simple stochastic events and warrants a closer examination of the molecular interactions that activate the promoter. Recent studies have identified transcription factor (TF) clusters as key precursors to transcriptional bursting. Often, these TF clusters form at chromatin segments that are physically distant from the promoter, making changes in chromatin conformation crucial for promoter-TF cluster interactions. In this review, I explore the formation and constituents of TF clusters, examining how the dynamic interplay between chromatin architecture and TF clustering influences transcriptional bursting. Additionally, I discuss techniques for visualizing TF clusters and provide an outlook on understanding the remaining gaps in this field.
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Affiliation(s)
- Rahul Munshi
- Joseph Henry Laboratories of Physics and Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA
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11
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Chen PT, Levo M, Zoller B, Gregor T. Gene activity fully predicts transcriptional bursting dynamics. ARXIV 2024:arXiv:2304.08770v3. [PMID: 37131882 PMCID: PMC10153294] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Transcription commonly occurs in bursts, with alternating productive (ON) and quiescent (OFF) periods, governing mRNA production rates. Yet, how transcription is regulated through bursting dynamics remains unresolved. Here, we conduct real-time measurements of endogenous transcriptional bursting with single-mRNA sensitivity. Leveraging the diverse transcriptional activities in early fly embryos, we uncover stringent relationships between bursting parameters. Specifically, we find that the durations of ON and OFF periods are linked. Regardless of the developmental stage or body-axis position, gene activity levels predict individual alleles' average ON and OFF periods. Lowly transcribing alleles predominantly modulate OFF periods (burst frequency), while highly transcribing alleles primarily tune ON periods (burst size). These relationships persist even under perturbations of cis-regulatory elements or trans-factors and account for bursting dynamics measured in other species. Our results suggest a novel mechanistic constraint governing bursting dynamics rather than a modular control of distinct parameters by distinct regulatory processes.
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Affiliation(s)
- Po-Ta Chen
- Joseph Henry Laboratories of Physics & Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA
| | - Michal Levo
- Joseph Henry Laboratories of Physics & Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, USA
| | - Benjamin Zoller
- Joseph Henry Laboratories of Physics & Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA
- Department of Stem Cell and Developmental Biology, CNRS UMR3738 Paris Cité, Institut Pasteur, 25 rue du Docteur Roux, 75015 Paris, France
| | - Thomas Gregor
- Joseph Henry Laboratories of Physics & Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA
- Department of Stem Cell and Developmental Biology, CNRS UMR3738 Paris Cité, Institut Pasteur, 25 rue du Docteur Roux, 75015 Paris, France
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12
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Berrocal A, Lammers NC, Garcia HG, Eisen MB. Unified bursting strategies in ectopic and endogenous even-skipped expression patterns. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.02.09.527927. [PMID: 36798351 PMCID: PMC9934701 DOI: 10.1101/2023.02.09.527927] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
Abstract
Transcription often occurs in bursts as gene promoters switch stochastically between active and inactive states. Enhancers can dictate transcriptional activity in animal development through the modulation of burst frequency, duration, or amplitude. Previous studies observed that different enhancers can achieve a wide range of transcriptional outputs through the same strategies of bursting control. For example, despite responding to different transcription factors, all even-skipped enhancers increase transcription by upregulating burst frequency and amplitude while burst duration remains largely constant. These shared bursting strategies suggest that a unified molecular mechanism constraints how enhancers modulate transcriptional output. Alternatively, different enhancers could have converged on the same bursting control strategy because of natural selection favoring one of these particular strategies. To distinguish between these two scenarios, we compared transcriptional bursting between endogenous and ectopic gene expression patterns. Because enhancers act under different regulatory inputs in ectopic patterns, dissimilar bursting control strategies between endogenous and ectopic patterns would suggest that enhancers adapted their bursting strategies to their trans-regulatory environment. Here, we generated ectopic even-skipped transcription patterns in fruit fly embryos and discovered that bursting strategies remain consistent in endogenous and ectopic even-skipped expression. These results provide evidence for a unified molecular mechanism shaping even-skipped bursting strategies and serve as a starting point to uncover the realm of strategies employed by other enhancers.
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Affiliation(s)
- Augusto Berrocal
- Department of Molecular & Cell Biology, University of California at Berkeley, Berkeley, CA, United States
- Current Address: Department of Pharmaceutical Chemistry, University of California at San Francisco, San Francisco, CA, United States
| | - Nicholas C Lammers
- Biophysics Graduate Group, University of California at Berkeley, Berkeley, CA, United States
- Current Address: Department of Genome Sciences, University of Washington, Seattle, WA, United States
| | - Hernan G Garcia
- Department of Molecular & Cell Biology, University of California at Berkeley, Berkeley, CA, United States
- Biophysics Graduate Group, University of California at Berkeley, Berkeley, CA, United States
- Department of Physics, University of California at Berkeley, Berkeley, CA, United States
- California Institute for Quantitative Biosciences (QB3), University of California at Berkeley, Berkeley, CA, United States
- Chan Zuckerberg Biohub–San Francisco, San Francisco, California, CA, United States
| | - Michael B Eisen
- Department of Molecular & Cell Biology, University of California at Berkeley, Berkeley, CA, United States
- Biophysics Graduate Group, University of California at Berkeley, Berkeley, CA, United States
- California Institute for Quantitative Biosciences (QB3), University of California at Berkeley, Berkeley, CA, United States
- Howard Hughes Medical Institute, University of California at Berkeley, Berkeley, CA, United States
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13
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Hayward-Lara G, Fischer MD, Mir M. Dynamic microenvironments shape nuclear organization and gene expression. Curr Opin Genet Dev 2024; 86:102177. [PMID: 38461773 PMCID: PMC11162947 DOI: 10.1016/j.gde.2024.102177] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2023] [Revised: 02/11/2024] [Accepted: 02/14/2024] [Indexed: 03/12/2024]
Abstract
Live imaging has revealed that the regulation of gene expression is largely driven by transient interactions. For example, many regulatory proteins bind chromatin for just seconds, and loop-like genomic contacts are rare and last only minutes. These discoveries have been difficult to reconcile with our canonical models that are predicated on stable and hierarchical interactions. Proteomic microenvironments that concentrate nuclear factors may explain how brief interactions can still mediate gene regulation by creating conditions where reactions occur more frequently. Here, we summarize new imaging technologies and recent discoveries implicating microenvironments as a potential driver of nuclear function. Finally, we propose that key properties of proteomic microenvironments, such as their size, enrichment, and lifetimes, are directly linked to regulatory function.
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Affiliation(s)
- Gabriela Hayward-Lara
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania. Philadelphia, PA 19104
- Center for Computational and Genomic Medicine, Children’s Hospital of Philadelphia. Philadelphia, PA 19104
- Developmental, Stem Cell, and Regenerative Biology Graduate Group, Perelman School of Medicine, University of Pennsylvania. Philadelphia, PA 19104
| | - Matthew D. Fischer
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania. Philadelphia, PA 19104
- Center for Computational and Genomic Medicine, Children’s Hospital of Philadelphia. Philadelphia, PA 19104
| | - Mustafa Mir
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania. Philadelphia, PA 19104
- Center for Computational and Genomic Medicine, Children’s Hospital of Philadelphia. Philadelphia, PA 19104
- Epigenetics Institute, Perelman School of Medicine, University of Pennsylvania. Philadelphia, PA 19104
- Howard Hughes Medical Institute, Children’s Hospital of Philadelphia. Philadelphia, PA 19104
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14
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Hwang DW, Maekiniemi A, Singer RH, Sato H. Real-time single-molecule imaging of transcriptional regulatory networks in living cells. Nat Rev Genet 2024; 25:272-285. [PMID: 38195868 DOI: 10.1038/s41576-023-00684-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/27/2023] [Indexed: 01/11/2024]
Abstract
Gene regulatory networks drive the specific transcriptional programmes responsible for the diversification of cell types during the development of multicellular organisms. Although our knowledge of the genes involved in these dynamic networks has expanded rapidly, our understanding of how transcription is spatiotemporally regulated at the molecular level over a wide range of timescales in the small volume of the nucleus remains limited. Over the past few decades, advances in the field of single-molecule fluorescence imaging have enabled real-time behaviours of individual transcriptional components to be measured in living cells and organisms. These efforts are now shedding light on the dynamic mechanisms of transcription, revealing not only the temporal rules but also the spatial coordination of underlying molecular interactions during various biological events.
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Affiliation(s)
- Dong-Woo Hwang
- Department of Cell Biology, Albert Einstein College of Medicine, New York, NY, USA
| | - Anna Maekiniemi
- Department of Cell Biology, Albert Einstein College of Medicine, New York, NY, USA
| | - Robert H Singer
- Department of Cell Biology, Albert Einstein College of Medicine, New York, NY, USA
| | - Hanae Sato
- Department of Cell Biology, Albert Einstein College of Medicine, New York, NY, USA.
- Nano Life Science Institute (WPI-Nano LSI), Kanazawa University, Kakuma-machi, Kanazawa, Japan.
