1
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Liu X, Chang Z, Sun P, Cao B, Wang Y, Fang J, Pei Y, Chen B, Zou W. MONITTR allows real-time imaging of transcription and endogenous proteins in C. elegans. J Cell Biol 2025; 224:e202403198. [PMID: 39400293 PMCID: PMC11473600 DOI: 10.1083/jcb.202403198] [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: 04/01/2024] [Revised: 08/26/2024] [Accepted: 09/24/2024] [Indexed: 10/15/2024] Open
Abstract
Maximizing cell survival under stress requires rapid and transient adjustments of RNA and protein synthesis. However, capturing these dynamic changes at both single-cell level and across an organism has been challenging. Here, we developed a system named MONITTR (MS2-embedded mCherry-based monitoring of transcription) for real-time simultaneous measurement of nascent transcripts and endogenous protein levels in C. elegans. Utilizing this system, we monitored the transcriptional bursting of fasting-induced genes and found that the epidermis responds to fasting by modulating the proportion of actively transcribing nuclei and transcriptional kinetics of individual alleles. Additionally, our findings revealed the essential roles of the transcription factors NHR-49 and HLH-30 in governing the transcriptional kinetics of fasting-induced genes under fasting. Furthermore, we tracked transcriptional dynamics during heat-shock response and ER unfolded protein response and observed rapid changes in the level of nascent transcripts under stress conditions. Collectively, our study provides a foundation for quantitatively investigating how animals spatiotemporally modulate transcription in various physiological and pathological conditions.
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Affiliation(s)
- Xiaofan Liu
- The Fourth Affiliated Hospital, Zhejiang University School of Medicine, Yiwu, China
- Institute of Translational Medicine, Zhejiang University, Hangzhou, China
| | - Zhi Chang
- School of Life and Health Sciences, Hainan University, Haikou, China
| | - Pingping Sun
- The Fourth Affiliated Hospital, Zhejiang University School of Medicine, Yiwu, China
- Institute of Translational Medicine, Zhejiang University, Hangzhou, China
| | - Beibei Cao
- The Fourth Affiliated Hospital, Zhejiang University School of Medicine, Yiwu, China
- Institute of Translational Medicine, Zhejiang University, Hangzhou, China
| | - Yuzhi Wang
- The Fourth Affiliated Hospital, Zhejiang University School of Medicine, Yiwu, China
- Institute of Translational Medicine, Zhejiang University, Hangzhou, China
| | - Jie Fang
- The Fourth Affiliated Hospital, Zhejiang University School of Medicine, Yiwu, China
- Institute of Translational Medicine, Zhejiang University, Hangzhou, China
- Department of Cell Biology, and Bone Marrow Transplantation Center of the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Yechun Pei
- School of Life and Health Sciences, Hainan University, Haikou, China
| | - Baohui Chen
- Department of Cell Biology, and Bone Marrow Transplantation Center of the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
- Zhejiang Laboratory for Systems & Precision Medicine, Zhejiang University Medical Center, Hangzhou, China
- Institute of Hematology, Zhejiang University and Zhejiang Engineering Laboratory for Stem Cell and Immunotherapy, Hangzhou, China
| | - Wei Zou
- The Fourth Affiliated Hospital, Zhejiang University School of Medicine, Yiwu, China
- Institute of Translational Medicine, Zhejiang University, Hangzhou, China
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2
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Dhillon N, Kamakaka RT. Transcriptional silencing in Saccharomyces cerevisiae: known unknowns. Epigenetics Chromatin 2024; 17:28. [PMID: 39272151 PMCID: PMC11401328 DOI: 10.1186/s13072-024-00553-7] [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: 07/02/2024] [Accepted: 09/02/2024] [Indexed: 09/15/2024] Open
Abstract
Transcriptional silencing in Saccharomyces cerevisiae is a persistent and highly stable form of gene repression. It involves DNA silencers and repressor proteins that bind nucleosomes. The silenced state is influenced by numerous factors including the concentration of repressors, nature of activators, architecture of regulatory elements, modifying enzymes and the dynamics of chromatin.Silencers function to increase the residence time of repressor Sir proteins at silenced domains while clustering of silenced domains enables increased concentrations of repressors and helps facilitate long-range interactions. The presence of an accessible NDR at the regulatory regions of silenced genes, the cycling of chromatin configurations at regulatory sites, the mobility of Sir proteins, and the non-uniform distribution of the Sir proteins across the silenced domain, all result in silenced chromatin that only stably silences weak promoters and enhancers via changes in transcription burst duration and frequency.These data collectively suggest that silencing is probabilistic and the robustness of silencing is achieved through sub-optimization of many different nodes of action such that a stable expression state is generated and maintained even though individual constituents are in constant flux.
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Affiliation(s)
- Namrita Dhillon
- Department of Biomolecular Engineering, University of California, 1156 High Street, Santa Cruz, CA, 95064, USA
| | - Rohinton T Kamakaka
- Department of MCD Biology, University of California, 1156 High Street, Santa Cruz, CA, 95064, USA.
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3
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Trzaskoma P, Jung S, Pękowska A, Bohrer CH, Wang X, Naz F, Dell’Orso S, Dubois WD, Olivera A, Vartak SV, Zhao Y, Nayak S, Overmiller A, Morasso MI, Sartorelli V, Larson DR, Chow CC, Casellas R, O’Shea JJ. 3D chromatin architecture, BRD4, and Mediator have distinct roles in regulating genome-wide transcriptional bursting and gene network. SCIENCE ADVANCES 2024; 10:eadl4893. [PMID: 39121214 PMCID: PMC11313860 DOI: 10.1126/sciadv.adl4893] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2023] [Accepted: 07/08/2024] [Indexed: 08/11/2024]
Abstract
Discontinuous transcription is evolutionarily conserved and a fundamental feature of gene regulation; yet, the exact mechanisms underlying transcriptional bursting are unresolved. Analyses of bursting transcriptome-wide have focused on the role of cis-regulatory elements, but other factors that regulate this process remain elusive. We applied mathematical modeling to single-cell RNA sequencing data to infer bursting dynamics transcriptome-wide under multiple conditions to identify possible molecular mechanisms. We found that Mediator complex subunit 26 (MED26) primarily regulates frequency, MYC regulates burst size, while cohesin and Bromodomain-containing protein 4 (BRD4) can modulate both. Despite comparable effects on RNA levels among these perturbations, acute depletion of MED26 had the most profound impact on the entire gene regulatory network, acting downstream of chromatin spatial architecture and without affecting TATA box-binding protein (TBP) recruitment. These results indicate that later steps in the initiation of transcriptional bursts are primary nodes for integrating gene networks in single cells.
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Affiliation(s)
- Pawel Trzaskoma
- National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD, USA
| | - SeolKyoung Jung
- National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Aleksandra Pękowska
- National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD, USA
- Dioscuri Centre for Chromatin Biology and Epigenomics, Nencki Institute of Experimental Biology, Polish Academy of Sciences, 3 Pasteur Street, 02-093 Warsaw, Poland
| | | | - Xiang Wang
- National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Faiza Naz
- National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Stefania Dell’Orso
- National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Wendy D. Dubois
- National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Ana Olivera
- National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Supriya V. Vartak
- National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Yongbing Zhao
- National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Subhashree Nayak
- National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Andrew Overmiller
- National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Maria I. Morasso
- National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Vittorio Sartorelli
- National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Daniel R. Larson
- National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Carson C. Chow
- National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Rafael Casellas
- National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD, USA
| | - John J. O’Shea
- National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD, USA
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4
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Whitney PH, Lionnet T. The method in the madness: Transcriptional control from stochastic action at the single-molecule scale. Curr Opin Struct Biol 2024; 87:102873. [PMID: 38954990 PMCID: PMC11373363 DOI: 10.1016/j.sbi.2024.102873] [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: 01/12/2024] [Revised: 05/07/2024] [Accepted: 06/05/2024] [Indexed: 07/04/2024]
Abstract
Cell states result from the ordered activation of gene expression by transcription factors. Transcription factors face opposing design constraints: they need to be dynamic to trigger rapid cell state transitions, but also stable enough to maintain terminal cell identities indefinitely. Recent progress in live-cell single-molecule microscopy has helped define the biophysical principles underlying this paradox. Beyond transcription factor activity, single-molecule experiments have revealed that at nearly every level of transcription regulation, control emerges from multiple short-lived stochastic interactions, rather than deterministic, stable interactions typical of other biochemical pathways. This architecture generates consistent outcomes that can be rapidly choreographed. Here, we highlight recent results that demonstrate how order in transcription regulation emerges from the apparent molecular-scale chaos and discuss remaining conceptual challenges.
