1
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Cui JH, Kwan JZJ, Faghihi A, Nguyen TF, Teves SS. Functional divergence of TBP homologs through distinct DNA-binding dynamics. Nucleic Acids Res 2025; 53:gkaf436. [PMID: 40396489 PMCID: PMC12093143 DOI: 10.1093/nar/gkaf436] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2024] [Revised: 04/02/2025] [Accepted: 05/12/2025] [Indexed: 05/22/2025] Open
Abstract
The TATA box-binding protein (TBP) is an evolutionarily conserved basal transcription factor common in the pre-initiation complex of all three eukaryotic RNA polymerases (RNA Pols). Despite their high conservation, homologous TBPs exhibit species- and tissue-specific functions that may contribute to the increasingly complex gene expression regulation across evolutionary time. To determine the molecular mechanisms of species- and tissue-specificity for homologous TBPs, we examined the ability of yeast TBP and murine TBP paralogs to replace the endogenous TBP in mouse embryonic stem cells (mESCs). We show that, despite the high conservation in the DNA-binding domain among the homologs, they cannot fully rescue the lethality of TBP depletion in mESCs, which correlates with their inability to support RNA Pol III transcription. Furthermore, we show that the homologs differentially support stress-induced transcription reprogramming, with the divergent N-terminal domain playing a role in modulating changes in transcriptional response. Lastly, we show that the homologs have vastly different DNA binding dynamics, suggesting a potential mechanism for the distinct functional behavior observed among the homologs. Taken together, these data show a remarkable balance between flexibility and essentiality for the different functions of homologous TBP in eukaryotic transcription.
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Affiliation(s)
- Jieying H Cui
- Department of Biochemistry and Molecular Biology, Life Sciences Institute, University of British Columbia, 2350 Health Sciences Mall, Vancouver, BCV6T 1Z3, Canada
| | - James Z J Kwan
- Department of Biochemistry and Molecular Biology, Life Sciences Institute, University of British Columbia, 2350 Health Sciences Mall, Vancouver, BCV6T 1Z3, Canada
| | - Armin Faghihi
- Department of Biochemistry and Molecular Biology, Life Sciences Institute, University of British Columbia, 2350 Health Sciences Mall, Vancouver, BCV6T 1Z3, Canada
| | - Thomas F Nguyen
- Department of Biochemistry and Molecular Biology, Life Sciences Institute, University of British Columbia, 2350 Health Sciences Mall, Vancouver, BCV6T 1Z3, Canada
| | - Sheila S Teves
- Department of Biochemistry and Molecular Biology, Life Sciences Institute, University of British Columbia, 2350 Health Sciences Mall, Vancouver, BCV6T 1Z3, Canada
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2
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Muñoz V, Goluguri RR, Ghosh C, Tanielian B, Sadqi M. Mechanisms for DNA Interplay in Eukaryotic Transcription Factors. Annu Rev Biophys 2025; 54:121-139. [PMID: 39879549 DOI: 10.1146/annurev-biophys-071524-111008] [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] [Indexed: 01/31/2025]
Abstract
Like their prokaryotic counterparts, eukaryotic transcription factors must recognize specific DNA sites, search for them efficiently, and bind to them to help recruit or block the transcription machinery. For eukaryotic factors, however, the genetic signals are extremely complex and scattered over vast, multichromosome genomes, while the DNA interplay occurs in a varying landscape defined by chromatin remodeling events and epigenetic modifications. Eukaryotic factors are rich in intrinsically disordered regions and are also distinct in their recognition of short DNA motifs and utilization of open DNA interaction interfaces as ways to gain access to DNA on nucleosomes. Recent findings are revealing the profound, unforeseen implications of such characteristics for the mechanisms of DNA interplay. In this review we discuss these implications and how they are shaping the eukaryotic transcription control paradigm into one of promiscuous signal recognition, highly dynamic interactions, heterogeneous DNA scanning, and multiprong conformational control.
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Affiliation(s)
- Victor Muñoz
- CREST Center for Cellular and Biomolecular Machines, University of California, Merced, California, USA;
- Department of Bioengineering, University of California, Merced, California, USA
| | - Rama Reddy Goluguri
- CREST Center for Cellular and Biomolecular Machines, University of California, Merced, California, USA;
- Department of Bioengineering, University of California, Merced, California, USA
- Department of Biochemistry, Stanford University, Palo Alto, California, USA
| | - Catherine Ghosh
- CREST Center for Cellular and Biomolecular Machines, University of California, Merced, California, USA;
- Department of Bioengineering, University of California, Merced, California, USA
| | - Benjamin Tanielian
- CREST Center for Cellular and Biomolecular Machines, University of California, Merced, California, USA;
- Chemistry and Biochemistry Graduate Program, University of California, Merced, California, USA
| | - Mourad Sadqi
- CREST Center for Cellular and Biomolecular Machines, University of California, Merced, California, USA;
- Department of Bioengineering, University of California, Merced, California, USA
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3
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Mao X, Rao G, Li G, Chen S. Insights into Extrachromosomal DNA in Cancer: Biogenesis, Methodologies, Functions, and Therapeutic Potential. Adv Biol (Weinh) 2025; 9:e2400433. [PMID: 39945006 DOI: 10.1002/adbi.202400433] [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: 07/25/2024] [Revised: 02/01/2025] [Indexed: 03/17/2025]
Abstract
Originating from, but independent of, linear chromosomes, extrachromosomal DNA (ecDNA) exists in a more active state of transcription and autonomous replication. It plays a crucial role in the development of malignancies and therapy resistance. Since its discovery in eukaryotic cells more than half a century ago, the biological characteristics and functions of ecDNA have remained unclear due to limitations in detection methods. However, recent advancements in research tools have transformed ecDNA research. It is believed that ecDNA exhibits greater activity in the abnormal amplification of oncogenes, thereby driving cancer progression through their overexpression. Notably, compared to linear DNA, ecDNA can also function as a genomic element with regulatory roles, including both trans- and cis-acting functions. Its critical roles in tumorigenesis, evolution, progression, and drug resistance in malignant tumors are increasingly recognized. This review provides a comprehensive summary of the evolutionary context of ecDNA and highlights significant progress in understanding its biological functions and potential applications as a therapeutic target in malignant tumors.
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Affiliation(s)
- Xudong Mao
- Department of Urology, The Affiliated Sir Run Run Shaw Hospital, College of Medicine, Zhejiang University, Hangzhou, 310000, P. R. China
| | - Guocheng Rao
- Department of Endocrinology & Metabolism, Daepartment of Biotherapy, Center for Diabetes and Metabolism Research, State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University and Collaborative Innovation Center of Biotherapy, Chengdu, Sichuan, 610000, P. R. China
| | - Gonghui Li
- Department of Urology, The Affiliated Sir Run Run Shaw Hospital, College of Medicine, Zhejiang University, Hangzhou, 310000, P. R. China
| | - Shihan Chen
- Department of Endocrinology, The Affiliated Sir Run Run Shaw Hospital, College of Medicine, Zhejiang University, Hangzhou, 310000, P. R. China
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4
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Sang M, Johnson ME. Mechanisms of enhanced or impaired DNA target selectivity driven by protein dimerization. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2025:2025.02.18.638941. [PMID: 40027831 PMCID: PMC11870488 DOI: 10.1101/2025.02.18.638941] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 03/05/2025]
Abstract
Successful DNA transcription demands coordination between proteins that bind DNA while simultaneously binding to one another into dimers or higher-order complexes. Measurements that report on the lifetime or occupancy of an individual protein on DNA thus represent a convolution over the protein interactions with specific DNA, nonspecific DNA, or protein partners on DNA. For some DNA-binding proteins, dimerization is considered an essential step for stable DNA association, but here we show that protein dimerization can also reduce dwell times on specific DNA targets, enhance or impair occupancy on target sequences, and spatially redistribute proteins on DNA. We use mass-action kinetic models of pairwise association reactions between proteins and DNA (specific and nonspecific) and protein dimers, along with theory and spatial stochastic simulations to isolate the role of dimerization on observed dwell times and occupancy. For proteins binding a spatially localized cluster of targets, dimerization can drive up dwell time by 1000-fold and produce high selectivity for clustered over isolated targets. However, this effect can become negligible when proteins outnumber target sequences. In contrast, for isolated DNA targets, dimerization often reduces dwell times by sequestering proteins from their target sites, in some cases thus reducing overall occupancy. The ability of these proteins to bind DNA nonspecifically and diffuse in 1D to exploit dimensional reduction is a key determinant controlling degree of enhancement, despite the presence of nucleosome barriers to 1D diffusion. By comparison with ChipSeq data, our model explains how the distribution of the GAF pioneer proteins throughout the genome is highly selective for clustered targets due to protein interactions and provides a framework to predict how even weak dimerization can redistribute or stabilize proteins on DNA.
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Affiliation(s)
- Mankun Sang
- TC Jenkins Department of Biophysics, Johns Hopkins University, 3400 N Charles St, Baltimore, MD 21218
| | - Margaret E. Johnson
- TC Jenkins Department of Biophysics, Johns Hopkins University, 3400 N Charles St, Baltimore, MD 21218
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5
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Stortz M, Oses C, Lafuente AL, Presman DM, Levi V. Catching the glucocorticoid receptor in the act: Lessons from fluorescence fluctuation methods. Biochem Biophys Res Commun 2025; 748:151327. [PMID: 39823895 DOI: 10.1016/j.bbrc.2025.151327] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2024] [Revised: 01/10/2025] [Accepted: 01/12/2025] [Indexed: 01/20/2025]
Abstract
Technological innovation can drive scientific inquiry by allowing researchers to answer questions that were once out of reach. Eukaryotic mRNA synthesis was not so long ago thought of as a deterministic, sequential process in which transcriptional regulators and general transcription factors assemble in an orderly fashion into chromatin to, ultimately, activate RNA polymerase II. Advances in fluorescence microscopy techniques have revealed a much more complex scenario, wherein transcriptional regulators dynamically engage with chromatin in a more stochastic, probabilistic way. In this review, we will concentrate on what fluorescence fluctuation methods have taught us about the journey of transcription factors within live cells. Specifically, we summarized how these techniques have contributed to reshaping our understanding of the mechanism(s) of action of the glucocorticoid receptor, a ligand-regulated transcription factor involved in many physiological and pathological processes. This receptor regulates a variety of gene networks in a context-specific manner and its activity can be quickly and easily controlled by the addition of specific ligands. Thus, it is widely used as a model to study the mechanisms of transcription factors through live-cell imaging.
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Affiliation(s)
- Martin Stortz
- Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales (IQUIBICEN), CONICET-Universidad de Buenos Aires, Buenos Aires, C1428EGA, Argentina; Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Camila Oses
- Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales (IQUIBICEN), CONICET-Universidad de Buenos Aires, Buenos Aires, C1428EGA, Argentina
| | - Agustina L Lafuente
- Instituto de Fisiología, Biología Molecular y Neurociencias (IFIBYNE), CONICET-Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Buenos Aires, C1428EGA, Argentina
| | - Diego M Presman
- Instituto de Fisiología, Biología Molecular y Neurociencias (IFIBYNE), CONICET-Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Buenos Aires, C1428EGA, Argentina; Departamento de Fisiología, Biología Molecular y Celular, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, C1428EGA, Argentina.
| | - Valeria Levi
- Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales (IQUIBICEN), CONICET-Universidad de Buenos Aires, Buenos Aires, C1428EGA, Argentina; Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, C1428EGA, Argentina.
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6
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Huynh D, Hoffmeister P, Friedrich T, Zhang K, Bartkuhn M, Ferrante F, Giaimo BD, Kovall RA, Borggrefe T, Oswald F, Gebhardt JCM. Effective in vivo binding energy landscape illustrates kinetic stability of RBPJ-DNA binding. Nat Commun 2025; 16:1259. [PMID: 39893191 PMCID: PMC11787368 DOI: 10.1038/s41467-025-56515-4] [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: 07/05/2024] [Accepted: 01/21/2025] [Indexed: 02/04/2025] Open
Abstract
Transcription factors (TFs) such as RBPJ in Notch signaling bind to specific DNA sequences to regulate transcription. How TF-DNA binding kinetics and cofactor interactions modulate gene regulation is mostly unknown. We determine the binding kinetics, transcriptional activity, and genome-wide chromatin occupation of RBPJ and mutant variants by live-cell single-molecule tracking, reporter assays, and ChIP-Seq. Importantly, the search time of RBPJ exceeds its residence time, indicating kinetic rather than thermodynamic binding stability. Impaired RBPJ-DNA binding as in Adams-Oliver-Syndrome affect both target site association and dissociation, while impaired cofactor binding mainly alters association and unspecific binding. Moreover, our data point to the possibility that cofactor binding contributes to target site specificity. Findings for other TFs comparable to RBPJ indicate that kinetic rather than thermodynamic DNA binding stability might prevail in vivo. We propose an effective in vivo binding energy landscape of TF-DNA interactions as instructive visualization of binding kinetics and mutation-induced changes.
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Affiliation(s)
- Duyen Huynh
- Institute of Experimental Physics and IQST, Ulm University, Ulm, Germany
| | | | - Tobias Friedrich
- Institute of Biochemistry, Justus-Liebig-Universität Gießen, Gießen, Germany
- Biomedical Informatics and Systems Medicine, Justus-Liebig-Universität Gießen, Gießen, Germany
- Institute for Lung Health (ILH), Gießen, Germany
| | - Kefan Zhang
- Institute of Experimental Physics and IQST, Ulm University, Ulm, Germany
| | - Marek Bartkuhn
- Biomedical Informatics and Systems Medicine, Justus-Liebig-Universität Gießen, Gießen, Germany
- Institute for Lung Health (ILH), Gießen, Germany
| | - Francesca Ferrante
- Institute of Biochemistry, Justus-Liebig-Universität Gießen, Gießen, Germany
| | | | - Rhett A Kovall
- Department of Molecular Genetics, Biochemistry and Microbiology, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Tilman Borggrefe
- Institute of Biochemistry, Justus-Liebig-Universität Gießen, Gießen, Germany
| | - Franz Oswald
- Clinic of Internal Medicine I, University Medical Center Ulm, Ulm, Germany.
