1
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Freund MM, Harrison MM, Torres-Zelada EF. Exploring the reciprocity between pioneer factors and development. Development 2024; 151:dev201921. [PMID: 38958075 PMCID: PMC11266817 DOI: 10.1242/dev.201921] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/04/2024]
Abstract
Development is regulated by coordinated changes in gene expression. Control of these changes in expression is largely governed by the binding of transcription factors to specific regulatory elements. However, the packaging of DNA into chromatin prevents the binding of many transcription factors. Pioneer factors overcome this barrier owing to unique properties that enable them to bind closed chromatin, promote accessibility and, in so doing, mediate binding of additional factors that activate gene expression. Because of these properties, pioneer factors act at the top of gene-regulatory networks and drive developmental transitions. Despite the ability to bind target motifs in closed chromatin, pioneer factors have cell type-specific chromatin occupancy and activity. Thus, developmental context clearly shapes pioneer-factor function. Here, we discuss this reciprocal interplay between pioneer factors and development: how pioneer factors control changes in cell fate and how cellular environment influences pioneer-factor binding and activity.
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Affiliation(s)
- Meghan M. Freund
- Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, WI 52706, USA
| | - Melissa M. Harrison
- Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, WI 52706, USA
| | - Eliana F. Torres-Zelada
- Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, WI 52706, USA
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2
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Orsetti A, van Oosten D, Vasarhelyi RG, Dănescu TM, Huertas J, van Ingen H, Cojocaru V. Structural dynamics in chromatin unraveling by pioneer transcription factors. Biophys Rev 2024; 16:365-382. [PMID: 39099839 PMCID: PMC11297019 DOI: 10.1007/s12551-024-01205-6] [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: 03/29/2024] [Accepted: 06/18/2024] [Indexed: 08/06/2024] Open
Abstract
Pioneer transcription factors are proteins with a dual function. First, they regulate transcription by binding to nucleosome-free DNA regulatory elements. Second, they bind to DNA while wrapped around histone proteins in the chromatin and mediate chromatin opening. The molecular mechanisms that connect the two functions are yet to be discovered. In recent years, pioneer factors received increased attention mainly because of their crucial role in promoting cell fate transitions that could be used for regenerative therapies. For example, the three factors required to induce pluripotency in somatic cells, Oct4, Sox2, and Klf4 were classified as pioneer factors and studied extensively. With this increased attention, several structures of complexes between pioneer factors and chromatin structural units (nucleosomes) have been resolved experimentally. Furthermore, experimental and computational approaches have been designed to study two unresolved, key scientific questions: First, do pioneer factors induce directly local opening of nucleosomes and chromatin fibers upon binding? And second, how do the unstructured tails of the histones impact the structural dynamics involved in such conformational transitions? Here we review the current knowledge about transcription factor-induced nucleosome dynamics and the role of the histone tails in this process. We discuss what is needed to bridge the gap between the static views obtained from the experimental structures and the key structural dynamic events in chromatin opening. Finally, we propose that integrating nuclear magnetic resonance spectroscopy with molecular dynamics simulations is a powerful approach to studying pioneer factor-mediated dynamics of nucleosomes and perhaps small chromatin fibers using native DNA sequences.
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Affiliation(s)
- Andrea Orsetti
- Bijvoet Center for Biomolecular Research, Utrecht University, Utrecht, Netherlands
| | - Daphne van Oosten
- Bijvoet Center for Biomolecular Research, Utrecht University, Utrecht, Netherlands
| | | | - Theodor-Marian Dănescu
- Faculty of Chemistry and Chemical Engineering, Babeş-Bolyai University, Cluj-Napoca, Romania
| | - Jan Huertas
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, England
| | - Hugo van Ingen
- Bijvoet Center for Biomolecular Research, Utrecht University, Utrecht, Netherlands
| | - Vlad Cojocaru
- Bijvoet Center for Biomolecular Research, Utrecht University, Utrecht, Netherlands
- STAR-UBB Institute, Babeş-Bolyai University, Cluj-Napoca, Romania
- Max Planck Institute for Molecular Biomedicine, Münster, Germany
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3
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Feng XA, Yamadi M, Fu Y, Ness KM, Liu C, Ahmed I, Bowman GD, Johnson ME, Ha T, Wu C. GAGA zinc finger transcription factor searches chromatin by 1D-3D facilitated diffusion. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.07.14.549009. [PMID: 37502885 PMCID: PMC10369947 DOI: 10.1101/2023.07.14.549009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/29/2023]
Abstract
To elucidate how eukaryotic sequence-specific transcription factors (TFs) search for gene targets on chromatin, we used multi-color smFRET and single-particle imaging to track the diffusion of purified GAGA-Associated Factor (GAF) on DNA and nucleosomes. Monomeric GAF DNA-binding domain (DBD) bearing one zinc finger finds its cognate site by 1D or 3D diffusion on bare DNA and rapidly slides back-and-forth between naturally clustered motifs for seconds before escape. Multimeric, full-length GAF also finds clustered motifs on DNA by 1D-3D diffusion, but remains locked on target for longer periods. Nucleosome architecture effectively blocks GAF-DBD 1D-sliding into the histone core but favors retention of GAF-DBD when targeting solvent-exposed sites by 3D-diffusion. Despite the occlusive power of nucleosomes, 1D-3D facilitated diffusion enables GAF to effectively search for clustered cognate motifs in chromatin, providing a mechanism for navigation to nucleosome and nucleosome-free sites by a member of the largest TF family.
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Affiliation(s)
- Xinyu A Feng
- Department of Biology, Johns Hopkins University, Baltimore, Maryland, USA
- Department of Biophysics, Johns Hopkins University, Baltimore, Maryland, USA
| | - Maryam Yamadi
- Department of Biology, Johns Hopkins University, Baltimore, Maryland, USA
| | - Yiben Fu
- Department of Biophysics, Johns Hopkins University, Baltimore, Maryland, USA
| | - Kaitlin M Ness
- Department of Biology, Johns Hopkins University, Baltimore, Maryland, USA
| | - Celina Liu
- Department of Biology, Johns Hopkins University, Baltimore, Maryland, USA
| | - Ishtiyaq Ahmed
- Department of Biophysics, Johns Hopkins University, Baltimore, Maryland, USA
| | - Gregory D Bowman
- Department of Biophysics, Johns Hopkins University, Baltimore, Maryland, USA
| | - Margaret E Johnson
- Department of Biophysics, Johns Hopkins University, Baltimore, Maryland, USA
| | - Taekjip Ha
- Department of Biophysics, Johns Hopkins University, Baltimore, Maryland, USA
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, Massachusetts, United States
- Department of Pediatrics, Harvard Medical School, Boston, Massachusetts, USA
- Howard Hughes Medical Institute, Boston, Massachusetts, USA
| | - Carl Wu
- Department of Biology, Johns Hopkins University, Baltimore, Maryland, USA
- Department of Molecular Biology and Genetics, Johns Hopkins School of Medicine, Baltimore, Maryland, USA
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4
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Stoeber S, Godin H, Xu C, Bai L. Pioneer factors: nature or nurture? Crit Rev Biochem Mol Biol 2024:1-15. [PMID: 38778580 DOI: 10.1080/10409238.2024.2355885] [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: 03/03/2024] [Accepted: 05/13/2024] [Indexed: 05/25/2024]
Abstract
Chromatin is densely packed with nucleosomes, which limits the accessibility of many chromatin-associated proteins. Pioneer factors (PFs) are usually viewed as a special group of sequence-specific transcription factors (TFs) that can recognize nucleosome-embedded motifs, invade compact chromatin, and generate open chromatin regions. Through this process, PFs initiate a cascade of events that play key roles in gene regulation and cell differentiation. A current debate in the field is if PFs belong to a unique subset of TFs with intrinsic "pioneering activity", or if all TFs have the potential to function as PFs within certain cellular contexts. There are also different views regarding the key feature(s) that define pioneering activity. In this review, we present evidence from the literature related to these alternative views and discuss how to potentially reconcile them. It is possible that both intrinsic properties, like tight nucleosome binding and structural compatibility, and cellular conditions, like concentration and co-factor availability, are important for PF function.
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Affiliation(s)
- Shane Stoeber
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, USA
- Center for Eukaryotic Gene Regulation, The Pennsylvania State University, University Park, PA, USA
| | - Holly Godin
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, USA
- Center for Eukaryotic Gene Regulation, The Pennsylvania State University, University Park, PA, USA
| | - Cheng Xu
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, USA
- Center for Eukaryotic Gene Regulation, The Pennsylvania State University, University Park, PA, USA
| | - Lu Bai
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, USA
- Center for Eukaryotic Gene Regulation, The Pennsylvania State University, University Park, PA, USA
- Department of Physics, The Pennsylvania State University, University Park, PA, USA
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5
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Oyarzún-Cisterna A, Gidi C, Raiqueo F, Amigo R, Rivas C, Torrejón M, Gutiérrez JL. General regulatory factors exert differential effects on nucleosome sliding activity of the ISW1a complex. Biol Res 2024; 57:22. [PMID: 38704609 PMCID: PMC11069190 DOI: 10.1186/s40659-024-00500-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2024] [Accepted: 04/15/2024] [Indexed: 05/06/2024] Open
Abstract
BACKGROUND Chromatin dynamics is deeply involved in processes that require access to DNA, such as transcriptional regulation. Among the factors involved in chromatin dynamics at gene regulatory regions are general regulatory factors (GRFs). These factors contribute to establishment and maintenance of nucleosome-depleted regions (NDRs). These regions are populated by nucleosomes through histone deposition and nucleosome sliding, the latter catalyzed by a number of ATP-dependent chromatin remodeling complexes, including ISW1a. It has been observed that GRFs can act as barriers against nucleosome sliding towards NDRs. However, the relative ability of the different GRFs to hinder sliding activity is currently unknown. RESULTS Considering this, we performed a comparative analysis for the main GRFs, with focus in their ability to modulate nucleosome sliding mediated by ISW1a. Among the GRFs tested in nucleosome remodeling assays, Rap1 was the only factor displaying the ability to hinder the activity of ISW1a. This effect requires location of the Rap1 cognate sequence on linker that becomes entry DNA in the nucleosome remodeling process. In addition, Rap1 was able to hinder nucleosome assembly in octamer transfer assays. Concurrently, Rap1 displayed the highest affinity for and longest dwell time from its target sequence, compared to the other GRFs tested. Consistently, through bioinformatics analyses of publicly available genome-wide data, we found that nucleosome occupancy and histone deposition in vivo are inversely correlated with the affinity of Rap1 for its target sequences in the genome. CONCLUSIONS Our findings point to DNA binding affinity, residence time and location at particular translational positions relative to the nucleosome core as the key features of GRFs underlying their roles played in nucleosome sliding and assembly.
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Affiliation(s)
- Andrea Oyarzún-Cisterna
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Biológicas, Universidad de Concepción, 4070043, Concepción, Chile
| | - Cristián Gidi
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Biológicas, Universidad de Concepción, 4070043, Concepción, Chile
| | - Fernanda Raiqueo
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Biológicas, Universidad de Concepción, 4070043, Concepción, Chile
| | - Roberto Amigo
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Biológicas, Universidad de Concepción, 4070043, Concepción, Chile
| | - Camila Rivas
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Biológicas, Universidad de Concepción, 4070043, Concepción, Chile
| | - Marcela Torrejón
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Biológicas, Universidad de Concepción, 4070043, Concepción, Chile
| | - José L Gutiérrez
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Biológicas, Universidad de Concepción, 4070043, Concepción, Chile.