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Affiliation(s)
- Peter H Whitney
- Institute for Systems Genetics, New York University School of Medicine, New York, NY 10016, USA; Department of Cell Biology, New York University School of Medicine, New York, NY 10016, USA
| | - Timothée Lionnet
- Institute for Systems Genetics, New York University School of Medicine, New York, NY 10016, USA; Department of Cell Biology, New York University School of Medicine, New York, NY 10016, USA; Department of Biomedical Engineering, NYU Tandon School of Engineering, Brooklyn, NY 11201, USA.
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5
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Shelansky R, Abrahamsson S, Brown CR, Doody M, Lenstra TL, Larson DR, Boeger H. Single gene analysis in yeast suggests nonequilibrium regulatory dynamics for transcription. Nat Commun 2024; 15:6226. [PMID: 39043639 PMCID: PMC11266658 DOI: 10.1038/s41467-024-50419-5] [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: 08/22/2023] [Accepted: 07/04/2024] [Indexed: 07/25/2024] Open
Abstract
Fluctuations in the initiation rate of transcription, the first step in gene expression, ensue from the stochastic behavior of the molecular process that controls transcription. In steady state, the regulatory process is often assumed to operate reversibly, i.e., in equilibrium. However, reversibility imposes fundamental limits to information processing. For instance, the assumption of equilibrium is difficult to square with the precision with which the regulatory process executes its task in eukaryotes. Here we provide evidence - from microscopic analyses of the transcription dynamics at a single gene copy of yeast - that the regulatory process for transcription is cyclic and irreversible (out of equilibrium). The necessary coupling to reservoirs of free energy occurs via sequence-specific transcriptional activators and the recruitment, in part, of ATP-dependent chromatin remodelers. Our findings may help explain how eukaryotic cells reconcile the dual but opposing requirements for fast regulatory kinetics and high regulatory specificity.
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Affiliation(s)
- Robert Shelansky
- Department of Molecular Cell and Developmental Biology, University of California, Santa Cruz, CA, USA
| | - Sara Abrahamsson
- Department of Electrical and Computer Engineering, University of California, Santa Cruz, CA, USA
| | - Christopher R Brown
- Department of Molecular Cell and Developmental Biology, University of California, Santa Cruz, CA, USA
- Korro Bio, Cambridge, MA, USA
| | - Michael Doody
- Department of Molecular Cell and Developmental Biology, University of California, Santa Cruz, CA, USA
| | - Tineke L Lenstra
- Division of Gene Regulation, The Netherlands Cancer Institute, Oncode Institute, Amsterdam, The Netherlands
| | - Daniel R Larson
- Laboratory of Receptor Biology and Gene Expression, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Hinrich Boeger
- Department of Molecular Cell and Developmental Biology, University of California, Santa Cruz, CA, USA.
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6
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Pal S, Dhar R. Living in a noisy world-origins of gene expression noise and its impact on cellular decision-making. FEBS Lett 2024; 598:1673-1691. [PMID: 38724715 DOI: 10.1002/1873-3468.14898] [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: 12/21/2023] [Revised: 03/23/2024] [Accepted: 03/27/2024] [Indexed: 07/23/2024]
Abstract
The expression level of a gene can vary between genetically identical cells under the same environmental condition-a phenomenon referred to as gene expression noise. Several studies have now elucidated a central role of transcription factors in the generation of expression noise. Transcription factors, as the key components of gene regulatory networks, drive many important cellular decisions in response to cellular and environmental signals. Therefore, a very relevant question is how expression noise impacts gene regulation and influences cellular decision-making. In this Review, we summarize the current understanding of the molecular origins of expression noise, highlighting the role of transcription factors in this process, and discuss the ways in which noise can influence cellular decision-making. As advances in single-cell technologies open new avenues for studying expression noise as well as gene regulatory circuits, a better understanding of the influence of noise on cellular decisions will have important implications for many biological processes.
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Affiliation(s)
- Sampriti Pal
- Department of Bioscience and Biotechnology, IIT Kharagpur, India
| | - Riddhiman Dhar
- Department of Bioscience and Biotechnology, IIT Kharagpur, India
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7
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Sahoo S, Kadam S, Padinhateeri R, Kumar PBS. Nonequilibrium switching of segmental states can influence compaction of chromatin. SOFT MATTER 2024; 20:4621-4632. [PMID: 38819321 DOI: 10.1039/d4sm00274a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2024]
Abstract
Knowledge about the dynamic nature of chromatin organization is essential to understand the regulation of processes like DNA transcription and repair. The existing models of chromatin assume that protein organization and chemical states along chromatin are static and the 3D organization is purely a result of protein-mediated intra-chromatin interactions. Here we present a new hypothesis that certain nonequilibrium processes, such as switching of chemical and physical states due to nucleosome assembly/disassembly or gene repression/activation, can also simultaneously influence chromatin configurations. To understand the implications of this inherent nonequilibrium switching, we present a block copolymer model of chromatin, with switching of its segmental states between two states, mimicking active/repressed or protein unbound/bound states. We show that competition between switching timescale Tt, polymer relaxation timescale τp, and segmental relaxation timescale τs can lead to non-trivial changes in chromatin organization, leading to changes in local compaction and contact probabilities. As a function of the switching timescale, the radius of gyration of chromatin shows a non-monotonic behavior with a prominent minimum when Tt ≈ τp and a maximum when Tt ≈ τs. We find that polymers with a small segment length exhibit a more compact structure than those with larger segment lengths. We also find that the switching can lead to higher contact probability and better mixing of far-away segments. Our study also shows that the nature of the distribution of chromatin clusters varies widely as we change the switching rate.
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Affiliation(s)
- Soudamini Sahoo
- Department of Physics, Indian Institute of Technology Palakkad, Palakkad, 678623, India
- Department of Physics and Astronomy, National Institute of Technology Rourkela, Rourkela, 769008, India
| | - Sangram Kadam
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai, 400076, India.
| | - Ranjith Padinhateeri
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai, 400076, India.
| | - P B Sunil Kumar
- Department of Physics, Indian Institute of Technology Palakkad, Palakkad, 678623, India
- Department of Physics, Indian Institute of Technology Madras, Chennai, 600036, India
- Center for Soft and Biological Matter, Indian Institute of Technology Madras, Chennai, 600036, India
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8
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Ayyamperumal P, Naik HC, Naskar AJ, Bammidi LS, Gayen S. Epigenomic states contribute to coordinated allelic transcriptional bursting in iPSC reprogramming. Life Sci Alliance 2024; 7:e202302337. [PMID: 38320809 PMCID: PMC10847334 DOI: 10.26508/lsa.202302337] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Revised: 01/30/2024] [Accepted: 01/30/2024] [Indexed: 02/12/2024] Open
Abstract
Two alleles of a gene can be transcribed independently or coordinatedly, which can lead to temporal expression heterogeneity with potentially distinct impacts on cell fate. Here, we profiled genome-wide allelic transcriptional burst kinetics during the reprogramming of MEF to induced pluripotent stem cells. We show that the degree of coordination of allelic bursting differs among genes, and alleles of many reprogramming-related genes burst in a highly coordinated fashion. Notably, we show that the chromatin accessibility of the two alleles of highly coordinated genes is similar, unlike the semi-coordinated or independent genes, suggesting the degree of coordination of allelic bursting is linked to allelic chromatin accessibility. Consistently, we show that many transcription factors have differential binding affinity between alleles of semi-coordinated or independent genes. We show that highly coordinated genes are enriched with chromatin accessibility regulators such as H3K4me3, H3K4me1, H3K36me3, H3K27ac, histone variant H3.3, and BRD4. Finally, we demonstrate that enhancer elements are highly enriched in highly coordinated genes. Our study demonstrates that epigenomic states contribute to coordinated allelic bursting to fine-tune gene expression during induced pluripotent stem cell reprogramming.