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7
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Wagh K, Stavreva DA, Hager GL. Transcription dynamics and genome organization in the mammalian nucleus: Recent advances. Mol Cell 2025; 85:208-224. [PMID: 39413793 PMCID: PMC11741928 DOI: 10.1016/j.molcel.2024.09.022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2024] [Revised: 07/31/2024] [Accepted: 09/19/2024] [Indexed: 10/18/2024]
Abstract
Single-molecule tracking (SMT) has emerged as the dominant technology to investigate the dynamics of chromatin-transcription factor (TF) interactions. How long a TF needs to bind to a regulatory site to elicit a transcriptional response is a fundamentally important question. However, highly divergent estimates of TF binding have been presented in the literature, stemming from differences in photobleaching correction and data analysis. TF movement is often interpreted as specific or non-specific association with chromatin, yet the dynamic nature of the chromatin polymer is often overlooked. In this perspective, we highlight how recent SMT studies have reshaped our understanding of TF dynamics, chromatin mobility, and genome organization in the mammalian nucleus, focusing on the technical details and biological implications of these approaches. In a remarkable convergence of fixed and live-cell imaging, we show how super-resolution and SMT studies of chromatin have dovetailed to provide a convincing nanoscale view of genome organization.
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Affiliation(s)
- Kaustubh Wagh
- Laboratory of Receptor Biology and Gene Expression, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Diana A Stavreva
- Laboratory of Receptor Biology and Gene Expression, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Gordon L Hager
- Laboratory of Receptor Biology and Gene Expression, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA.
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8
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Antani JD, Ward T, Emonet T, Turner PE. Microscopic phage adsorption assay: High-throughput quantification of virus particle attachment to host bacterial cells. Proc Natl Acad Sci U S A 2024; 121:e2410905121. [PMID: 39700139 DOI: 10.1073/pnas.2410905121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2024] [Accepted: 11/12/2024] [Indexed: 12/21/2024] Open
Abstract
Phages, viruses of bacteria, play a pivotal role in Earth's biosphere and hold great promise as therapeutic and diagnostic tools in combating infectious diseases. Attachment of phages to bacterial cells is a crucial initial step of the interaction. The classic assay to quantify the dynamics of phage attachment involves coculturing and enumeration of bacteria and phages, which is laborious, lengthy, hence low-throughput, and only provides ensemble estimates of model-based adsorption rate constants. Here, we utilized fluorescence microscopy and particle tracking to obtain trajectories of individual virus particles interacting with cells. The trajectory durations quantified the heterogeneity in dwell time, the time that each phage spends interacting with a bacterium. The average dwell time strongly correlated with the classically measured adsorption rate constant. We successfully applied this technique to quantify host-attachment dynamics of several phages including those targeting key bacterial pathogens. This approach should benefit the field of phage biology by providing highly quantitative, model-free readouts at single-virus resolution, helping to uncover single-virus phenomena missed by traditional measurements. Owing to significant reduction in manual effort, our method should enable rapid, high-throughput screening of a phage library against a target bacterial strain for applications such as therapy or diagnosis.
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Affiliation(s)
- Jyot D Antani
- Department of Ecology and Evolutionary Biology, Yale University, New Haven, CT 06520
- Center for Phage Biology & Therapy, Yale University, New Haven, CT 06520
- Quantitative Biology Institute, Yale University, New Haven, CT 06520
| | - Timothy Ward
- Department of Ecology and Evolutionary Biology, Yale University, New Haven, CT 06520
| | - Thierry Emonet
- Quantitative Biology Institute, Yale University, New Haven, CT 06520
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT 06520
- Department of Physics, Yale University, New Haven, CT 06520
| | - Paul E Turner
- Department of Ecology and Evolutionary Biology, Yale University, New Haven, CT 06520
- Center for Phage Biology & Therapy, Yale University, New Haven, CT 06520
- Quantitative Biology Institute, Yale University, New Haven, CT 06520
- Program in Microbiology, Yale School of Medicine, New Haven, CT 06520
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9
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Antani JD, Ward T, Emonet T, Turner PE. Microscopic Phage Adsorption Assay: High-throughput quantification of virus particle attachment to host bacterial cells. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.10.09.617072. [PMID: 39416219 PMCID: PMC11482966 DOI: 10.1101/2024.10.09.617072] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 10/19/2024]
Abstract
Phages, viruses of bacteria, play a pivotal role in Earth's biosphere and hold great promise as therapeutic and diagnostic tools in combating infectious diseases. Attachment of phages to bacterial cells is a crucial initial step of the interaction. The classic assay to quantify the dynamics of phage attachment involves co-culturing and enumeration of bacteria and phages, which is laborious, lengthy, hence low-throughput, and only provides ensemble estimates of model-based adsorption rate constants. Here, we utilized fluorescence microscopy and particle tracking to obtain trajectories of individual virus particles interacting with cells. The trajectory durations quantified the heterogeneity in dwell time, the time that each phage spends interacting with a bacterium. The average dwell time strongly correlated with the classically-measured adsorption rate constant. We successfully applied this technique to quantify host-attachment dynamics of several phages including those targeting key bacterial pathogens. This approach should benefit the field of phage biology by providing highly quantitative, model-free readouts at single-virus resolution, helping to uncover single-virus phenomena missed by traditional measurements. Owing to significant reduction in manual effort, our method should enable rapid, high-throughput screening of a phage library against a target bacterial strain for applications such as therapy or diagnosis.
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Affiliation(s)
- Jyot D. Antani
- Department of Ecology and Evolutionary Biology, Yale University, New Haven, CT 06520, USA
- Center for Phage Biology & Therapy, Yale University, New Haven, CT 06520, USA
- Quantitative Biology Institute, Yale University, New Haven, CT 06520, USA
| | - Timothy Ward
- Department of Ecology and Evolutionary Biology, Yale University, New Haven, CT 06520, USA
| | - Thierry Emonet
- Quantitative Biology Institute, Yale University, New Haven, CT 06520, USA
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT 06520, USA
- Department of Physics, Yale University, New Haven, CT 06520, USA
| | - Paul E. Turner
- Department of Ecology and Evolutionary Biology, Yale University, New Haven, CT 06520, USA
- Center for Phage Biology & Therapy, Yale University, New Haven, CT 06520, USA
- Quantitative Biology Institute, Yale University, New Haven, CT 06520, USA
- Program in Microbiology, Yale School of Medicine, New Haven, CT 06520, USA
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10
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Garate X, Gómez-García PA, Merino MF, Angles MC, Zhu C, Castells-García A, Ed-Daoui I, Martin L, Ochiai H, Neguembor MV, Cosma MP. The relationship between nanoscale genome organization and gene expression in mouse embryonic stem cells during pluripotency transition. Nucleic Acids Res 2024; 52:8146-8164. [PMID: 38850157 DOI: 10.1093/nar/gkae476] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Revised: 05/16/2024] [Accepted: 06/05/2024] [Indexed: 06/10/2024] Open
Abstract
During early development, gene expression is tightly regulated. However, how genome organization controls gene expression during the transition from naïve embryonic stem cells to epiblast stem cells is still poorly understood. Using single-molecule microscopy approaches to reach nanoscale resolution, we show that genome remodeling affects gene transcription during pluripotency transition. Specifically, after exit from the naïve pluripotency state, chromatin becomes less compacted, and the OCT4 transcription factor has lower mobility and is more bound to its cognate sites. In epiblast cells, the active transcription hallmark, H3K9ac, decreases within the Oct4 locus, correlating with reduced accessibility of OCT4 and, in turn, with reduced expression of Oct4 nascent RNAs. Despite the high variability in the distances between active pluripotency genes, distances between Nodal and Oct4 decrease during epiblast specification. In particular, highly expressed Oct4 alleles are closer to nuclear speckles during all stages of the pluripotency transition, while only a distinct group of highly expressed Nodal alleles are in close proximity to Oct4 when associated with a nuclear speckle in epiblast cells. Overall, our results provide new insights into the role of the spatiotemporal genome remodeling during mouse pluripotency transition and its correlation with the expression of key pluripotency genes.
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Affiliation(s)
- Ximena Garate
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Dr. Aiguader 88, Barcelona 08003, Spain
| | - Pablo Aurelio Gómez-García
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Dr. Aiguader 88, Barcelona 08003, Spain
| | - Manuel Fernández Merino
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Dr. Aiguader 88, Barcelona 08003, Spain
| | - Marta Cadevall Angles
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Dr. Aiguader 88, Barcelona 08003, Spain
| | - Chenggan Zhu
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Dr. Aiguader 88, Barcelona 08003, Spain
| | - Alvaro Castells-García
- Medical Research Institute, Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, 106 Zhongshan Er Road, Yuexiu district, 510080 Guangzhou, China
| | - Ilyas Ed-Daoui
- Medical Research Institute, Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, 106 Zhongshan Er Road, Yuexiu district, 510080 Guangzhou, China
| | - Laura Martin
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Dr. Aiguader 88, Barcelona 08003, Spain
| | - Hiroshi Ochiai
- Graduate School of Integrated Sciences for Life, Hiroshima University, Higashi-Hiroshima, 739-0046, Japan
| | - Maria Victoria Neguembor
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Dr. Aiguader 88, Barcelona 08003, Spain
| | - Maria Pia Cosma
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Dr. Aiguader 88, Barcelona 08003, Spain
- Medical Research Institute, Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, 106 Zhongshan Er Road, Yuexiu district, 510080 Guangzhou, China
- ICREA, Pg. Lluis Companys 23, Barcelona 08010, Spain
- Universitat Pompeu Fabra (UPF), Barcelona, Spain
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11
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Thonnekottu D, Chatterjee D. Probing the modulation in facilitated diffusion guided by DNA-protein interactions in target search processes. Phys Chem Chem Phys 2024. [PMID: 38922594 DOI: 10.1039/d4cp01580k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/27/2024]
Abstract
Many fundamental biophysical processes involving gene regulation and gene editing rely, at the molecular level, on an intricate methodology of searching and locating the precise target base pair sequence on the genome by specific binding proteins. A unique mechanism, known as 'facilitated diffusion', which is a combination of 1D sliding along with 3D movement, is considered to be the key step for such events. This also explains the relatively much shorter timescale of the target searching process, compared to other diffusion-controlled biophysical processes. In this work, we aim to probe the modulation of target search dynamics of a protein moiety by estimating the rate of the target search process, and the statistics of the search rounds and timescales accomplished by the 1D and 3D motions, based on first passage time (FPT) calculations. This is studied with its characteristics getting influenced by various given conditions such as, when the DNA is rigid or flexible, and when the target is placed at different locations on the DNA. The current theoretical framework includes a Brownian dynamics simulation setup adopting a straightforward coarse-grained model for a diffusing protein on DNA. Moreover, this theoretical analysis provides insights into the complex target search dynamics by highlighting the significance of the chain dynamics in the mechanistic details of the facilitated diffusion process.
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Affiliation(s)
- Diljith Thonnekottu
- Department of Physics, Indian Institute of Technology Palakkad, Kerala 678623, India
| | - Debarati Chatterjee
- Department of Chemistry, Indian Institute of Technology Palakkad, Kerala 678623, India.
- Department of Physics, Indian Institute of Technology Palakkad, Kerala 678623, India
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12
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Hao S, Lee YJ, Benhamou Goldfajn N, Flores E, Liang J, Fuehrer H, Demmerle J, Lippincott-Schwartz J, Liu Z, Sukenik S, Cai D. YAP condensates are highly organized hubs. iScience 2024; 27:109927. [PMID: 38784009 PMCID: PMC11111833 DOI: 10.1016/j.isci.2024.109927] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Revised: 10/24/2023] [Accepted: 05/03/2024] [Indexed: 05/25/2024] Open
Abstract
YAP/TEAD signaling is essential for organismal development, cell proliferation, and cancer progression. As a transcriptional coactivator, how YAP activates its downstream target genes is incompletely understood. YAP forms biomolecular condensates in response to hyperosmotic stress, concentrating transcription-related factors to activate downstream target genes. However, whether YAP forms condensates under other signals, how YAP condensates organize and function, and how YAP condensates activate transcription in general are unknown. Here, we report that endogenous YAP forms sub-micron scale condensates in response to Hippo pathway regulation and actin cytoskeletal tension. YAP condensates are stabilized by the transcription factor TEAD1, and recruit BRD4, a coactivator that is enriched at active enhancers. Using single-particle tracking, we found that YAP condensates slowed YAP diffusion within condensate boundaries, a possible mechanism for promoting YAP target search. These results reveal that YAP condensate formation is a highly regulated process that is critical for YAP/TEAD target gene expression.
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Affiliation(s)
- Siyuan Hao
- Department of Biochemistry and Molecular Biology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205, USA
| | - Ye Jin Lee
- Department of Biochemistry and Molecular Biology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205, USA
| | - Nadav Benhamou Goldfajn
- Department of Biochemistry and Molecular Biology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205, USA
- Department of Biophysics, Johns Hopkins University, 3400 N. Charles St., Baltimore, MD 21218, USA
| | - Eduardo Flores
- Department of Chemistry and Chemical Biology, University of California, Merced, Merced, CA 95343, USA
| | - Jindayi Liang
- Department of Biochemistry and Molecular Biology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205, USA
| | - Hannah Fuehrer
- Department of Biochemistry and Molecular Biology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205, USA
| | - Justin Demmerle
- Department of Biochemistry and Molecular Biology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205, USA
| | | | - Zhe Liu
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA
| | - Shahar Sukenik
- Department of Chemistry and Chemical Biology, University of California, Merced, Merced, CA 95343, USA
| | - Danfeng Cai
- Department of Biochemistry and Molecular Biology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205, USA
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA
- Department of Oncology, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA
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13
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Liu Z, Gillis TG, Raman S, Cui Q. A parameterized two-domain thermodynamic model explains diverse mutational effects on protein allostery. eLife 2024; 12:RP92262. [PMID: 38836839 PMCID: PMC11152574 DOI: 10.7554/elife.92262] [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: 06/06/2024] Open
Abstract
New experimental findings continue to challenge our understanding of protein allostery. Recent deep mutational scanning study showed that allosteric hotspots in the tetracycline repressor (TetR) and its homologous transcriptional factors are broadly distributed rather than spanning well-defined structural pathways as often assumed. Moreover, hotspot mutation-induced allostery loss was rescued by distributed additional mutations in a degenerate fashion. Here, we develop a two-domain thermodynamic model for TetR, which readily rationalizes these intriguing observations. The model accurately captures the in vivo activities of various mutants with changes in physically transparent parameters, allowing the data-based quantification of mutational effects using statistical inference. Our analysis reveals the intrinsic connection of intra- and inter-domain properties for allosteric regulation and illustrate epistatic interactions that are consistent with structural features of the protein. The insights gained from this study into the nature of two-domain allostery are expected to have broader implications for other multi-domain allosteric proteins.