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6
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Kim JM, Carcamo CC, Jazani S, Xie Z, Feng XA, Yamadi M, Poyton M, Holland KL, Grimm JB, Lavis LD, Ha T, Wu C. Dynamic 1D search and processive nucleosome translocations by RSC and ISW2 chromatin remodelers. eLife 2024; 12:RP91433. [PMID: 38497611 PMCID: PMC10948146 DOI: 10.7554/elife.91433] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/19/2024] Open
Abstract
Eukaryotic gene expression is linked to chromatin structure and nucleosome positioning by ATP-dependent chromatin remodelers that establish and maintain nucleosome-depleted regions (NDRs) near transcription start sites. Conserved yeast RSC and ISW2 remodelers exert antagonistic effects on nucleosomes flanking NDRs, but the temporal dynamics of remodeler search, engagement, and directional nucleosome mobilization for promoter accessibility are unknown. Using optical tweezers and two-color single-particle imaging, we investigated the Brownian diffusion of RSC and ISW2 on free DNA and sparse nucleosome arrays. RSC and ISW2 rapidly scan DNA by one-dimensional hopping and sliding, respectively, with dynamic collisions between remodelers followed by recoil or apparent co-diffusion. Static nucleosomes block remodeler diffusion resulting in remodeler recoil or sequestration. Remarkably, both RSC and ISW2 use ATP hydrolysis to translocate mono-nucleosomes processively at ~30 bp/s on extended linear DNA under tension. Processivity and opposing push-pull directionalities of nucleosome translocation shown by RSC and ISW2 shape the distinctive landscape of promoter chromatin.
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Affiliation(s)
- Jee Min Kim
- Department of Biology, Johns Hopkins UniversityBaltimoreUnited States
| | - Claudia C Carcamo
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of MedicineBaltimoreUnited States
| | - Sina Jazani
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of MedicineBaltimoreUnited States
| | - Zepei Xie
- Department of Biology, Johns Hopkins UniversityBaltimoreUnited States
| | - Xinyu A Feng
- Department of Biology, Johns Hopkins UniversityBaltimoreUnited States
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of MedicineBaltimoreUnited States
| | - Maryam Yamadi
- Department of Biology, Johns Hopkins UniversityBaltimoreUnited States
| | - Matthew Poyton
- Department of Biology, Johns Hopkins UniversityBaltimoreUnited States
| | - Katie L Holland
- Janelia Research Campus, Howard Hughes Medical InstituteAshburnUnited States
| | - Jonathan B Grimm
- Janelia Research Campus, Howard Hughes Medical InstituteAshburnUnited States
| | - Luke D Lavis
- Janelia Research Campus, Howard Hughes Medical InstituteAshburnUnited States
| | - Taekjip Ha
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of MedicineBaltimoreUnited States
- Howard Hughes Medical InstituteBostonUnited States
| | - Carl Wu
- Department of Biology, Johns Hopkins UniversityBaltimoreUnited States
- Department of Molecular Biology and Genetics, Johns Hopkins School of MedicineBaltimoreUnited States
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7
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Meeussen JVW, Lenstra TL. Time will tell: comparing timescales to gain insight into transcriptional bursting. Trends Genet 2024; 40:160-174. [PMID: 38216391 PMCID: PMC10860890 DOI: 10.1016/j.tig.2023.11.003] [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: 09/13/2023] [Revised: 11/27/2023] [Accepted: 11/27/2023] [Indexed: 01/14/2024]
Abstract
Recent imaging studies have captured the dynamics of regulatory events of transcription inside living cells. These events include transcription factor (TF) DNA binding, chromatin remodeling and modification, enhancer-promoter (E-P) proximity, cluster formation, and preinitiation complex (PIC) assembly. Together, these molecular events culminate in stochastic bursts of RNA synthesis, but their kinetic relationship remains largely unclear. In this review, we compare the timescales of upstream regulatory steps (input) with the kinetics of transcriptional bursting (output) to generate mechanistic models of transcription dynamics in single cells. We highlight open questions and potential technical advances to guide future endeavors toward a quantitative and kinetic understanding of transcription regulation.
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Affiliation(s)
- Joseph V W Meeussen
- Division of Gene Regulation, The Netherlands Cancer Institute, Oncode Institute, Amsterdam 1066CX, The Netherlands
| | - Tineke L Lenstra
- Division of Gene Regulation, The Netherlands Cancer Institute, Oncode Institute, Amsterdam 1066CX, The Netherlands.
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8
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Barral A, Zaret KS. Pioneer factors: roles and their regulation in development. Trends Genet 2024; 40:134-148. [PMID: 37940484 PMCID: PMC10873006 DOI: 10.1016/j.tig.2023.10.007] [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: 08/29/2023] [Revised: 10/06/2023] [Accepted: 10/06/2023] [Indexed: 11/10/2023]
Abstract
Pioneer factors are a subclass of transcription factors that can bind and initiate opening of silent chromatin regions. Pioneer factors subsequently regulate lineage-specific genes and enhancers and, thus, activate the zygotic genome after fertilization, guide cell fate transitions during development, and promote various forms of human cancers. As such, pioneer factors are useful in directed cell reprogramming. In this review, we define the structural and functional characteristics of pioneer factors, how they bind and initiate opening of closed chromatin regions, and the consequences for chromatin dynamics and gene expression during cell differentiation. We also discuss emerging mechanisms that modulate pioneer factors during development.
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Affiliation(s)
- Amandine Barral
- Institute for Regenerative Medicine and Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, 3400 Civic Boulevard, Philadelphia, PA 19104, USA
| | - Kenneth S Zaret
- Institute for Regenerative Medicine and Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, 3400 Civic Boulevard, Philadelphia, PA 19104, USA.
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9
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Ahmad K, Brahma S, Henikoff S. Epigenetic pioneering by SWI/SNF family remodelers. Mol Cell 2024; 84:194-201. [PMID: 38016477 PMCID: PMC10842064 DOI: 10.1016/j.molcel.2023.10.045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Revised: 09/20/2023] [Accepted: 10/31/2023] [Indexed: 11/30/2023]
Abstract
In eukaryotic genomes, transcriptional machinery and nucleosomes compete for binding to DNA sequences; thus, a crucial aspect of gene regulatory element function is to modulate chromatin accessibility for transcription factor (TF) and RNA polymerase binding. Recent structural studies have revealed multiple modes of TF engagement with nucleosomes, but how initial "pioneering" results in steady-state DNA accessibility for further TF binding and RNA polymerase II (RNAPII) engagement has been unclear. Even less well understood is how distant sites of open chromatin interact with one another, such as when developmental enhancers activate promoters to release RNAPII for productive elongation. Here, we review evidence for the centrality of the conserved SWI/SNF family of nucleosome remodeling complexes, both in pioneering and in mediating enhancer-promoter contacts. Consideration of the nucleosome unwrapping and ATP hydrolysis activities of SWI/SNF complexes, together with their architectural features, may reconcile steady-state TF occupancy with rapid TF dynamics observed by live imaging.
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Affiliation(s)
- Kami Ahmad
- Basic Sciences Division, Fred Hutchinson Cancer Center, Seattle, WA, USA
| | - Sandipan Brahma
- University of Nebraska Medical Center, Department of Genetics, Cell Biology & Anatomy, Omaha, NE, USA
| | - Steven Henikoff
- Basic Sciences Division, Fred Hutchinson Cancer Center, Seattle, WA, USA; Howard Hughes Medical Institute, Chevy Chase, MD, USA.
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10
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Kim JM, Carcamo CC, Jazani S, Xie Z, Feng XA, Yamadi M, Poyton M, Holland KL, Grimm JB, Lavis LD, Ha T, Wu C. Dynamic 1D Search and Processive Nucleosome Translocations by RSC and ISW2 Chromatin Remodelers. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.06.13.544671. [PMID: 38293098 PMCID: PMC10827135 DOI: 10.1101/2023.06.13.544671] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2024]
Abstract
Eukaryotic gene expression is linked to chromatin structure and nucleosome positioning by ATP-dependent chromatin remodelers that establish and maintain nucleosome-depleted regions (NDRs) near transcription start-sites. Conserved yeast RSC and ISW2 remodelers exert antagonistic effects on nucleosomes flanking NDRs, but the temporal dynamics of remodeler search, engagement and directional nucleosome mobilization for promoter accessibility are unknown. Using optical tweezers and 2-color single-particle imaging, we investigated the Brownian diffusion of RSC and ISW2 on free DNA and sparse nucleosome arrays. RSC and ISW2 rapidly scan DNA by one-dimensional hopping and sliding respectively, with dynamic collisions between remodelers followed by recoil or apparent co-diffusion. Static nucleosomes block remodeler diffusion resulting in remodeler recoil or sequestration. Remarkably, both RSC and ISW2 use ATP hydrolysis to translocate mono-nucleosomes processively at ~30 bp/sec on extended linear DNA under tension. Processivity and opposing push-pull directionalities of nucleosome translocation shown by RSC and ISW2 shape the distinctive landscape of promoter chromatin.
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Affiliation(s)
- Jee Min Kim
- Department of Biology, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Claudia C. Carcamo
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Sina Jazani
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Zepei Xie
- Department of Biology, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Xinyu A. Feng
- Department of Biology, Johns Hopkins University, Baltimore, MD 21218, USA
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Maryam Yamadi
- Department of Biology, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Matthew Poyton
- Department of Biology, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Katie L. Holland
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Jonathan B. Grimm
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Luke D. Lavis
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Taekjip Ha
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Howard Hughes Medical Institute, Boston, Massachusetts, USA
| | - Carl Wu
- Department of Biology, Johns Hopkins University, Baltimore, MD 21218, USA
- Department of Molecular Biology and Genetics, Johns Hopkins School of Medicine, Baltimore, MD 21287, USA
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11
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Khamwachirapithak P, Guillaume-Schoepfer D, Chansongkrow P, Teichmann SA, Wigge PA, Charoensawan V. Characterizing Different Modes of Interplay Between Rap1 and H3 Using Inducible H3-depletion Yeast. J Mol Biol 2023; 435:168355. [PMID: 37935256 DOI: 10.1016/j.jmb.2023.168355] [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: 08/02/2023] [Revised: 10/31/2023] [Accepted: 11/01/2023] [Indexed: 11/09/2023]
Abstract
Histones and transcription factors (TFs) are two important DNA-binding proteins that interact, compete, and together regulate transcriptional processes in response to diverse internal and external stimuli. Condition-specific depletion of histones in Saccharomyces cerevisiae using a galactose-inducible H3 promoter provides a suitable framework for examining transcriptional alteration resulting from reduced nucleosome content. However, the effect on DNA binding activities of TFs is yet to be fully explored. In this work, we combine ChIP-seq of H3 with RNA-seq to elucidate the genome-scale relationships between H3 occupancy patterns and transcriptional dynamics before and after global H3 depletion. ChIP-seq of Rap1 is also conducted in the H3-depletion and control treatments, to investigate the interplay between this master regulator TF and nucleosomal H3, and to explore the impact on diverse transcriptional responses of different groups of target genes and functions. Ultimately, we propose a working model and testable hypotheses regarding the impact of global and local H3 depletion on transcriptional changes. We also demonstrate different potential modes of interaction between Rap1 and H3, which sheds light on the potential multifunctional regulatory capabilities of Rap1 and potentially other pioneer factors.
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Affiliation(s)
- Peerapat Khamwachirapithak
- Doctor of Philosophy Program in Biochemistry (International Program), Faculty of Science, Mahidol University, Bangkok, Thailand; Department of Biochemistry, Faculty of Science, Mahidol University, Bangkok, Thailand
| | | | - Pakkanan Chansongkrow
- Department of Biochemistry, Faculty of Science, Mahidol University, Bangkok, Thailand
| | - Sarah A Teichmann
- Wellcome Sanger Institute, Wellcome Genome Campus, Cambridge, UK; Department of Physics, Cavendish Laboratory, University of Cambridge, Cambridge, UK.
| | - Philip A Wigge
- Sainsbury Laboratory, University of Cambridge, Cambridge, United Kingdom; University Potsdam, Institute for Biochemistry and Biology, Molecular Biology, Karl-Liebknecht-Str, Potsdam-Golm, Germany; Institute of Biochemistry and Biology, University of Potsdam, Potsdam-Golm, Germany.
| | - Varodom Charoensawan
- Department of Biochemistry, Faculty of Science, Mahidol University, Bangkok, Thailand; Sainsbury Laboratory, University of Cambridge, Cambridge, United Kingdom; Systems Biology of Diseases Research Unit, Faculty of Science, Mahidol University, Bangkok, Thailand; Integrative Computational BioScience (ICBS) center, Mahidol University, Nakhon Pathom, Thailand; School of Chemistry, Institute of Science, Suranaree University of Technology, Nakhon Ratchasima, Thailand.