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Affiliation(s)
- Parichitran Ayyamperumal
- Chromatin, RNA and Genome (CRG) Laboratory, Department of Developmental Biology and Genetics, Indian Institute of Science, Bangalore, India
| | - Hemant Chandru Naik
- Chromatin, RNA and Genome (CRG) Laboratory, Department of Developmental Biology and Genetics, Indian Institute of Science, Bangalore, India
| | - Amlan Jyoti Naskar
- Chromatin, RNA and Genome (CRG) Laboratory, Department of Developmental Biology and Genetics, Indian Institute of Science, Bangalore, India
| | - Lakshmi Sowjanya Bammidi
- Chromatin, RNA and Genome (CRG) Laboratory, Department of Developmental Biology and Genetics, Indian Institute of Science, Bangalore, India
| | - Srimonta Gayen
- Chromatin, RNA and Genome (CRG) Laboratory, Department of Developmental Biology and Genetics, Indian Institute of Science, Bangalore, India
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9
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Bai G, Dhillon N, Felton C, Meissner B, Saint-John B, Shelansky R, Meyerson E, Hrabeta-Robinson E, Hodjat B, Boeger H, Brooks AN. Probing chromatin accessibility with small molecule DNA intercalation and nanopore sequencing. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.20.585815. [PMID: 38562899 PMCID: PMC10983977 DOI: 10.1101/2024.03.20.585815] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
Genome-wide identification of chromatin organization and structure has been generally probed by measuring accessibility of the underlying DNA to nucleases or methyltransferases. These methods either only observe the positioning of a single nucleosome or rely on large enzymes to modify or cleave the DNA. We developed adduct sequencing (Add-seq), a method to probe chromatin accessibility by treating chromatin with the small molecule angelicin, which preferentially intercalates into DNA not bound to core nucleosomes. We show that Nanopore sequencing of the angelicin-modified DNA is possible and allows visualization and analysis of long single molecules with distinct chromatin structure. The angelicin modification can be detected from the Nanopore current signal data using a neural network model trained on unmodified and modified chromatin-free DNA. Applying Add-seq to Saccharomyces cerevisiae nuclei, we identified expected patterns of accessibility around annotated gene loci in yeast. We also identify individual clusters of single molecule reads displaying different chromatin structure at specific yeast loci, which demonstrates heterogeneity in the chromatin structure of the yeast population. Thus, using Add-seq, we are able to profile DNA accessibility in the yeast genome across long molecules.
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Affiliation(s)
- Gali Bai
- Department of Biomolecular Engineering, University of California, Santa Cruz, Santa Cruz, California, 95064, United States of America
| | - Namrita Dhillon
- Department of Biomolecular Engineering, University of California, Santa Cruz, Santa Cruz, California, 95064, United States of America
| | - Colette Felton
- Department of Biomolecular Engineering, University of California, Santa Cruz, Santa Cruz, California, 95064, United States of America
| | - Brett Meissner
- Department of Molecular, Cell, and Developmental Biology, University of California, Santa Cruz, Santa Cruz, California, 95064, United States of America
| | - Brandon Saint-John
- Department of Biomolecular Engineering, University of California, Santa Cruz, Santa Cruz, California, 95064, United States of America
| | - Robert Shelansky
- Department of Biomolecular Engineering, University of California, Santa Cruz, Santa Cruz, California, 95064, United States of America
| | - Elliot Meyerson
- Cognizant AI Labs, San Francisco, California, 94105, United States of America
| | - Eva Hrabeta-Robinson
- Department of Biomolecular Engineering, University of California, Santa Cruz, Santa Cruz, California, 95064, United States of America
| | - Babak Hodjat
- Cognizant AI Labs, San Francisco, California, 94105, United States of America
| | - Hinrich Boeger
- Department of Molecular, Cell, and Developmental Biology, University of California, Santa Cruz, Santa Cruz, California, 95064, United States of America
| | - Angela N. Brooks
- Department of Biomolecular Engineering, University of California, Santa Cruz, Santa Cruz, California, 95064, United States of America
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10
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Chanou A, Weiβ M, Holler K, Sajid A, Straub T, Krietsch J, Sanchi A, Ummethum H, Lee CSK, Kruse E, Trauner M, Werner M, Lalonde M, Lopes M, Scialdone A, Hamperl S. Single molecule MATAC-seq reveals key determinants of DNA replication origin efficiency. Nucleic Acids Res 2023; 51:12303-12324. [PMID: 37956271 PMCID: PMC10711542 DOI: 10.1093/nar/gkad1022] [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: 11/25/2022] [Revised: 10/12/2023] [Accepted: 10/20/2023] [Indexed: 11/15/2023] Open
Abstract
Stochastic origin activation gives rise to significant cell-to-cell variability in the pattern of genome replication. The molecular basis for heterogeneity in efficiency and timing of individual origins is a long-standing question. Here, we developed Methylation Accessibility of TArgeted Chromatin domain Sequencing (MATAC-Seq) to determine single-molecule chromatin accessibility of four specific genomic loci. MATAC-Seq relies on preferential modification of accessible DNA by methyltransferases combined with Nanopore-Sequencing for direct readout of methylated DNA-bases. Applying MATAC-Seq to selected early-efficient and late-inefficient yeast replication origins revealed large heterogeneity of chromatin states. Disruption of INO80 or ISW2 chromatin remodeling complexes leads to changes at individual nucleosomal positions that correlate with changes in their replication efficiency. We found a chromatin state with an accessible nucleosome-free region in combination with well-positioned +1 and +2 nucleosomes as a strong predictor for efficient origin activation. Thus, MATAC-Seq identifies the large spectrum of alternative chromatin states that co-exist on a given locus previously masked in population-based experiments and provides a mechanistic basis for origin activation heterogeneity during eukaryotic DNA replication. Consequently, our single-molecule chromatin accessibility assay will be ideal to define single-molecule heterogeneity across many fundamental biological processes such as transcription, replication, or DNA repair in vitro and ex vivo.