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Affiliation(s)
- Zhuang Liu
- Department of Physics, Boston UniversityBostonUnited States
| | - Thomas G Gillis
- Department of Biochemistry, University of WisconsinMadisonUnited States
| | - Srivatsan Raman
- Department of Biochemistry, University of WisconsinMadisonUnited States
- Department of Chemistry, University of WisconsinMadisonUnited States
- Department of Bacteriology, University of WisconsinMadisonUnited States
| | - Qiang Cui
- Department of Physics, Boston UniversityBostonUnited States
- Department of Chemistry, Boston UniversityBostonUnited States
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14
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Scherer NM, Maurel C, Graus M, McAlary L, Richter G, Radford RW, Hogan A, Don E, Lee A, Yerbury J, Francois M, Chung R, Morsch M. RNA-binding properties orchestrate TDP-43 homeostasis through condensate formation in vivo. Nucleic Acids Res 2024; 52:5301-5319. [PMID: 38381071 PMCID: PMC11109982 DOI: 10.1093/nar/gkae112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Revised: 01/12/2024] [Accepted: 02/06/2024] [Indexed: 02/22/2024] Open
Abstract
Insoluble cytoplasmic aggregate formation of the RNA-binding protein TDP-43 is a major hallmark of neurodegenerative diseases including Amyotrophic Lateral Sclerosis. TDP-43 localizes predominantly in the nucleus, arranging itself into dynamic condensates through liquid-liquid phase separation (LLPS). Mutations and post-translational modifications can alter the condensation properties of TDP-43, contributing to the transition of liquid-like biomolecular condensates into solid-like aggregates. However, to date it has been a challenge to study the dynamics of this process in vivo. We demonstrate through live imaging that human TDP-43 undergoes nuclear condensation in spinal motor neurons in a living animal. RNA-binding deficiencies as well as post-translational modifications can lead to aberrant condensation and altered TDP-43 compartmentalization. Single-molecule tracking revealed an altered mobility profile for RNA-binding deficient TDP-43. Overall, these results provide a critically needed in vivo characterization of TDP-43 condensation, demonstrate phase separation as an important regulatory mechanism of TDP-43 accessibility, and identify a molecular mechanism of how functional TDP-43 can be regulated.
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Affiliation(s)
- Natalie M Scherer
- Faculty of Medicine, Health & Human Sciences, Macquarie Medical School, MND Research Centre, Macquarie University, Sydney, NSW 2109, Australia
| | - Cindy Maurel
- Faculty of Medicine, Health & Human Sciences, Macquarie Medical School, MND Research Centre, Macquarie University, Sydney, NSW 2109, Australia
| | - Matthew S Graus
- The David Richmond Laboratory for Cardio-Vascular Development: gene regulation and editing, Centenary Institute, The University of Sydney, School of Medical Sciences, Sydney, NSW 2006, Australia
- Genome Imaging Centre, Centenary Institute, The University of Sydney, Sydney, NSW 2006, Australia
| | - Luke McAlary
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW 2522, Australia
| | - Grant Richter
- Faculty of Medicine, Health & Human Sciences, Macquarie Medical School, MND Research Centre, Macquarie University, Sydney, NSW 2109, Australia
| | - Rowan A W Radford
- Faculty of Medicine, Health & Human Sciences, Macquarie Medical School, MND Research Centre, Macquarie University, Sydney, NSW 2109, Australia
| | - Alison Hogan
- Faculty of Medicine, Health & Human Sciences, Macquarie Medical School, MND Research Centre, Macquarie University, Sydney, NSW 2109, Australia
| | - Emily K Don
- Faculty of Medicine, Health & Human Sciences, Macquarie Medical School, MND Research Centre, Macquarie University, Sydney, NSW 2109, Australia
| | - Albert Lee
- Faculty of Medicine, Health & Human Sciences, Macquarie Medical School, MND Research Centre, Macquarie University, Sydney, NSW 2109, Australia
| | - Justin Yerbury
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW 2522, Australia
| | - Mathias Francois
- The David Richmond Laboratory for Cardio-Vascular Development: gene regulation and editing, Centenary Institute, The University of Sydney, School of Medical Sciences, Sydney, NSW 2006, Australia
- Genome Imaging Centre, Centenary Institute, The University of Sydney, Sydney, NSW 2006, Australia
| | - Roger S Chung
- Faculty of Medicine, Health & Human Sciences, Macquarie Medical School, MND Research Centre, Macquarie University, Sydney, NSW 2109, Australia
| | - Marco Morsch
- Faculty of Medicine, Health & Human Sciences, Macquarie Medical School, MND Research Centre, Macquarie University, Sydney, NSW 2109, Australia
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15
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Hwang DW, Maekiniemi A, Singer RH, Sato H. Real-time single-molecule imaging of transcriptional regulatory networks in living cells. Nat Rev Genet 2024; 25:272-285. [PMID: 38195868 DOI: 10.1038/s41576-023-00684-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/27/2023] [Indexed: 01/11/2024]
Abstract
Gene regulatory networks drive the specific transcriptional programmes responsible for the diversification of cell types during the development of multicellular organisms. Although our knowledge of the genes involved in these dynamic networks has expanded rapidly, our understanding of how transcription is spatiotemporally regulated at the molecular level over a wide range of timescales in the small volume of the nucleus remains limited. Over the past few decades, advances in the field of single-molecule fluorescence imaging have enabled real-time behaviours of individual transcriptional components to be measured in living cells and organisms. These efforts are now shedding light on the dynamic mechanisms of transcription, revealing not only the temporal rules but also the spatial coordination of underlying molecular interactions during various biological events.
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Affiliation(s)
- Dong-Woo Hwang
- Department of Cell Biology, Albert Einstein College of Medicine, New York, NY, USA
| | - Anna Maekiniemi
- Department of Cell Biology, Albert Einstein College of Medicine, New York, NY, USA
| | - Robert H Singer
- Department of Cell Biology, Albert Einstein College of Medicine, New York, NY, USA
| | - Hanae Sato
- Department of Cell Biology, Albert Einstein College of Medicine, New York, NY, USA.
- Nano Life Science Institute (WPI-Nano LSI), Kanazawa University, Kakuma-machi, Kanazawa, Japan.
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16
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Emanuelson C, Bardhan A, Deiters A. DNA Logic Gates for Small Molecule Activation Circuits in Cells. ACS Synth Biol 2024; 13:538-545. [PMID: 38306634 PMCID: PMC10877608 DOI: 10.1021/acssynbio.3c00474] [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: 08/02/2023] [Revised: 01/09/2024] [Accepted: 01/09/2024] [Indexed: 02/04/2024]
Abstract
DNA-based devices such as DNA logic gates self-assemble into supramolecular structures, as dictated by the sequences of the constituent oligonucleotides and their predictable Watson-Crick base pairing interactions. The programmable nature of DNA-based devices permits the design and implementation of DNA circuits that interact in a dynamic and sequential manner capable of spatially arranging disparate DNA species. Here, we report the application of an activatable fluorescence reporter based on a proximity-driven inverse electron demand Diels-Alder (IEDDA) reaction and its robust integration with DNA strand displacement circuits. In response to specific DNA input patterns, sequential strand displacement reactions are initiated and culminate in the hybridization of two modified DNA strands carrying probes capable of undergoing an IEDDA reaction between a vinyl-ether-caged fluorophore and its reactive partner tetrazine, leading to the activation of fluorescence. This approach provides a major advantage for DNA computing in mammalian cells since circuit degradation does not induce fluorescence, in contrast to traditional fluorophore-quencher designs. We demonstrate the robustness and sensitivity of the reporter by testing its ability to serve as a readout for DNA logic circuits of varying complexity inside cells.
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Affiliation(s)
- Cole Emanuelson
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
| | - Anirban Bardhan
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
| | - Alexander Deiters
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
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17
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Liu Z, Gillis T, Raman S, Cui Q. A parametrized two-domain thermodynamic model explains diverse mutational effects on protein allostery. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.08.06.552196. [PMID: 37662419 PMCID: PMC10473640 DOI: 10.1101/2023.08.06.552196] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/05/2023]
Abstract
New experimental findings continue to challenge our understanding of protein allostery. Recent deep mutational scanning study showed that allosteric hotspots in the tetracycline repressor (TetR) and its homologous transcriptional factors are broadly distributed rather than spanning well-defined structural pathways as often assumed. Moreover, hotspot mutation-induced allostery loss was rescued by distributed additional mutations in a degenerate fashion. Here, we develop a two-domain thermodynamic model for TetR, which readily rationalizes these intriguing observations. The model accurately captures the in vivo activities of various mutants with changes in physically transparent parameters, allowing the data-based quantification of mutational effects using statistical inference. Our analysis reveals the intrinsic connection of intra- and inter-domain properties for allosteric regulation and illustrate epistatic interactions that are consistent with structural features of the protein. The insights gained from this study into the nature of two-domain allostery are expected to have broader implications for other multidomain allosteric proteins.
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Affiliation(s)
- Zhuang Liu
- Department of Physics, Boston University, Boston, United States
| | - Thomas Gillis
- Department of Biochemistry, University of Wisconsin, Madison, United States
| | - Srivatsan Raman
- Department of Biochemistry, University of Wisconsin, Madison, United States
- Department of Chemistry, University of Wisconsin, Madison, United States
- Department of Bacteriology, University of Wisconsin, Madison, United States
| | - Qiang Cui
- Department of Physics, Boston University, Boston, United States
- Department of Chemistry, Boston University, Boston, United States
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18
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Salomone J, Farrow E, Gebelein B. Homeodomain complex formation and biomolecular condensates in Hox gene regulation. Semin Cell Dev Biol 2024; 152-153:93-100. [PMID: 36517343 PMCID: PMC10258226 DOI: 10.1016/j.semcdb.2022.11.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2022] [Revised: 10/21/2022] [Accepted: 11/30/2022] [Indexed: 12/15/2022]
Abstract
Hox genes are a family of homeodomain transcription factors that regulate specialized morphological structures along the anterior-posterior axis of metazoans. Over the past few decades, researchers have focused on defining how Hox factors with similar in vitro DNA binding activities achieve sufficient target specificity to regulate distinct cell fates in vivo. In this review, we highlight how protein interactions with other transcription factors, many of which are also homeodomain proteins, result in the formation of transcription factor complexes with enhanced DNA binding specificity. These findings suggest that Hox-regulated enhancers utilize distinct combinations of homeodomain binding sites, many of which are low-affinity, to recruit specific Hox complexes. However, low-affinity sites can only yield reproducible responses with high transcription factor concentrations. To overcome this limitation, recent studies revealed how transcription factors, including Hox factors, use intrinsically disordered domains (IDRs) to form biomolecular condensates that increase protein concentrations. Moreover, Hox factors with altered IDRs have been associated with altered transcriptional activity and human disease states, demonstrating the importance of IDRs in mediating essential Hox output. Collectively, these studies highlight how Hox factors use their DNA binding domains, protein-protein interaction domains, and IDRs to form specific transcription factor complexes that yield accurate gene expression.
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Affiliation(s)
- Joseph Salomone
- Graduate Program in Molecular and Developmental Biology, Cincinnati Children's Hospital Research Foundation, Cincinnati, OH 45229, USA; Medical-Scientist Training Program, University of Cincinnati College of Medicine, Cincinnati, OH 45229, USA
| | - Edward Farrow
- Graduate Program in Molecular and Developmental Biology, Cincinnati Children's Hospital Research Foundation, Cincinnati, OH 45229, USA; Medical-Scientist Training Program, University of Cincinnati College of Medicine, Cincinnati, OH 45229, USA
| | - Brian Gebelein
- Division of Developmental Biology, Cincinnati Children's Hospital Medical Center, 3333 Burnet Ave, MLC 7007, Cincinnati, OH 45229, USA; Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH 45229, USA.
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19
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Wan Y, Mu Q, Krzysztoń R, Cohen J, Coraci D, Helenek C, Tompkins C, Lin A, Farquhar K, Cross E, Wang J, Balázsi G. Adaptive DNA amplification of synthetic gene circuit opens a way to overcome cancer chemoresistance. Proc Natl Acad Sci U S A 2023; 120:e2303114120. [PMID: 38019857 DOI: 10.1073/pnas.2303114120] [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: 02/22/2023] [Accepted: 09/27/2023] [Indexed: 12/01/2023] Open
Abstract
Drug resistance continues to impede the success of cancer treatments, creating a need for experimental model systems that are broad, yet simple, to allow the identification of mechanisms and novel countermeasures applicable to many cancer types. To address these needs, we investigated a set of engineered mammalian cell lines with synthetic gene circuits integrated into their genome that evolved resistance to Puromycin. We identified DNA amplification as the mechanism underlying drug resistance in 4 out of 6 replicate populations. Triplex-forming oligonucleotide (TFO) treatment combined with Puromycin could efficiently suppress the growth of cell populations with DNA amplification. Similar observations in human cancer cell lines suggest that TFOs could be broadly applicable to mitigate drug resistance, one of the major difficulties in treating cancer.