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12
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Nagpal H, Ali-Ahmad A, Hirano Y, Cai W, Halic M, Fukagawa T, Sekulić N, Fierz B. CENP-A and CENP-B collaborate to create an open centromeric chromatin state. Nat Commun 2023; 14:8227. [PMID: 38086807 PMCID: PMC10716449 DOI: 10.1038/s41467-023-43739-5] [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] [Received: 06/26/2022] [Accepted: 11/17/2023] [Indexed: 12/18/2023] Open
Abstract
Centromeres are epigenetically defined via the presence of the histone H3 variant CENP-A. Contacting CENP-A nucleosomes, the constitutive centromere associated network (CCAN) and the kinetochore assemble, connecting the centromere to spindle microtubules during cell division. The DNA-binding centromeric protein CENP-B is involved in maintaining centromere stability and, together with CENP-A, shapes the centromeric chromatin state. The nanoscale organization of centromeric chromatin is not well understood. Here, we use single-molecule fluorescence and cryoelectron microscopy (cryoEM) to show that CENP-A incorporation establishes a dynamic and open chromatin state. The increased dynamics of CENP-A chromatin create an opening for CENP-B DNA access. In turn, bound CENP-B further opens the chromatin fiber structure and induces nucleosomal DNA unwrapping. Finally, removal of CENP-A increases CENP-B mobility in cells. Together, our studies show that the two centromere-specific proteins collaborate to reshape chromatin structure, enabling the binding of centromeric factors and establishing a centromeric chromatin state.
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Affiliation(s)
- Harsh Nagpal
- École Polytechnique Fédérale de Lausanne (EPFL), SB ISIC LCBM, Station 6, CH-1015, Lausanne, Switzerland
| | - Ahmad Ali-Ahmad
- Centre for Molecular Medicine Norway (NCMM), Nordic EMBL Partnership, Faculty of Medicine, University of Oslo, Oslo, 0318, Norway
| | - Yasuhiro Hirano
- Graduate School of Frontier Biosciences, Osaka University, Suita, 565-0871, Japan
| | - Wei Cai
- École Polytechnique Fédérale de Lausanne (EPFL), SB ISIC LCBM, Station 6, CH-1015, Lausanne, Switzerland
| | - Mario Halic
- Structural Biology, St. Jude Children's Research Hospital, Memphis, TN, 38105-3678, USA
| | - Tatsuo Fukagawa
- Graduate School of Frontier Biosciences, Osaka University, Suita, 565-0871, Japan
| | - Nikolina Sekulić
- Centre for Molecular Medicine Norway (NCMM), Nordic EMBL Partnership, Faculty of Medicine, University of Oslo, Oslo, 0318, Norway.
- Department of Chemistry, University of Oslo, P.O. Box 1033, Blindern, 0315, Norway.
| | - Beat Fierz
- École Polytechnique Fédérale de Lausanne (EPFL), SB ISIC LCBM, Station 6, CH-1015, Lausanne, Switzerland.
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13
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Bondra ER, Rine J. Context-dependent function of the transcriptional regulator Rap1 in gene silencing and activation in Saccharomyces cerevisiae. Proc Natl Acad Sci U S A 2023; 120:e2304343120. [PMID: 37769255 PMCID: PMC10556627 DOI: 10.1073/pnas.2304343120] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Accepted: 08/04/2023] [Indexed: 09/30/2023] Open
Abstract
In Saccharomyces cerevisiae, heterochromatin is formed through interactions between site-specific DNA-binding factors, including the transcriptional activator Repressor Activator Protein (Rap1), and Sir proteins. Despite an understanding of the establishment and maintenance of Sir-silenced chromatin, the mechanism of gene silencing by Sir proteins has remained a mystery. Utilizing high-resolution chromatin immunoprecipitation, we found that Rap1, the native activator of the bidirectional HMLα promoter, bound its recognition sequence in silenced chromatin, and its binding was enhanced by the presence of Sir proteins. In contrast to prior results, various components of transcription machinery were not able to access HMLα in the silenced state. These findings disproved the long-standing model of indiscriminate steric occlusion by Sir proteins and led to investigation of the role of the transcriptional activator Rap1 in Sir-silenced chromatin. Using a highly sensitive assay that monitors loss-of-silencing events, we identified a role for promoter-bound Rap1 in the maintenance of silent chromatin through interactions with the Sir complex. We also found that promoter-bound Rap1 activated HMLα when in an expressed state, and aided in the transition from transcription initiation to elongation. Highlighting the importance of epigenetic context in transcription factor function, these results point toward a model in which the duality of Rap1 function was mediated by local chromatin environment rather than binding-site availability.
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Affiliation(s)
- Eliana R. Bondra
- Department of Molecular and Cell Biology, University of California, Berkeley, CA94720
| | - Jasper Rine
- Department of Molecular and Cell Biology, University of California, Berkeley, CA94720
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14
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Abdulhay NJ, Hsieh LJ, McNally CP, Ostrowski MS, Moore CM, Ketavarapu M, Kasinathan S, Nanda AS, Wu K, Chio US, Zhou Z, Goodarzi H, Narlikar GJ, Ramani V. Nucleosome density shapes kilobase-scale regulation by a mammalian chromatin remodeler. Nat Struct Mol Biol 2023; 30:1571-1581. [PMID: 37696956 PMCID: PMC10584690 DOI: 10.1038/s41594-023-01093-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Accepted: 08/09/2023] [Indexed: 09/13/2023]
Abstract
Nearly all essential nuclear processes act on DNA packaged into arrays of nucleosomes. However, our understanding of how these processes (for example, DNA replication, RNA transcription, chromatin extrusion and nucleosome remodeling) occur on individual chromatin arrays remains unresolved. Here, to address this deficit, we present SAMOSA-ChAAT: a massively multiplex single-molecule footprinting approach to map the primary structure of individual, reconstituted chromatin templates subject to virtually any chromatin-associated reaction. We apply this method to distinguish between competing models for chromatin remodeling by the essential imitation switch (ISWI) ATPase SNF2h: nucleosome-density-dependent spacing versus fixed-linker-length nucleosome clamping. First, we perform in vivo single-molecule nucleosome footprinting in murine embryonic stem cells, to discover that ISWI-catalyzed nucleosome spacing correlates with the underlying nucleosome density of specific epigenomic domains. To establish causality, we apply SAMOSA-ChAAT to quantify the activities of ISWI ATPase SNF2h and its parent complex ACF on reconstituted nucleosomal arrays of varying nucleosome density, at single-molecule resolution. We demonstrate that ISWI remodelers operate as density-dependent, length-sensing nucleosome sliders, whose ability to program DNA accessibility is dictated by single-molecule nucleosome density. We propose that the long-observed, context-specific regulatory effects of ISWI complexes can be explained in part by the sensing of nucleosome density within epigenomic domains. More generally, our approach promises molecule-precise views of the essential processes that shape nuclear physiology.
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Affiliation(s)
- Nour J Abdulhay
- Gladstone Institute for Data Science and Biotechnology, J. David Gladstone Institutes, San Francisco, CA, USA
- Department of Biochemistry and Biophysics, University of California San Francisco, San Francisco, CA, USA
- Biomedical Sciences Graduate Program, University of California San Francisco, San Francisco, CA, USA
| | - Laura J Hsieh
- Department of Biochemistry and Biophysics, University of California San Francisco, San Francisco, CA, USA
| | - Colin P McNally
- Gladstone Institute for Data Science and Biotechnology, J. David Gladstone Institutes, San Francisco, CA, USA
- Department of Biochemistry and Biophysics, University of California San Francisco, San Francisco, CA, USA
| | - Megan S Ostrowski
- Gladstone Institute for Data Science and Biotechnology, J. David Gladstone Institutes, San Francisco, CA, USA
| | - Camille M Moore
- Gladstone Institute for Data Science and Biotechnology, J. David Gladstone Institutes, San Francisco, CA, USA
- Department of Biochemistry and Biophysics, University of California San Francisco, San Francisco, CA, USA
- Tetrad Graduate Program, University of California San Francisco, San Francisco, CA, USA
| | | | - Sivakanthan Kasinathan
- Department of Pediatrics, Lucille Packard Children's Hospital, Stanford University, Palo Alto, CA, USA
| | - Arjun S Nanda
- Gladstone Institute for Data Science and Biotechnology, J. David Gladstone Institutes, San Francisco, CA, USA
- Department of Biochemistry and Biophysics, University of California San Francisco, San Francisco, CA, USA
| | - Ke Wu
- Gladstone Institute for Data Science and Biotechnology, J. David Gladstone Institutes, San Francisco, CA, USA
| | - Un Seng Chio
- Department of Biochemistry and Biophysics, University of California San Francisco, San Francisco, CA, USA
| | - Ziling Zhou
- Department of Biochemistry and Biophysics, University of California San Francisco, San Francisco, CA, USA
| | - Hani Goodarzi
- Department of Biochemistry and Biophysics, University of California San Francisco, San Francisco, CA, USA
- Bakar Computational Health Sciences Institute, San Francisco, CA, USA
| | - Geeta J Narlikar
- Department of Biochemistry and Biophysics, University of California San Francisco, San Francisco, CA, USA.
| | - Vijay Ramani
- Gladstone Institute for Data Science and Biotechnology, J. David Gladstone Institutes, San Francisco, CA, USA.
- Department of Biochemistry and Biophysics, University of California San Francisco, San Francisco, CA, USA.
- Bakar Computational Health Sciences Institute, San Francisco, CA, USA.
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15
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Woodhouse M, Brooks Crickard J. DNA curtains to visualize chromatin interactions. Methods 2023; 217:36-42. [PMID: 37437647 PMCID: PMC10529070 DOI: 10.1016/j.ymeth.2023.07.001] [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: 01/11/2023] [Revised: 05/26/2023] [Accepted: 07/09/2023] [Indexed: 07/14/2023] Open
Abstract
Recent advances in single molecule imaging have allowed the evolution of biochemical techniques that directly visualize protein-DNA interactions in real-time. These techniques rely on diffraction limited total internal reflection microscopy (TIRFM), and have significantly improved our understanding of RNA transcription, DNA replication, homologous recombination, and general DNA repair in the context of chromatin. Here we described a general single molecule TIRFM technique called DNA curtains to directly visualize how enzymes function on chromatinized DNA. The goal of this manuscript is to introduce the reader to methods to express and reconstitute nucleosomes on long stretches of DNA, and to directly visualize this process using DNA curtains with TIRFM.
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Affiliation(s)
- Mitchell Woodhouse
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA
| | - J Brooks Crickard
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA.
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16
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Abstract
Nearly three-fourths of all eukaryotic DNA is occupied by nucleosomes, protein-DNA complexes comprising octameric histone core proteins and ∼150 base pairs of DNA. In addition to acting as a DNA compaction vehicle, the dynamics of nucleosomes regulate the DNA site accessibility for the nonhistone proteins, thereby controlling regulatory processes involved in determining the cell identity and cell fate. Here, we propose an analytical framework to analyze the role of nucleosome dynamics on the target search process of transcription factors through a simple discrete-state stochastic description of the search process. By considering the experimentally determined kinetic rates associated with protein and nucleosome dynamics as the only inputs, we estimate the target search time of a protein via first-passage probability calculations separately during nucleosome breathing and sliding dynamics. Although both the nucleosome dynamics permit transient access to the DNA sites that are otherwise occluded by the histone proteins, our result suggests substantial differences between the protein search mechanism on a nucleosome performing breathing and sliding dynamics. Furthermore, we identify the molecular factors that influence the search efficiency and demonstrate how these factors together portray a highly dynamic landscape of gene regulation. Our analytical results are validated using extensive Monte Carlo simulations.