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Affiliation(s)
- Anna Chanou
- Institute of Epigenetics and Stem Cells, Helmholtz Zentrum München, Munich, Germany
| | - Matthias Weiβ
- Institute of Epigenetics and Stem Cells, Helmholtz Zentrum München, Munich, Germany
| | - Karoline Holler
- Institute of Epigenetics and Stem Cells, Helmholtz Zentrum München, Munich, Germany
- Institute of Functional Epigenetics, Helmholtz Zentrum München, Neuherberg, Germany
- Institute of Computational Biology, Helmholtz Zentrum München, Neuherberg, Germany
| | - Atiqa Sajid
- Institute of Epigenetics and Stem Cells, Helmholtz Zentrum München, Munich, Germany
| | - Tobias Straub
- Core Facility Bioinformatics, Biomedical Center, Faculty of Medicine, Ludwig-Maximilians-Universität München, Martinsried, Germany
| | - Jana Krietsch
- Institute of Molecular Cancer Research, University of Zurich, Zurich, Switzerland
| | - Andrea Sanchi
- Institute of Molecular Cancer Research, University of Zurich, Zurich, Switzerland
| | - Henning Ummethum
- Institute of Epigenetics and Stem Cells, Helmholtz Zentrum München, Munich, Germany
| | - Clare S K Lee
- Institute of Epigenetics and Stem Cells, Helmholtz Zentrum München, Munich, Germany
| | - Elisabeth Kruse
- Institute of Epigenetics and Stem Cells, Helmholtz Zentrum München, Munich, Germany
| | - Manuel Trauner
- Institute of Epigenetics and Stem Cells, Helmholtz Zentrum München, Munich, Germany
| | - Marcel Werner
- Institute of Epigenetics and Stem Cells, Helmholtz Zentrum München, Munich, Germany
| | - Maxime Lalonde
- Institute of Epigenetics and Stem Cells, Helmholtz Zentrum München, Munich, Germany
| | - Massimo Lopes
- Institute of Molecular Cancer Research, University of Zurich, Zurich, Switzerland
| | - Antonio Scialdone
- Institute of Epigenetics and Stem Cells, Helmholtz Zentrum München, Munich, Germany
- Institute of Functional Epigenetics, Helmholtz Zentrum München, Neuherberg, Germany
- Institute of Computational Biology, Helmholtz Zentrum München, Neuherberg, Germany
| | - Stephan Hamperl
- Institute of Epigenetics and Stem Cells, Helmholtz Zentrum München, Munich, Germany
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11
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Wu R, Zhou B, Wang W, Liu F. Regulatory Mechanisms for Transcriptional Bursting Revealed by an Event-Based Model. RESEARCH (WASHINGTON, D.C.) 2023; 6:0253. [PMID: 39290237 PMCID: PMC11407585 DOI: 10.34133/research.0253] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Accepted: 10/01/2023] [Indexed: 09/19/2024]
Abstract
Gene transcription often occurs in discrete bursts, and it can be difficult to deduce the underlying regulatory mechanisms for transcriptional bursting with limited experimental data. Here, we categorize numerous states of single eukaryotic genes and identify 6 essential transcriptional events, each comprising a series of state transitions; transcriptional bursting is characterized as a sequence of 4 events, capable of being organized in various configurations, in addition to the beginning and ending events. By associating transcriptional kinetics with mean durations and recurrence probabilities of the events, we unravel how transcriptional bursting is modulated by various regulators including transcription factors. Through analytical derivation and numerical simulation, this study reveals key state transitions contributing to transcriptional sensitivity and specificity, typical characteristics of burst profiles, global constraints on intrinsic transcriptional noise, major regulatory modes in individual genes and across the genome, and requirements for fast gene induction upon stimulation. It is illustrated how biochemical reactions on different time scales are modulated to separately shape the durations and ordering of the events. Our results suggest that transcriptional patterns are essentially controlled by a shared set of transcriptional events occurring under specific promoter architectures and regulatory modes, the number of which is actually limited.
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Affiliation(s)
- Renjie Wu
- National Laboratory of Solid State Microstructures, Department of Physics, and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, P. R. China
| | - Bangyan Zhou
- National Laboratory of Solid State Microstructures, Department of Physics, and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, P. R. China
| | - Wei Wang
- National Laboratory of Solid State Microstructures, Department of Physics, and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, P. R. China
- Institute for Brain Sciences, Nanjing University, Nanjing 210093, P. R. China
| | - Feng Liu
- National Laboratory of Solid State Microstructures, Department of Physics, and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, P. R. China
- Institute for Brain Sciences, Nanjing University, Nanjing 210093, P. R. China
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12
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Quantifying how promoter-associated nucleosomes regulate transcriptional bursting. Nat Struct Mol Biol 2023; 30:577-578. [PMID: 37130986 DOI: 10.1038/s41594-023-00982-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
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13
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Brouwer I, Kerklingh E, van Leeuwen F, Lenstra TL. Dynamic epistasis analysis reveals how chromatin remodeling regulates transcriptional bursting. Nat Struct Mol Biol 2023; 30:692-702. [PMID: 37127821 DOI: 10.1038/s41594-023-00981-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2022] [Accepted: 03/30/2023] [Indexed: 05/03/2023]
Abstract
Transcriptional bursting has been linked to the stochastic positioning of nucleosomes. However, how bursting is regulated by the remodeling of promoter nucleosomes is unknown. Here, we use single-molecule live-cell imaging of GAL10 transcription in Saccharomyces cerevisiae to measure how bursting changes upon combined perturbations of chromatin remodelers, the transcription factor Gal4 and preinitiation complex components. Using dynamic epistasis analysis, we reveal how the remodeling of different nucleosomes regulates transcriptional bursting parameters. At the nucleosome covering the Gal4 binding sites, RSC and Gal4 binding synergistically facilitate each burst. Conversely, nucleosome remodeling at the TATA box controls only the first burst upon galactose induction. At canonical TATA boxes, the nucleosomes are displaced by TBP binding to allow for transcription activation even in the absence of remodelers. Overall, our results reveal how promoter nucleosome remodeling together with Gal4 and preinitiation complex binding regulates transcriptional bursting.
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Affiliation(s)
- Ineke Brouwer
- Division of Gene Regulation, the Netherlands Cancer Institute, Oncode Institute, Amsterdam, the Netherlands
| | - Emma Kerklingh
- Division of Gene Regulation, the Netherlands Cancer Institute, Oncode Institute, Amsterdam, the Netherlands
| | - Fred van Leeuwen
- Division of Gene Regulation, the Netherlands Cancer Institute, Amsterdam, the Netherlands
- Department of Medical Biology, Amsterdam UMC, University of Amsterdam, Amsterdam, the Netherlands
| | - Tineke L Lenstra
- Division of Gene Regulation, the Netherlands Cancer Institute, Oncode Institute, Amsterdam, the Netherlands.
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14
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Sheu KM, Guru AA, Hoffmann A. Quantifying stimulus-response specificity to probe the functional state of macrophages. Cell Syst 2023; 14:180-195.e5. [PMID: 36657439 PMCID: PMC10023480 DOI: 10.1016/j.cels.2022.12.012] [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: 06/01/2022] [Revised: 10/05/2022] [Accepted: 12/22/2022] [Indexed: 01/19/2023]
Abstract
Immune sentinel macrophages initiate responses to pathogens via hundreds of immune response genes. Each immune threat demands a tailored response, suggesting that the capacity for stimulus-specific gene expression is a key functional hallmark of healthy macrophages. To quantify this property, termed "stimulus-response specificity" (SRS), we developed a single-cell experimental workflow and analytical approaches based on information theory and machine learning. We found that the response specificity of macrophages is driven by combinations of specific immune genes that show low cell-to-cell heterogeneity and are targets of separate signaling pathways. The "response specificity profile," a systematic comparison of multiple stimulus-response distributions, was distinctly altered by polarizing cytokines, and it enabled an assessment of the functional state of macrophages. Indeed, the response specificity profile of peritoneal macrophages from old and obese mice showed characteristic differences, suggesting that SRS may be a basis for measuring the functional state of innate immune cells. A record of this paper's transparent peer review process is included in the supplemental information.
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Affiliation(s)
- Katherine M Sheu
- Department of Microbiology, Immunology, and Molecular Genetics, and Institute for Quantitative and Computational Biosciences, University of California, Los Angeles, 611 Charles E. Young Dr S, Los Angeles, CA 90093, USA
| | - Aditya A Guru
- Department of Microbiology, Immunology, and Molecular Genetics, and Institute for Quantitative and Computational Biosciences, University of California, Los Angeles, 611 Charles E. Young Dr S, Los Angeles, CA 90093, USA
| | - Alexander Hoffmann
- Department of Microbiology, Immunology, and Molecular Genetics, and Institute for Quantitative and Computational Biosciences, University of California, Los Angeles, 611 Charles E. Young Dr S, Los Angeles, CA 90093, USA.