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Affiliation(s)
- Yiming Wan
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY 11794
- The Louis and Beatrice Laufer Center for Physical and Quantitative Biology, Stony Brook University, Stony Brook, NY 11794
| | - Quanhua Mu
- Department of Chemical and Biological Engineering, Division of Life Science, State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Hong Kong Special Administrative Region 999077, China
| | - Rafał Krzysztoń
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY 11794
- The Louis and Beatrice Laufer Center for Physical and Quantitative Biology, Stony Brook University, Stony Brook, NY 11794
| | - Joseph Cohen
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY 11794
- The Louis and Beatrice Laufer Center for Physical and Quantitative Biology, Stony Brook University, Stony Brook, NY 11794
| | - Damiano Coraci
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY 11794
- The Louis and Beatrice Laufer Center for Physical and Quantitative Biology, Stony Brook University, Stony Brook, NY 11794
| | - Christopher Helenek
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY 11794
- The Louis and Beatrice Laufer Center for Physical and Quantitative Biology, Stony Brook University, Stony Brook, NY 11794
| | | | - Annie Lin
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY 11794
- The Louis and Beatrice Laufer Center for Physical and Quantitative Biology, Stony Brook University, Stony Brook, NY 11794
| | - Kevin Farquhar
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY 11794
- The Louis and Beatrice Laufer Center for Physical and Quantitative Biology, Stony Brook University, Stony Brook, NY 11794
| | | | - Jiguang Wang
- Department of Chemical and Biological Engineering, Division of Life Science, State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Hong Kong Special Administrative Region 999077, China
| | - Gábor Balázsi
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY 11794
- The Louis and Beatrice Laufer Center for Physical and Quantitative Biology, Stony Brook University, Stony Brook, NY 11794
- Stony Brook Cancer Center, Stony Brook University, Stony Brook, NY 11794
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20
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Tang Q, Sensale S, Bond C, Xing J, Qiao A, Hugelier S, Arab A, Arya G, Lakadamyali M. Interplay between stochastic enzyme activity and microtubule stability drives detyrosination enrichment on microtubule subsets. Curr Biol 2023; 33:5169-5184.e8. [PMID: 37979580 PMCID: PMC10843832 DOI: 10.1016/j.cub.2023.10.068] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2023] [Revised: 08/03/2023] [Accepted: 10/30/2023] [Indexed: 11/20/2023]
Abstract
Microtubules in cells consist of functionally diverse subpopulations carrying distinct post-translational modifications (PTMs). Akin to the histone code, the tubulin code regulates a myriad of microtubule functions, ranging from intracellular transport to chromosome segregation. However, how individual PTMs only occur on subsets of microtubules to contribute to microtubule specialization is not well understood. In particular, microtubule detyrosination, the removal of the C-terminal tyrosine on α-tubulin subunits, marks the stable population of microtubules and modifies how microtubules interact with other microtubule-associated proteins to regulate a wide range of cellular processes. Previously, we found that in certain cell types, only ∼30% of microtubules are highly enriched with the detyrosination mark and that detyrosination spans most of the length of a microtubule, often adjacent to a completely tyrosinated microtubule. How the activity of a cytosolic detyrosinase, vasohibin (VASH), leads to only a small subpopulation of highly detyrosinated microtubules is unclear. Here, using quantitative super-resolution microscopy, we visualized nascent microtubule detyrosination events in cells consisting of 1-3 detyrosinated α-tubulin subunits after nocodazole washout. Microtubule detyrosination accumulates slowly and in a dispersed pattern across the microtubule length. By visualizing single molecules of VASH in live cells, we found that VASH engages with microtubules stochastically on a short timescale, suggesting limited removal of tyrosine per interaction, consistent with the super-resolution results. Combining these quantitative imaging results with simulations incorporating parameters from our experiments, we provide evidence for a stochastic model for cells to establish a subset of detyrosinated microtubules via a detyrosination-stabilization feedback mechanism.
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Affiliation(s)
- Qing Tang
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Sebastian Sensale
- Department of Mechanical Engineering and Materials Science, Duke University, Durham, NC 27708, USA; Department of Physics, Cleveland State University, Cleveland, OH 44115-2214, USA.
| | - Charles Bond
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Jiazheng Xing
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Andy Qiao
- Department of Mechanical Engineering and Materials Science, Duke University, Durham, NC 27708, USA
| | - Siewert Hugelier
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Arian Arab
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Gaurav Arya
- Department of Mechanical Engineering and Materials Science, Duke University, Durham, NC 27708, USA
| | - Melike Lakadamyali
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
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21
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Waigh TA, Korabel N. Heterogeneous anomalous transport in cellular and molecular biology. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2023; 86:126601. [PMID: 37863075 DOI: 10.1088/1361-6633/ad058f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Accepted: 10/20/2023] [Indexed: 10/22/2023]
Abstract
It is well established that a wide variety of phenomena in cellular and molecular biology involve anomalous transport e.g. the statistics for the motility of cells and molecules are fractional and do not conform to the archetypes of simple diffusion or ballistic transport. Recent research demonstrates that anomalous transport is in many cases heterogeneous in both time and space. Thus single anomalous exponents and single generalised diffusion coefficients are unable to satisfactorily describe many crucial phenomena in cellular and molecular biology. We consider advances in the field ofheterogeneous anomalous transport(HAT) highlighting: experimental techniques (single molecule methods, microscopy, image analysis, fluorescence correlation spectroscopy, inelastic neutron scattering, and nuclear magnetic resonance), theoretical tools for data analysis (robust statistical methods such as first passage probabilities, survival analysis, different varieties of mean square displacements, etc), analytic theory and generative theoretical models based on simulations. Special emphasis is made on high throughput analysis techniques based on machine learning and neural networks. Furthermore, we consider anomalous transport in the context of microrheology and the heterogeneous viscoelasticity of complex fluids. HAT in the wavefronts of reaction-diffusion systems is also considered since it plays an important role in morphogenesis and signalling. In addition, we present specific examples from cellular biology including embryonic cells, leucocytes, cancer cells, bacterial cells, bacterial biofilms, and eukaryotic microorganisms. Case studies from molecular biology include DNA, membranes, endosomal transport, endoplasmic reticula, mucins, globular proteins, and amyloids.
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Affiliation(s)
- Thomas Andrew Waigh
- Biological Physics, School of Physics and Astronomy, University of Manchester, Manchester M13 9PL, United Kingdom
| | - Nickolay Korabel
- Department of Mathematics, The University of Manchester, Manchester M13 9PL, United Kingdom
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22
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Abstract
Cells must tightly regulate their gene expression programs and yet rapidly respond to acute biochemical and biophysical cues within their environment. This information is transmitted to the nucleus through various signaling cascades, culminating in the activation or repression of target genes. Transcription factors (TFs) are key mediators of these signals, binding to specific regulatory elements within chromatin. While live-cell imaging has conclusively proven that TF-chromatin interactions are highly dynamic, how such transient interactions can have long-term impacts on developmental trajectories and disease progression is still largely unclear. In this review, we summarize our current understanding of the dynamic nature of TF functions, starting with a historical overview of early live-cell experiments. We highlight key factors that govern TF dynamics and how TF dynamics, in turn, affect downstream transcriptional bursting. Finally, we conclude with open challenges and emerging technologies that will further our understanding of transcriptional regulation.
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Affiliation(s)
- Kaustubh Wagh
- Laboratory of Receptor Biology and Gene Expression, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA; , ,
- Department of Physics, University of Maryland, College Park, Maryland, USA;
| | - Diana A Stavreva
- Laboratory of Receptor Biology and Gene Expression, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA; , ,
| | - Arpita Upadhyaya
- Department of Physics, University of Maryland, College Park, Maryland, USA;
- Institute for Physical Science and Technology, University of Maryland, College Park, Maryland, USA
| | - Gordon L Hager
- Laboratory of Receptor Biology and Gene Expression, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA; , ,
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23
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Mazzocca M, Loffreda A, Colombo E, Fillot T, Gnani D, Falletta P, Monteleone E, Capozi S, Bertrand E, Legube G, Lavagnino Z, Tacchetti C, Mazza D. Chromatin organization drives the search mechanism of nuclear factors. Nat Commun 2023; 14:6433. [PMID: 37833263 PMCID: PMC10575952 DOI: 10.1038/s41467-023-42133-5] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Accepted: 10/02/2023] [Indexed: 10/15/2023] Open
Abstract
Nuclear factors rapidly scan the genome for their targets, but the role of nuclear organization in such search is uncharted. Here we analyzed how multiple factors explore chromatin, combining live-cell single-molecule tracking with multifocal structured illumination of DNA density. We find that factors displaying higher bound fractions sample DNA-dense regions more exhaustively. Focusing on the tumor-suppressor p53, we demonstrate that it searches for targets by alternating between rapid diffusion in the interchromatin compartment and compact sampling of chromatin dense regions. Efficient targeting requires balanced interactions with chromatin: fusing p53 with an exogenous intrinsically disordered region potentiates p53-mediated target gene activation at low concentrations, but leads to condensates at higher levels, derailing its search and downregulating transcription. Our findings highlight the role of disordered regions on factors search and showcase a powerful method to generate traffic maps of the eukaryotic nucleus to dissect how its organization guides nuclear factors action.
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Affiliation(s)
- Matteo Mazzocca
- Università Vita-Salute San Raffaele, Via Olgettina 58, 20132, Milan, Italy
| | - Alessia Loffreda
- IRCCS Ospedale San Raffaele, Experimental Imaging Center, Via Olgettina 58, 20132, Milan, Italy
| | - Emanuele Colombo
- Università Vita-Salute San Raffaele, Via Olgettina 58, 20132, Milan, Italy
| | - Tom Fillot
- Università Vita-Salute San Raffaele, Via Olgettina 58, 20132, Milan, Italy
- IRCCS Ospedale San Raffaele, Experimental Imaging Center, Via Olgettina 58, 20132, Milan, Italy
| | - Daniela Gnani
- Università Vita-Salute San Raffaele, Via Olgettina 58, 20132, Milan, Italy
| | - Paola Falletta
- Università Vita-Salute San Raffaele, Via Olgettina 58, 20132, Milan, Italy
| | | | - Serena Capozi
- Institut de Génétique Moléculaire de Montpellier, CNRS, Montpellier, 34293, France
| | - Edouard Bertrand
- Institut de Génétique Moléculaire de Montpellier, CNRS, Montpellier, 34293, France
| | - Gaelle Legube
- MCD, Centre de Biologie Intégrative (CBI), CNRS, Université de Toulouse, UT3, Toulouse, France
| | - Zeno Lavagnino
- IRCCS Ospedale San Raffaele, Experimental Imaging Center, Via Olgettina 58, 20132, Milan, Italy
- IFOM ETS- The AIRC Institute of Molecular Oncology-Via Adamello 16, 20139, Milan, Italy
| | - Carlo Tacchetti
- Università Vita-Salute San Raffaele, Via Olgettina 58, 20132, Milan, Italy
- IRCCS Ospedale San Raffaele, Experimental Imaging Center, Via Olgettina 58, 20132, Milan, Italy
| | - Davide Mazza
- Università Vita-Salute San Raffaele, Via Olgettina 58, 20132, Milan, Italy.
- IRCCS Ospedale San Raffaele, Experimental Imaging Center, Via Olgettina 58, 20132, Milan, Italy.
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24
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Chen L, Zhang Z, Han Q, Maity BK, Rodrigues L, Zboril E, Adhikari R, Ko SH, Li X, Yoshida SR, Xue P, Smith E, Xu K, Wang Q, Huang THM, Chong S, Liu Z. Hormone-induced enhancer assembly requires an optimal level of hormone receptor multivalent interactions. Mol Cell 2023; 83:3438-3456.e12. [PMID: 37738977 PMCID: PMC10592010 DOI: 10.1016/j.molcel.2023.08.027] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 07/11/2023] [Accepted: 08/29/2023] [Indexed: 09/24/2023]
Abstract
Transcription factors (TFs) activate enhancers to drive cell-specific gene programs in response to signals, but our understanding of enhancer assembly during signaling events is incomplete. Here, we show that androgen receptor (AR) forms condensates through multivalent interactions mediated by its N-terminal intrinsically disordered region (IDR) to orchestrate enhancer assembly in response to androgen signaling. AR IDR can be substituted by IDRs from selective proteins for AR condensation capacity and its function on enhancers. Expansion of the poly(Q) track within AR IDR results in a higher AR condensation propensity as measured by multiple methods, including live-cell single-molecule microscopy. Either weakening or strengthening AR condensation propensity impairs its heterotypic multivalent interactions with other enhancer components and diminishes its transcriptional activity. Our work reveals the requirement of an optimal level of AR condensation in mediating enhancer assembly and suggests that alteration of the fine-tuned multivalent IDR-IDR interactions might underlie AR-related human pathologies.
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Affiliation(s)
- Lizhen Chen
- Department of Molecular Medicine, Mays Cancer Center, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA; Barshop Institute for Longevity and Aging Studies, Department of Cell Systems and Anatomy, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA.
| | - Zhao Zhang
- Department of Molecular Medicine, Mays Cancer Center, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - Qinyu Han
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Barun K Maity
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Leticia Rodrigues
- Department of Molecular Medicine, Mays Cancer Center, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - Emily Zboril
- Department of Molecular Medicine, Mays Cancer Center, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - Rashmi Adhikari
- Department of Molecular Medicine, Mays Cancer Center, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - Su-Hyuk Ko
- Department of Molecular Medicine, Mays Cancer Center, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA; Barshop Institute for Longevity and Aging Studies, Department of Cell Systems and Anatomy, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - Xin Li
- Department of Molecular Medicine, Mays Cancer Center, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA; Barshop Institute for Longevity and Aging Studies, Department of Cell Systems and Anatomy, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - Shawn R Yoshida
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA; Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Pengya Xue
- Department of Molecular Medicine, Mays Cancer Center, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - Emilie Smith
- Department of Molecular Medicine, Mays Cancer Center, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - Kexin Xu
- Department of Molecular Medicine, Mays Cancer Center, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - Qianben Wang
- Department of Pathology, Duke Cancer Institute, Duke University School of Medicine, Durham, NC 27710, USA
| | - Tim Hui-Ming Huang
- Department of Molecular Medicine, Mays Cancer Center, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - Shasha Chong
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA.
| | - Zhijie Liu
- Department of Molecular Medicine, Mays Cancer Center, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA.