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15
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Ugolini M, Kerlin MA, Kuznetsova K, Oda H, Kimura H, Vastenhouw NL. Transcription bodies regulate gene expression by sequestering CDK9. Nat Cell Biol 2024; 26:604-612. [PMID: 38589534 PMCID: PMC11021188 DOI: 10.1038/s41556-024-01389-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Accepted: 02/28/2024] [Indexed: 04/10/2024]
Abstract
The localization of transcriptional activity in specialized transcription bodies is a hallmark of gene expression in eukaryotic cells. It remains unclear, however, if and how transcription bodies affect gene expression. Here we disrupted the formation of two prominent endogenous transcription bodies that mark the onset of zygotic transcription in zebrafish embryos and analysed the effect on gene expression using enriched SLAM-seq and live-cell imaging. We find that the disruption of transcription bodies results in the misregulation of hundreds of genes. Here we focus on genes that are upregulated. These genes have accessible chromatin and are poised to be transcribed in the presence of the two transcription bodies, but they do not go into elongation. Live-cell imaging shows that disruption of the two large transcription bodies enables these poised genes to be transcribed in ectopic transcription bodies, suggesting that the large transcription bodies sequester a pause release factor. Supporting this hypothesis, we find that CDK9-the kinase that releases paused polymerase II-is highly enriched in the two large transcription bodies. Overexpression of CDK9 in wild-type embryos results in the formation of ectopic transcription bodies and thus phenocopies the removal of the two large transcription bodies. Taken together, our results show that transcription bodies regulate transcription by sequestering machinery, thereby preventing genes elsewhere in the nucleus from being transcribed.
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Affiliation(s)
- Martino Ugolini
- Center for Integrative Genomics (CIG), University of Lausanne (UNIL), Lausanne, Switzerland
- Max Planck Institute of Molecular Cell Biology and Genetics (MPI-CBG), Dresden, Germany
| | - Maciej A Kerlin
- Center for Integrative Genomics (CIG), University of Lausanne (UNIL), Lausanne, Switzerland
| | - Ksenia Kuznetsova
- Max Planck Institute of Molecular Cell Biology and Genetics (MPI-CBG), Dresden, Germany
| | - Haruka Oda
- Cell Biology Center, Institute of Innovative Research, Tokyo Institute of Technology, Yokohama, Japan
- Institute of Human Genetics, CNRS, Montpellier, France
| | - Hiroshi Kimura
- Cell Biology Center, Institute of Innovative Research, Tokyo Institute of Technology, Yokohama, Japan
| | - Nadine L Vastenhouw
- Center for Integrative Genomics (CIG), University of Lausanne (UNIL), Lausanne, Switzerland.
- Max Planck Institute of Molecular Cell Biology and Genetics (MPI-CBG), Dresden, Germany.
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16
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Salomone J, Farrow E, Gebelein B. Homeodomain complex formation and biomolecular condensates in Hox gene regulation. Semin Cell Dev Biol 2024; 152-153:93-100. [PMID: 36517343 PMCID: PMC10258226 DOI: 10.1016/j.semcdb.2022.11.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2022] [Revised: 10/21/2022] [Accepted: 11/30/2022] [Indexed: 12/15/2022]
Abstract
Hox genes are a family of homeodomain transcription factors that regulate specialized morphological structures along the anterior-posterior axis of metazoans. Over the past few decades, researchers have focused on defining how Hox factors with similar in vitro DNA binding activities achieve sufficient target specificity to regulate distinct cell fates in vivo. In this review, we highlight how protein interactions with other transcription factors, many of which are also homeodomain proteins, result in the formation of transcription factor complexes with enhanced DNA binding specificity. These findings suggest that Hox-regulated enhancers utilize distinct combinations of homeodomain binding sites, many of which are low-affinity, to recruit specific Hox complexes. However, low-affinity sites can only yield reproducible responses with high transcription factor concentrations. To overcome this limitation, recent studies revealed how transcription factors, including Hox factors, use intrinsically disordered domains (IDRs) to form biomolecular condensates that increase protein concentrations. Moreover, Hox factors with altered IDRs have been associated with altered transcriptional activity and human disease states, demonstrating the importance of IDRs in mediating essential Hox output. Collectively, these studies highlight how Hox factors use their DNA binding domains, protein-protein interaction domains, and IDRs to form specific transcription factor complexes that yield accurate gene expression.
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Affiliation(s)
- Joseph Salomone
- Graduate Program in Molecular and Developmental Biology, Cincinnati Children's Hospital Research Foundation, Cincinnati, OH 45229, USA; Medical-Scientist Training Program, University of Cincinnati College of Medicine, Cincinnati, OH 45229, USA
| | - Edward Farrow
- Graduate Program in Molecular and Developmental Biology, Cincinnati Children's Hospital Research Foundation, Cincinnati, OH 45229, USA; Medical-Scientist Training Program, University of Cincinnati College of Medicine, Cincinnati, OH 45229, USA
| | - Brian Gebelein
- Division of Developmental Biology, Cincinnati Children's Hospital Medical Center, 3333 Burnet Ave, MLC 7007, Cincinnati, OH 45229, USA; Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH 45229, USA.
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17
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Syed S, Duan Y, Lim B. Modulation of protein-DNA binding reveals mechanisms of spatiotemporal gene control in early Drosophila embryos. eLife 2023; 12:e85997. [PMID: 37934571 PMCID: PMC10629816 DOI: 10.7554/elife.85997] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2023] [Accepted: 10/19/2023] [Indexed: 11/08/2023] Open
Abstract
It is well known that enhancers regulate the spatiotemporal expression of their target genes by recruiting transcription factors (TFs) to the cognate binding sites in the region. However, the role of multiple binding sites for the same TFs and their specific spatial arrangement in determining the overall competency of the enhancer has yet to be fully understood. In this study, we utilized the MS2-MCP live imaging technique to quantitatively analyze the regulatory logic of the snail distal enhancer in early Drosophila embryos. Through systematic modulation of Dorsal and Twist binding motifs in this enhancer, we found that a mutation in any one of these binding sites causes a drastic reduction in transcriptional amplitude, resulting in a reduction in mRNA production of the target gene. We provide evidence of synergy, such that multiple binding sites with moderate affinities cooperatively recruit more TFs to drive stronger transcriptional activity than a single site. Moreover, a Hidden Markov-based stochastic model of transcription reveals that embryos with mutated binding sites have a higher probability of returning to the inactive promoter state. We propose that TF-DNA binding regulates spatial and temporal gene expression and drives robust pattern formation by modulating transcriptional kinetics and tuning bursting rates.
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Affiliation(s)
- Sahla Syed
- Department of Chemical and Biomolecular Engineering, University of PennsylvaniaPhiladelphiaUnited States
| | - Yifei Duan
- Department of Chemical and Biomolecular Engineering, University of PennsylvaniaPhiladelphiaUnited States
- Master of Biotechnology Program, University of PennsylvaniaPhiladelphiaUnited States
| | - Bomyi Lim
- Department of Chemical and Biomolecular Engineering, University of PennsylvaniaPhiladelphiaUnited States
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18
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Jindal GA, Bantle AT, Solvason JJ, Grudzien JL, D'Antonio-Chronowska A, Lim F, Le SH, Song BP, Ragsac MF, Klie A, Larsen RO, Frazer KA, Farley EK. Single-nucleotide variants within heart enhancers increase binding affinity and disrupt heart development. Dev Cell 2023; 58:2206-2216.e5. [PMID: 37848026 PMCID: PMC10720985 DOI: 10.1016/j.devcel.2023.09.005] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Revised: 06/07/2023] [Accepted: 09/20/2023] [Indexed: 10/19/2023]
Abstract
Transcriptional enhancers direct precise gene expression patterns during development and harbor the majority of variants associated with phenotypic diversity, evolutionary adaptations, and disease. Pinpointing which enhancer variants contribute to changes in gene expression and phenotypes is a major challenge. Here, we find that suboptimal or low-affinity binding sites are necessary for precise gene expression during heart development. Single-nucleotide variants (SNVs) can optimize the affinity of ETS binding sites, causing gain-of-function (GOF) gene expression, cell migration defects, and phenotypes as severe as extra beating hearts in the marine chordate Ciona robusta. In human induced pluripotent stem cell (iPSC)-derived cardiomyocytes, a SNV within a human GATA4 enhancer increases ETS binding affinity and causes GOF enhancer activity. The prevalence of suboptimal-affinity sites within enhancers creates a vulnerability whereby affinity-optimizing SNVs can lead to GOF gene expression, changes in cellular identity, and organismal-level phenotypes that could contribute to the evolution of novel traits or diseases.