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Affiliation(s)
- Sujeet Kumar Mishra
- School of Computational and Integrative Sciences, Jawaharlal Nehru University, New Delhi 110067, India
| | - Arnab Bhattacherjee
- School of Computational and Integrative Sciences, Jawaharlal Nehru University, New Delhi 110067, India
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17
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Pan Y, Hu C, Hou LJ, Chen YL, Shi J, Liu JC, Zhou JQ. Swc4 protects nucleosome-free rDNA, tDNA and telomere loci to inhibit genome instability. DNA Repair (Amst) 2023; 127:103512. [PMID: 37230009 DOI: 10.1016/j.dnarep.2023.103512] [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: 11/22/2022] [Revised: 04/17/2023] [Accepted: 05/11/2023] [Indexed: 05/27/2023]
Abstract
In the baker's yeast Saccharomyces cerevisiae, NuA4 and SWR1-C, two multisubunit complexes, are involved in histone acetylation and chromatin remodeling, respectively. Eaf1 is the assembly platform subunit of NuA4, Swr1 is the assembly platform and catalytic subunit of SWR1-C, while Swc4, Yaf9, Arp4 and Act1 form a functional module, and is present in both NuA4 and SWR1 complexes. ACT1 and ARP4 are essential for cell survival. Deletion of SWC4, but not YAF9, EAF1 or SWR1 results in a severe growth defect, but the underlying mechanism remains largely unknown. Here, we show that swc4Δ, but not yaf9Δ, eaf1Δ, or swr1Δ cells display defects in DNA ploidy and chromosome segregation, suggesting that the defects observed in swc4Δ cells are independent of NuA4 or SWR1-C integrity. Swc4 is enriched in the nucleosome-free regions (NFRs) of the genome, including characteristic regions of RDN5s, tDNAs and telomeres, independently of Yaf9, Eaf1 or Swr1. In particular, rDNA, tDNA and telomere loci are more unstable and prone to recombination in the swc4Δ cells than in wild-type cells. Taken together, we conclude that the chromatin associated Swc4 protects nucleosome-free chromatin of rDNA, tDNA and telomere loci to ensure genome integrity.
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Affiliation(s)
- Yue Pan
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China; The State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Can Hu
- The State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Lin-Jun Hou
- The State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Yu-Long Chen
- The State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Jiantao Shi
- The State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Jia-Cheng Liu
- The State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai 200031, China.
| | - Jin-Qiu Zhou
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China; The State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai 200031, China; Key Laboratory of Systems Health Science of Zhejiang Province, School of Life Science, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou 310024, China.
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18
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Bondra ER, Rine J. Context dependent function of the transcriptional regulator Rap1 in gene silencing and activation in Saccharomyces cerevisiae. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.08.539937. [PMID: 37214837 PMCID: PMC10197613 DOI: 10.1101/2023.05.08.539937] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
In Saccharomyces cerevisiae, heterochromatin is formed through interactions between site-specific DNA-binding factors, including the transcriptional activator Rap1, and Sir proteins. Despite a vast understanding of the establishment and maintenance of Sir-silenced chromatin, the mechanism of gene silencing by Sir proteins has remained a mystery. Utilizing high resolution chromatin immunoprecipitation, we found that Rap1, the native activator of the bi-directional HML α promoter, bound its recognition sequence in silenced chromatin and its binding was enhanced by the presence of Sir proteins. In contrast to prior results, various components of transcription machinery were not able to access HML α in the silenced state. These findings disproved the long-standing model of indiscriminate steric occlusion by Sir proteins and led to investigation of the transcriptional activator Rap1 in Sir-silenced chromatin. Using a highly sensitive assay that monitors loss-of-silencing events, we identified a novel role for promoter-bound Rap1 in the maintenance of silent chromatin through interactions with the Sir complex. We also found that promoter-bound Rap1 activated HML α when in an expressed state, and aided in the transition from transcription initiation to elongation. Highlighting the importance of epigenetic context in transcription factor function, these results point toward a model in which the duality of Rap1 function was mediated by local chromatin environment rather than binding-site availability. Significance Statement The coarse partitioning of the genome into regions of active euchromatin and repressed heterochromatin is an important, and conserved, level gene expression regulation in eukaryotes. Repressor Activator Protein (Rap1) is a transcription factor that promotes the activation of genes when recruited to promoters, and aids in the establishment of heterochromatin through interactions with silencer elements. Here, we investigate the role of Rap1 when bound to a promoter in silent chromatin and dissect the context-specific epigenetic cues that regulate the dual properties of this transcription factor. Together, our data highlight the importance of protein-protein interactions and local chromatin state on transcription factor function.
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Affiliation(s)
- Eliana R Bondra
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, United States
| | - Jasper Rine
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, United States
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19
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Brouwer I, Kerklingh E, van Leeuwen F, Lenstra TL. Dynamic epistasis analysis reveals how chromatin remodeling regulates transcriptional bursting. Nat Struct Mol Biol 2023; 30:692-702. [PMID: 37127821 DOI: 10.1038/s41594-023-00981-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2022] [Accepted: 03/30/2023] [Indexed: 05/03/2023]
Abstract
Transcriptional bursting has been linked to the stochastic positioning of nucleosomes. However, how bursting is regulated by the remodeling of promoter nucleosomes is unknown. Here, we use single-molecule live-cell imaging of GAL10 transcription in Saccharomyces cerevisiae to measure how bursting changes upon combined perturbations of chromatin remodelers, the transcription factor Gal4 and preinitiation complex components. Using dynamic epistasis analysis, we reveal how the remodeling of different nucleosomes regulates transcriptional bursting parameters. At the nucleosome covering the Gal4 binding sites, RSC and Gal4 binding synergistically facilitate each burst. Conversely, nucleosome remodeling at the TATA box controls only the first burst upon galactose induction. At canonical TATA boxes, the nucleosomes are displaced by TBP binding to allow for transcription activation even in the absence of remodelers. Overall, our results reveal how promoter nucleosome remodeling together with Gal4 and preinitiation complex binding regulates transcriptional bursting.
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Affiliation(s)
- Ineke Brouwer
- Division of Gene Regulation, the Netherlands Cancer Institute, Oncode Institute, Amsterdam, the Netherlands
| | - Emma Kerklingh
- Division of Gene Regulation, the Netherlands Cancer Institute, Oncode Institute, Amsterdam, the Netherlands
| | - Fred van Leeuwen
- Division of Gene Regulation, the Netherlands Cancer Institute, Amsterdam, the Netherlands
- Department of Medical Biology, Amsterdam UMC, University of Amsterdam, Amsterdam, the Netherlands
| | - Tineke L Lenstra
- Division of Gene Regulation, the Netherlands Cancer Institute, Oncode Institute, Amsterdam, the Netherlands.
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20
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Schuhmacher M, Hoogendoorn S. Out With a Bang: Celebrating Global Chemical Biology. ACS Chem Biol 2023; 18:218-222. [PMID: 36648442 DOI: 10.1021/acschembio.2c00905] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
On November 8-10, 2022, 163 participants from all over the world gathered at the Campus Biotech in Geneva, Switzerland to share in the latest research in chemical biology. The fourth international symposium of the Swiss National Centres of Competence in Research (NCCR) Chemical Biology coincided with the end of this successful research consortium, and as such this event marked a celebration of the past 12 years of chemical biology research in Switzerland. The inspiring talks delivered by the 15 well-known scientists, balanced in gender, expertise, and geographic location, as well as the numerous poster presentations by junior scientists showcased the breadth of global chemical biology and the bright future ahead.
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Affiliation(s)
- Milena Schuhmacher
- Swiss Federal Institute of Technology Lausanne (EPFL), CH-1015, Lausanne, Switzerland
| | - Sascha Hoogendoorn
- Department of Organic Chemistry, Faculty of Sciences, University of Geneva, 1205 Geneva, Switzerland
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21
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Contribution of smFRET to Chromatin Research. BIOPHYSICA 2023. [DOI: 10.3390/biophysica3010007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
Abstract
Chromatins are structural components of chromosomes and consist of DNA and histone proteins. The structure, dynamics, and function of chromatins are important in regulating genetic processes. Several different experimental and theoretical tools have been employed to understand chromatins better. In this review, we will focus on the literatures engrossed in understanding of chromatins using single-molecule Förster resonance energy transfer (smFRET). smFRET is a single-molecule fluorescence microscopic technique that can furnish information regarding the distance between two points in space. This has been utilized to efficiently unveil the structural details of chromatins.
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22
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Zhang X, Li J, Wang X, Jie Y, Sun C, Zheng J, Li J, Yang N, Chen S. ATAC-seq and RNA-seq analysis unravel the mechanism of sex differentiation and infertility in sex reversal chicken. Epigenetics Chromatin 2023; 16:2. [PMID: 36617567 PMCID: PMC9827654 DOI: 10.1186/s13072-022-00476-1] [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] [Received: 09/02/2022] [Accepted: 12/20/2022] [Indexed: 01/10/2023] Open
Abstract
BACKGROUND Sex determination and differentiation are complex and delicate processes. In female chickens, the process of sex differentiation is sensitive and prone to be affected by the administration of aromatase inhibitors, which result in chicken sex reversal and infertility. However, the molecular mechanisms underlying sex differentiation and infertility in chicken sex reversal remain unclear. Therefore, we established a sex-reversed chicken flock by injecting an aromatase inhibitor, fadrozole, and constructed relatively high-resolution profiles of the gene expression and chromatin accessibility of embryonic gonads. RESULTS We revealed that fadrozole affected the transcriptional activities of several genes, such as DMRT1, SOX9, FOXL2, and CYP19A1, related to sex determination and differentiation, and the expression of a set of gonadal development-related genes, such as FGFR3 and TOX3, by regulating nearby open chromatin regions in sex-reversed chicken embryos. After sexual maturity, the sex-reversed chickens were confirmed to be infertile, and the possible causes of this infertility were further investigated. We found that the structure of the gonads and sperm were greatly deformed, and we identified several promising genes related to spermatogenesis and infertility, such as SPEF2, DNAI1, and TACR3, through RNA-seq. CONCLUSIONS This study provides clear insights into the exploration of potential molecular basis underlying sex differentiation and infertility in sex-reversed chickens and lays a foundation for further research into the sex development of birds.
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Affiliation(s)
- Xiuan Zhang
- grid.22935.3f0000 0004 0530 8290National Engineering Laboratory for Animal Breeding and Key Laboratory of Animal Genetics, Breeding and Reproduction, Ministry of Agriculture and Rural Affairs, China Agricultural University, Beijing, China
| | - Jianbo Li
- grid.22935.3f0000 0004 0530 8290National Engineering Laboratory for Animal Breeding and Key Laboratory of Animal Genetics, Breeding and Reproduction, Ministry of Agriculture and Rural Affairs, China Agricultural University, Beijing, China
| | - Xiqiong Wang
- grid.22935.3f0000 0004 0530 8290National Engineering Laboratory for Animal Breeding and Key Laboratory of Animal Genetics, Breeding and Reproduction, Ministry of Agriculture and Rural Affairs, China Agricultural University, Beijing, China
| | - Yuchen Jie
- grid.22935.3f0000 0004 0530 8290National Engineering Laboratory for Animal Breeding and Key Laboratory of Animal Genetics, Breeding and Reproduction, Ministry of Agriculture and Rural Affairs, China Agricultural University, Beijing, China
| | - Congjiao Sun
- grid.22935.3f0000 0004 0530 8290National Engineering Laboratory for Animal Breeding and Key Laboratory of Animal Genetics, Breeding and Reproduction, Ministry of Agriculture and Rural Affairs, China Agricultural University, Beijing, China
| | - Jiangxia Zheng
- grid.22935.3f0000 0004 0530 8290National Engineering Laboratory for Animal Breeding and Key Laboratory of Animal Genetics, Breeding and Reproduction, Ministry of Agriculture and Rural Affairs, China Agricultural University, Beijing, China
| | - Junying Li
- grid.22935.3f0000 0004 0530 8290National Engineering Laboratory for Animal Breeding and Key Laboratory of Animal Genetics, Breeding and Reproduction, Ministry of Agriculture and Rural Affairs, China Agricultural University, Beijing, China
| | - Ning Yang
- grid.22935.3f0000 0004 0530 8290National Engineering Laboratory for Animal Breeding and Key Laboratory of Animal Genetics, Breeding and Reproduction, Ministry of Agriculture and Rural Affairs, China Agricultural University, Beijing, China
| | - Sirui Chen
- grid.22935.3f0000 0004 0530 8290National Engineering Laboratory for Animal Breeding and Key Laboratory of Animal Genetics, Breeding and Reproduction, Ministry of Agriculture and Rural Affairs, China Agricultural University, Beijing, China
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23
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Kumar Mishra S, Bhattacherjee A. Understanding the Target Search by Multiple Transcription Factors on Nucleosomal DNA. Chemphyschem 2023; 24:e202200644. [PMID: 36602094 DOI: 10.1002/cphc.202200644] [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: 08/26/2022] [Revised: 01/04/2023] [Accepted: 01/05/2023] [Indexed: 01/06/2023]
Abstract
The association of multiple Transcription Factors (TFs) in the cis-regulatory region is imperative for developmental changes in eukaryotes. The underlying process is exceedingly complex, and it is not at all clear what orchestrates the overall search process by multiple TFs. In this study, by developing a theoretical model based on a discrete-state stochastic approach, we investigated the target search mechanism of multiple TFs on nucleosomal DNA. Experimental kinetic rate constants of different TFs are taken as input to estimate the Mean-First-Passage time to recognize the binding motifs by two TFs on a dynamic nucleosome model. The theory systematically analyzes when the TFs search their binding motifs hierarchically and when simultaneously by proceeding via the formation of a protein-protein complex. Our results, validated by extensive Monte Carlo simulations, elucidate the molecular basis of the complex target search phenomenon of multiple TFs on nucleosomal DNA.