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15
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Levinsohn J, Li S, Ha E, Susztak K. Combing Genome-Wide Association Studies and Single-Cell Analysis to Elucidate the Mechanisms of Kidney Disease: Proceedings of the Henry Shavelle Professorship. GLOMERULAR DISEASES 2023; 3:258-265. [PMID: 38033715 PMCID: PMC10686632 DOI: 10.1159/000534678] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/05/2023] [Accepted: 10/13/2023] [Indexed: 12/02/2023]
Abstract
Background Kidney diseases pose a significant global health burden; there is an urgent need to deepen our understanding of their underlying mechanisms. Summary This review focuses on new innovative approaches that merge genome-wide association studies (GWAS) and single-cell omics (including transcriptomics) in kidney disease research. We begin by detailing how GWAS has identified numerous genetic risk factors, offering valuable insight into disease susceptibility. Then, we explore the application of scRNA-seq, highlighting its ability to unravel how genetic variants influence cellular phenotypes. Through a synthesis of recent studies, we illuminate the synergy between these two powerful methodologies, demonstrating their potential in elucidating the complex etiology of kidney diseases. Moreover, we discuss how this integrative approach could pave the way for precise diagnostics and personalized treatments. Key Message This review underscores the transformative potential of combining GWAS and scRNA-seq in the journey toward a deeper understanding of kidney diseases.
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Affiliation(s)
- Jonathan Levinsohn
- Division of Nephrology, Department of Medicine, University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA, USA
- Children’s Hospital of Philadelphia, Philadelphia, PA, USA
- Penn/CHOP Kidney Innovation Center, Philadelphia, PA, USA
| | - Shen Li
- Division of Nephrology, Department of Medicine, University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA, USA
- Penn/CHOP Kidney Innovation Center, Philadelphia, PA, USA
| | - Eunji Ha
- Division of Nephrology, Department of Medicine, University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA, USA
- Penn/CHOP Kidney Innovation Center, Philadelphia, PA, USA
| | - Katalin Susztak
- Division of Nephrology, Department of Medicine, University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA, USA
- Penn/CHOP Kidney Innovation Center, Philadelphia, PA, USA
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16
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Halder K, Chaudhuri A, Abdin MZ, Majee M, Datta A. Chromatin-Based Transcriptional Reprogramming in Plants under Abiotic Stresses. PLANTS (BASEL, SWITZERLAND) 2022; 11:1449. [PMID: 35684223 PMCID: PMC9182740 DOI: 10.3390/plants11111449] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/26/2022] [Revised: 03/23/2022] [Accepted: 03/23/2022] [Indexed: 06/15/2023]
Abstract
Plants' stress response machinery is characterized by an intricate network of signaling cascades that receive and transmit environmental cues and ultimately trigger transcriptional reprogramming. The family of epigenetic regulators that are the key players in the stress-induced signaling cascade comprise of chromatin remodelers, histone modifiers, DNA modifiers and regulatory non-coding RNAs. Changes in the histone modification and DNA methylation lead to major alterations in the expression level and pattern of stress-responsive genes to adjust with abiotic stress conditions namely heat, cold, drought and salinity. The spotlight of this review falls primarily on the chromatin restructuring under severe abiotic stresses, crosstalk between epigenetic regulators along with a brief discussion on stress priming in plants.
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Affiliation(s)
- Koushik Halder
- National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi 110067, India; (K.H.); (A.C.); (M.M.)
- Centre for Transgenic Plant Development, Department of Biotechnology, School of Chemical and Life Sciences, Jamia Hamdard, New Delhi 110062, India;
| | - Abira Chaudhuri
- National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi 110067, India; (K.H.); (A.C.); (M.M.)
| | - Malik Z. Abdin
- Centre for Transgenic Plant Development, Department of Biotechnology, School of Chemical and Life Sciences, Jamia Hamdard, New Delhi 110062, India;
| | - Manoj Majee
- National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi 110067, India; (K.H.); (A.C.); (M.M.)
| | - Asis Datta
- National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi 110067, India; (K.H.); (A.C.); (M.M.)
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17
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Huertas J, Woods EJ, Collepardo-Guevara R. Multiscale modelling of chromatin organisation: Resolving nucleosomes at near-atomistic resolution inside genes. Curr Opin Cell Biol 2022; 75:102067. [DOI: 10.1016/j.ceb.2022.02.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Revised: 01/24/2022] [Accepted: 02/04/2022] [Indexed: 12/15/2022]
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18
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Abstract
Biochemistry and molecular biology rely on the recognition of structural complementarity between molecules. Molecular interactions must be both quickly reversible, i.e., tenuous, and specific. How the cell reconciles these conflicting demands is the subject of this article. The problem and its theoretical solution are discussed within the wider theoretical context of the thermodynamics of stochastic processes (stochastic thermodynamics). The solution-an irreversible reaction cycle that decreases internal error at the expense of entropy export into the environment-is shown to be widely employed by biological processes that transmit genetic and regulatory information. Expected final online publication date for the Annual Review of Biochemistry, Volume 91 is June 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- Hinrich Boeger
- Department of Molecular, Cell and Developmental Biology, University of California, Santa Cruz, California;
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19
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Merkl PE, Schächner C, Pilsl M, Schwank K, Hergert K, Längst G, Milkereit P, Griesenbeck J, Tschochner H. Analysis of Yeast RNAP I Transcription of Nucleosomal Templates In Vitro. Methods Mol Biol 2022; 2533:39-59. [PMID: 35796981 PMCID: PMC9761914 DOI: 10.1007/978-1-0716-2501-9_3] [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: 06/15/2023]
Abstract
Nuclear eukaryotic RNA polymerases (RNAPs) transcribe a chromatin template in vivo. Since the basic unit of chromatin, the nucleosome, renders the DNA largely inaccessible, RNAPs have to overcome the nucleosomal barrier for efficient RNA synthesis. Gaining mechanistical insights in the transcription of chromatin templates will be essential to understand the complex process of eukaryotic gene expression. In this article we describe the use of defined in vitro transcription systems for comparative analysis of highly purified RNAPs I-III from S. cerevisiae (hereafter called yeast) transcribing in vitro reconstituted nucleosomal templates. We also provide a protocol to study promoter-dependent RNAP I transcription of purified native 35S ribosomal RNA (rRNA) gene chromatin.
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Affiliation(s)
- Philipp E Merkl
- Universität Regensburg, Regensburg Center for Biochemistry (RCB), Lehrstuhl Biochemie III, Regensburg, Germany
- TUM ForTe, Technische Universität München, Munich, Germany
| | - Christopher Schächner
- Universität Regensburg, Regensburg Center for Biochemistry (RCB), Lehrstuhl Biochemie III, Regensburg, Germany
| | - Michael Pilsl
- Universität Regensburg, Regensburg Center for Biochemistry (RCB), Lehrstuhl Biochemie III, Regensburg, Germany
| | - Katrin Schwank
- Universität Regensburg, Regensburg Center for Biochemistry (RCB), Lehrstuhl Biochemie III, Regensburg, Germany
| | - Kristin Hergert
- Universität Regensburg, Regensburg Center for Biochemistry (RCB), Lehrstuhl Biochemie III, Regensburg, Germany
| | - Gernot Längst
- Universität Regensburg, Regensburg Center for Biochemistry (RCB), Lehrstuhl Biochemie III, Regensburg, Germany
| | - Philipp Milkereit
- Universität Regensburg, Regensburg Center for Biochemistry (RCB), Lehrstuhl Biochemie III, Regensburg, Germany.
| | - Joachim Griesenbeck
- Universität Regensburg, Regensburg Center for Biochemistry (RCB), Lehrstuhl Biochemie III, Regensburg, Germany.