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Affiliation(s)
- Granton A Jindal
- Department of Medicine, Health Sciences, University of California, San Diego, La Jolla, CA 92093, USA; Department of Molecular Biology, School of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Alexis T Bantle
- Department of Medicine, Health Sciences, University of California, San Diego, La Jolla, CA 92093, USA; Department of Molecular Biology, School of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA; Biological Sciences Graduate Program, University of California, San Diego, La Jolla, CA 92093, USA
| | - Joe J Solvason
- Department of Medicine, Health Sciences, University of California, San Diego, La Jolla, CA 92093, USA; Department of Molecular Biology, School of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA; Bioinformatics and Systems Biology Graduate Program, University of California, San Diego, La Jolla, CA 92093, USA
| | - Jessica L Grudzien
- Department of Medicine, Health Sciences, University of California, San Diego, La Jolla, CA 92093, USA; Department of Molecular Biology, School of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA
| | | | - Fabian Lim
- Department of Medicine, Health Sciences, University of California, San Diego, La Jolla, CA 92093, USA; Department of Molecular Biology, School of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA; Biological Sciences Graduate Program, University of California, San Diego, La Jolla, CA 92093, USA
| | - Sophia H Le
- Department of Medicine, Health Sciences, University of California, San Diego, La Jolla, CA 92093, USA; Department of Molecular Biology, School of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Benjamin P Song
- Department of Medicine, Health Sciences, University of California, San Diego, La Jolla, CA 92093, USA; Department of Molecular Biology, School of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA; Biological Sciences Graduate Program, University of California, San Diego, La Jolla, CA 92093, USA
| | - Michelle F Ragsac
- Department of Medicine, Health Sciences, University of California, San Diego, La Jolla, CA 92093, USA; Department of Molecular Biology, School of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA; Bioinformatics and Systems Biology Graduate Program, University of California, San Diego, La Jolla, CA 92093, USA
| | - Adam Klie
- Bioinformatics and Systems Biology Graduate Program, University of California, San Diego, La Jolla, CA 92093, USA
| | - Reid O Larsen
- Biomedical Sciences Graduate Program, University of California, San Diego, La Jolla, CA 92093, USA
| | - Kelly A Frazer
- Department of Pediatrics, School of Medicine, University of California, San Diego, La Jolla, CA 92093, USA; Institute for Genomic Medicine, Health Sciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Emma K Farley
- Department of Medicine, Health Sciences, University of California, San Diego, La Jolla, CA 92093, USA; Department of Molecular Biology, School of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA.
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19
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Gaskill MM, Soluri IV, Branks AE, Boka AP, Stadler MR, Vietor K, Huang HYS, Gibson TJ, Mukherjee A, Mir M, Blythe SA, Harrison MM. Localization of the Drosophila pioneer factor GAF to subnuclear foci is driven by DNA binding and required to silence satellite repeat expression. Dev Cell 2023; 58:1610-1624.e8. [PMID: 37478844 PMCID: PMC10528433 DOI: 10.1016/j.devcel.2023.06.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Revised: 04/19/2023] [Accepted: 06/29/2023] [Indexed: 07/23/2023]
Abstract
The eukaryotic genome is organized to enable the precise regulation of gene expression. This organization is established as the embryo transitions from a fertilized gamete to a totipotent zygote. To understand the factors and processes that drive genomic organization, we focused on the pioneer factor GAGA factor (GAF) that is required for early development in Drosophila. GAF transcriptionally activates the zygotic genome and is localized to subnuclear foci. This non-uniform distribution is driven by binding to highly abundant GA repeats. At GA repeats, GAF is necessary to form heterochromatin and silence transcription. Thus, GAF is required to establish both active and silent regions. We propose that foci formation enables GAF to have opposing transcriptional roles within a single nucleus. Our data support a model in which the subnuclear concentration of transcription factors acts to organize the nucleus into functionally distinct domains essential for the robust regulation of gene expression.
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Affiliation(s)
- Marissa M Gaskill
- Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Isabella V Soluri
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208, USA
| | - Annemarie E Branks
- Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Alan P Boka
- Biochemistry and Molecular Biophysics Graduate Group, University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA 19104, USA; Center for Computational and Genomic Medicine, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Michael R Stadler
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Katherine Vietor
- Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Hao-Yu S Huang
- Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Tyler J Gibson
- Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Apratim Mukherjee
- Center for Computational and Genomic Medicine, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA; Department of Cell and Developmental Biology, University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Mustafa Mir
- Center for Computational and Genomic Medicine, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA; Epigenetics Institute, University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA 19104, USA; Institute for Regenerative, University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA 19104, USA; Department of Cell and Developmental Biology, University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Shelby A Blythe
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208, USA
| | - Melissa M Harrison
- Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, WI 53706, USA.
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20
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Mohana G, Dorier J, Li X, Mouginot M, Smith RC, Malek H, Leleu M, Rodriguez D, Khadka J, Rosa P, Cousin P, Iseli C, Restrepo S, Guex N, McCabe BD, Jankowski A, Levine MS, Gambetta MC. Chromosome-level organization of the regulatory genome in the Drosophila nervous system. Cell 2023; 186:3826-3844.e26. [PMID: 37536338 PMCID: PMC10529364 DOI: 10.1016/j.cell.2023.07.008] [Citation(s) in RCA: 29] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2022] [Revised: 03/31/2023] [Accepted: 07/06/2023] [Indexed: 08/05/2023]
Abstract
Previous studies have identified topologically associating domains (TADs) as basic units of genome organization. We present evidence of a previously unreported level of genome folding, where distant TAD pairs, megabases apart, interact to form meta-domains. Within meta-domains, gene promoters and structural intergenic elements present in distant TADs are specifically paired. The associated genes encode neuronal determinants, including those engaged in axonal guidance and adhesion. These long-range associations occur in a large fraction of neurons but support transcription in only a subset of neurons. Meta-domains are formed by diverse transcription factors that are able to pair over long and flexible distances. We present evidence that two such factors, GAF and CTCF, play direct roles in this process. The relative simplicity of higher-order meta-domain interactions in Drosophila, compared with those previously described in mammals, allowed the demonstration that genomes can fold into highly specialized cell-type-specific scaffolds that enable megabase-scale regulatory associations.
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Affiliation(s)
- Giriram Mohana
- Center for Integrative Genomics, University of Lausanne, 1015 Lausanne, Switzerland
| | - Julien Dorier
- Bioinformatics Competence Center, University of Lausanne, 1015 Lausanne, Switzerland; Bioinformatics Competence Center, Swiss Federal Institute of Technology Lausanne, 1015 Lausanne, Switzerland
| | - Xiao Li
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ, USA
| | - Marion Mouginot
- Center for Integrative Genomics, University of Lausanne, 1015 Lausanne, Switzerland
| | - Rebecca C Smith
- Brain Mind Institute, Swiss Federal Institute of Technology Lausanne, 1015 Lausanne, Switzerland
| | - Héléna Malek
- Center for Integrative Genomics, University of Lausanne, 1015 Lausanne, Switzerland
| | - Marion Leleu
- Bioinformatics Competence Center, University of Lausanne, 1015 Lausanne, Switzerland; Bioinformatics Competence Center, Swiss Federal Institute of Technology Lausanne, 1015 Lausanne, Switzerland
| | - Daniel Rodriguez
- Center for Integrative Genomics, University of Lausanne, 1015 Lausanne, Switzerland
| | - Jenisha Khadka
- Center for Integrative Genomics, University of Lausanne, 1015 Lausanne, Switzerland
| | - Patrycja Rosa
- Faculty of Mathematics, Informatics and Mechanics, University of Warsaw, 02-097 Warsaw, Poland
| | - Pascal Cousin
- Center for Integrative Genomics, University of Lausanne, 1015 Lausanne, Switzerland
| | - Christian Iseli
- Bioinformatics Competence Center, University of Lausanne, 1015 Lausanne, Switzerland; Bioinformatics Competence Center, Swiss Federal Institute of Technology Lausanne, 1015 Lausanne, Switzerland
| | - Simon Restrepo
- Arcoris bio AG, Lüssirainstrasse 52, 6300 Zug, Switzerland
| | - Nicolas Guex
- Bioinformatics Competence Center, University of Lausanne, 1015 Lausanne, Switzerland; Bioinformatics Competence Center, Swiss Federal Institute of Technology Lausanne, 1015 Lausanne, Switzerland
| | - Brian D McCabe
- Brain Mind Institute, Swiss Federal Institute of Technology Lausanne, 1015 Lausanne, Switzerland
| | - Aleksander Jankowski
- Faculty of Mathematics, Informatics and Mechanics, University of Warsaw, 02-097 Warsaw, Poland.
| | - Michael S Levine
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ, USA.
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21
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Theis A, Harrison MM. Reprogramming of three-dimensional chromatin organization in the early embryo. Curr Opin Struct Biol 2023; 81:102613. [PMID: 37224641 PMCID: PMC10524315 DOI: 10.1016/j.sbi.2023.102613] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Revised: 04/24/2023] [Accepted: 04/26/2023] [Indexed: 05/26/2023]
Abstract
Chromatin organization within the three-dimensional (3D) nuclear space is important for proper gene expression and developmental programming. This organization is established during the dramatic reprogramming that occurs in early embryonic development. Thus, the early embryo is an ideal model for examining the formation and dynamics of 3D chromatin structure. Advances in high-resolution microscopy and single-nucleus genomic analyses have provided fundamental insights into the mechanisms driving genome organization in the early embryo. Here, we highlight recent findings describing the dynamics and driving mechanisms for establishing 3D chromatin organization and discuss the role such organization has on gene regulation in early embryonic development.
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Affiliation(s)
- Alexandra Theis
- Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, WI, USA.
| | - Melissa M Harrison
- Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, WI, USA.
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22
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Afzal Z, Lange JJ, Nolte C, McKinney S, Wood C, Paulson A, De Kumar B, Unruh J, Slaughter BD, Krumlauf R. Shared retinoic acid responsive enhancers coordinately regulate nascent transcription of Hoxb coding and non-coding RNAs in the developing mouse neural tube. Development 2023; 150:dev201259. [PMID: 37102683 PMCID: PMC10233718 DOI: 10.1242/dev.201259] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Accepted: 04/19/2023] [Indexed: 04/28/2023]
Abstract
Signaling pathways regulate the patterns of Hox gene expression that underlie their functions in the specification of axial identity. Little is known about the properties of cis-regulatory elements and underlying transcriptional mechanisms that integrate graded signaling inputs to coordinately control Hox expression. Here, we optimized a single molecule fluorescent in situ hybridization (smFISH) technique with probes spanning introns to evaluate how three shared retinoic acid response element (RARE)-dependent enhancers in the Hoxb cluster regulate patterns of nascent transcription in vivo at the level of single cells in wild-type and mutant embryos. We predominately detect nascent transcription of only a single Hoxb gene in each cell, with no evidence for simultaneous co-transcriptional coupling of all or specific subsets of genes. Single and/or compound RARE mutations indicate that each enhancer differentially impacts global and local patterns of nascent transcription, suggesting that selectivity and competitive interactions between these enhancers is important to robustly maintain the proper levels and patterns of nascent Hoxb transcription. This implies that rapid and dynamic regulatory interactions potentiate transcription of genes through combined inputs from these enhancers in coordinating the retinoic acid response.