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Affiliation(s)
- Sujeet Kumar Mishra
- School of Computational and Integrative Sciences, Jawaharlal Nehru University, New Delhi, India
| | - Arnab Bhattacherjee
- School of Computational and Integrative Sciences, Jawaharlal Nehru University, New Delhi, India
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24
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Gu Y, Zhou Y, Ju S, Liu X, Zhang Z, Guo J, Gao J, Zang J, Sun H, Chen Q, Wang J, Xu J, Xu Y, Chen Y, Guo Y, Dai J, Ma H, Wang C, Jin G, Li C, Xia Y, Shen H, Yang Y, Guo X, Hu Z. Multi-omics profiling visualizes dynamics of cardiac development and functions. Cell Rep 2022; 41:111891. [PMID: 36577384 DOI: 10.1016/j.celrep.2022.111891] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Revised: 09/14/2022] [Accepted: 12/05/2022] [Indexed: 12/29/2022] Open
Abstract
Cardiogenesis is a tightly regulated dynamic process through a continuum of differentiation and proliferation events. Key factors and pathways governing this process remain incompletely understood. Here, we investigate mice hearts from embryonic day 10.5 to postnatal week 8 and dissect developmental changes in phosphoproteome-, proteome-, metabolome-, and transcriptome-encompassing cardiogenesis and cardiac maturation. We identify mitogen-activated protein kinases as core kinases involved in transcriptional regulation by mediating the phosphorylation of chromatin remodeling proteins during early cardiogenesis. We construct the reciprocal regulatory network of transcription factors (TFs) and identify a series of TFs controlling early cardiogenesis involved in cycling-dependent proliferation. After birth, we identify cardiac resident macrophages with high arachidonic acid metabolism activities likely involved in the clearance of injured apoptotic cardiomyocytes. Together, our comprehensive multi-omics data offer a panoramic view of cardiac development and maturation that provides a resource for further in-depth functional exploration.
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Affiliation(s)
- Yayun Gu
- State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing, Jiangsu 211100, China; School of Public Health, Center for Global Health, Nanjing Medical University, Nanjing, Jiangsu 211100, China
| | - Yan Zhou
- State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing, Jiangsu 211100, China; School of Public Health, Center for Global Health, Nanjing Medical University, Nanjing, Jiangsu 211100, China
| | - Sihan Ju
- State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing, Jiangsu 211100, China; Department of Neurosurgery, Huashan Hospital, Fudan University, Shanghai 200040, China
| | - Xiaofei Liu
- State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing, Jiangsu 211100, China
| | - Zicheng Zhang
- State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing, Jiangsu 211100, China
| | - Jia Guo
- State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing, Jiangsu 211100, China
| | - Jimiao Gao
- State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing, Jiangsu 211100, China; School of Public Health, Center for Global Health, Nanjing Medical University, Nanjing, Jiangsu 211100, China
| | - Jie Zang
- School of Public Health, Center for Global Health, Nanjing Medical University, Nanjing, Jiangsu 211100, China
| | - Hao Sun
- State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing, Jiangsu 211100, China
| | - Qi Chen
- State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing, Jiangsu 211100, China; School of Public Health, Center for Global Health, Nanjing Medical University, Nanjing, Jiangsu 211100, China
| | - Jinghan Wang
- State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing, Jiangsu 211100, China; School of Public Health, Center for Global Health, Nanjing Medical University, Nanjing, Jiangsu 211100, China
| | - Jiani Xu
- School of Public Health, Center for Global Health, Nanjing Medical University, Nanjing, Jiangsu 211100, China
| | - Yiqun Xu
- State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing, Jiangsu 211100, China; School of Public Health, Center for Global Health, Nanjing Medical University, Nanjing, Jiangsu 211100, China
| | - Yingjia Chen
- State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing, Jiangsu 211100, China
| | - Yueshuai Guo
- State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing, Jiangsu 211100, China
| | - Juncheng Dai
- State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing, Jiangsu 211100, China; School of Public Health, Center for Global Health, Nanjing Medical University, Nanjing, Jiangsu 211100, China
| | - Hongxia Ma
- State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing, Jiangsu 211100, China; School of Public Health, Center for Global Health, Nanjing Medical University, Nanjing, Jiangsu 211100, China
| | - Cheng Wang
- State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing, Jiangsu 211100, China
| | - Guangfu Jin
- State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing, Jiangsu 211100, China; School of Public Health, Center for Global Health, Nanjing Medical University, Nanjing, Jiangsu 211100, China
| | - Chaojun Li
- State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing, Jiangsu 211100, China
| | - Yankai Xia
- State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing, Jiangsu 211100, China; School of Public Health, Center for Global Health, Nanjing Medical University, Nanjing, Jiangsu 211100, China
| | - Hongbing Shen
- State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing, Jiangsu 211100, China; School of Public Health, Center for Global Health, Nanjing Medical University, Nanjing, Jiangsu 211100, China
| | - Yang Yang
- State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing, Jiangsu 211100, China
| | - Xuejiang Guo
- State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing, Jiangsu 211100, China
| | - Zhibin Hu
- State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing, Jiangsu 211100, China; School of Public Health, Center for Global Health, Nanjing Medical University, Nanjing, Jiangsu 211100, China.
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25
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Schüller A, Studt-Reinhold L, Strauss J. How to Completely Squeeze a Fungus-Advanced Genome Mining Tools for Novel Bioactive Substances. Pharmaceutics 2022; 14:1837. [PMID: 36145585 PMCID: PMC9505985 DOI: 10.3390/pharmaceutics14091837] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Revised: 08/23/2022] [Accepted: 08/29/2022] [Indexed: 11/17/2022] Open
Abstract
Fungal species have the capability of producing an overwhelming diversity of bioactive substances that can have beneficial but also detrimental effects on human health. These so-called secondary metabolites naturally serve as antimicrobial "weapon systems", signaling molecules or developmental effectors for fungi and hence are produced only under very specific environmental conditions or stages in their life cycle. However, as these complex conditions are difficult or even impossible to mimic in laboratory settings, only a small fraction of the true chemical diversity of fungi is known so far. This also implies that a large space for potentially new pharmaceuticals remains unexplored. We here present an overview on current developments in advanced methods that can be used to explore this chemical space. We focus on genetic and genomic methods, how to detect genes that harbor the blueprints for the production of these compounds (i.e., biosynthetic gene clusters, BGCs), and ways to activate these silent chromosomal regions. We provide an in-depth view of the chromatin-level regulation of BGCs and of the potential to use the CRISPR/Cas technology as an activation tool.
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Affiliation(s)
| | | | - Joseph Strauss
- Institute of Microbial Genetics, Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences Vienna, A-3430 Tulln/Donau, Austria
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26
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Blomberg A. Yeast osmoregulation - glycerol still in pole position. FEMS Yeast Res 2022; 22:6655991. [PMID: 35927716 PMCID: PMC9428294 DOI: 10.1093/femsyr/foac035] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 06/29/2022] [Accepted: 08/02/2022] [Indexed: 11/14/2022] Open
Abstract
In response to osmotic dehydration cells sense, signal, alter gene expression, and metabolically counterbalance osmotic differences. The main compatible solute/osmolyte that accumulates in yeast cells is glycerol, which is produced from the glycolytic intermediate dihydroxyacetone phosphate. This review covers recent advancements in understanding mechanisms involved in sensing, signaling, cell-cycle delays, transcriptional responses as well as post-translational modifications on key proteins in osmoregulation. The protein kinase Hog1 is a key-player in many of these events, however, there is also a growing body of evidence for important Hog1-independent mechanisms playing vital roles. Several missing links in our understanding of osmoregulation will be discussed and future avenues for research proposed. The review highlights that this rather simple experimental system—salt/sorbitol and yeast—has developed into an enormously potent model system unravelling important fundamental aspects in biology.
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Affiliation(s)
- Anders Blomberg
- Dept. of Chemistry and Molecular Biology, University of Gothenburg, Sweden
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27
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Luzete-Monteiro E, Zaret KS. Structures and consequences of pioneer factor binding to nucleosomes. Curr Opin Struct Biol 2022; 75:102425. [PMID: 35863165 PMCID: PMC9976633 DOI: 10.1016/j.sbi.2022.102425] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 06/10/2022] [Accepted: 06/16/2022] [Indexed: 11/15/2022]
Abstract
Pioneer transcription factors are able to bind a partially exposed motif on the surface of a nucleosome, enabling the proteins to target sites in silent regions of chromatin that have been compacted by linker histone. The targeting of nucleosomal DNA by pioneer factors has been observed in vitro and in vivo, where binding can promote local nucleosome exposure that allows other transcription factors, nucleosome remodelers, and histone modifiers to engage the chromatin and elicit gene activation or further repression. Pioneer factors thereby establish new gene expression programs during cell fate changes that occur during embryonic development, regeneration, and cancer. Here, we review recent biophysical studies that reveal the structural features and strategies used by pioneer factors to accomplish nucleosome binding and the consequential changes to nucleosomes that can lead to DNA accessibility.
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Affiliation(s)
- Edgar Luzete-Monteiro
- Institute for Regenerative Medicine, Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, 9-131 SCTR, 3400 Civic Center Blvd., Philadelphia, PA 19104-5157, USA.,Department of Biology, School of Arts and Sciences, University of Pennsylvania, 433 S University Ave, Philadelphia, PA 19104-4544
| | - Kenneth S. Zaret
- Institute for Regenerative Medicine, Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, 9-131 SCTR, 3400 Civic Center Blvd., Philadelphia, PA 19104-5157, USA
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28
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Hajheidari M, Huang SSC. Elucidating the biology of transcription factor-DNA interaction for accurate identification of cis-regulatory elements. CURRENT OPINION IN PLANT BIOLOGY 2022; 68:102232. [PMID: 35679803 PMCID: PMC10103634 DOI: 10.1016/j.pbi.2022.102232] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Revised: 04/26/2022] [Accepted: 05/02/2022] [Indexed: 05/03/2023]
Abstract
Transcription factors (TFs) play a critical role in determining cell fate decisions by integrating developmental and environmental signals through binding to specific cis-regulatory modules and regulating spatio-temporal specificity of gene expression patterns. Precise identification of functional TF binding sites in time and space not only will revolutionize our understanding of regulatory networks governing cell fate decisions but is also instrumental to uncover how genetic variations cause morphological diversity or disease. In this review, we discuss recent advances in mapping TF binding sites and characterizing the various parameters underlying the complexity of binding site recognition by TFs.