| | - Herbert Tschochner
- Universität Regensburg, Regensburg Center for Biochemistry (RCB), Lehrstuhl Biochemie III, Regensburg, Germany
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20
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Xiong K, Gerstein M, Masel J. Differences in evolutionary accessibility determine which equally effective regulatory motif evolves to generate pulses. Genetics 2021; 219:6358726. [PMID: 34740240 DOI: 10.1093/genetics/iyab140] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2021] [Accepted: 08/17/2021] [Indexed: 01/02/2023] Open
Abstract
Transcriptional regulatory networks (TRNs) are enriched for certain "motifs." Motif usage is commonly interpreted in adaptationist terms, i.e., that the optimal motif evolves. But certain motifs can also evolve more easily than others. Here, we computationally evolved TRNs to produce a pulse of an effector protein. Two well-known motifs, type 1 incoherent feed-forward loops (I1FFLs) and negative feedback loops (NFBLs), evolved as the primary solutions. The relative rates at which these two motifs evolve depend on selection conditions, but under all conditions, either motif achieves similar performance. I1FFLs generally evolve more often than NFBLs. Selection for a tall pulse favors NFBLs, while selection for a fast response favors I1FFLs. I1FFLs are more evolutionarily accessible early on, before the effector protein evolves high expression; when NFBLs subsequently evolve, they tend to do so from a conjugated I1FFL-NFBL genotype. In the empirical S. cerevisiae TRN, output genes of NFBLs had higher expression levels than those of I1FFLs. These results suggest that evolutionary accessibility, and not relative functionality, shapes which motifs evolve in TRNs, and does so as a function of the expression levels of particular genes.
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Affiliation(s)
- Kun Xiong
- Department of Molecular and Cellular Biology, University of Arizona, Tucson, AZ 85721, USA.,Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA
| | - Mark Gerstein
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA.,Program in Computational Biology and Bioinformatics, Yale University, New Haven, CT 06520, USA.,Department of Computer Science, Yale University, New Haven, CT 06520, USA.,Department of Statistics and Data Science, Yale University, New Haven, CT 06520, USA
| | - Joanna Masel
- Department of Ecology and Evolutionary Biology, University of Arizona, Tucson,AZ 85721, USA
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21
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Van Dyke K, Lutz S, Mekonnen G, Myers CL, Albert FW. Trans-acting genetic variation affects the expression of adjacent genes. Genetics 2021; 217:6126816. [PMID: 33789351 DOI: 10.1093/genetics/iyaa051] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Accepted: 12/16/2020] [Indexed: 11/13/2022] Open
Abstract
Gene expression differences among individuals are shaped by trans-acting expression quantitative trait loci (eQTLs). Most trans-eQTLs map to hotspot locations that influence many genes. The molecular mechanisms perturbed by hotspots are often assumed to involve "vertical" cascades of effects in pathways that can ultimately affect the expression of thousands of genes. Here, we report that trans-eQTLs can affect the expression of adjacent genes via "horizontal" mechanisms that extend along a chromosome. Genes affected by trans-eQTL hotspots in the yeast Saccharomyces cerevisiae were more likely to be located next to each other than expected by chance. These paired hotspot effects tended to occur at adjacent genes that also show coexpression in response to genetic and environmental perturbations, suggesting shared mechanisms. Physical proximity and shared chromatin state, in addition to regulation of adjacent genes by similar transcription factors, were independently associated with paired hotspot effects among adjacent genes. Paired effects of trans-eQTLs can occur at neighboring genes even when these genes do not share a common function. This phenomenon could result in unexpected connections between regulatory genetic variation and phenotypes.
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Affiliation(s)
- Krisna Van Dyke
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, MN 55455, USA
| | - Sheila Lutz
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, MN 55455, USA
| | - Gemechu Mekonnen
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, MN 55455, USA
| | - Chad L Myers
- Department of Computer Science and Engineering, University of Minnesota, Minneapolis, MN 55455, USA
| | - Frank W Albert
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, MN 55455, USA
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22
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Garbuzov FE, Gursky VV. Nonequilibrium model of short-range repression in gene transcription regulation. Phys Rev E 2021; 104:014407. [PMID: 34412298 DOI: 10.1103/physreve.104.014407] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Accepted: 06/24/2021] [Indexed: 11/07/2022]
Abstract
Transcription factors are proteins that regulate gene activity by activating or repressing gene transcription. A special class of transcriptional repressors operates via a short-range mechanism, making local DNA regions inaccessible to binding by activators, and thus providing an indirect repressive action on the target gene. This mechanism is commonly modeled assuming that repressors interact with DNA under thermodynamic equilibrium and neglecting some configurations of the gene regulatory region. We elaborate on a more general nonequilibrium model of short-range repression using the graph formalism for transitions between gene states, and we apply analytical calculations to compare it with the equilibrium model in terms of the repression strength and expression noise. In contrast to the equilibrium approach, the new model allows us to separate two basic mechanisms of short-range repression. The first mechanism is associated with the recruiting of factors that mediate chromatin condensation, and the second one concerns the blocking of factors that mediate chromatin loosening. The nonequilibrium model demonstrates better performance on previously published gene expression data obtained for transcription factors controlling Drosophila development, and furthermore it predicts that the first repression mechanism is the most favorable in this system. The presented approach can be scaled to larger gene networks and can be used to infer specific modes and parameters of transcriptional regulation from gene expression data.
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Affiliation(s)
- F E Garbuzov
- Ioffe Institute, 26 Polytekhnicheskaya, St. Petersburg 194021, Russia
| | - V V Gursky
- Ioffe Institute, 26 Polytekhnicheskaya, St. Petersburg 194021, Russia
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23
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Chanou A, Hamperl S. Single-Molecule Techniques to Study Chromatin. Front Cell Dev Biol 2021; 9:699771. [PMID: 34291054 PMCID: PMC8287188 DOI: 10.3389/fcell.2021.699771] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2021] [Accepted: 05/26/2021] [Indexed: 12/14/2022] Open
Abstract
Besides the basic organization in nucleosome core particles (NCPs), eukaryotic chromatin is further packed through interactions with numerous protein complexes including transcription factors, chromatin remodeling and modifying enzymes. This nucleoprotein complex provides the template for many important biological processes, such as DNA replication, transcription, and DNA repair. Thus, to understand the molecular basis of these DNA transactions, it is critical to define individual changes of the chromatin structure at precise genomic regions where these machineries assemble and drive biological reactions. Single-molecule approaches provide the only possible solution to overcome the heterogenous nature of chromatin and monitor the behavior of individual chromatin transactions in real-time. In this review, we will give an overview of currently available single-molecule methods to obtain mechanistic insights into nucleosome positioning, histone modifications and DNA replication and transcription analysis-previously unattainable with population-based assays.
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Affiliation(s)
| | - Stephan Hamperl
- Chromosome Dynamics and Genome Stability, Institute of Epigenetics and Stem Cells, Helmholtz Zentrum München, Munich, Germany
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24
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Farr SE, Woods EJ, Joseph JA, Garaizar A, Collepardo-Guevara R. Nucleosome plasticity is a critical element of chromatin liquid-liquid phase separation and multivalent nucleosome interactions. Nat Commun 2021; 12:2883. [PMID: 34001913 PMCID: PMC8129070 DOI: 10.1038/s41467-021-23090-3] [Citation(s) in RCA: 101] [Impact Index Per Article: 25.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Accepted: 03/23/2021] [Indexed: 12/19/2022] Open
Abstract
Liquid-liquid phase separation (LLPS) is an important mechanism that helps explain the membraneless compartmentalization of the nucleus. Because chromatin compaction and LLPS are collective phenomena, linking their modulation to the physicochemical features of nucleosomes is challenging. Here, we develop an advanced multiscale chromatin model-integrating atomistic representations, a chemically-specific coarse-grained model, and a minimal model-to resolve individual nucleosomes within sub-Mb chromatin domains and phase-separated systems. To overcome the difficulty of sampling chromatin at high resolution, we devise a transferable enhanced-sampling Debye-length replica-exchange molecular dynamics approach. We find that nucleosome thermal fluctuations become significant at physiological salt concentrations and destabilize the 30-nm fiber. Our simulations show that nucleosome breathing favors stochastic folding of chromatin and promotes LLPS by simultaneously boosting the transient nature and heterogeneity of nucleosome-nucleosome contacts, and the effective nucleosome valency. Our work puts forward the intrinsic plasticity of nucleosomes as a key element in the liquid-like behavior of nucleosomes within chromatin, and the regulation of chromatin LLPS.