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Affiliation(s)
- Zainab Afzal
- Stowers Institute for Medical Research, Kansas City, MO 64110, USA
- Anatomy and Cell Biology Department, Kansas University Medical Center, Kansas City, KS 66160, USA
| | - Jeffrey J. Lange
- Stowers Institute for Medical Research, Kansas City, MO 64110, USA
| | - Christof Nolte
- Stowers Institute for Medical Research, Kansas City, MO 64110, USA
| | - Sean McKinney
- Stowers Institute for Medical Research, Kansas City, MO 64110, USA
| | - Christopher Wood
- Stowers Institute for Medical Research, Kansas City, MO 64110, USA
| | - Ariel Paulson
- Stowers Institute for Medical Research, Kansas City, MO 64110, USA
| | - Bony De Kumar
- Stowers Institute for Medical Research, Kansas City, MO 64110, USA
| | - Jay Unruh
- Stowers Institute for Medical Research, Kansas City, MO 64110, USA
| | | | - Robb Krumlauf
- Stowers Institute for Medical Research, Kansas City, MO 64110, USA
- Anatomy and Cell Biology Department, Kansas University Medical Center, Kansas City, KS 66160, USA
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23
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A de novo transcription-dependent TAD boundary underpins critical multiway interactions during antibody class switch recombination. Mol Cell 2023; 83:681-697.e7. [PMID: 36736317 DOI: 10.1016/j.molcel.2023.01.014] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2022] [Revised: 11/04/2022] [Accepted: 01/09/2023] [Indexed: 02/05/2023]
Abstract
Interactions between transcription and cohesin-mediated loop extrusion can influence 3D chromatin architecture. However, their relevance in biology is unclear. Here, we report a direct role for such interactions in the mechanism of antibody class switch recombination (CSR) at the murine immunoglobulin heavy chain locus (Igh). Using Tri-C to measure higher-order multiway interactions on single alleles, we find that the juxtaposition (synapsis) of transcriptionally active donor and acceptor Igh switch (S) sequences, an essential step in CSR, occurs via the interaction of loop extrusion complexes with a de novo topologically associating domain (TAD) boundary formed via transcriptional activity across S regions. Surprisingly, synapsis occurs predominantly in proximity to the 3' CTCF-binding element (3'CBE) rather than the Igh super-enhancer, suggesting a two-step mechanism whereby transcription of S regions is not topologically coupled to synapsis, as has been previously proposed. Altogether, these insights advance our understanding of how 3D chromatin architecture regulates CSR.
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24
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van Mierlo G, Pushkarev O, Kribelbauer JF, Deplancke B. Chromatin modules and their implication in genomic organization and gene regulation. Trends Genet 2023; 39:140-153. [PMID: 36549923 DOI: 10.1016/j.tig.2022.11.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Revised: 11/04/2022] [Accepted: 11/27/2022] [Indexed: 12/24/2022]
Abstract
Regulation of gene expression is a complex but highly guided process. While genomic technologies and computational approaches have allowed high-throughput mapping of cis-regulatory elements (CREs) and their interactions in 3D, their precise role in regulating gene expression remains obscure. Recent complementary observations revealed that interactions between CREs frequently result in the formation of small-scale functional modules within topologically associating domains. Such chromatin modules likely emerge from a complex interplay between regulatory machineries assembled at CREs, including site-specific binding of transcription factors. Here, we review the methods that allow identifying chromatin modules, summarize possible mechanisms that steer CRE interactions within these modules, and discuss outstanding challenges to uncover how chromatin modules fit in our current understanding of the functional 3D genome.
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Affiliation(s)
- Guido van Mierlo
- Laboratory of Systems Biology and Genetics, Institute of Bioengineering, School of Life Sciences, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland; Swiss Institute of Bioinformatics (SIB), Lausanne, Switzerland
| | - Olga Pushkarev
- Laboratory of Systems Biology and Genetics, Institute of Bioengineering, School of Life Sciences, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland; Swiss Institute of Bioinformatics (SIB), Lausanne, Switzerland
| | - Judith F Kribelbauer
- Laboratory of Systems Biology and Genetics, Institute of Bioengineering, School of Life Sciences, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland; Swiss Institute of Bioinformatics (SIB), Lausanne, Switzerland
| | - Bart Deplancke
- Laboratory of Systems Biology and Genetics, Institute of Bioengineering, School of Life Sciences, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland; Swiss Institute of Bioinformatics (SIB), Lausanne, Switzerland.
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25
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Lyons H, Veettil RT, Pradhan P, Fornero C, De La Cruz N, Ito K, Eppert M, Roeder RG, Sabari BR. Functional partitioning of transcriptional regulators by patterned charge blocks. Cell 2023; 186:327-345.e28. [PMID: 36603581 PMCID: PMC9910284 DOI: 10.1016/j.cell.2022.12.013] [Citation(s) in RCA: 141] [Impact Index Per Article: 70.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Revised: 10/15/2022] [Accepted: 12/07/2022] [Indexed: 01/05/2023]
Abstract
Components of transcriptional machinery are selectively partitioned into specific condensates, often mediated by protein disorder, yet we know little about how this specificity is achieved. Here, we show that condensates composed of the intrinsically disordered region (IDR) of MED1 selectively partition RNA polymerase II together with its positive allosteric regulators while excluding negative regulators. This selective compartmentalization is sufficient to activate transcription and is required for gene activation during a cell-state transition. The IDRs of partitioned proteins are necessary and sufficient for selective compartmentalization and require alternating blocks of charged amino acids. Disrupting this charge pattern prevents partitioning, whereas adding the pattern to proteins promotes partitioning with functional consequences for gene activation. IDRs with similar patterned charge blocks show similar partitioning and function. These findings demonstrate that disorder-mediated interactions can selectively compartmentalize specific functionally related proteins from a complex mixture of biomolecules, leading to regulation of a biochemical pathway.
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Affiliation(s)
- Heankel Lyons
- Laboratory of Nuclear Organization, Cecil H. and Ida Green Center for Reproductive Biology Sciences, Division of Basic Research, Department of Obstetrics and Gynecology, Department of Molecular Biology, Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Reshma T Veettil
- Laboratory of Nuclear Organization, Cecil H. and Ida Green Center for Reproductive Biology Sciences, Division of Basic Research, Department of Obstetrics and Gynecology, Department of Molecular Biology, Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Prashant Pradhan
- Laboratory of Nuclear Organization, Cecil H. and Ida Green Center for Reproductive Biology Sciences, Division of Basic Research, Department of Obstetrics and Gynecology, Department of Molecular Biology, Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Christy Fornero
- Laboratory of Nuclear Organization, Cecil H. and Ida Green Center for Reproductive Biology Sciences, Division of Basic Research, Department of Obstetrics and Gynecology, Department of Molecular Biology, Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Nancy De La Cruz
- Laboratory of Nuclear Organization, Cecil H. and Ida Green Center for Reproductive Biology Sciences, Division of Basic Research, Department of Obstetrics and Gynecology, Department of Molecular Biology, Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Keiichi Ito
- Laboratory of Biochemistry and Molecular Biology, the Rockefeller University, New York, NY 10065, USA
| | - Mikayla Eppert
- Laboratory of Nuclear Organization, Cecil H. and Ida Green Center for Reproductive Biology Sciences, Division of Basic Research, Department of Obstetrics and Gynecology, Department of Molecular Biology, Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Robert G Roeder
- Laboratory of Biochemistry and Molecular Biology, the Rockefeller University, New York, NY 10065, USA
| | - Benjamin R Sabari
- Laboratory of Nuclear Organization, Cecil H. and Ida Green Center for Reproductive Biology Sciences, Division of Basic Research, Department of Obstetrics and Gynecology, Department of Molecular Biology, Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
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26
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Kuznetsova K, Chabot NM, Ugolini M, Wu E, Lalit M, Oda H, Sato Y, Kimura H, Jug F, Vastenhouw NL. Nanog organizes transcription bodies. Curr Biol 2023; 33:164-173.e5. [PMID: 36476751 DOI: 10.1016/j.cub.2022.11.015] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Revised: 09/21/2022] [Accepted: 11/07/2022] [Indexed: 12/12/2022]
Abstract
The localization of transcriptional activity in specialized transcription bodies is a hallmark of gene expression in eukaryotic cells.1-3 How proteins of the transcriptional machinery come together to form such bodies, however, is unclear. Here, we take advantage of two large, isolated, and long-lived transcription bodies that reproducibly form during early zebrafish embryogenesis to characterize the dynamics of transcription body formation. Once formed, these transcription bodies are enriched for initiating and elongating RNA polymerase II, as well as the transcription factors Nanog and Sox19b. Analyzing the events leading up to transcription, we find that Nanog and Sox19b cluster prior to transcription. The clustering of transcription factors is sequential; Nanog clusters first, and this is required for the clustering of Sox19b and the initiation of transcription. Mutant analysis revealed that both the DNA-binding domain as well as one of the two intrinsically disordered regions of Nanog are required to organize the two bodies of transcriptional activity. Taken together, our data suggest that the clustering of transcription factors dictates the formation of transcription bodies.