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25
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Manrubia S, Cuesta JA. Physics of diffusion in viral genome evolution. Proc Natl Acad Sci U S A 2023; 120:e2310999120. [PMID: 37556488 PMCID: PMC10450443 DOI: 10.1073/pnas.2310999120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/11/2023] Open
Affiliation(s)
- Susanna Manrubia
- Departamento de Biología de Sistemas, Centro Nacional de Biotecnología (CSIC), 28049Madrid, Spain
- Grupo Interdisciplinar de Sistemas Complejos, 28911Madrid, Spain
| | - José A. Cuesta
- Grupo Interdisciplinar de Sistemas Complejos, 28911Madrid, Spain
- Instituto de Biocomputación y Física de Sistemas Complejos, Campus Río Ebro, Universidad de Zaragoza, 50018Zaragoza, Spain
- Departamento de Matemáticas, Universidad Carlos III de Madrid, 28911Leganés, Spain
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26
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Price RM, Budzyński MA, Shen J, Mitchell JE, Kwan JJ, Teves S. Heat shock transcription factors demonstrate a distinct mode of interaction with mitotic chromosomes. Nucleic Acids Res 2023; 51:5040-5055. [PMID: 37114996 PMCID: PMC10250243 DOI: 10.1093/nar/gkad304] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Revised: 04/05/2023] [Accepted: 04/11/2023] [Indexed: 04/29/2023] Open
Abstract
A large number of transcription factors have been shown to bind and interact with mitotic chromosomes, which may promote the efficient reactivation of transcriptional programs following cell division. Although the DNA-binding domain (DBD) contributes strongly to TF behavior, the mitotic behaviors of TFs from the same DBD family may vary. To define the mechanisms governing TF behavior during mitosis in mouse embryonic stem cells, we examined two related TFs: Heat Shock Factor 1 and 2 (HSF1 and HSF2). We found that HSF2 maintains site-specific binding genome-wide during mitosis, whereas HSF1 binding is somewhat decreased. Surprisingly, live-cell imaging shows that both factors appear excluded from mitotic chromosomes to the same degree, and are similarly more dynamic in mitosis than in interphase. Exclusion from mitotic DNA is not due to extrinsic factors like nuclear import and export mechanisms. Rather, we found that the HSF DBDs can coat mitotic chromosomes, and that HSF2 DBD is able to establish site-specific binding. These data further confirm that site-specific binding and chromosome coating are independent properties, and that for some TFs, mitotic behavior is largely determined by the non-DBD regions.
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Affiliation(s)
- Rachel M Price
- Department of Biochemistry and Molecular Biology, Life Sciences Institute, University of British Columbia, 2350 Health Sciences Mall, Vancouver BC V6T 1Z3, Canada
| | - Marek A Budzyński
- Department of Biochemistry and Molecular Biology, Life Sciences Institute, University of British Columbia, 2350 Health Sciences Mall, Vancouver BC V6T 1Z3, Canada
| | - Junzhou Shen
- Department of Biochemistry and Molecular Biology, Life Sciences Institute, University of British Columbia, 2350 Health Sciences Mall, Vancouver BC V6T 1Z3, Canada
| | - Jennifer E Mitchell
- Department of Biochemistry and Molecular Biology, Life Sciences Institute, University of British Columbia, 2350 Health Sciences Mall, Vancouver BC V6T 1Z3, Canada
| | - James Z J Kwan
- Department of Biochemistry and Molecular Biology, Life Sciences Institute, University of British Columbia, 2350 Health Sciences Mall, Vancouver BC V6T 1Z3, Canada
| | - Sheila S Teves
- Department of Biochemistry and Molecular Biology, Life Sciences Institute, University of British Columbia, 2350 Health Sciences Mall, Vancouver BC V6T 1Z3, Canada
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27
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Dahal L, Walther N, Tjian R, Darzacq X, Graham TG. Single-molecule tracking (SMT): a window into live-cell transcription biochemistry. Biochem Soc Trans 2023; 51:557-569. [PMID: 36876879 PMCID: PMC10212543 DOI: 10.1042/bst20221242] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Revised: 02/15/2023] [Accepted: 02/16/2023] [Indexed: 03/07/2023]
Abstract
How molecules interact governs how they move. Single-molecule tracking (SMT) thus provides a unique window into the dynamic interactions of biomolecules within live cells. Using transcription regulation as a case study, we describe how SMT works, what it can tell us about molecular biology, and how it has changed our perspective on the inner workings of the nucleus. We also describe what SMT cannot yet tell us and how new technical advances seek to overcome its limitations. This ongoing progress will be imperative to address outstanding questions about how dynamic molecular machines function in live cells.
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Affiliation(s)
- Liza Dahal
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, U.S.A
- Howard Hughes Medical Institute, University of California, Berkeley, Berkeley, U.S.A
- Li Ka Shing Center for Biomedical & Health Sciences, University of California, Berkeley, Berkeley, U.S.A
| | - Nike Walther
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, U.S.A
- Li Ka Shing Center for Biomedical & Health Sciences, University of California, Berkeley, Berkeley, U.S.A
| | - Robert Tjian
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, U.S.A
- Howard Hughes Medical Institute, University of California, Berkeley, Berkeley, U.S.A
- Li Ka Shing Center for Biomedical & Health Sciences, University of California, Berkeley, Berkeley, U.S.A
| | - Xavier Darzacq
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, U.S.A
- Li Ka Shing Center for Biomedical & Health Sciences, University of California, Berkeley, Berkeley, U.S.A
| | - Thomas G.W. Graham
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, U.S.A
- Howard Hughes Medical Institute, University of California, Berkeley, Berkeley, U.S.A
- Li Ka Shing Center for Biomedical & Health Sciences, University of California, Berkeley, Berkeley, U.S.A
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28
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He Y, Zhang Q, Wang S, Chen Z, Cui Z, Guo ZH, Huang DS. Predicting the Sequence Specificities of DNA-Binding Proteins by DNA Fine-Tuned Language Model With Decaying Learning Rates. IEEE/ACM TRANSACTIONS ON COMPUTATIONAL BIOLOGY AND BIOINFORMATICS 2023; 20:616-624. [PMID: 35389869 DOI: 10.1109/tcbb.2022.3165592] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
DNA-binding proteins (DBPs) play vital roles in the regulation of biological systems. Although there are already many deep learning methods for predicting the sequence specificities of DBPs, they face two challenges as follows. Classic deep learning methods for DBPs prediction usually fail to capture the dependencies between genomic sequences since their commonly used one-hot codes are mutually orthogonal. Besides, these methods usually perform poorly when samples are inadequate. To address these two challenges, we developed a novel language model for mining DBPs using human genomic data and ChIP-seq datasets with decaying learning rates, named DNA Fine-tuned Language Model (DFLM). It can capture the dependencies between genome sequences based on the context of human genomic data and then fine-tune the features of DBPs tasks using different ChIP-seq datasets. First, we compared DFLM with the existing widely used methods on 69 datasets and we achieved excellent performance. Moreover, we conducted comparative experiments on complex DBPs and small datasets. The results show that DFLM still achieved a significant improvement. Finally, through visualization analysis of one-hot encoding and DFLM, we found that one-hot encoding completely cut off the dependencies of DNA sequences themselves, while DFLM using language models can well represent the dependency of DNA sequences. Source code are available at: https://github.com/Deep-Bioinfo/DFLM.
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29
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Ball DA, Jalloh B, Karpova TS. Impact of Saccharomyces cerevisiae on the Field of Single-Molecule Biophysics. Int J Mol Sci 2022; 23:15895. [PMID: 36555532 PMCID: PMC9781480 DOI: 10.3390/ijms232415895] [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: 11/04/2022] [Revised: 12/10/2022] [Accepted: 12/11/2022] [Indexed: 12/15/2022] Open
Abstract
Cellular functions depend on the dynamic assembly of protein regulator complexes at specific cellular locations. Single Molecule Tracking (SMT) is a method of choice for the biochemical characterization of protein dynamics in vitro and in vivo. SMT follows individual molecules in live cells and provides direct information about their behavior. SMT was successfully applied to mammalian models. However, mammalian cells provide a complex environment where protein mobility depends on numerous factors that are difficult to control experimentally. Therefore, yeast cells, which are unicellular and well-studied with a small and completely sequenced genome, provide an attractive alternative for SMT. The simplicity of organization, ease of genetic manipulation, and tolerance to gene fusions all make yeast a great model for quantifying the kinetics of major enzymes, membrane proteins, and nuclear and cellular bodies. However, very few researchers apply SMT techniques to yeast. Our goal is to promote SMT in yeast to a wider research community. Our review serves a dual purpose. We explain how SMT is conducted in yeast cells, and we discuss the latest insights from yeast SMT while putting them in perspective with SMT of higher eukaryotes.
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Affiliation(s)
| | | | - Tatiana S. Karpova
- CCR/LRBGE Optical Microscopy Core, National Cancer Institute, National Institutes of Health, Bethesda, MD 20852, USA
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30
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Punia B, Chaudhury S. Theoretical insights into the full description of DNA target search by subdiffusing proteins. Phys Chem Chem Phys 2022; 24:29074-29083. [PMID: 36440504 DOI: 10.1039/d2cp04934a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
DNA binding proteins (DBPs) diffuse in the cytoplasm to recognise and bind with their respective target sites on the DNA to initiate several biologically important processes. The first passage time distributions (FPTDs) of DBPs are useful in quantifying the timescales of the most-probable search paths in addition to the mean value of the distribution which, strikingly, are decades of order apart in time. However, extremely crowded in vivo conditions or the viscoelasticity of the cellular medium among other factors causes biomolecules to exhibit anomalous diffusion which is usually overlooked in most theoretical studies. We have obtained approximate analytical expressions of a general FPTD and the two characteristic timescales that are valid for any single subdiffusing protein searching for its target in vivo. Our results can be applied to single-particle tracking experiments of target search.
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Affiliation(s)
- Bhawakshi Punia
- Department of Chemistry, Indian Institute of Science Education and Research, Dr Homi Bhabha Road, Pune, Maharashtra, India.
| | - Srabanti Chaudhury
- Department of Chemistry, Indian Institute of Science Education and Research, Dr Homi Bhabha Road, Pune, Maharashtra, India.
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31
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Heckert A, Dahal L, Tjian R, Darzacq X. Recovering mixtures of fast-diffusing states from short single-particle trajectories. eLife 2022; 11:e70169. [PMID: 36066004 PMCID: PMC9451534 DOI: 10.7554/elife.70169] [Citation(s) in RCA: 42] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Accepted: 08/04/2022] [Indexed: 12/15/2022] Open
Abstract
Single-particle tracking (SPT) directly measures the dynamics of proteins in living cells and is a powerful tool to dissect molecular mechanisms of cellular regulation. Interpretation of SPT with fast-diffusing proteins in mammalian cells, however, is complicated by technical limitations imposed by fast image acquisition. These limitations include short trajectory length due to photobleaching and shallow depth of field, high localization error due to the low photon budget imposed by short integration times, and cell-to-cell variability. To address these issues, we investigated methods inspired by Bayesian nonparametrics to infer distributions of state parameters from SPT data with short trajectories, variable localization precision, and absence of prior knowledge about the number of underlying states. We discuss the advantages and disadvantages of these approaches relative to other frameworks for SPT analysis.
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Affiliation(s)
- Alec Heckert
- Department of Molecular and Cell Biology, Li Ka Shing Center for Biomedical and Health Sciences, University of California, BerkeleyBerkeleyUnited States
| | - Liza Dahal
- Department of Molecular and Cell Biology, Li Ka Shing Center for Biomedical and Health Sciences, University of California, BerkeleyBerkeleyUnited States
- CIRM Center of Excellence, University of California, BerkeleyBerkeleyUnited States
| | - Robert Tjian
- CIRM Center of Excellence, University of California, BerkeleyBerkeleyUnited States
- Howard Hughes Medical InstituteBerkeleyUnited States
| | - Xavier Darzacq
- Department of Molecular and Cell Biology, Li Ka Shing Center for Biomedical and Health Sciences, University of California, BerkeleyBerkeleyUnited States
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32
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Stochastic particle unbinding modulates growth dynamics and size of transcription factor condensates in living cells. Proc Natl Acad Sci U S A 2022; 119:e2200667119. [PMID: 35881789 PMCID: PMC9351496 DOI: 10.1073/pnas.2200667119] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Living cells organize internal compartments by forming molecular condensates that operate as versatile biochemical “hubs.” Their occurrence is particularly relevant in the nucleus where they regulate, amongst others, gene transcription. However, the biophysics of transcription factor (TF) condensation remains highly unexplored. Through single-molecule experiments in living cells, theory, and simulations, we assessed the diffusion, growth dynamics, and sizes of TF condensates of the nuclear progesterone receptor (PR). Interestingly, PR condensates obey classical growth dynamics at shorter times but deviate at longer times, reaching finite sizes at steady-state. We demonstrate that condensate growth dynamics and nanoscale-size arrested growth is regulated by molecular escaping from condensates, providing an exquisite control of condensate size in nonequilibrium systems such as living cells. Liquid–liquid phase separation (LLPS) is emerging as a key physical principle for biological organization inside living cells, forming condensates that play important regulatory roles. Inside living nuclei, transcription factor (TF) condensates regulate transcriptional initiation and amplify the transcriptional output of expressed genes. However, the biophysical parameters controlling TF condensation are still poorly understood. Here we applied a battery of single-molecule imaging, theory, and simulations to investigate the physical properties of TF condensates of the progesterone receptor (PR) in living cells. Analysis of individual PR trajectories at different ligand concentrations showed marked signatures of a ligand-tunable LLPS process. Using a machine learning architecture, we found that receptor diffusion within condensates follows fractional Brownian motion resulting from viscoelastic interactions with chromatin. Interestingly, condensate growth dynamics at shorter times is dominated by Brownian motion coalescence (BMC), followed by a growth plateau at longer timescales that result in nanoscale condensate sizes. To rationalize these observations, we extended on the BMC model by including the stochastic unbinding of particles within condensates. Our model reproduced the BMC behavior together with finite condensate sizes at the steady state, fully recapitulating our experimental data. Overall, our results are consistent with condensate growth dynamics being regulated by the escaping probability of PR molecules from condensates. The interplay between condensation assembly and molecular escaping maintains an optimum physical condensate size. Such phenomena must have implications for the biophysical regulation of other nuclear condensates and could also operate in multiple biological scenarios.