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Affiliation(s)
- Stephen E Farr
- Maxwell Centre, Cavendish Laboratory, Department of Physics, University of Cambridge, Cambridge, UK
| | - Esmae J Woods
- Maxwell Centre, Cavendish Laboratory, Department of Physics, University of Cambridge, Cambridge, UK
| | - Jerelle A Joseph
- Maxwell Centre, Cavendish Laboratory, Department of Physics, University of Cambridge, Cambridge, UK
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, UK
- Department of Genetics, University of Cambridge, Cambridge, UK
| | - Adiran Garaizar
- Maxwell Centre, Cavendish Laboratory, Department of Physics, University of Cambridge, Cambridge, UK
| | - Rosana Collepardo-Guevara
- Maxwell Centre, Cavendish Laboratory, Department of Physics, University of Cambridge, Cambridge, UK.
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, UK.
- Department of Genetics, University of Cambridge, Cambridge, UK.
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25
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Crooijmans ME, Delzenne TO, Hensen T, Darehei M, de Winde JH, van Heusden GPH. Cell-to-cell heterogeneity of phosphate gene expression in yeast is controlled by alternative transcription, 14-3-3 and Spl2. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2021; 1864:194714. [PMID: 33971368 DOI: 10.1016/j.bbagrm.2021.194714] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Revised: 04/27/2021] [Accepted: 04/27/2021] [Indexed: 11/25/2022]
Abstract
Dependent on phosphate availability the yeast Saccharomyces cerevisiae expresses either low or high affinity phosphate transporters. In the presence of phosphate yeast cells still express low levels of the high affinity phosphate transporter Pho84. The regulator Spl2 is expressed in approximately 90% of the cells, and is not expressed in the remaining cells. Here we report that deletion of RRP6, encoding an exonuclease degrading non-coding RNA, or BMH1, encoding the major 14-3-3 isoform, resulted in less cells expressing SPL2 and in increased levels of RNA transcribed from sequences upstream of the SPL2 coding region. SPL2 stimulates its own expression and that of PHO84 ensuing a positive feedback. Upon deletion of the region responsible for upstream SPL2 transcription almost all cells express SPL2. These results indicate that the cell-to-cell variation in PHO84 and SPL2 expression is dependent on a specific part of the SPL2 promoter and is controlled by Bmh1 and Spl2.
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Affiliation(s)
| | - Tijn O Delzenne
- Institute of Biology, Leiden University, Leiden, the Netherlands
| | - Tim Hensen
- Institute of Biology, Leiden University, Leiden, the Netherlands
| | - Mina Darehei
- Institute of Biology, Leiden University, Leiden, the Netherlands
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26
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Capp J. Interplay between genetic, epigenetic, and gene expression variability: Considering complexity in evolvability. Evol Appl 2021; 14:893-901. [PMID: 33897810 PMCID: PMC8061278 DOI: 10.1111/eva.13204] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Revised: 01/27/2021] [Accepted: 01/30/2021] [Indexed: 12/11/2022] Open
Abstract
Genetic variability, epigenetic variability, and gene expression variability (noise) are generally considered independently in their relationship with phenotypic variation. However, they appear to be intrinsically interconnected and influence it in combination. The study of the interplay between genetic and epigenetic variability has the longest history. This article rather considers the introduction of gene expression variability in its relationships with the two others and reviews for the first time experimental evidences over the four relationships connected to gene expression noise. They show how introducing this third source of variability complicates the way of thinking evolvability and the emergence of biological novelty. Finally, cancer cells are proposed to be an ideal model to decipher the dynamic interplay between genetic, epigenetic, and gene expression variability when one of them is either experimentally increased or therapeutically targeted. This interplay is also discussed in an evolutionary perspective in the context of cancer cell drug resistance.
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Affiliation(s)
- Jean‐Pascal Capp
- Toulouse Biotechnology InstituteINSACNRSINRAEUniversity of ToulouseToulouseFrance
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27
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Wolff MR, Schmid A, Korber P, Gerland U. Effective dynamics of nucleosome configurations at the yeast PHO5 promoter. eLife 2021; 10:58394. [PMID: 33666171 PMCID: PMC8004102 DOI: 10.7554/elife.58394] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Accepted: 03/04/2021] [Indexed: 12/11/2022] Open
Abstract
Chromatin dynamics are mediated by remodeling enzymes and play crucial roles in gene regulation, as established in a paradigmatic model, the Saccharomyces cerevisiae PHO5 promoter. However, effective nucleosome dynamics, that is, trajectories of promoter nucleosome configurations, remain elusive. Here, we infer such dynamics from the integration of published single-molecule data capturing multi-nucleosome configurations for repressed to fully active PHO5 promoter states with other existing histone turnover and new chromatin accessibility data. We devised and systematically investigated a new class of 'regulated on-off-slide' models simulating global and local nucleosome (dis)assembly and sliding. Only seven of 68,145 models agreed well with all data. All seven models involve sliding and the known central role of the N-2 nucleosome, but regulate promoter state transitions by modulating just one assembly rather than disassembly process. This is consistent with but challenges common interpretations of previous observations at the PHO5 promoter and suggests chromatin opening by binding competition.
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Affiliation(s)
| | - Andrea Schmid
- Molecular Biology Division, Biomedical Center, Faculty of Medicine, Ludwig-Maximilians-Universität München, Planegg-Martinsried, Germany
| | - Philipp Korber
- Molecular Biology Division, Biomedical Center, Faculty of Medicine, Ludwig-Maximilians-Universität München, Planegg-Martinsried, Germany
| | - Ulrich Gerland
- Department of Physics, Technical University of Munich, Garching, Germany
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28
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Multifaceted Chromatin Structure and Transcription Changes in Plant Stress Response. Int J Mol Sci 2021; 22:ijms22042013. [PMID: 33670556 PMCID: PMC7922328 DOI: 10.3390/ijms22042013] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Revised: 02/15/2021] [Accepted: 02/16/2021] [Indexed: 01/06/2023] Open
Abstract
Sessile plants are exposed throughout their existence to environmental abiotic and biotic stress factors, such as cold, heat, salinity, drought, dehydration, submergence, waterlogging, and pathogen infection. Chromatin organization affects genome stability, and its dynamics are crucial in plant stress responses. Chromatin dynamics are epigenetically regulated and are required for stress-induced transcriptional regulation or reprogramming. Epigenetic regulators facilitate the phenotypic plasticity of development and the survival and reproduction of plants in unfavorable environments, and they are highly diversified, including histone and DNA modifiers, histone variants, chromatin remodelers, and regulatory non-coding RNAs. They contribute to chromatin modifications, remodeling and dynamics, and constitute a multilayered and multifaceted circuitry for sophisticated and robust epigenetic regulation of plant stress responses. However, this complicated epigenetic regulatory circuitry creates challenges for elucidating the common or differential roles of chromatin modifications for transcriptional regulation or reprogramming in different plant stress responses. Particularly, interacting chromatin modifications and heritable stress memories are difficult to identify in the aspect of chromatin-based epigenetic regulation of transcriptional reprogramming and memory. Therefore, this review discusses the recent updates from the three perspectives—stress specificity or dependence of transcriptional reprogramming, the interplay of chromatin modifications, and transcriptional stress memory in plants. This helps solidify our knowledge on chromatin-based transcriptional reprogramming for plant stress response and memory.