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Affiliation(s)
- Ksenia Kuznetsova
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, 01307 Dresden, Germany
| | - Noémie M Chabot
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, 01307 Dresden, Germany; Center for Integrative Genomics, University of Lausanne, Quartier Sorge, 1015 Lausanne, Switzerland
| | - Martino Ugolini
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, 01307 Dresden, Germany; Center for Integrative Genomics, University of Lausanne, Quartier Sorge, 1015 Lausanne, Switzerland
| | - Edlyn Wu
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, 01307 Dresden, Germany; Center for Integrative Genomics, University of Lausanne, Quartier Sorge, 1015 Lausanne, Switzerland
| | - Manan Lalit
- Center for Systems Biology Dresden, Pfotenhauerstrasse 108, 01307 Dresden, Germany
| | - Haruka Oda
- Cell Biology Center, Institute of Innovative Research, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa 226-8503, Japan
| | - Yuko Sato
- Cell Biology Center, Institute of Innovative Research, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa 226-8503, Japan
| | - Hiroshi Kimura
- Cell Biology Center, Institute of Innovative Research, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa 226-8503, Japan
| | - Florian Jug
- Center for Systems Biology Dresden, Pfotenhauerstrasse 108, 01307 Dresden, Germany; Fondazione Human Technopole, Viale Rita Levi-Montalcini 1, Area MIND, 20157 Milano, Italy
| | - Nadine L Vastenhouw
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, 01307 Dresden, Germany; Center for Integrative Genomics, University of Lausanne, Quartier Sorge, 1015 Lausanne, Switzerland.
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27
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Syed S, Duan Y, Lim B. Modulation of protein-DNA binding reveals mechanisms of spatiotemporal gene control in early Drosophila embryos. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.05.522923. [PMID: 36711729 PMCID: PMC9881968 DOI: 10.1101/2023.01.05.522923] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
It is well known that enhancers regulate the spatiotemporal expression of their target genes by recruiting transcription factors (TFs) to the cognate binding sites in the region. However, the role of multiple binding sites for the same TFs and their specific spatial arrangement in determining the overall competency of the enhancer has yet to be fully understood. In this study, we utilized the MS2-MCP live imaging technique to quantitatively analyze the regulatory logic of the snail distal enhancer in early Drosophila embryos. Through systematic modulation of Dorsal and Twist binding motifs in this enhancer, we found that a mutation in any one of these binding sites causes a drastic reduction in transcriptional amplitude, resulting in a reduction in total mRNA production of the target gene. We provide evidence of synergy, such that multiple binding sites with moderate affinities cooperatively recruit more TFs to drive stronger transcriptional activity than a single site. Moreover, a Hidden Markov-based stochastic model of transcription reveals that embryos with mutated binding sites have a higher probability of returning to the inactive promoter state. We propose that TF-DNA binding regulates spatial and temporal gene expression and drives robust pattern formation by modulating transcriptional kinetics and tuning bursting rates.
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Affiliation(s)
- Sahla Syed
- Department of Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, PA 19104
| | - Yifei Duan
- Department of Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, PA 19104
- Master of Biotechnology Program, University of Pennsylvania, Philadelphia, PA 19104
| | - Bomyi Lim
- Department of Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, PA 19104
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28
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Developmental phenomics suggests that H3K4 monomethylation confers multi-level phenotypic robustness. Cell Rep 2022; 41:111832. [PMID: 36516782 PMCID: PMC9764455 DOI: 10.1016/j.celrep.2022.111832] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Revised: 08/29/2022] [Accepted: 11/22/2022] [Indexed: 12/15/2022] Open
Abstract
How histone modifications affect animal development remains difficult to ascertain. Despite the prevalence of histone 3 lysine 4 monomethylation (H3K4me1) on enhancers, hypomethylation appears to have minor effects on phenotype and viability. Here, we genetically reduce H3K4me1 deposition in Drosophila melanogaster and find that hypomethylation reduces transcription factor enrichment in nuclear microenvironments, disrupts gene expression, and reduces phenotypic robustness. Using a developmental phenomics approach, we find changes in morphology, metabolism, behavior, and offspring production. However, many phenotypic changes are only detected when hypomethylated flies develop outside of standard laboratory environments or with specific genetic backgrounds. Therefore, quantitative phenomics measurements can unravel how pleiotropic modulators of gene expression affect developmental robustness under conditions resembling the natural environments of a species.
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29
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Merabet S, Carnesecchi J. Hox dosage and morphological diversification during development and evolution. Semin Cell Dev Biol 2022:S1084-9521(22)00360-3. [PMID: 36481343 DOI: 10.1016/j.semcdb.2022.11.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Revised: 10/15/2022] [Accepted: 11/30/2022] [Indexed: 12/12/2022]
Abstract
Hox genes encode for evolutionary conserved transcription factors that have long fascinated biologists since the observation of the first homeotic transformations in flies. Hox genes are developmental architects that instruct the formation of various and precise morphologies along the body axes in cnidarian and bilaterian species. In contrast to these highly specific developmental functions, Hox genes encode for proteins that display poorly selective DNA-binding properties in vitro. This "Hox paradox" has been partially solved with the discovery of the TALE-class cofactors, which interact with all Hox members and form versatile Hox/TALE protein complexes on DNA. Here, we describe the role of the Hox dosage as an additional molecular strategy contributing to further resolve the Hox paradox. We present several cases where the Hox dosage is involved in the formation of different morphologies in invertebrates and vertebrates, with a particular emphasis on flight appendages in insects. We also discuss how the Hox dosage could be interpreted in different types of target enhancers within the nuclear environment in vivo. Altogether our survey underlines the Hox dosage as a key mechanism for shaping Hox molecular function during development and evolution.
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30
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Unveiling dynamic enhancer–promoter interactions in Drosophila melanogaster. Biochem Soc Trans 2022; 50:1633-1642. [DOI: 10.1042/bst20220325] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2022] [Revised: 10/18/2022] [Accepted: 10/20/2022] [Indexed: 11/11/2022]
Abstract
Proper enhancer–promoter interactions are essential to maintaining specific transcriptional patterns and preventing ectopic gene expression. Drosophila is an ideal model organism to study transcriptional regulation due to extensively characterized regulatory regions and the ease of implementing new genetic and molecular techniques for quantitative analysis. The mechanisms of enhancer–promoter interactions have been investigated over a range of length scales. At a DNA level, compositions of both enhancer and promoter sequences affect transcriptional dynamics, including duration, amplitude, and frequency of transcriptional bursting. 3D chromatin topology is also important for proper enhancer–promoter contacts. By working competitively or cooperatively with one another, multiple, simultaneous enhancer–enhancer, enhancer–promoter, and promoter–promoter interactions often occur to maintain appropriate levels of mRNAs. For some long-range enhancer–promoter interactions, extra regulatory elements like insulators and tethering elements are required to promote proper interactions while blocking aberrant ones. This review provides an overview of our current understanding of the mechanism of enhancer–promoter interactions and how perturbations of such interactions affect transcription and subsequent physiological outcomes.
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31
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Gandin V, English BP, Freeman M, Leroux LP, Preibisch S, Walpita D, Jaramillo M, Singer RH. Cap-dependent translation initiation monitored in living cells. Nat Commun 2022; 13:6558. [PMID: 36323665 PMCID: PMC9630388 DOI: 10.1038/s41467-022-34052-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Accepted: 10/06/2022] [Indexed: 11/19/2022] Open
Abstract
mRNA translation is tightly regulated to preserve cellular homeostasis. Despite extensive biochemical, genetic, and structural studies, a detailed understanding of mRNA translation regulation is lacking. Imaging methodologies able to resolve the binding dynamics of translation factors at single-cell and single-mRNA resolution were necessary to fully elucidate regulation of this paramount process. Here live-cell spectroscopy and single-particle tracking were combined to interrogate the binding dynamics of endogenous initiation factors to the 5'cap. The diffusion of initiation factors (IFs) changed markedly upon their association with mRNA. Quantifying their diffusion characteristics revealed the sequence of IFs assembly and disassembly in cell lines and the clustering of translation in neurons. This approach revealed translation regulation at high spatial and temporal resolution that can be applied to the formation of any endogenous complex that results in a measurable shift in diffusion.