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33
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Mehra D, Adhikari S, Banerjee C, Puchner EM. Characterizing locus specific chromatin structure and dynamics with correlative conventional and super-resolution imaging in living cells. Nucleic Acids Res 2022; 50:e78. [PMID: 35524554 PMCID: PMC9303368 DOI: 10.1093/nar/gkac314] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 04/08/2022] [Accepted: 05/02/2022] [Indexed: 11/23/2022] Open
Abstract
The dynamic rearrangement of chromatin is critical for gene regulation, but mapping both the spatial organization of chromatin and its dynamics remains a challenge. Many structural conformations are too small to be resolved via conventional fluorescence microscopy and the long acquisition time of super-resolution photoactivated localization microscopy (PALM) precludes the structural characterization of chromatin below the optical diffraction limit in living cells due to chromatin motion. Here we develop a correlative conventional fluorescence and PALM imaging approach to quantitatively map time-averaged chromatin structure and dynamics below the optical diffraction limit in living cells. By assigning localizations to a locus as it moves, we reliably discriminate between bound and unbound dCas9 molecules, whose mobilities overlap. Our approach accounts for changes in DNA mobility and relates local chromatin motion to larger scale domain movement. In our experimental system, we show that compacted telomeres move faster and have a higher density of bound dCas9 molecules, but the relative motion of those molecules is more restricted than in less compacted telomeres. Correlative conventional and PALM imaging therefore improves the ability to analyze the mobility and time-averaged nanoscopic structural features of locus specific chromatin with single molecule sensitivity and yields unprecedented insights across length and time scales.
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Affiliation(s)
- Dushyant Mehra
- School of Physics and Astronomy, University of Minnesota, Minneapolis MN, USA
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester MN, USA
| | - Santosh Adhikari
- School of Physics and Astronomy, University of Minnesota, Minneapolis MN, USA
| | - Chiranjib Banerjee
- School of Physics and Astronomy, University of Minnesota, Minneapolis MN, USA
| | - Elias M Puchner
- School of Physics and Astronomy, University of Minnesota, Minneapolis MN, USA
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34
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Loell K, Wu Y, Staller MV, Cohen B. Activation domains can decouple the mean and noise of gene expression. Cell Rep 2022; 40:111118. [PMID: 35858548 PMCID: PMC9912357 DOI: 10.1016/j.celrep.2022.111118] [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: 09/08/2021] [Revised: 01/18/2022] [Accepted: 06/28/2022] [Indexed: 11/03/2022] Open
Abstract
Regulatory mechanisms set a gene's average level of expression, but a gene's expression constantly fluctuates around that average. These stochastic fluctuations, or expression noise, play a role in cell-fate transitions, bet hedging in microbes, and the development of chemotherapeutic resistance in cancer. An outstanding question is what regulatory mechanisms contribute to noise. Here, we demonstrate that, for a fixed mean level of expression, strong activation domains (ADs) at low abundance produce high expression noise, while weak ADs at high abundance generate lower expression noise. We conclude that differences in noise can be explained by the interplay between a TF's nuclear concentration and the strength of its AD's effect on mean expression, without invoking differences between classes of ADs. These results raise the possibility of engineering gene expression noise independently of mean levels in synthetic biology contexts and provide a potential mechanism for natural selection to tune the noisiness of gene expression.
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Affiliation(s)
- Kaiser Loell
- Department of Genetics, Washington University School of Medicine in St. Louis, St. Louis, MO 63108, USA,The Edison Family Center for Genome Sciences & Systems Biology, Washington University School of Medicine in St. Louis, St. Louis, MO 63108, USA
| | - Yawei Wu
- Department of Genetics, Washington University School of Medicine in St. Louis, St. Louis, MO 63108, USA,The Edison Family Center for Genome Sciences & Systems Biology, Washington University School of Medicine in St. Louis, St. Louis, MO 63108, USA
| | - Max V. Staller
- Center for Computational Biology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Barak Cohen
- Department of Genetics, Washington University School of Medicine in St. Louis, St. Louis, MO 63108, USA; The Edison Family Center for Genome Sciences & Systems Biology, Washington University School of Medicine in St. Louis, St. Louis, MO 63108, USA.
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35
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Solano A, Lou J, Scipioni L, Gratton E, Hinde E. Radial pair correlation of molecular brightness fluctuations maps protein diffusion as a function of oligomeric state within live-cell nuclear architecture. Biophys J 2022; 121:2152-2167. [PMID: 35490296 PMCID: PMC9247470 DOI: 10.1016/j.bpj.2022.04.030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Revised: 11/16/2021] [Accepted: 04/26/2022] [Indexed: 11/22/2022] Open
Abstract
Nuclear proteins can modulate their DNA binding activity and the exploration volume available during DNA target search by self-associating into higher-order oligomers. Directly tracking this process in the nucleoplasm of a living cell is, however, a complex task. Thus, here we present a microscopy method based on radial pair correlation of molecular brightness fluctuations (radial pCOMB) that can extract the mobility of a fluorescently tagged nuclear protein as a function of its oligomeric state and spatiotemporally map the anisotropy of this parameter with respect to nuclear architecture. By simply performing a rapid frame scan acquisition, radial pCOMB has the capacity to detect, within each pixel, protein oligomer formation and the size-dependent obstruction nuclear architecture imparts on this complex's transport across sub-micrometer distances. From application of radial pCOMB to an oligomeric transcription factor and DNA repair protein, we demonstrate that homo-oligomer formation differentially regulates chromatin accessibility and interaction with the DNA template.
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Affiliation(s)
- Ashleigh Solano
- School of Physics, University of Melbourne; Department of Biochemistry and Pharmacology, University of Melbourne
| | - Jieqiong Lou
- School of Physics, University of Melbourne; Department of Biochemistry and Pharmacology, University of Melbourne
| | - Lorenzo Scipioni
- Department of Biomedical Engineering, University of California, Irvine
| | - Enrico Gratton
- Department of Biomedical Engineering, University of California, Irvine.
| | - Elizabeth Hinde
- School of Physics, University of Melbourne; Department of Biochemistry and Pharmacology, University of Melbourne.
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36
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Nollmann M, Bennabi I, Götz M, Gregor T. The Impact of Space and Time on the Functional Output of the Genome. Cold Spring Harb Perspect Biol 2022; 14:a040378. [PMID: 34230036 PMCID: PMC8733053 DOI: 10.1101/cshperspect.a040378] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Over the past two decades, it has become clear that the multiscale spatial and temporal organization of the genome has important implications for nuclear function. This review centers on insights gained from recent advances in light microscopy on our understanding of transcription. We discuss spatial and temporal aspects that shape nuclear order and their consequences on regulatory components, focusing on genomic scales most relevant to function. The emerging picture is that spatiotemporal constraints increase the complexity in transcriptional regulation, highlighting new challenges, such as uncertainty about how information travels from molecular factors through the genome and space to generate a functional output.
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Affiliation(s)
- Marcelo Nollmann
- Centre de Biologie Structurale, CNRS UMR5048, INSERM U1054, Univ Montpellier, 34090 Montpellier, France
| | - Isma Bennabi
- Department of Stem Cell and Developmental Biology, CNRS UMR3738, Institut Pasteur, 75015 Paris, France
| | - Markus Götz
- Centre de Biologie Structurale, CNRS UMR5048, INSERM U1054, Univ Montpellier, 34090 Montpellier, France
| | - Thomas Gregor
- Department of Stem Cell and Developmental Biology, CNRS UMR3738, Institut Pasteur, 75015 Paris, France
- Joseph Henry Laboratory of Physics & Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, New Jersey 08544, USA
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37
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Kenworthy CA, Haque N, Liou SH, Chandris P, Wong V, Dziuba P, Lavis LD, Liu WL, Singer RH, Coleman RA. Bromodomains regulate dynamic targeting of the PBAF chromatin-remodeling complex to chromatin hubs. Biophys J 2022; 121:1738-1752. [PMID: 35364106 PMCID: PMC9117891 DOI: 10.1016/j.bpj.2022.03.027] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Revised: 09/20/2021] [Accepted: 03/24/2022] [Indexed: 11/12/2022] Open
Abstract
Chromatin remodelers actively target arrays of acetylated nucleosomes at select enhancers and promoters to facilitate or shut down the repeated recruitment of RNA polymerase II during transcriptional bursting. It is poorly understood how chromatin remodelers such as PBAF dynamically target different chromatin states inside a live cell. Our live-cell single-molecule fluorescence microscopy study reveals chromatin hubs throughout the nucleus where PBAF rapidly cycles on and off the genome. Deletion of PBAF's bromodomains impairs targeting and stable engagement of chromatin in hubs. Dual color imaging reveals that PBAF targets both euchromatic and heterochromatic hubs with distinct genome-binding kinetic profiles that mimic chromatin stability. Removal of PBAF's bromodomains stabilizes H3.3 binding within chromatin, indicating that bromodomains may play a direct role in remodeling of the nucleosome. Our data suggests that PBAF's dynamic bromodomain-mediated engagement of a nucleosome may reflect the chromatin-remodeling potential of differentially bound chromatin states.
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Affiliation(s)
- Charles A Kenworthy
- Gruss-Lipper Biophotonics Center, Department of Cell Biology, Albert Einstein College of Medicine, New York
| | - Nayem Haque
- Gruss-Lipper Biophotonics Center, Department of Cell Biology, Albert Einstein College of Medicine, New York
| | - Shu-Hao Liou
- Gruss-Lipper Biophotonics Center, Department of Cell Biology, Albert Einstein College of Medicine, New York
| | - Panagiotis Chandris
- Section on High Resolution Optical Imaging, National Institute on Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, Maryland
| | - Vincent Wong
- Gruss-Lipper Biophotonics Center, Department of Cell Biology, Albert Einstein College of Medicine, New York
| | - Patrycja Dziuba
- Gruss-Lipper Biophotonics Center, Department of Cell Biology, Albert Einstein College of Medicine, New York
| | - Luke D Lavis
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, Virginia
| | - Wei-Li Liu
- Gruss-Lipper Biophotonics Center, Department of Cell Biology, Albert Einstein College of Medicine, New York
| | - Robert H Singer
- Gruss-Lipper Biophotonics Center, Department of Cell Biology, Albert Einstein College of Medicine, New York; Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, Virginia
| | - Robert A Coleman
- Gruss-Lipper Biophotonics Center, Department of Cell Biology, Albert Einstein College of Medicine, New York.
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38
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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: 26] [Impact Index Per Article: 8.7] [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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39
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Irgen-Gioro S, Yoshida S, Walling V, Chong S. Fixation can change the appearance of phase separation in living cells. eLife 2022; 11:79903. [PMID: 36444977 PMCID: PMC9817179 DOI: 10.7554/elife.79903] [Citation(s) in RCA: 61] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Accepted: 11/28/2022] [Indexed: 11/30/2022] Open
Abstract
Fixing cells with paraformaldehyde (PFA) is an essential step in numerous biological techniques as it is thought to preserve a snapshot of biomolecular transactions in living cells. Fixed-cell imaging techniques such as immunofluorescence have been widely used to detect liquid-liquid phase separation (LLPS) in vivo. Here, we compared images, before and after fixation, of cells expressing intrinsically disordered proteins that are able to undergo LLPS. Surprisingly, we found that PFA fixation can both enhance and diminish putative LLPS behaviors. For specific proteins, fixation can even cause their droplet-like puncta to artificially appear in cells that do not have any detectable puncta in the live condition. Fixing cells in the presence of glycine, a molecule that modulates fixation rates, can reverse the fixation effect from enhancing to diminishing LLPS appearance. We further established a kinetic model of fixation in the context of dynamic protein-protein interactions. Simulations based on the model suggest that protein localization in fixed cells depends on an intricate balance of protein-protein interaction dynamics, the overall rate of fixation, and notably, the difference between fixation rates of different proteins. Consistent with simulations, live-cell single-molecule imaging experiments showed that a fast overall rate of fixation relative to protein-protein interaction dynamics can minimize fixation artifacts. Our work reveals that PFA fixation changes the appearance of LLPS from living cells, presents a caveat in studying LLPS using fixation-based methods, and suggests a mechanism underlying the fixation artifact.
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Affiliation(s)
- Shawn Irgen-Gioro
- Division of Chemistry and Chemical Engineering, California Institute of TechnologyPasadenaUnited States
| | - Shawn Yoshida
- Division of Chemistry and Chemical Engineering, California Institute of TechnologyPasadenaUnited States,Division of Biology and Biological Engineering, California Institute of TechnologyPasadenaUnited States
| | - Victoria Walling
- Division of Chemistry and Chemical Engineering, California Institute of TechnologyPasadenaUnited States
| | - Shasha Chong
- Division of Chemistry and Chemical Engineering, California Institute of TechnologyPasadenaUnited States
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40
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Nozaki T, Chang F, Weiner B, Kleckner N. High Temporal Resolution 3D Live-Cell Imaging of Budding Yeast Meiosis Defines Discontinuous Actin/Telomere-Mediated Chromosome Motion, Correlated Nuclear Envelope Deformation and Actin Filament Dynamics. Front Cell Dev Biol 2021; 9:687132. [PMID: 34900979 PMCID: PMC8656277 DOI: 10.3389/fcell.2021.687132] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Accepted: 10/05/2021] [Indexed: 11/24/2022] Open
Abstract
Chromosome movement is prominent at mid-meiotic prophase and is proposed to enhance the efficiency and/or stringency of homolog pairing and/or to help prevent or resolve topological entanglements. Here, we combine fluorescent repressor operator system (FROS) labeling with three-dimensional (3D) live-cell imaging at high spatio-temporal resolution to define the detailed kinetics of mid-meiotic prophase motion for a single telomere-proximal locus in budding yeast. Telomere motions can be grouped into three general categories: (i) pauses, in which the telomere “jiggles in place”; (ii) rapid, straight/curvilinear motion which reflects Myo2/actin-mediated transport of the monitored telomere; and (iii) slower directional motions, most of which likely reflect indirectly promoted motion of the monitored telomere in coordination with actin-mediated motion of an unmarked telomere. These and other findings highlight the importance of dynamic assembly/disassembly of telomere/LINC/actin ensembles and also suggest important roles for nuclear envelope deformations promoted by actin-mediated telomere/LINC movement. The presented low-SNR (signal-to-noise ratio) imaging methodology provides opportunities for future exploration of homolog pairing and related phenomena.