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Affiliation(s)
- Mohsen Hajheidari
- Center for Genomics and Systems Biology, Department of Biology, New York University, 12 Waverly Pl, New York, NY 10003, USA
| | - Shao-Shan Carol Huang
- Center for Genomics and Systems Biology, Department of Biology, New York University, 12 Waverly Pl, New York, NY 10003, USA.
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29
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Isbel L, Grand RS, Schübeler D. Generating specificity in genome regulation through transcription factor sensitivity to chromatin. Nat Rev Genet 2022; 23:728-740. [PMID: 35831531 DOI: 10.1038/s41576-022-00512-6] [Citation(s) in RCA: 33] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/30/2022] [Indexed: 12/11/2022]
Abstract
Cell type-specific gene expression relies on transcription factors (TFs) binding DNA sequence motifs embedded in chromatin. Understanding how motifs are accessed in chromatin is crucial to comprehend differential transcriptional responses and the phenotypic impact of sequence variation. Chromatin obstacles to TF binding range from DNA methylation to restriction of DNA access by nucleosomes depending on their position, composition and modification. In vivo and in vitro approaches now enable the study of TF binding in chromatin at unprecedented resolution. Emerging insights suggest that TFs vary in their ability to navigate chromatin states. However, it remains challenging to link binding and transcriptional outcomes to molecular characteristics of TFs or the local chromatin substrate. Here, we discuss our current understanding of how TFs access DNA in chromatin and novel techniques and directions towards a better understanding of this critical step in genome regulation.
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Affiliation(s)
- Luke Isbel
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland.,School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, New South Wales, Australia
| | - Ralph S Grand
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland.,Zentrum für Molekulare Biologie der Universität Heidelberg, Heidelberg, Germany
| | - Dirk Schübeler
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland. .,Faculty of Sciences, University of Basel, Basel, Switzerland.
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30
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Shi X, Zhai Z, Chen Y, Li J, Nordenskiöld L. Recent Advances in Investigating Functional Dynamics of Chromatin. Front Genet 2022; 13:870640. [PMID: 35450211 PMCID: PMC9017861 DOI: 10.3389/fgene.2022.870640] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Accepted: 03/11/2022] [Indexed: 11/26/2022] Open
Abstract
Dynamics spanning the picosecond-minute time domain and the atomic-subcellular spatial window have been observed for chromatin in vitro and in vivo. The condensed organization of chromatin in eukaryotic cells prevents regulatory factors from accessing genomic DNA, which requires dynamic stabilization and destabilization of structure to initiate downstream DNA activities. Those processes are achieved through altering conformational and dynamic properties of nucleosomes and nucleosome–protein complexes, of which delineating the atomistic pictures is essential to understand the mechanisms of chromatin regulation. In this review, we summarize recent progress in determining chromatin dynamics and their modulations by a number of factors including post-translational modifications (PTMs), incorporation of histone variants, and binding of effector proteins. We focus on experimental observations obtained using high-resolution techniques, primarily including nuclear magnetic resonance (NMR) spectroscopy, Förster (or fluorescence) resonance energy transfer (FRET) microscopy, and molecular dynamics (MD) simulations, and discuss the elucidated dynamics in the context of functional response and relevance.
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Affiliation(s)
- Xiangyan Shi
- Department of Biology, Shenzhen MSU-BIT University, Shenzhen, China
| | - Ziwei Zhai
- Department of Biology, Shenzhen MSU-BIT University, Shenzhen, China
| | - Yinglu Chen
- Department of Biology, Shenzhen MSU-BIT University, Shenzhen, China
| | - Jindi Li
- Department of Biology, Shenzhen MSU-BIT University, Shenzhen, China
| | - Lars Nordenskiöld
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
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31
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de Jonge WJ, Patel HP, Meeussen JVW, Lenstra TL. Following the tracks: how transcription factor binding dynamics control transcription. Biophys J 2022; 121:1583-1592. [PMID: 35337845 PMCID: PMC9117886 DOI: 10.1016/j.bpj.2022.03.026] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 02/28/2022] [Accepted: 03/21/2022] [Indexed: 11/29/2022] Open
Abstract
Transcription, the process of copying genetic information from DNA to messenger RNA, is regulated by sequence-specific DNA binding proteins known as transcription factors (TFs). Recent advances in single-molecule tracking (SMT) technologies have enabled visualization of individual TF molecules as they diffuse and interact with the DNA in the context of living cells. These SMT studies have uncovered multiple populations of DNA binding events characterized by their distinctive DNA residence times. In this perspective, we review recent insights into how these residence times relate to specific and non-specific DNA binding, as well as the contribution of TF domains on the DNA binding dynamics. We discuss different models that aim to link transient DNA binding by TFs to bursts of transcription and present an outlook for how future advances in microscopy development may broaden our understanding of the dynamics of the molecular steps that underlie transcription activation.
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Affiliation(s)
- Wim J de Jonge
- Division of Gene Regulation, The Netherlands Cancer Institute, Oncode Institute, 1066CX Amsterdam, the Netherlands
| | - Heta P Patel
- Division of Gene Regulation, The Netherlands Cancer Institute, Oncode Institute, 1066CX Amsterdam, the Netherlands
| | - Joseph V W Meeussen
- Division of Gene Regulation, The Netherlands Cancer Institute, Oncode Institute, 1066CX Amsterdam, the Netherlands
| | - Tineke L Lenstra
- Division of Gene Regulation, The Netherlands Cancer Institute, Oncode Institute, 1066CX Amsterdam, the Netherlands.
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32
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Zhang H, Romero H, Schmidt A, Gagova K, Qin W, Bertulat B, Lehmkuhl A, Milden M, Eck M, Meckel T, Leonhardt H, Cardoso MC. MeCP2-induced heterochromatin organization is driven by oligomerization-based liquid–liquid phase separation and restricted by DNA methylation. Nucleus 2022; 13:1-34. [PMID: 35156529 PMCID: PMC8855868 DOI: 10.1080/19491034.2021.2024691] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Affiliation(s)
- Hui Zhang
- Department of Biology, Technical University of Darmstadt, Darmstadt, Germany
| | - Hector Romero
- Department of Biology, Technical University of Darmstadt, Darmstadt, Germany
| | - Annika Schmidt
- Department of Biology, Technical University of Darmstadt, Darmstadt, Germany
| | - Katalina Gagova
- Department of Biology, Technical University of Darmstadt, Darmstadt, Germany
| | - Weihua Qin
- Faculty of Biology, Ludwig Maximilians University Munich, Munich, Germany
| | - Bianca Bertulat
- Department of Biology, Technical University of Darmstadt, Darmstadt, Germany
| | - Anne Lehmkuhl
- Department of Biology, Technical University of Darmstadt, Darmstadt, Germany
| | - Manuela Milden
- Department of Biology, Technical University of Darmstadt, Darmstadt, Germany
| | - Malte Eck
- Department of Biology, Technical University of Darmstadt, Darmstadt, Germany
| | - Tobias Meckel
- Department of Chemistry, Technical University of Darmstadt, Darmstadt, Germany
| | - Heinrich Leonhardt
- Faculty of Biology, Ludwig Maximilians University Munich, Munich, Germany
| | - M. Cristina Cardoso
- Department of Biology, Technical University of Darmstadt, Darmstadt, Germany
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33
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Mondal A, Mishra SK, Bhattacherjee A. Kinetic origin of nucleosome invasion by pioneer transcription factors. Biophys J 2021; 120:5219-5230. [PMID: 34757077 DOI: 10.1016/j.bpj.2021.10.039] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2020] [Revised: 05/14/2021] [Accepted: 10/27/2021] [Indexed: 01/25/2023] Open
Abstract
Recently, a cryo-electron microscopy study has captured different stages of nucleosome breathing dynamics that show partial unwrapping of DNA from histone core to permit transient access to the DNA sites by transcription factors. In practice, however, only a subset of transcription factors named pioneer factors can invade nucleosomes and bind to specific DNA sites to trigger essential DNA metabolic processes. We propose a discrete-state stochastic model that considers the interplay of nucleosome breathing and protein dynamics explicitly and estimate the mean time to search the target DNA sites. It is found that the molecular principle governing the search process on nucleosome is very different compared to that on naked DNA. The pioneer factors minimize their search times on nucleosomal DNA by compensating their nucleosome association rates by dissociation rates. A fine balance between the two presents a tradeoff between their nuclear mobility and error associated with the search process.
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Affiliation(s)
- Anupam Mondal
- School of Computational and Integrative Sciences, Jawaharlal Nehru University, New Delhi, India
| | - Sujeet Kumar Mishra
- School of Computational and Integrative Sciences, Jawaharlal Nehru University, New Delhi, India; Institute for Theoretical Physics, Heidelberg University, Heidelberg, Germany
| | - Arnab Bhattacherjee
- School of Computational and Integrative Sciences, Jawaharlal Nehru University, New Delhi, India.
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34
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Khamis H, Rudnizky S, Melamed P, Kaplan A. Single molecule characterization of the binding kinetics of a transcription factor and its modulation by DNA sequence and methylation. Nucleic Acids Res 2021; 49:10975-10987. [PMID: 34606618 PMCID: PMC8565314 DOI: 10.1093/nar/gkab843] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Revised: 08/04/2021] [Accepted: 09/24/2021] [Indexed: 12/14/2022] Open
Abstract
The interaction of transcription factors with their response elements in DNA is emerging as a highly complex process, whose characterization requires measuring the full distribution of binding and dissociation times in a well-controlled assay. Here, we present a single-molecule assay that exploits the thermal fluctuations of a DNA hairpin to detect the association and dissociation of individual, unlabeled transcription factors. We demonstrate this new approach by following the binding of Egr1 to its consensus motif and the three binding sites found in the promoter of the Lhb gene, and find that both association and dissociation are modulated by the 9 bp core motif and the sequences around it. In addition, CpG methylation modulates the dissociation kinetics in a sequence and position-dependent manner, which can both stabilize or destabilize the complex. Together, our findings show how variations in sequence and methylation patterns synergistically extend the spectrum of a protein's binding properties, and demonstrate how the proposed approach can provide new insights on the function of transcription factors.
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Affiliation(s)
- Hadeel Khamis
- Faculty of Biology, Technion – Israel Institute of Technology, Haifa 32000, Israel
- Faculty of Physics, Technion – Israel Institute of Technology, Haifa 32000, Israel
| | - Sergei Rudnizky
- Faculty of Biology, Technion – Israel Institute of Technology, Haifa 32000, Israel
| | - Philippa Melamed
- Faculty of Biology, Technion – Israel Institute of Technology, Haifa 32000, Israel
| | - Ariel Kaplan
- Faculty of Biology, Technion – Israel Institute of Technology, Haifa 32000, Israel
- Faculty of Biomedical Engineering, Technion – Israel Institute of Technology, Haifa 32000, Israel
- Russell Berrie Nanotechnology Institute, Technion – Israel Institute of Technology, Haifa 32000, Israel
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35
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Abstract
Transcription factors (TFs) are essential mediators of epigenetic regulation and modifiers of penetrance. Studies from the past decades have revealed a sub-class of TF that is capable of remodeling closed chromatin states through targeting nucleosomal motifs. This pioneer factor (PF) class of chromatin remodeler is ATP independent in its roles in epigenetic initiation, with nucleosome-motif recognition and association with repressive chromatin regions. Increasing evidence suggests that the fundamental properties of PFs can be coopted in human cancers. We explore the role of PFs in the larger context of tissue-specific epigenetic regulation. Moreover, we highlight an emerging class of chimeric PF derived from translocation partners in human disease and PFs associated with rare tumors. In the age of site-directed genome editing and targeted protein degradation, increasing our understanding of PFs will provide access to next-generation therapy for human disease driven from altered transcriptional circuitry.