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Affiliation(s)
- Valentina Gandin
- grid.443970.dJanelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA USA
| | - Brian P. English
- grid.443970.dJanelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA USA
| | - Melanie Freeman
- grid.443970.dJanelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA USA
| | - Louis-Philippe Leroux
- grid.418084.10000 0000 9582 2314Institut National de la Recherche Scientifique (INRS)-Centre Armand-Frappier Santé Biotechnologie (CAFSB), Laval, QC Canada
| | - Stephan Preibisch
- grid.443970.dJanelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA USA
| | - Deepika Walpita
- grid.443970.dJanelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA USA
| | - Maritza Jaramillo
- grid.418084.10000 0000 9582 2314Institut National de la Recherche Scientifique (INRS)-Centre Armand-Frappier Santé Biotechnologie (CAFSB), Laval, QC Canada
| | - Robert H. Singer
- grid.443970.dJanelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA USA
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32
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Srivastava M, Payne JL. On the incongruence of genotype-phenotype and fitness landscapes. PLoS Comput Biol 2022; 18:e1010524. [PMID: 36121840 PMCID: PMC9521842 DOI: 10.1371/journal.pcbi.1010524] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Revised: 09/29/2022] [Accepted: 08/30/2022] [Indexed: 11/22/2022] Open
Abstract
The mapping from genotype to phenotype to fitness typically involves multiple nonlinearities that can transform the effects of mutations. For example, mutations may contribute additively to a phenotype, but their effects on fitness may combine non-additively because selection favors a low or intermediate value of that phenotype. This can cause incongruence between the topographical properties of a fitness landscape and its underlying genotype-phenotype landscape. Yet, genotype-phenotype landscapes are often used as a proxy for fitness landscapes to study the dynamics and predictability of evolution. Here, we use theoretical models and empirical data on transcription factor-DNA interactions to systematically study the incongruence of genotype-phenotype and fitness landscapes when selection favors a low or intermediate phenotypic value. Using the theoretical models, we prove a number of fundamental results. For example, selection for low or intermediate phenotypic values does not change simple sign epistasis into reciprocal sign epistasis, implying that genotype-phenotype landscapes with only simple sign epistasis motifs will always give rise to single-peaked fitness landscapes under such selection. More broadly, we show that such selection tends to create fitness landscapes that are more rugged than the underlying genotype-phenotype landscape, but this increased ruggedness typically does not frustrate adaptive evolution because the local adaptive peaks in the fitness landscape tend to be nearly as tall as the global peak. Many of these results carry forward to the empirical genotype-phenotype landscapes, which may help to explain why low- and intermediate-affinity transcription factor-DNA interactions are so prevalent in eukaryotic gene regulation.
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Affiliation(s)
- Malvika Srivastava
- Institute of Integrative Biology, ETH Zurich, Zurich, Switzerland
- Swiss Institute of Bioinformatics, Lausanne, Switzerland
| | - Joshua L. Payne
- Institute of Integrative Biology, ETH Zurich, Zurich, Switzerland
- Swiss Institute of Bioinformatics, Lausanne, Switzerland
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33
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Deng H, Lim B. Shared Transcriptional Machinery at Homologous Alleles Leads to Reduced Transcription in Early Drosophila Embryos. Front Cell Dev Biol 2022; 10:912838. [PMID: 35898395 PMCID: PMC9311490 DOI: 10.3389/fcell.2022.912838] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Accepted: 06/21/2022] [Indexed: 02/05/2023] Open
Abstract
The mechanism by which transcriptional machinery is recruited to enhancers and promoters to regulate gene expression is one of the most challenging and extensively studied questions in modern biology. We explored the possibility that interallelic interactions between two homologous alleles might affect gene regulation. Using an MS2- and PP7-based, allele-specific live imaging assay, we visualized de novo transcripts of a reporter gene in hemizygous and homozygous Drosophila embryos. Surprisingly, each homozygous allele produced fewer RNAs than the corresponding hemizygous allele, suggesting the possibility of allelic competition in homozygotes. However, the competition was not observed when the enhancer-promoter interaction was weakened by placing the reporter construct in a different chromosome location or by moving the enhancer further away from the promoter. Moreover, the reporter gene showed reduced transcriptional activity when a partial transcription unit (either an enhancer or reporter gene only) was in the homologous position. We propose that the transcriptional machinery that binds both the enhancer and promoter regions, such as RNA Pol II or preinitiation complexes, may be responsible for the allelic competition. We showed that the degree of allelic interference increased over developmental time as more Pol II was needed to activate zygotic genes. Such allelic competition was observed for an endogenous gene as well. Our study provides new insights into the role of 3D interallelic interactions in gene regulation.
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34
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Nollmann M, Bennabi I, Götz M, Gregor T. The Impact of Space and Time on the Functional Output of the Genome. Cold Spring Harb Perspect Biol 2022; 14:a040378. [PMID: 34230036 PMCID: PMC8733053 DOI: 10.1101/cshperspect.a040378] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Over the past two decades, it has become clear that the multiscale spatial and temporal organization of the genome has important implications for nuclear function. This review centers on insights gained from recent advances in light microscopy on our understanding of transcription. We discuss spatial and temporal aspects that shape nuclear order and their consequences on regulatory components, focusing on genomic scales most relevant to function. The emerging picture is that spatiotemporal constraints increase the complexity in transcriptional regulation, highlighting new challenges, such as uncertainty about how information travels from molecular factors through the genome and space to generate a functional output.
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Affiliation(s)
- Marcelo Nollmann
- Centre de Biologie Structurale, CNRS UMR5048, INSERM U1054, Univ Montpellier, 34090 Montpellier, France
| | - Isma Bennabi
- Department of Stem Cell and Developmental Biology, CNRS UMR3738, Institut Pasteur, 75015 Paris, France
| | - Markus Götz
- Centre de Biologie Structurale, CNRS UMR5048, INSERM U1054, Univ Montpellier, 34090 Montpellier, France
| | - Thomas Gregor
- Department of Stem Cell and Developmental Biology, CNRS UMR3738, Institut Pasteur, 75015 Paris, France
- Joseph Henry Laboratory of Physics & Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, New Jersey 08544, USA
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35
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Zhang Y, Lu Y, El Sayyed H, Bian J, Lin J, Li X. Transcription factor dynamics in plants: Insights and technologies for in vivo imaging. PLANT PHYSIOLOGY 2022; 189:23-36. [PMID: 35134239 PMCID: PMC9070795 DOI: 10.1093/plphys/kiac042] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Accepted: 01/08/2022] [Indexed: 06/14/2023]
Abstract
Biochemical and genetic approaches have been extensively used to study transcription factor (TF) functions, but their dynamic behaviors and the complex ways in which they regulate transcription in plant cells remain unexplored, particularly behaviors such as translocation and binding to DNA. Recent developments in labeling and imaging techniques provide the necessary sensitivity and resolution to study these behaviors in living cells. In this review, we present an up-to-date portrait of the dynamics and regulation of TFs under physiologically relevant conditions and then summarize recent advances in fluorescent labeling strategies and imaging techniques. We then discuss future prospects and challenges associated with the application of these techniques to examine TFs' intricate dance in living plants.
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Affiliation(s)
- Yuan Zhang
- Key Laboratory of Genetics and Breeding in Forest Trees and Ornamental Plants Ministry of Education, College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing 100083, China
- Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, Beijing Forestry University, Beijing 100083, China
| | - Yuqing Lu
- Key Laboratory of Genetics and Breeding in Forest Trees and Ornamental Plants Ministry of Education, College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing 100083, China
- Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, Beijing Forestry University, Beijing 100083, China
| | - Hafez El Sayyed
- Department of Physics, University of Oxford, Oxford OX1 3PU, UK
| | - Jiahui Bian
- Key Laboratory of Genetics and Breeding in Forest Trees and Ornamental Plants Ministry of Education, College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing 100083, China
- Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, Beijing Forestry University, Beijing 100083, China
| | - Jinxing Lin
- Key Laboratory of Genetics and Breeding in Forest Trees and Ornamental Plants Ministry of Education, College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing 100083, China
- Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, Beijing Forestry University, Beijing 100083, China
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36
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Levo M, Raimundo J, Bing XY, Sisco Z, Batut PJ, Ryabichko S, Gregor T, Levine MS. Transcriptional coupling of distant regulatory genes in living embryos. Nature 2022; 605:754-760. [PMID: 35508662 PMCID: PMC9886134 DOI: 10.1038/s41586-022-04680-7] [Citation(s) in RCA: 104] [Impact Index Per Article: 34.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Accepted: 03/23/2022] [Indexed: 02/01/2023]
Abstract
The prevailing view of metazoan gene regulation is that individual genes are independently regulated by their own dedicated sets of transcriptional enhancers. Past studies have reported long-range gene-gene associations1-3, but their functional importance in regulating transcription remains unclear. Here we used quantitative single-cell live imaging methods to provide a demonstration of co-dependent transcriptional dynamics of genes separated by large genomic distances in living Drosophila embryos. We find extensive physical and functional associations of distant paralogous genes, including co-regulation by shared enhancers and co-transcriptional initiation over distances of nearly 250 kilobases. Regulatory interconnectivity depends on promoter-proximal tethering elements, and perturbations in these elements uncouple transcription and alter the bursting dynamics of distant genes, suggesting a role of genome topology in the formation and stability of co-transcriptional hubs. Transcriptional coupling is detected throughout the fly genome and encompasses a broad spectrum of conserved developmental processes, suggesting a general strategy for long-range integration of gene activity.
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Affiliation(s)
- Michal Levo
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ, USA
| | - João Raimundo
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ, USA
| | - Xin Yang Bing
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ, USA
| | - Zachary Sisco
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ, USA
| | - Philippe J Batut
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ, USA
| | - Sergey Ryabichko
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ, USA
| | - Thomas Gregor
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ, USA.
- Joseph Henry Laboratories of Physics, Princeton University, Princeton, NJ, USA.
- Department of Developmental and Stem Cell Biology, UMR3738, Institut Pasteur, Paris, France.
| | - Michael S Levine
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ, USA.