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Affiliation(s)
- Tadasu Nozaki
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA, United States
| | - Frederick Chang
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA, United States
| | - Beth Weiner
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA, United States
| | - Nancy Kleckner
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA, United States
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41
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Wang Z, Deng W. Dynamic transcription regulation at the single-molecule level. Dev Biol 2021; 482:67-81. [PMID: 34896367 DOI: 10.1016/j.ydbio.2021.11.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Revised: 11/14/2021] [Accepted: 11/15/2021] [Indexed: 02/07/2023]
Abstract
Cell fate changes during development, differentiation, and reprogramming are largely controlled at the transcription level. The DNA-binding transcription factors (TFs) often act in a combinatorial fashion to alter chromatin states and drive cell type-specific gene expression. Recent advances in fluorescent microscopy technologies have enabled direct visualization of biomolecules involved in the process of transcription and its regulatory events at the single-molecule level in living cells. Remarkably, imaging and tracking individual TF molecules at high temporal and spatial resolution revealed that they are highly dynamic in searching and binding cognate targets, rather than static and binding constantly. In combination with investigation using techniques from biochemistry, structure biology, genetics, and genomics, a more well-rounded view of transcription regulation is emerging. In this review, we briefly cover the technical aspects of live-cell single-molecule imaging and focus on the biological relevance and interpretation of the single-molecule dynamic features of transcription regulatory events observed in the native chromatin environment of living eukaryotic cells. We also discuss how these dynamic features might shed light on mechanistic understanding of transcription regulation.
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Affiliation(s)
- Zuhui Wang
- Biomedical Pioneering Innovation Center (BIOPIC), Peking University, Beijing, 100871, China; Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, 100871, China
| | - Wulan Deng
- Biomedical Pioneering Innovation Center (BIOPIC), Peking University, Beijing, 100871, China; Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, 100871, China; Beijing Advanced Innovation Center for Genomics (ICG), Peking University, Beijing, 100871, China; Peking-Tsinghua Center for Life Sciences (CLS), Peking University, Beijing, 100871, China; School of Life Sciences, Peking University, Beijing, 100871, China.
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42
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Seebauer CT, Graus MS, Huang L, McCann AJ, Wylie-Sears J, Fontaine FR, Karnezis T, Zurakowski D, Staffa SJ, Meunier FA, Mulliken JB, Bischoff J, Francois M. Non-β-blocker enantiomers of propranolol and atenolol inhibit vasculogenesis in infantile hemangioma. J Clin Invest 2021; 132:151109. [PMID: 34874911 PMCID: PMC8803322 DOI: 10.1172/jci151109] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Accepted: 12/02/2021] [Indexed: 12/02/2022] Open
Abstract
Propranolol and atenolol, current therapies for problematic infantile hemangioma (IH), are composed of R(+) and S(–) enantiomers: the R(+) enantiomer is largely devoid of beta blocker activity. We investigated the effect of R(+) enantiomers of propranolol and atenolol on the formation of IH-like blood vessels from hemangioma stem cells (HemSCs) in a murine xenograft model. Both R(+) enantiomers inhibited HemSC vessel formation in vivo. In vitro, similar to R(+) propranolol, both atenolol and its R(+) enantiomer inhibited HemSC to endothelial cell differentiation. As our previous work implicated the transcription factor sex-determining region Y (SRY) box transcription factor 18 (SOX18) in propranolol-mediated inhibition of HemSC to endothelial differentiation, we tested in parallel a known SOX18 small-molecule inhibitor (Sm4) and show that this compound inhibited HemSC vessel formation in vivo with efficacy similar to that seen with the R(+) enantiomers. We next examined how R(+) propranolol alters SOX18 transcriptional activity. Using a suite of biochemical, biophysical, and quantitative molecular imaging assays, we show that R(+) propranolol directly interfered with SOX18 target gene trans-activation, disrupted SOX18-chromatin binding dynamics, and reduced SOX18 dimer formation. We propose that the R(+) enantiomers of widely used beta blockers could be repurposed to increase the efficiency of current IH treatment and lower adverse associated side effects.
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Affiliation(s)
- Caroline T Seebauer
- Department of Surgery, Boston Children's Hospital and Harvard Medical School, Boston, United States of America
| | - Matthew S Graus
- David Richmond Laboratory for Cardiovascular Development, University of Sydney, Sydney, Australia
| | - Lan Huang
- Department of Surgery, Boston Children's Hospital and Harvard Medical School, Boston, United States of America
| | - Alex J McCann
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Australia
| | - Jill Wylie-Sears
- Department of Surgery, Boston Children's Hospital and Harvard Medical School, Boston, United States of America
| | - Frank R Fontaine
- Gertrude Biomedical, Gertrude Biomedical Pty Ltd, Melbourne, Australia
| | - Tara Karnezis
- Gertrude Biomedical, Gertrude Biomedical Pty Ltd, Melbourne, Australia
| | - David Zurakowski
- Department of Anesthesiology, Boston Children's Hospital and Harvard Medical School, Boston, United States of America
| | - Steven J Staffa
- Department of Anesthesiology, Boston Children's Hospital and Harvard Medical School, Boston, United States of America
| | - Frédéric A Meunier
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Australia
| | - John B Mulliken
- Department of Surgery, Boston Children's Hospital and Harvard Medical School, Boston, United States of America
| | - Joyce Bischoff
- Department of Surgery, Boston Children's Hospital and Harvard Medical School, Boston, United States of America
| | - Mathias Francois
- David Richmond Laboratory for Cardiovascular Development, University of Sydney, Sydney, Australia
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Hung KL, Yost KE, Xie L, Shi Q, Helmsauer K, Luebeck J, Schöpflin R, Lange JT, Chamorro González R, Weiser NE, Chen C, Valieva ME, Wong ITL, Wu S, Dehkordi SR, Duffy CV, Kraft K, Tang J, Belk JA, Rose JC, Corces MR, Granja JM, Li R, Rajkumar U, Friedlein J, Bagchi A, Satpathy AT, Tjian R, Mundlos S, Bafna V, Henssen AG, Mischel PS, Liu Z, Chang HY. ecDNA hubs drive cooperative intermolecular oncogene expression. Nature 2021; 600:731-736. [PMID: 34819668 PMCID: PMC9126690 DOI: 10.1038/s41586-021-04116-8] [Citation(s) in RCA: 174] [Impact Index Per Article: 43.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Accepted: 10/08/2021] [Indexed: 02/07/2023]
Abstract
Extrachromosomal DNA (ecDNA) is prevalent in human cancers and mediates high expression of oncogenes through gene amplification and altered gene regulation1. Gene induction typically involves cis-regulatory elements that contact and activate genes on the same chromosome2,3. Here we show that ecDNA hubs-clusters of around 10-100 ecDNAs within the nucleus-enable intermolecular enhancer-gene interactions to promote oncogene overexpression. ecDNAs that encode multiple distinct oncogenes form hubs in diverse cancer cell types and primary tumours. Each ecDNA is more likely to transcribe the oncogene when spatially clustered with additional ecDNAs. ecDNA hubs are tethered by the bromodomain and extraterminal domain (BET) protein BRD4 in a MYC-amplified colorectal cancer cell line. The BET inhibitor JQ1 disperses ecDNA hubs and preferentially inhibits ecDNA-derived-oncogene transcription. The BRD4-bound PVT1 promoter is ectopically fused to MYC and duplicated in ecDNA, receiving promiscuous enhancer input to drive potent expression of MYC. Furthermore, the PVT1 promoter on an exogenous episome suffices to mediate gene activation in trans by ecDNA hubs in a JQ1-sensitive manner. Systematic silencing of ecDNA enhancers by CRISPR interference reveals intermolecular enhancer-gene activation among multiple oncogene loci that are amplified on distinct ecDNAs. Thus, protein-tethered ecDNA hubs enable intermolecular transcriptional regulation and may serve as units of oncogene function and cooperative evolution and as potential targets for cancer therapy.
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Affiliation(s)
- King L Hung
- Center for Personal Dynamic Regulomes, Stanford University School of Medicine, Stanford, CA, USA
| | - Kathryn E Yost
- Center for Personal Dynamic Regulomes, Stanford University School of Medicine, Stanford, CA, USA
| | - Liangqi Xie
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
- Department of Molecular and Cell Biology, Li Ka Shing Center for Biomedical and Health Sciences, CIRM Center of Excellence, University of California, Berkeley, Berkeley, CA, USA
- Howard Hughes Medical Institute, Berkeley, CA, USA
| | - Quanming Shi
- Center for Personal Dynamic Regulomes, Stanford University School of Medicine, Stanford, CA, USA
| | - Konstantin Helmsauer
- Department of Pediatric Oncology and Hematology, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Jens Luebeck
- Bioinformatics and Systems Biology Graduate Program, University of California, San Diego, La Jolla, CA, USA
- Department of Computer Science and Engineering, University of California, San Diego, La Jolla, CA, USA
| | - Robert Schöpflin
- Development and Disease Research Group, Max Planck Institute for Molecular Genetics, Berlin, Germany
- Institute for Medical and Human Genetics, Charité-Universitätsmedizin Berlin, Berlin, Germany
- Department of Computational Molecular Biology, Max Planck Institute for Molecular Genetics, Berlin, Germany
| | - Joshua T Lange
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA, USA
- ChEM-H, Stanford University, Stanford, CA, USA
- Department of Pathology, Stanford University, Stanford, CA, USA
| | - Rocío Chamorro González
- Department of Pediatric Oncology and Hematology, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Natasha E Weiser
- Center for Personal Dynamic Regulomes, Stanford University School of Medicine, Stanford, CA, USA
- Department of Pathology, Stanford University, Stanford, CA, USA
| | - Celine Chen
- Department of Pediatric Oncology and Hematology, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Maria E Valieva
- Development and Disease Research Group, Max Planck Institute for Molecular Genetics, Berlin, Germany
- Institute for Medical and Human Genetics, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Ivy Tsz-Lo Wong
- ChEM-H, Stanford University, Stanford, CA, USA
- Department of Pathology, Stanford University, Stanford, CA, USA
| | - Sihan Wu
- Children's Medical Center Research Institute, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Siavash R Dehkordi
- Department of Computer Science and Engineering, University of California, San Diego, La Jolla, CA, USA
| | - Connor V Duffy
- Center for Personal Dynamic Regulomes, Stanford University School of Medicine, Stanford, CA, USA
| | - Katerina Kraft
- Center for Personal Dynamic Regulomes, Stanford University School of Medicine, Stanford, CA, USA
| | - Jun Tang
- ChEM-H, Stanford University, Stanford, CA, USA
- Department of Pathology, Stanford University, Stanford, CA, USA
| | - Julia A Belk
- Department of Pathology, Stanford University, Stanford, CA, USA
- Department of Computer Science, Stanford University, Stanford, CA, USA
| | - John C Rose
- Center for Personal Dynamic Regulomes, Stanford University School of Medicine, Stanford, CA, USA
| | - M Ryan Corces
- Center for Personal Dynamic Regulomes, Stanford University School of Medicine, Stanford, CA, USA
| | - Jeffrey M Granja
- Center for Personal Dynamic Regulomes, Stanford University School of Medicine, Stanford, CA, USA
| | - Rui Li
- Center for Personal Dynamic Regulomes, Stanford University School of Medicine, Stanford, CA, USA
| | - Utkrisht Rajkumar
- Department of Computer Science and Engineering, University of California, San Diego, La Jolla, CA, USA
| | - Jordan Friedlein
- Tumor Initiation and Maintenance Program, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, USA
| | - Anindya Bagchi
- Tumor Initiation and Maintenance Program, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, USA
| | | | - Robert Tjian
- Department of Molecular and Cell Biology, Li Ka Shing Center for Biomedical and Health Sciences, CIRM Center of Excellence, University of California, Berkeley, Berkeley, CA, USA
- Howard Hughes Medical Institute, Berkeley, CA, USA
| | - Stefan Mundlos
- Development and Disease Research Group, Max Planck Institute for Molecular Genetics, Berlin, Germany
- Institute for Medical and Human Genetics, Charité-Universitätsmedizin Berlin, Berlin, Germany
- Berlin-Brandenburg Center for Regenerative Therapies (BCRT), Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Vineet Bafna
- Department of Computer Science and Engineering, University of California, San Diego, La Jolla, CA, USA
| | - Anton G Henssen
- Department of Pediatric Oncology and Hematology, Charité-Universitätsmedizin Berlin, Berlin, Germany
- Experimental and Clinical Research Center (ECRC), Max Delbrück Center for Molecular Medicine and Charité-Universitätsmedizin Berlin, Berlin, Germany
- German Cancer Consortium (DKTK), partner site Berlin, and German Cancer Research Center DKFZ, Heidelberg, Germany
- Berlin Institute of Health, Berlin, Germany
| | - Paul S Mischel
- ChEM-H, Stanford University, Stanford, CA, USA
- Department of Pathology, Stanford University, Stanford, CA, USA
| | - Zhe Liu
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - Howard Y Chang
- Center for Personal Dynamic Regulomes, Stanford University School of Medicine, Stanford, CA, USA.
- Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, CA, USA.
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44
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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: 0.5] [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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45
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Wiegard A, Kuzin V, Cameron DP, Grosser J, Ceribelli M, Mehmood R, Ballarino R, Valant F, Grochowski R, Karabogdan I, Crosetto N, Lindqvist A, Bizard AH, Kouzine F, Natsume T, Baranello L. Topoisomerase 1 activity during mitotic transcription favors the transition from mitosis to G1. Mol Cell 2021; 81:5007-5024.e9. [PMID: 34767771 DOI: 10.1016/j.molcel.2021.10.015] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 08/26/2021] [Accepted: 10/15/2021] [Indexed: 12/13/2022]
Abstract
As cells enter mitosis, chromatin compacts to facilitate chromosome segregation yet remains transcribed. Transcription supercoils DNA to levels that can impede further progression of RNA polymerase II (RNAPII) unless it is removed by DNA topoisomerase 1 (TOP1). Using ChIP-seq on mitotic cells, we found that TOP1 is required for RNAPII translocation along genes. The stimulation of TOP1 activity by RNAPII during elongation allowed RNAPII clearance from genes in prometaphase and enabled chromosomal segregation. Disruption of the TOP1-RNAPII interaction impaired RNAPII spiking at promoters and triggered defects in the post-mitotic transcription program. This program includes factors necessary for cell growth, and cells with impaired TOP1-RNAPII interaction are more sensitive to inhibitors of mTOR signaling. We conclude that TOP1 is necessary for assisting transcription during mitosis with consequences for growth and gene expression long after mitosis is completed. In this sense, TOP1 ensures that cellular memory is preserved in subsequent generations.