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36
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Makasheva K, Bryan LC, Anders C, Panikulam S, Jinek M, Fierz B. Multiplexed Single-Molecule Experiments Reveal Nucleosome Invasion Dynamics of the Cas9 Genome Editor. J Am Chem Soc 2021; 143:16313-16319. [PMID: 34597515 PMCID: PMC8517959 DOI: 10.1021/jacs.1c06195] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Indexed: 12/29/2022]
Abstract
Single-molecule measurements provide detailed mechanistic insights into molecular processes, for example in genome regulation where DNA access is controlled by nucleosomes and the chromatin machinery. However, real-time single-molecule observations of nuclear factors acting on defined chromatin substrates are challenging to perform quantitatively and reproducibly. Here we present XSCAN (multiplexed single-molecule detection of chromatin association), a method to parallelize single-molecule experiments by simultaneous imaging of a nucleosome library, where each nucleosome type carries an identifiable DNA sequence within its nucleosomal DNA. Parallel experiments are subsequently spatially decoded, via the detection of specific binding of dye-labeled DNA probes. We use this method to reveal how the Cas9 nuclease overcomes the nucleosome barrier when invading chromatinized DNA as a function of PAM position.
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Affiliation(s)
- Kristina Makasheva
- Laboratory
of Biophysical Chemistry of Macromolecules, Institute of Chemical
Sciences and Engineering (ISIC), École
Polytechnique Fédérale de Lausanne (EPFL), Station 6, 1015 Lausanne, Switzerland
| | - Louise C. Bryan
- Laboratory
of Biophysical Chemistry of Macromolecules, Institute of Chemical
Sciences and Engineering (ISIC), École
Polytechnique Fédérale de Lausanne (EPFL), Station 6, 1015 Lausanne, Switzerland
| | - Carolin Anders
- Department
of Biochemistry, University of Zurich, Winterthurerstr. 190, 8057 Zurich, Switzerland
| | - Sherin Panikulam
- Department
of Biochemistry, University of Zurich, Winterthurerstr. 190, 8057 Zurich, Switzerland
| | - Martin Jinek
- Department
of Biochemistry, University of Zurich, Winterthurerstr. 190, 8057 Zurich, Switzerland
| | - Beat Fierz
- Laboratory
of Biophysical Chemistry of Macromolecules, Institute of Chemical
Sciences and Engineering (ISIC), École
Polytechnique Fédérale de Lausanne (EPFL), Station 6, 1015 Lausanne, Switzerland
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37
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Transcriptional control of ribosome biogenesis in yeast: links to growth and stress signals. Biochem Soc Trans 2021; 49:1589-1599. [PMID: 34240738 PMCID: PMC8421047 DOI: 10.1042/bst20201136] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Revised: 06/14/2021] [Accepted: 06/18/2021] [Indexed: 12/15/2022]
Abstract
Ribosome biogenesis requires prodigious transcriptional output in rapidly growing yeast cells and is highly regulated in response to both growth and stress signals. This minireview focuses on recent developments in our understanding of this regulatory process, with an emphasis on the 138 ribosomal protein genes (RPGs) themselves and a group of >200 ribosome biogenesis (RiBi) genes whose products contribute to assembly but are not part of the ribosome. Expression of most RPGs depends upon Rap1, a pioneer transcription factor (TF) required for the binding of a pair of RPG-specific TFs called Fhl1 and Ifh1. RPG expression is correlated with Ifh1 promoter binding, whereas Rap1 and Fhl1 remain promoter-associated upon stress-induced down regulation. A TF called Sfp1 has also been implicated in RPG regulation, though recent work reveals that its primary function is in activation of RiBi and other growth-related genes. Sfp1 plays an important regulatory role at a small number of RPGs where Rap1–Fhl1–Ifh1 action is subsidiary or non-existent. In addition, nearly half of all RPGs are bound by Hmo1, which either stabilizes or re-configures Fhl1–Ifh1 binding. Recent studies identified the proline rotamase Fpr1, known primarily for its role in rapamycin-mediated inhibition of the TORC1 kinase, as an additional TF at RPG promoters. Fpr1 also affects Fhl1–Ifh1 binding, either independently or in cooperation with Hmo1. Finally, a major recent development was the discovery of a protein homeostasis mechanism driven by unassembled ribosomal proteins, referred to as the Ribosome Assembly Stress Response (RASTR), that controls RPG transcription through the reversible condensation of Ifh1.
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38
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Mazzocca M, Fillot T, Loffreda A, Gnani D, Mazza D. The needle and the haystack: single molecule tracking to probe the transcription factor search in eukaryotes. Biochem Soc Trans 2021; 49:1121-1132. [PMID: 34003257 PMCID: PMC8286828 DOI: 10.1042/bst20200709] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Revised: 04/18/2021] [Accepted: 04/19/2021] [Indexed: 12/13/2022]
Abstract
Transcription factors (TFs) regulate transcription of their target genes by identifying and binding to regulatory regions of the genome among billions of potential non-specific decoy sites, a task that is often presented as a 'needle in the haystack' challenge. The TF search process is now well understood in bacteria, but its characterization in eukaryotes needs to account for the complex organization of the nuclear environment. Here we review how live-cell single molecule tracking is starting to shed light on the TF search mechanism in the eukaryotic cell and we outline the future challenges to tackle in order to understand how nuclear organization modulates the TF search process in physiological and pathological conditions.
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Affiliation(s)
- Matteo Mazzocca
- Experimental Imaging Center, IRCCS San Raffaele Scientific Institute, Milan 20132, Italy
| | - Tom Fillot
- Experimental Imaging Center, IRCCS San Raffaele Scientific Institute, Milan 20132, Italy
| | - Alessia Loffreda
- Experimental Imaging Center, IRCCS San Raffaele Scientific Institute, Milan 20132, Italy
| | - Daniela Gnani
- Experimental Imaging Center, IRCCS San Raffaele Scientific Institute, Milan 20132, Italy
| | - Davide Mazza
- Experimental Imaging Center, IRCCS San Raffaele Scientific Institute, Milan 20132, Italy
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39
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Michael AK, Thomä NH. Reading the chromatinized genome. Cell 2021; 184:3599-3611. [PMID: 34146479 DOI: 10.1016/j.cell.2021.05.029] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Revised: 05/11/2021] [Accepted: 05/19/2021] [Indexed: 02/07/2023]
Abstract
Eukaryotic DNA-binding proteins operate in the context of chromatin, where nucleosomes are the elementary building blocks. Nucleosomal DNA is wrapped around a histone core, thereby rendering a large fraction of the DNA surface inaccessible to DNA-binding proteins. Nevertheless, first responders in DNA repair and sequence-specific transcription factors bind DNA target sites obstructed by chromatin. While early studies examined protein binding to histone-free DNA, it is only now beginning to emerge how DNA sequences are interrogated on nucleosomes. These readout strategies range from the release of nucleosomal DNA from histones, to rotational/translation register shifts of the DNA motif, and nucleosome-specific DNA binding modes that differ from those observed on naked DNA. Since DNA motif engagement on nucleosomes strongly depends on position and orientation, we argue that motif location and nucleosome positioning co-determine protein access to DNA in transcription and DNA repair.
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Affiliation(s)
- Alicia K Michael
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, 4058 Basel, Switzerland
| | - Nicolas H Thomä
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, 4058 Basel, Switzerland.
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40
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Abstract
In eukaryotes, genomic DNA is packaged into chromatin in the nucleus. The accessibility of DNA is dependent on the chromatin structure and dynamics, which essentially control DNA-related processes, including transcription, DNA replication, and repair. All of the factors that affect the structure and dynamics of nucleosomes, the nucleosome-nucleosome interaction interfaces, and the binding of linker histones or other chromatin-binding proteins need to be considered to understand the organization and function of chromatin fibers. In this review, we provide a summary of recent progress on the structure of chromatin fibers in vitro and in the nucleus, highlight studies on the dynamic regulation of chromatin fibers, and discuss their related biological functions and abnormal organization in diseases.
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Affiliation(s)
- Ping Chen
- Department of Immunology, School of Basic Medical Sciences, Advanced Innovation Center for Human Brain Protection, Capital Medical University, Beijing 100069, China; .,National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China;
| | - Wei Li
- National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China; .,Key Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.,Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
| | - Guohong Li
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China; .,University of Chinese Academy of Sciences, Beijing 100049, China
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41
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Feng XA, Poyton MF, Ha T. Multicolor single-molecule FRET for DNA and RNA processes. Curr Opin Struct Biol 2021; 70:26-33. [PMID: 33894656 DOI: 10.1016/j.sbi.2021.03.005] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2021] [Accepted: 03/10/2021] [Indexed: 12/31/2022]
Abstract
Single-molecule fluorescence resonance energy transfer (smFRET) is a useful tool for observing the dynamics of protein-nucleic acid interactions. Although most smFRET measurements have used two fluorophores, multicolor smFRET measurements using more than two fluorophores offer more information about how protein-nucleic acid complexes dynamically move, assemble, and disassemble. Multicolor smFRET experiments include three or more fluorophores and at least one donor-acceptor pair. This review highlights how multicolor smFRET is being used to probe the dynamics of three different classes of biochemical processes-protein-DNA interactions, chromatin remodeling, and protein translation.
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Affiliation(s)
- Xinyu A Feng
- Department of Biology, Johns Hopkins University, Baltimore, MD, USA; Department of Biophysics, Johns Hopkins University, Baltimore, MD, USA
| | - Matthew F Poyton
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - Taekjip Ha
- Department of Biophysics, Johns Hopkins University, Baltimore, MD, USA; Department of Biophysics and Biophysical Chemistry, Johns Hopkins School of Medicine, Baltimore, MD, USA; Department of Biomedical Engineering, Johns Hopkins School of Medicine, Baltimore, MD, USA; Howard Hughes Medical Institute, Baltimore, MD, USA.
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42
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Nagpal H, Fierz B. The Elusive Structure of Centro-Chromatin: Molecular Order or Dynamic Heterogenetity? J Mol Biol 2021; 433:166676. [PMID: 33065112 DOI: 10.1016/j.jmb.2020.10.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Revised: 10/07/2020] [Accepted: 10/08/2020] [Indexed: 01/09/2023]
Abstract
The centromere is an essential chromatin domain required for kinetochore recruitment and chromosome segregation in eukaryotes. To perform this role, centro-chromatin adopts a unique structure that provides access to kinetochore proteins and maintains stability under tension during mitosis. This is achieved by the presence of nucleosomes containing the H3 variant CENP-A, which also acts as the epigenetic mark defining the centromere. In this review, we discuss the role of CENP-A on the structure and dynamics of centromeric chromatin. We further discuss the impact of the CENP-A binding proteins CENP-C, CENP-N, and CENP-B on modulating centro-chromatin structure. Based on these findings we provide an overview of the higher order structure of the centromere.
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Affiliation(s)
- Harsh Nagpal
- Laboratory of Biophysical Chemistry of Macromolecules, Institute of Chemical Sciences and Engineering, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland.
| | - Beat Fierz
- Laboratory of Biophysical Chemistry of Macromolecules, Institute of Chemical Sciences and Engineering, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland.
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43
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Nucleosome Positioning and Spacing: From Mechanism to Function. J Mol Biol 2021; 433:166847. [PMID: 33539878 DOI: 10.1016/j.jmb.2021.166847] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2020] [Revised: 01/16/2021] [Accepted: 01/22/2021] [Indexed: 02/08/2023]
Abstract
Eukaryotes associate their genomes with histone proteins, forming nucleosome particles. Nucleosomes regulate and protect the genetic information. They often assemble into evenly spaced arrays of nucleosomes. These regular nucleosome arrays cover significant portions of the genome, in particular over genes. The presence of these evenly spaced nucleosome arrays is highly conserved throughout the entire eukaryotic domain. Here, we review the mechanisms behind the establishment of this primary structure of chromatin with special emphasis on the biogenesis of evenly spaced nucleosome arrays. We highlight the roles that transcription, nucleosome remodelers, DNA sequence, and histone density play towards the formation of evenly spaced nucleosome arrays and summarize our current understanding of their cellular functions. We end with key unanswered questions that remain to be explored to obtain an in-depth understanding of the biogenesis and function of the nucleosome landscape.