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37
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Herrmann JC, Beagrie RA, Hughes JR. Making connections: enhancers in cellular differentiation. Trends Genet 2022; 38:395-408. [PMID: 34753603 DOI: 10.1016/j.tig.2021.10.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Revised: 10/17/2021] [Accepted: 10/19/2021] [Indexed: 01/23/2023]
Abstract
Deciphering the process by which hundreds of distinct cell types emerge from a single zygote to form a complex multicellular organism remains one of the greatest challenges in biological research. Enhancers are known to be central to cell type-specific gene expression, yet many questions regarding how these genomic elements interact both temporally and spatially with other cis- and trans-acting factors to control transcriptional activity during differentiation and development remain unanswered. Here, we review our current understanding of the role of enhancers and their interactions in this context and highlight recent progress achieved with experimental methods of unprecedented resolution.
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Affiliation(s)
- Jennifer C Herrmann
- MRC Molecular Haematology Unit, MRC Weatherall Institute of Molecular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, UK; MRC WIMM Centre for Computational Biology, MRC Weatherall Institute of Molecular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | - Robert A Beagrie
- MRC Weatherall Institute of Molecular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | - Jim R Hughes
- MRC Molecular Haematology Unit, MRC Weatherall Institute of Molecular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, UK; MRC WIMM Centre for Computational Biology, MRC Weatherall Institute of Molecular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, UK.
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38
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Tsai A, Crocker J. Nuclear morphogenesis: forming a heterogeneous nucleus during embryogenesis. Development 2022; 149:274325. [PMID: 35142344 PMCID: PMC8918797 DOI: 10.1242/dev.200266] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Accepted: 01/18/2022] [Indexed: 11/20/2022]
Abstract
ABSTRACT
An embryo experiences increasingly complex spatial and temporal patterns of gene expression as it matures, guiding the morphogenesis of its body. Using super-resolution fluorescence microscopy in Drosophila melanogaster embryos, we observed that the nuclear distributions of transcription factors and histone modifications undergo a similar transformation of increasing heterogeneity. This spatial partitioning of the nucleus could lead to distinct local regulatory environments in space and time that are tuned for specific genes. Accordingly, transcription sites driven by different cis-regulatory regions each had their own temporally and spatially varying local histone environments, which could facilitate the finer spatial and temporal regulation of genes to consistently differentiate cells into organs and tissues. Thus, ‘nuclear morphogenesis’ may be a microscopic counterpart of the macroscopic process that shapes the animal body.
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Affiliation(s)
- Albert Tsai
- European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | - Justin Crocker
- European Molecular Biology Laboratory, 69117 Heidelberg, Germany
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39
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Farrants H, Tebo AG. Fluorescent chemigenetic actuators and indicators for use in living animals. Curr Opin Pharmacol 2022; 62:159-167. [DOI: 10.1016/j.coph.2021.12.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Revised: 12/03/2021] [Accepted: 12/12/2021] [Indexed: 11/28/2022]
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40
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Molecular architecture of enhancer–promoter interaction. Curr Opin Cell Biol 2022; 74:62-70. [DOI: 10.1016/j.ceb.2022.01.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Revised: 12/29/2021] [Accepted: 01/10/2022] [Indexed: 12/26/2022]
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41
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Perelsman O, Asano S, Freifeld L. Expansion Microscopy of Larval Zebrafish Brains and Zebrafish Embryos. Methods Mol Biol 2022; 2440:211-222. [PMID: 35218542 DOI: 10.1007/978-1-0716-2051-9_13] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Since its introduction in 2015, expansion microscopy (ExM) allowed imaging a broad variety of biological structures in many models, at nanoscale resolution. Here, we describe in detail a protocol for application of ExM in whole-brains of zebrafish larvae and intact embryos, and discuss the considerations involved in the imaging of nonflat, whole-organ or organism samples, more broadly.
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Affiliation(s)
- Ory Perelsman
- Department of Biomedical Engineering, Technion-Israel Institute of Technology, Haifa, Israel
| | - Shoh Asano
- Internal Medicine Research Unit, Pfizer, Cambridge, MA, USA
| | - Limor Freifeld
- Department of Biomedical Engineering, Technion-Israel Institute of Technology, Haifa, Israel.
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42
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Karr JP, Ferrie JJ, Tjian R, Darzacq X. The transcription factor activity gradient (TAG) model: contemplating a contact-independent mechanism for enhancer-promoter communication. Genes Dev 2022; 36:7-16. [PMID: 34969825 PMCID: PMC8763055 DOI: 10.1101/gad.349160.121] [Citation(s) in RCA: 71] [Impact Index Per Article: 23.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
How distal cis-regulatory elements (e.g., enhancers) communicate with promoters remains an unresolved question of fundamental importance. Although transcription factors and cofactors are known to mediate this communication, the mechanism by which diffusible molecules relay regulatory information from one position to another along the chromosome is a biophysical puzzle-one that needs to be revisited in light of recent data that cannot easily fit into previous solutions. Here we propose a new model that diverges from the textbook enhancer-promoter looping paradigm and offer a synthesis of the literature to make a case for its plausibility, focusing on the coactivator p300.
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Affiliation(s)
- Jonathan P Karr
- University of California at Berkeley, Berkeley, California 94720, USA
| | - John J Ferrie
- University of California at Berkeley, Berkeley, California 94720, USA
- Howard Hughes Medical Institute, Berkeley, California 94720, USA
| | - Robert Tjian
- University of California at Berkeley, Berkeley, California 94720, USA
- Howard Hughes Medical Institute, Berkeley, California 94720, USA
| | - Xavier Darzacq
- University of California at Berkeley, Berkeley, California 94720, USA
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43
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Castells-Garcia A, Ed-Daoui I, González-Almela E, Vicario C, Ottestrom J, Lakadamyali M, Neguembor MV, Cosma MP. Super resolution microscopy reveals how elongating RNA polymerase II and nascent RNA interact with nucleosome clutches. Nucleic Acids Res 2021; 50:175-190. [PMID: 34929735 PMCID: PMC8754629 DOI: 10.1093/nar/gkab1215] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Revised: 10/13/2021] [Accepted: 11/26/2021] [Indexed: 11/17/2022] Open
Abstract
Transcription and genome architecture are interdependent, but it is still unclear how nucleosomes in the chromatin fiber interact with nascent RNA, and which is the relative nuclear distribution of these RNAs and elongating RNA polymerase II (RNAP II). Using super-resolution (SR) microscopy, we visualized the nascent transcriptome, in both nucleoplasm and nucleolus, with nanoscale resolution. We found that nascent RNAs organize in structures we termed RNA nanodomains, whose characteristics are independent of the number of transcripts produced over time. Dual-color SR imaging of nascent RNAs, together with elongating RNAP II and H2B, shows the physical relation between nucleosome clutches, RNAP II, and RNA nanodomains. The distance between nucleosome clutches and RNA nanodomains is larger than the distance measured between elongating RNAP II and RNA nanodomains. Elongating RNAP II stands between nascent RNAs and the small, transcriptionally active, nucleosome clutches. Moreover, RNA factories are small and largely formed by few RNAP II. Finally, we describe a novel approach to quantify the transcriptional activity at an individual gene locus. By measuring local nascent RNA accumulation upon transcriptional activation at single alleles, we confirm the measurements made at the global nuclear level.
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Affiliation(s)
- Alvaro Castells-Garcia
- Bioland Laboratory, Guangzhou Regenerative Medicine and Health Guangdong Laboratory, Guangzhou 510005, China
| | - Ilyas Ed-Daoui
- CAS Key Laboratory of Regenerative Biology, Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou 510530, China
| | - Esther González-Almela
- Bioland Laboratory, Guangzhou Regenerative Medicine and Health Guangdong Laboratory, Guangzhou 510005, China
| | - Chiara Vicario
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, 08003 Barcelona, Spain
| | - Jason Ottestrom
- ICFO-Institute of Photonic Sciences, The Barcelona Institute of Science and Technology, Barcelona, 08860, Spain
| | - Melike Lakadamyali
- Perelman School of Medicine, Department of Physiology, University of Pennsylvania, Philadelphia, PA 19104, USA.,Perelman School of Medicine, Department of Cell and Developmental Biology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Maria Victoria Neguembor
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, 08003 Barcelona, Spain
| | - Maria Pia Cosma
- Bioland Laboratory, Guangzhou Regenerative Medicine and Health Guangdong Laboratory, Guangzhou 510005, China.,CAS Key Laboratory of Regenerative Biology, Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou 510530, China.,Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, 08003 Barcelona, Spain.,ICREA, Pg. Lluís Companys 23, 08010 Barcelona, Spain.,Universitat Pompeu Fabra (UPF), Dr Aiguader 88, 08003 Barcelona, Spain
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44
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Carnesecchi J, Boumpas P, van Nierop Y Sanchez P, Domsch K, Pinto HD, Borges Pinto P, Lohmann I. The Hox transcription factor Ultrabithorax binds RNA and regulates co-transcriptional splicing through an interplay with RNA polymerase II. Nucleic Acids Res 2021; 50:763-783. [PMID: 34931250 PMCID: PMC8789087 DOI: 10.1093/nar/gkab1250] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Revised: 12/01/2021] [Accepted: 12/07/2021] [Indexed: 11/13/2022] Open
Abstract
Transcription factors (TFs) play a pivotal role in cell fate decision by coordinating gene expression programs. Although most TFs act at the DNA layer, few TFs bind RNA and modulate splicing. Yet, the mechanistic cues underlying TFs activity in splicing remain elusive. Focusing on the Drosophila Hox TF Ultrabithorax (Ubx), our work shed light on a novel layer of Ubx function at the RNA level. Transcriptome and genome-wide binding profiles in embryonic mesoderm and Drosophila cells indicate that Ubx regulates mRNA expression and splicing to promote distinct outcomes in defined cellular contexts. Our results demonstrate a new RNA-binding ability of Ubx. We find that the N51 amino acid of the DNA-binding Homeodomain is non-essential for RNA interaction in vitro, but is required for RNA interaction in vivo and Ubx splicing activity. Moreover, mutation of the N51 amino acid weakens the interaction between Ubx and active RNA Polymerase II (Pol II). Our results reveal that Ubx regulates elongation-coupled splicing, which could be coordinated by a dynamic interplay with active Pol II on chromatin. Overall, our work uncovered a novel role of the Hox TFs at the mRNA regulatory layer. This could be an essential function for other classes of TFs to control cell diversity.