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Affiliation(s)
- Anika Wiegard
- Department of Cell and Molecular Biology, Karolinska Institutet, 17177 Stockholm, Sweden
| | - Vladislav Kuzin
- Department of Cell and Molecular Biology, Karolinska Institutet, 17177 Stockholm, Sweden
| | - Donald P Cameron
- Department of Cell and Molecular Biology, Karolinska Institutet, 17177 Stockholm, Sweden
| | - Jan Grosser
- Department of Cell and Molecular Biology, Karolinska Institutet, 17177 Stockholm, Sweden
| | - Michele Ceribelli
- Division of Pre-Clinical Innovation, NCATS, National Institutes of Health, Rockville, MD 20850, USA
| | - Rashid Mehmood
- Department of Cell and Molecular Biology, Karolinska Institutet, 17177 Stockholm, Sweden; Department of Software Engineering, University of Kotli, AJ&K, 45320 Kotli Azad Kashmir, Pakistan
| | - Roberto Ballarino
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, 17165 Stockholm, Sweden
| | - Francesco Valant
- Department of Cell and Molecular Biology, Karolinska Institutet, 17177 Stockholm, Sweden
| | - Radosław Grochowski
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, 17165 Stockholm, Sweden
| | | | - Nicola Crosetto
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, 17165 Stockholm, Sweden
| | - Arne Lindqvist
- Department of Cell and Molecular Biology, Karolinska Institutet, 17177 Stockholm, Sweden
| | - Anna Helene Bizard
- Department of Cellular and Molecular Medicine, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Fedor Kouzine
- Laboratory of Pathology, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Toyoaki Natsume
- Department of Chromosome Science, National Institute of Genetics, Shizuoka 411-8540, Japan; Research Center for Genome & Medical Sciences, Tokyo Metropolitan Institute of Medical Science, Tokyo 156-8506, Japan
| | - Laura Baranello
- Department of Cell and Molecular Biology, Karolinska Institutet, 17177 Stockholm, Sweden.
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46
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Abstract
To predict transcription, one needs a mechanistic understanding of how the numerous required transcription factors (TFs) explore the nuclear space to find their target genes, assemble, cooperate, and compete with one another. Advances in fluorescence microscopy have made it possible to visualize real-time TF dynamics in living cells, leading to two intriguing observations: first, most TFs contact chromatin only transiently; and second, TFs can assemble into clusters through their intrinsically disordered regions. These findings suggest that highly dynamic events and spatially structured nuclear microenvironments might play key roles in transcription regulation that are not yet fully understood. The emerging model is that while some promoters directly convert TF-binding events into on/off cycles of transcription, many others apply complex regulatory layers that ultimately lead to diverse phenotypic outputs. Cracking this kinetic code is an ongoing and challenging task that is made possible by combining innovative imaging approaches with biophysical models.
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Affiliation(s)
- Feiyue Lu
- Institute for Systems Genetics and Cell Biology Department, NYU School of Medicine, New York, New York 10016, USA
| | - Timothée Lionnet
- Institute for Systems Genetics and Cell Biology Department, NYU School of Medicine, New York, New York 10016, USA
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47
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Pan L, Hoffmeister P, Turkiewicz A, Huynh NND, Große-Berkenbusch A, Knippschild U, Gebhardt JCM, Baumann B, Borggrefe T, Oswald F. Transcription Factor RBPJL Is Able to Repress Notch Target Gene Expression but Is Non-Responsive to Notch Activation. Cancers (Basel) 2021; 13:cancers13195027. [PMID: 34638511 PMCID: PMC8508133 DOI: 10.3390/cancers13195027] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Revised: 09/28/2021] [Accepted: 09/30/2021] [Indexed: 12/01/2022] Open
Abstract
Simple Summary The transcription factor RBPJ is an integral part of the Notch signaling cascade. RBPJ can function as a coactivator when Notch signaling is activated but acts as a repressor in the absence of a Notch stimulus. Here, we characterized the function of RBPJL, a pancreas-specific paralog of RBPJ. Upon depletion of RBPJ using CRISPR/Cas9, we observed specific upregulation of Notch target gene expression. Reconstitution with RBPJL can compensate for the lack of RBPJ function in the repression of Notch target genes but is not able to mediate the Notch-dependent activation of gene expression. On the molecular level, we identified a limited capacity of RBPJL to interact with activated Notch1–4. Abstract The Notch signaling pathway is an evolutionary conserved signal transduction cascade present in almost all tissues and is required for embryonic and postnatal development, as well as for stem cell maintenance, but it is also implicated in tumorigenesis including pancreatic cancer and leukemia. The transcription factor RBPJ forms a coactivator complex in the presence of a Notch signal, whereas it represses Notch target genes in the absence of a Notch stimulus. In the pancreas, a specific paralog of RBPJ, called RBPJL, is expressed and found as part of the heterotrimeric PTF1-complex. However, the function of RBPJL in Notch signaling remains elusive. Using molecular modeling, biochemical and functional assays, as well as single-molecule time-lapse imaging, we show that RBPJL and RBPJ, despite limited sequence homology, possess a high degree of structural similarity. RBPJL is specifically expressed in the exocrine pancreas, whereas it is mostly undetectable in pancreatic tumour cell lines. Importantly, RBPJL is not able to interact with Notch−1 to −4 and it does not support Notch-mediated transactivation. However, RBPJL can bind to canonical RBPJ DNA elements and shows migration dynamics comparable to that of RBPJ in the nuclei of living cells. Importantly, RBPJL is able to interact with SHARP/SPEN, the central corepressor of the Notch pathway. In line with this, RBPJL is able to fully reconstitute transcriptional repression at Notch target genes in cells lacking RBPJ. Together, RBPJL can act as an antagonist of RBPJ, which renders cells unresponsive to the activation of Notch.
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Affiliation(s)
- Leiling Pan
- Center for Internal Medicine, Department of Internal Medicine I, University Medical Center Ulm, Ulm University, Albert-Einstein-Allee 23, 89081 Ulm, Germany; (L.P.); (P.H.)
| | - Philipp Hoffmeister
- Center for Internal Medicine, Department of Internal Medicine I, University Medical Center Ulm, Ulm University, Albert-Einstein-Allee 23, 89081 Ulm, Germany; (L.P.); (P.H.)
| | - Aleksandra Turkiewicz
- Institute of Biochemistry, University of Giessen, Friedrichstrasse 24, 35392 Giessen, Germany;
| | - N. N. Duyen Huynh
- Institute of Biophysics, Ulm University, Albert-Einstein-Allee 11, 89081 Ulm, Germany; (N.N.D.H.); (A.G.-B.); (J.C.M.G.)
| | - Andreas Große-Berkenbusch
- Institute of Biophysics, Ulm University, Albert-Einstein-Allee 11, 89081 Ulm, Germany; (N.N.D.H.); (A.G.-B.); (J.C.M.G.)
| | - Uwe Knippschild
- Department of General and Visceral Surgery, Surgery Center, Ulm University, Albert-Einstein-Allee 23, 89081 Ulm, Germany;
| | - J. Christof M. Gebhardt
- Institute of Biophysics, Ulm University, Albert-Einstein-Allee 11, 89081 Ulm, Germany; (N.N.D.H.); (A.G.-B.); (J.C.M.G.)
| | - Bernd Baumann
- Institute of Physiological Chemistry, Ulm University, Albert-Einstein-Allee 11, 89081 Ulm, Germany;
| | - Tilman Borggrefe
- Institute of Biochemistry, University of Giessen, Friedrichstrasse 24, 35392 Giessen, Germany;
- Correspondence: (T.B.); (F.O.); Tel.: +49-731-500-44544 (F.O.)
| | - Franz Oswald
- Center for Internal Medicine, Department of Internal Medicine I, University Medical Center Ulm, Ulm University, Albert-Einstein-Allee 23, 89081 Ulm, Germany; (L.P.); (P.H.)
- Correspondence: (T.B.); (F.O.); Tel.: +49-731-500-44544 (F.O.)
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48
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Zentout S, Smith R, Jacquier M, Huet S. New Methodologies to Study DNA Repair Processes in Space and Time Within Living Cells. Front Cell Dev Biol 2021; 9:730998. [PMID: 34589495 PMCID: PMC8473836 DOI: 10.3389/fcell.2021.730998] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Accepted: 08/25/2021] [Indexed: 01/02/2023] Open
Abstract
DNA repair requires a coordinated effort from an array of factors that play different roles in the DNA damage response from recognizing and signaling the presence of a break, creating a repair competent environment, and physically repairing the lesion. Due to the rapid nature of many of these events, live-cell microscopy has become an invaluable method to study this process. In this review we outline commonly used tools to induce DNA damage under the microscope and discuss spatio-temporal analysis tools that can bring added information regarding protein dynamics at sites of damage. In particular, we show how to go beyond the classical analysis of protein recruitment curves to be able to assess the dynamic association of the repair factors with the DNA lesions as well as the target-search strategies used to efficiently find these lesions. Finally, we discuss how the use of mathematical models, combined with experimental evidence, can be used to better interpret the complex dynamics of repair proteins at DNA lesions.
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Affiliation(s)
- Siham Zentout
- Univ Rennes, CNRS, IGDR (Institut de Génétique et Développement de Rennes)-UMR 6290, BIOSIT-UMS 3480, Rennes, France
| | - Rebecca Smith
- Univ Rennes, CNRS, IGDR (Institut de Génétique et Développement de Rennes)-UMR 6290, BIOSIT-UMS 3480, Rennes, France
| | - Marine Jacquier
- Univ Rennes, CNRS, IGDR (Institut de Génétique et Développement de Rennes)-UMR 6290, BIOSIT-UMS 3480, Rennes, France
| | - Sébastien Huet
- Univ Rennes, CNRS, IGDR (Institut de Génétique et Développement de Rennes)-UMR 6290, BIOSIT-UMS 3480, Rennes, France
- Institut Universitaire de France, Paris, France
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49
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Mazzocca M, Colombo E, Callegari A, Mazza D. Transcription factor binding kinetics and transcriptional bursting: What do we really know? Curr Opin Struct Biol 2021; 71:239-248. [PMID: 34481381 DOI: 10.1016/j.sbi.2021.08.002] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Revised: 08/02/2021] [Accepted: 08/06/2021] [Indexed: 11/18/2022]
Abstract
In eukaryotes, transcription is a discontinuous process with mRNA being generated in bursts, after the binding of transcription factors (TFs) to regulatory elements on the genome. Live-cell single-molecule microscopy has highlighted that transcriptional bursting can be controlled by tuning TF/DNA binding kinetics. Yet the timescales of these two processes seem disconnected with TF/DNA interactions typically lasting orders of magnitude shorter than transcriptional bursts. To test models that could reconcile these discrepancies, reliable measurements of TF binding kinetics are needed, also accounting for the current limitations in performing these single-molecule measurements at specific regulatory elements. Here, we review the recent studies linking TF binding kinetics to transcriptional bursting and outline some current and future challenges that need to be addressed to provide a microscopic description of transcriptional regulation kinetics.
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Affiliation(s)
- Matteo Mazzocca
- Experimental Imaging Center, IRCCS San Raffaele Scientific Institute, Milan 20132, Italy
| | - Emanuele Colombo
- 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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50
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Garcia DA, Fettweis G, Presman DM, Paakinaho V, Jarzynski C, Upadhyaya A, Hager GL. Power-law behavior of transcription factor dynamics at the single-molecule level implies a continuum affinity model. Nucleic Acids Res 2021; 49:6605-6620. [PMID: 33592625 DOI: 10.1093/nar/gkab072] [Citation(s) in RCA: 71] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Revised: 01/13/2021] [Accepted: 02/11/2021] [Indexed: 12/11/2022] Open
Abstract
Single-molecule tracking (SMT) allows the study of transcription factor (TF) dynamics in the nucleus, giving important information regarding the diffusion and binding behavior of these proteins in the nuclear environment. Dwell time distributions obtained by SMT for most TFs appear to follow bi-exponential behavior. This has been ascribed to two discrete populations of TFs-one non-specifically bound to chromatin and another specifically bound to target sites, as implied by decades of biochemical studies. However, emerging studies suggest alternate models for dwell-time distributions, indicating the existence of more than two populations of TFs (multi-exponential distribution), or even the absence of discrete states altogether (power-law distribution). Here, we present an analytical pipeline to evaluate which model best explains SMT data. We find that a broad spectrum of TFs (including glucocorticoid receptor, oestrogen receptor, FOXA1, CTCF) follow a power-law distribution of dwell-times, blurring the temporal line between non-specific and specific binding, suggesting that productive binding may involve longer binding events than previously believed. From these observations, we propose a continuum of affinities model to explain TF dynamics, that is consistent with complex interactions of TFs with multiple nuclear domains as well as binding and searching on the chromatin template.
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Affiliation(s)
- David A Garcia
- Laboratory of Receptor Biology and Gene Expression, National Cancer Institute, National Institutes of Health, Bethesda, MD 20893, USA.,Department of Physics, University of Maryland, College Park, MD 20742, USA
| | - Gregory Fettweis
- Laboratory of Receptor Biology and Gene Expression, National Cancer Institute, National Institutes of Health, Bethesda, MD 20893, USA
| | - Diego M Presman
- Laboratory of Receptor Biology and Gene Expression, National Cancer Institute, National Institutes of Health, Bethesda, MD 20893, USA.,Instituto de Fisiología, Biología Molecular y Neurociencias (IFIBYNE), CONICET-Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, C1428EGA, Buenos Aires, Argentina
| | - Ville Paakinaho
- Laboratory of Receptor Biology and Gene Expression, National Cancer Institute, National Institutes of Health, Bethesda, MD 20893, USA.,Institute of Biomedicine, University of Eastern Finland, Kuopio, PO Box 1627, FI-70211 Kuopio, Finland
| | - Christopher Jarzynski
- Department of Physics, University of Maryland, College Park, MD 20742, USA.,Department of Chemistry and Biochemistry, University of Maryland, College Park, MD 20742, USA.,Institute for Physical Science and Technology, University of Maryland, College Park, MD 20742, USA
| | - Arpita Upadhyaya
- Department of Physics, University of Maryland, College Park, MD 20742, USA.,Institute for Physical Science and Technology, University of Maryland, College Park, MD 20742, USA
| | - Gordon L Hager
- Laboratory of Receptor Biology and Gene Expression, National Cancer Institute, National Institutes of Health, Bethesda, MD 20893, USA
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