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44
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Medina E, R Latham D, Sanabria H. Unraveling protein's structural dynamics: from configurational dynamics to ensemble switching guides functional mesoscale assemblies. Curr Opin Struct Biol 2021; 66:129-138. [PMID: 33246199 PMCID: PMC7965259 DOI: 10.1016/j.sbi.2020.10.016] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Revised: 10/16/2020] [Accepted: 10/19/2020] [Indexed: 12/18/2022]
Abstract
Evidence regarding protein structure and function manifest the imperative role that dynamics play in proteins, underlining reconsideration of the unanimated sequence-to-structure-to-function paradigm. Structural dynamics portray a heterogeneous energy landscape described by conformational ensembles where each structural representation can be responsible for unique functions or enable macromolecular assemblies. Using the human p27/Cdk2/Cyclin A ternary complex as an example, we highlight the vital role of intramolecular and intermolecular dynamics for target recognition, binding, and inhibition as a critical modulator of cell division. Rapidly sampling configurations is critical for the population of different conformational ensembles encoding functional roles. To garner this knowledge, we present how the integration of (sub)ensemble and single-molecule fluorescence spectroscopy with molecular dynamic simulations can characterize structural dynamics linking the heterogeneous ensembles to function. The incorporation of dynamics into the sequence-to-structure-to-function paradigm promises to assist in tackling various challenges, including understanding the formation and regulation of mesoscale assemblies inside cells.
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Affiliation(s)
- Exequiel Medina
- Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Las Palmeras 3425, Casilla 653, Santiago 7800003, Chile; Department of Physics and Astronomy, Clemson University, Clemson 29634, United States
| | - Danielle R Latham
- Department of Physics and Astronomy, Clemson University, Clemson 29634, United States
| | - Hugo Sanabria
- Department of Physics and Astronomy, Clemson University, Clemson 29634, United States.
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45
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LEAFY is a pioneer transcription factor and licenses cell reprogramming to floral fate. Nat Commun 2021; 12:626. [PMID: 33504790 PMCID: PMC7840934 DOI: 10.1038/s41467-020-20883-w] [Citation(s) in RCA: 52] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Accepted: 12/22/2020] [Indexed: 01/31/2023] Open
Abstract
Master transcription factors reprogram cell fate in multicellular eukaryotes. Pioneer transcription factors have prominent roles in this process because of their ability to contact their cognate binding motifs in closed chromatin. Reprogramming is pervasive in plants, whose development is plastic and tuned by the environment, yet little is known about pioneer transcription factors in this kingdom. Here, we show that the master transcription factor LEAFY (LFY), which promotes floral fate through upregulation of the floral commitment factor APETALA1 (AP1), is a pioneer transcription factor. In vitro, LFY binds to the endogenous AP1 target locus DNA assembled into a nucleosome. In vivo, LFY associates with nucleosome occupied binding sites at the majority of its target loci, including AP1. Upon binding, LFY 'unlocks' chromatin locally by displacing the H1 linker histone and by recruiting SWI/SNF chromatin remodelers, but broad changes in chromatin accessibility occur later. Our study provides a mechanistic framework for patterning of inflorescence architecture and uncovers striking similarities between LFY and animal pioneer transcription factor.
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46
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Lobbia VR, Trueba Sanchez MC, van Ingen H. Beyond the Nucleosome: Nucleosome-Protein Interactions and Higher Order Chromatin Structure. J Mol Biol 2021; 433:166827. [PMID: 33460684 DOI: 10.1016/j.jmb.2021.166827] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Revised: 01/05/2021] [Accepted: 01/06/2021] [Indexed: 12/20/2022]
Abstract
The regulation of chromatin biology ultimately depends on the manipulation of its smallest subunit, the nucleosome. The proteins that bind and operate on the nucleosome do so, while their substrate is part of a polymer embedded in the dense nuclear environment. Their molecular interactions must in some way be tuned to deal with this complexity. Due to the rapid increase in the number of high-resolution structures of nucleosome-protein complexes and the increasing understanding of the cellular chromatin structure, it is starting to become clearer how chromatin factors operate in this complex environment. In this review, we analyze the current literature on the interplay between nucleosome-protein interactions and higher-order chromatin structure. We examine in what way nucleosomes-protein interactions can affect and can be affected by chromatin organization at the oligonucleosomal level. In addition, we review the characteristics of nucleosome-protein interactions that can cause phase separation of chromatin. Throughout, we hope to illustrate the exciting challenges in characterizing nucleosome-protein interactions beyond the nucleosome.
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Affiliation(s)
- Vincenzo R Lobbia
- NMR Spectroscopy, Bijvoet Center for Biomolecular Research, Utrecht University, Padualaan 8, 3584 CH Utrecht, the Netherlands
| | - Maria Cristina Trueba Sanchez
- NMR Spectroscopy, Bijvoet Center for Biomolecular Research, Utrecht University, Padualaan 8, 3584 CH Utrecht, the Netherlands
| | - Hugo van Ingen
- NMR Spectroscopy, Bijvoet Center for Biomolecular Research, Utrecht University, Padualaan 8, 3584 CH Utrecht, the Netherlands.
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47
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Kasahara K. Physiological function of FKBP12, a primary target of rapamycin/FK506: a newly identified role in transcription of ribosomal protein genes in yeast. Curr Genet 2021; 67:383-388. [PMID: 33438053 DOI: 10.1007/s00294-020-01142-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Revised: 11/15/2020] [Accepted: 12/01/2020] [Indexed: 11/28/2022]
Abstract
In this review, we have summarized the information from a study on FKBP12 (FK506 binding protein 12 kDa) with a view to understand its drug-free, physiological roles in transcription of ribosomal protein gene in Saccharomyces cerevisiae. FKBP12 with peptidyl-prolylisomerase (PPIase) activity is widely conserved among many eukaryotes. FKBP12 is a primary target for the two structurally related drugs, FK506 and rapamycin. FKBP12 bound with FK506 or rapamycin inhibits calcineurin and target of rapamycin complex 1 (TORC1), respectively. The molecular mechanisms of the effect of FKBP12 in the presence of these drugs have been elucidated. Conversely, the physiological role of FKBP12 has been unclear, especially in yeast. Our study revealed that the deletion of FPR1 (FK506-sensitive prolinerotamase 1 gene), which encodes yeast FKBP12, induced severe growth defect synthetically with deletion of HMO1 (high mobility group family 1). HMO1 encodes an HMGB family protein involved in transcription of ribosomal component genes. Fpr1 was shown to bind specifically to the promoters of ribosomal protein genes (RPGs) dependent on Rap1 (repressor/activator binding protein 1). Importantly, Fpr1 and Hmo1 promote the binding of Fhl1/Ifh1 (forkhead-like 1/interacts with forkhead 1), key regulators of RPG transcription, to certain RPG promoters independently and/or cooperatively with each other. Taken together, we conclude that Fpr1 physiologically functions as transcription factor of RPGs in S. cerevisiae. To our knowledge, this is the first study to demonstrate that FKBP12 participates in ribosome synthesis independently of drugs, and it may also provide a clue to the unidentified function of other PPIase proteins.
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Affiliation(s)
- Koji Kasahara
- Department of Molecular Microbiology, Tokyo University of Agriculture, Tokyo, Japan.
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48
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Lionnet T, Wu C. Single-molecule tracking of transcription protein dynamics in living cells: seeing is believing, but what are we seeing? Curr Opin Genet Dev 2021; 67:94-102. [PMID: 33422933 DOI: 10.1016/j.gde.2020.12.001] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Revised: 11/24/2020] [Accepted: 12/01/2020] [Indexed: 12/20/2022]
Abstract
A universe of transcription factors (TFs), cofactors, as well as chromatin remodeling and modifying enzymes combine or compete on chromatin to control transcription. Measuring quantitatively how these proteins dynamically interact is required in order to formulate models with predictive ability to elucidate transcription control mechanisms. Single molecule tracking (SMT) provides a powerful tool towards this goal: it is a fluorescence microscopy approach that measures the location and mobility of individual TF molecules, as well as their rates of association with and dissociation from chromatin in the physiological context of the living cell. Here we review SMT principles, and discuss key TF properties uncovered by live-cell SMT, such as fast turnover (seconds), and formation of clusters that locally increase activity.
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Affiliation(s)
- Timothée Lionnet
- Institute for Systems Genetics, Science Building 807, 435 E 30th Street, NYC, NY 10016, USA.
| | - Carl Wu
- Johns Hopkins University, Department of Biology, 3400 N Charles St, Baltimore, MD 21218, USA.
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49
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Auer JMT, Stoddart JJ, Christodoulou I, Lima A, Skouloudaki K, Hall HN, Vukojević V, Papadopoulos DK. Of numbers and movement - understanding transcription factor pathogenesis by advanced microscopy. Dis Model Mech 2020; 13:dmm046516. [PMID: 33433399 PMCID: PMC7790199 DOI: 10.1242/dmm.046516] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Transcription factors (TFs) are life-sustaining and, therefore, the subject of intensive research. By regulating gene expression, TFs control a plethora of developmental and physiological processes, and their abnormal function commonly leads to various developmental defects and diseases in humans. Normal TF function often depends on gene dosage, which can be altered by copy-number variation or loss-of-function mutations. This explains why TF haploinsufficiency (HI) can lead to disease. Since aberrant TF numbers frequently result in pathogenic abnormalities of gene expression, quantitative analyses of TFs are a priority in the field. In vitro single-molecule methodologies have significantly aided the identification of links between TF gene dosage and transcriptional outcomes. Additionally, advances in quantitative microscopy have contributed mechanistic insights into normal and aberrant TF function. However, to understand TF biology, TF-chromatin interactions must be characterised in vivo, in a tissue-specific manner and in the context of both normal and altered TF numbers. Here, we summarise the advanced microscopy methodologies most frequently used to link TF abundance to function and dissect the molecular mechanisms underlying TF HIs. Increased application of advanced single-molecule and super-resolution microscopy modalities will improve our understanding of how TF HIs drive disease.
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Affiliation(s)
- Julia M T Auer
- MRC Human Genetics Unit, University of Edinburgh, Edinburgh EH4 1XU, UK
| | - Jack J Stoddart
- MRC Human Genetics Unit, University of Edinburgh, Edinburgh EH4 1XU, UK
| | | | - Ana Lima
- MRC Human Genetics Unit, University of Edinburgh, Edinburgh EH4 1XU, UK
| | | | - Hildegard N Hall
- MRC Human Genetics Unit, University of Edinburgh, Edinburgh EH4 1XU, UK
| | - Vladana Vukojević
- Center for Molecular Medicine (CMM), Department of Clinical Neuroscience, Karolinska Institutet, 17176 Stockholm, Sweden
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50
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Serebreni L, Stark A. Insights into gene regulation: From regulatory genomic elements to DNA-protein and protein-protein interactions. Curr Opin Cell Biol 2020; 70:58-66. [PMID: 33385708 DOI: 10.1016/j.ceb.2020.11.009] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Revised: 11/19/2020] [Accepted: 11/29/2020] [Indexed: 01/19/2023]
Abstract
Transcription is orchestrated by non-coding regulatory elements embedded in chromatin, which exist within the larger context of chromosome topology. Here, we review recent insights into the functions of non-coding regulatory elements and their protein interactors during transcription control. A picture emerges in which the topological environment constraints enhancer-promoter interactions and specific enhancer-bound proteins with distinct promoter-compatibilities refine target promoter choice. Such compatibilities are encoded within the sequences of enhancers and promoters and realized by diverse transcription factors and cofactors with distinct biochemical activities. An emerging property of transcription factors and cofactors is the formation of nuclear microenvironments or membraneless compartments that can have properties of phase-separated liquids. These environments are able to selectively enrich certain proteins and small molecules over others. Further investigation into the interaction of transcriptional regulators with themselves and regulatory DNA elements will help reveal the complexities of gene regulation within the context of the nucleus.
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Affiliation(s)
- Leonid Serebreni
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), Vienna, Austria
| | - Alexander Stark
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), Vienna, Austria; Medical University of Vienna, Vienna BioCenter (VBC), Vienna, Austria.
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