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Affiliation(s)
- Julie Carnesecchi
- Heidelberg University, Centre for Organismal Studies (COS) Heidelberg, Department of Developmental Biology, Heidelberg, Germany.,Institut de Génomique Fonctionnelle de Lyon, Université de Lyon, CNRS UMR5242, Ecole Normale Supérieure de Lyon, Lyon, France
| | - Panagiotis Boumpas
- Heidelberg University, Centre for Organismal Studies (COS) Heidelberg, Department of Developmental Biology, Heidelberg, Germany
| | - Patrick van Nierop Y Sanchez
- Heidelberg University, Centre for Organismal Studies (COS) Heidelberg, Department of Developmental Biology, Heidelberg, Germany
| | - Katrin Domsch
- Heidelberg University, Centre for Organismal Studies (COS) Heidelberg, Department of Developmental Biology, Heidelberg, Germany.,Friedrich-Alexander-University Erlangen-Nürnberg, Department Biology, Division of Developmental Biology, Erlangen, Germany
| | - Hugo Daniel Pinto
- Department of Cell Biology, Albert Einstein College of Medicine, New York, NY, USA
| | - Pedro Borges Pinto
- Heidelberg University, Centre for Organismal Studies (COS) Heidelberg, Department of Developmental Biology, Heidelberg, Germany.,Institut de Génomique Fonctionnelle de Lyon, Université de Lyon, CNRS UMR5242, Ecole Normale Supérieure de Lyon, Lyon, France
| | - Ingrid Lohmann
- Heidelberg University, Centre for Organismal Studies (COS) Heidelberg, Department of Developmental Biology, Heidelberg, Germany
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45
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Olfactory receptor choice: a case study for gene regulation in a multi-enhancer system. Curr Opin Genet Dev 2021; 72:101-109. [PMID: 34896807 DOI: 10.1016/j.gde.2021.11.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Revised: 10/25/2021] [Accepted: 11/11/2021] [Indexed: 12/14/2022]
Abstract
The mammalian genome possesses >2000 olfactory receptor (OR) alleles regulated by 63 known OR-Enhancer elements, yet each olfactory sensory neuron (OSN) expresses only a single OR allele. Choreographed changes to OSN nuclear architecture are evidently necessary for OR expression. Additionally, the insulated organization of OR-enhancers around an OR allele is a hallmark of the chosen OR. However, the biology guiding OR choice itself is unclear. Innovations in single-cell and biophysics-based analysis of nuclear architecture are revising previous models of the nucleus to include its dynamic and probabilistic nature. In this review, we ground current knowledge of OR gene regulation in these emerging theories to speculate on mechanisms that may give rise to diverse and singular OR expression.
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46
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Biswas J, Li W, Singer RH, Coleman RA. Imaging Organization of RNA Processing within the Nucleus. Cold Spring Harb Perspect Biol 2021; 13:a039453. [PMID: 34127450 PMCID: PMC8635003 DOI: 10.1101/cshperspect.a039453] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Within the nucleus, messenger RNA is generated and processed in a highly organized and regulated manner. Messenger RNA processing begins during transcription initiation and continues until the RNA is translated and degraded. Processes such as 5' capping, alternative splicing, and 3' end processing have been studied extensively with biochemical methods and more recently with single-molecule imaging approaches. In this review, we highlight how imaging has helped understand the highly dynamic process of RNA processing. We conclude with open questions and new technological developments that may further our understanding of RNA processing.
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Affiliation(s)
- Jeetayu Biswas
- Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, Bronx, New York 10461, USA
| | - Weihan Li
- Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, Bronx, New York 10461, USA
| | - Robert H Singer
- Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, Bronx, New York 10461, USA
| | - Robert A Coleman
- Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, Bronx, New York 10461, USA
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47
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Waymack R, Gad M, Wunderlich Z. Molecular competition can shape enhancer activity in the Drosophila embryo. iScience 2021; 24:103034. [PMID: 34568782 PMCID: PMC8449247 DOI: 10.1016/j.isci.2021.103034] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Revised: 07/27/2021] [Accepted: 08/20/2021] [Indexed: 01/12/2023] Open
Abstract
Transgenic reporters allow the measurement of regulatory DNA activity in vivo and consequently have long been useful tools for studying enhancers. Despite their utility, few studies have investigated the effects these reporters may have on the expression of other genes. Understanding these effects is required to accurately interpret reporter data and characterize gene regulatory mechanisms. By measuring the expression of Kruppel (Kr) enhancer reporters in live Drosophila embryos, we find reporters inhibit one another's expression and that of a nearby endogenous gene. Using synthetic transcription factor (TF) binding site arrays, we present evidence that competition for TFs is partially responsible for the observed transcriptional inhibition. We develop a simple thermodynamic model that predicts competition of the measured magnitude specifically when TF binding is restricted to distinct nuclear subregions. Our findings underline an unexpected role of the non-homogenous nature of the nucleus in regulating gene expression.
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Affiliation(s)
- Rachel Waymack
- Department of Developmental and Cell Biology, University of California, Irvine, CA 92697, USA
| | - Mario Gad
- Department of Developmental and Cell Biology, University of California, Irvine, CA 92697, USA
| | - Zeba Wunderlich
- Department of Developmental and Cell Biology, University of California, Irvine, CA 92697, USA
- Department of Biology, Boston University, 610 Commonwealth Ave., Boston, MA 02215, USA
- Biological Design Center, Boston University, 610 Commonwealth Avenue, Boston, MA 02215, USA
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48
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Krebs AR. Studying transcription factor function in the genome at molecular resolution. Trends Genet 2021; 37:798-806. [DOI: 10.1016/j.tig.2021.03.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2021] [Revised: 03/22/2021] [Accepted: 03/23/2021] [Indexed: 12/11/2022]
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49
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Frank F, Liu X, Ortlund EA. Glucocorticoid receptor condensates link DNA-dependent receptor dimerization and transcriptional transactivation. Proc Natl Acad Sci U S A 2021; 118:e2024685118. [PMID: 34285072 PMCID: PMC8325269 DOI: 10.1073/pnas.2024685118] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The glucocorticoid receptor (GR) is a ligand-regulated transcription factor (TF) that controls the tissue- and gene-specific transactivation and transrepression of thousands of target genes. Distinct GR DNA-binding sequences with activating or repressive activities have been identified, but how they modulate transcription in opposite ways is not known. We show that GR forms phase-separated condensates that specifically concentrate known coregulators via their intrinsically disordered regions (IDRs) in vitro. A combination of dynamic, multivalent (between IDRs) and specific, stable interactions (between LxxLL motifs and the GR ligand-binding domain) control the degree of recruitment. Importantly, GR DNA binding directs the selective partitioning of coregulators within GR condensates such that activating DNAs cause enhanced recruitment of coactivators. Our work shows that condensation controls GR function by modulating coregulator recruitment and provides a mechanism for the up- and down-regulation of GR target genes controlled by distinct DNA recognition elements.
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Affiliation(s)
- Filipp Frank
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322
| | - Xu Liu
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322
| | - Eric A Ortlund
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322
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50
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Wagh K, Garcia DA, Upadhyaya A. Phase separation in transcription factor dynamics and chromatin organization. Curr Opin Struct Biol 2021; 71:148-155. [PMID: 34303933 DOI: 10.1016/j.sbi.2021.06.009] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2021] [Accepted: 06/16/2021] [Indexed: 02/07/2023]
Abstract
Studies over the past decade have highlighted the key role of liquid-liquid phase separation in cellular organization and function. Dynamic compartmentalization of transcription factors and coactivators by such phase-separated condensates regulates the assembly of transcriptional machinery at genomic loci. Although rapid advances in microscopy have demonstrated the ubiquity of such condensates, a rigorous characterization of the physics of phase separation in transcription remains to be carried out. In this review, we discuss theoretical and experimental evidence for biomolecular condensates as dynamic regulators of transcription. Looking beyond, we highlight functional consequences for transcription factor dynamics and gene expression and discuss potential pitfalls of misclassifying biomolecular condensates as liquid droplets in the absence of a rigorous physical description.
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Affiliation(s)
- Kaustubh Wagh
- Department of Physics, University of Maryland, College Park, MD, 20742, USA; Laboratory of Receptor Biology and Gene Expression, National Cancer Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - David A Garcia
- Department of Physics, University of Maryland, College Park, MD, 20742, USA; Laboratory of Receptor Biology and Gene Expression, National Cancer Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Arpita Upadhyaya
- Department of Physics, University of Maryland, College Park, MD, 20742, USA; Institute for Physical Science and Technology, University of Maryland, College Park, MD, 20742, USA.
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