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Ramalingam V, Natarajan M, Johnston J, Zeitlinger J. TATA and paused promoters active in differentiated tissues have distinct expression characteristics. Mol Syst Biol 2021; 17:e9866. [PMID: 33543829 PMCID: PMC7863008 DOI: 10.15252/msb.20209866] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Revised: 12/22/2020] [Accepted: 01/07/2021] [Indexed: 12/18/2022] Open
Abstract
Core promoter types differ in the extent to which RNA polymerase II (Pol II) pauses after initiation, but how this affects their tissue-specific gene expression characteristics is not well understood. While promoters with Pol II pausing elements are active throughout development, TATA promoters are highly active in differentiated tissues. We therefore used a genomics approach on late-stage Drosophila embryos to analyze the properties of promoter types. Using tissue-specific Pol II ChIP-seq, we found that paused promoters have high levels of paused Pol II throughout the embryo, even in tissues where the gene is not expressed, while TATA promoters only show Pol II occupancy when the gene is active. The promoter types are associated with different chromatin accessibility in ATAC-seq data and have different expression characteristics in single-cell RNA-seq data. The two promoter types may therefore be optimized for different properties: paused promoters show more consistent expression when active, while TATA promoters have lower background expression when inactive. We propose that tissue-specific genes have evolved to use two different strategies for their differential expression across tissues.
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Affiliation(s)
- Vivekanandan Ramalingam
- Stowers Institute for Medical ResearchKansas CityMOUSA
- Department of Pathology and Laboratory MedicineUniversity of Kansas Medical CenterKansas CityKSUSA
- Present address:
Department of GeneticsStanford UniversityStanfordCAUSA
| | - Malini Natarajan
- Stowers Institute for Medical ResearchKansas CityMOUSA
- Present address:
Department of Molecular Biology, Cell Biology and BiochemistryBrown UniversityProvidenceRIUSA
| | - Jeff Johnston
- Stowers Institute for Medical ResearchKansas CityMOUSA
- Present address:
Center for Pediatric Genomic MedicineChildren's MercyKansas CityMOUSA
| | - Julia Zeitlinger
- Stowers Institute for Medical ResearchKansas CityMOUSA
- Department of Pathology and Laboratory MedicineUniversity of Kansas Medical CenterKansas CityKSUSA
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30
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Abstract
Determining whether and how a gene is transcribed are two of the central processes of life. The conceptual basis for understanding such gene regulation arose from pioneering biophysical studies in eubacteria. However, eukaryotic genomes exhibit vastly greater complexity, which raises questions not addressed by this bacterial paradigm. First, how is information integrated from many widely separated binding sites to determine how a gene is transcribed? Second, does the presence of multiple energy-expending mechanisms, which are absent from eubacterial genomes, indicate that eukaryotes are capable of improved forms of genetic information processing? An updated biophysical foundation is needed to answer such questions. We describe the linear framework, a graph-based approach to Markov processes, and show that it can accommodate many previous studies in the field. Under the assumption of thermodynamic equilibrium, we introduce a language of higher-order cooperativities and show how it can rigorously quantify gene regulatory properties suggested by experiment. We point out that fundamental limits to information processing arise at thermodynamic equilibrium and can only be bypassed through energy expenditure. Finally, we outline some of the mathematical challenges that must be overcome to construct an improved biophysical understanding of gene regulation.
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Affiliation(s)
- Felix Wong
- Institute for Medical Engineering & Science, Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.,Infectious Disease and Microbiome Program, Broad Institute of MIT and Harvard, Cambridge, Massachusetts 02142, USA
| | - Jeremy Gunawardena
- Department of Systems Biology, Harvard Medical School, Boston, Massachusetts 02115, USA;
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31
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Vasdekis AE, Singh A. Microbial metabolic noise. WIREs Mech Dis 2020; 13:e1512. [PMID: 33225608 DOI: 10.1002/wsbm.1512] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2019] [Revised: 09/23/2020] [Accepted: 10/26/2020] [Indexed: 11/06/2022]
Abstract
From the time a cell was first placed under the microscope, it became apparent that identifying two clonal cells that "look" identical is extremely challenging. Since then, cell-to-cell differences in shape, size, and protein content have been carefully examined, informing us of the ultimate limits that hinder two cells from occupying an identical phenotypic state. Here, we present recent experimental and computational evidence that similar limits emerge also in cellular metabolism. These limits pertain to stochastic metabolic dynamics and, thus, cell-to-cell metabolic variability, including the resulting adapting benefits. We review these phenomena with a focus on microbial metabolism and conclude with a brief outlook on the potential relationship between metabolic noise and adaptive evolution. This article is categorized under: Metabolic Diseases > Computational Models Metabolic Diseases > Biomedical Engineering.
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Affiliation(s)
| | - Abhyudai Singh
- Department of Electrical and Computer Engineering, University of Delaware, Newark, Delaware, USA
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32
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Capturing and Understanding the Dynamics and Heterogeneity of Gene Expression in the Living Cell. Int J Mol Sci 2020; 21:ijms21218278. [PMID: 33167354 PMCID: PMC7663833 DOI: 10.3390/ijms21218278] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Revised: 10/29/2020] [Accepted: 11/03/2020] [Indexed: 11/21/2022] Open
Abstract
The regulation of gene expression is a fundamental process enabling cells to respond to internal and external stimuli or to execute developmental programs. Changes in gene expression are highly dynamic and depend on many intrinsic and extrinsic factors. In this review, we highlight the dynamic nature of transient gene expression changes to better understand cell physiology and development in general. We will start by comparing recent in vivo procedures to capture gene expression in real time. Intrinsic factors modulating gene expression dynamics will then be discussed, focusing on chromatin modifications. Furthermore, we will dissect how cell physiology or age impacts on dynamic gene regulation and especially discuss molecular insights into acquired transcriptional memory. Finally, this review will give an update on the mechanisms of heterogeneous gene expression among genetically identical individual cells. We will mainly focus on state-of-the-art developments in the yeast model but also cover higher eukaryotic systems.
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33
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Sullivan KM, Susztak K. Unravelling the complex genetics of common kidney diseases: from variants to mechanisms. Nat Rev Nephrol 2020; 16:628-640. [PMID: 32514149 PMCID: PMC8014547 DOI: 10.1038/s41581-020-0298-1] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/23/2020] [Indexed: 12/20/2022]
Abstract
Genome-wide association studies (GWAS) have identified hundreds of loci associated with kidney-related traits such as glomerular filtration rate, albuminuria, hypertension, electrolyte and metabolite levels. However, these impressive, large-scale mapping approaches have not always translated into an improved understanding of disease or development of novel therapeutics. GWAS have several important limitations. Nearly all disease-associated risk loci are located in the non-coding region of the genome and therefore, their target genes, affected cell types and regulatory mechanisms remain unknown. Genome-scale approaches can be used to identify associations between DNA sequence variants and changes in gene expression (quantified through bulk and single-cell methods), gene regulation and other molecular quantitative trait studies, such as chromatin accessibility, DNA methylation, protein expression and metabolite levels. Data obtained through these approaches, used in combination with robust computational methods, can deliver robust mechanistic inferences for translational exploitation. Understanding the genetic basis of common kidney diseases means having a comprehensive picture of the genes that have a causal role in disease development and progression, of the cells, tissues and organs in which these genes act to affect the disease, of the cellular pathways and mechanisms that drive disease, and of potential targets for disease prevention, detection and therapy.
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Affiliation(s)
- Katie Marie Sullivan
- Department of Medicine, Renal Electrolyte and Hypertension Division, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Katalin Susztak
- Department of Medicine, Renal Electrolyte and Hypertension Division, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA.
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34
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Zeitlinger J. Seven myths of how transcription factors read the cis-regulatory code. CURRENT OPINION IN SYSTEMS BIOLOGY 2020; 23:22-31. [PMID: 33134611 PMCID: PMC7592701 DOI: 10.1016/j.coisb.2020.08.002] [Citation(s) in RCA: 65] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Genomics data are now being generated at large quantities, of exquisite high resolution and from single cells. They offer a unique opportunity to develop powerful machine learning algorithms, including neural networks, to uncover the rules of the cis-regulatory code. However, current modeling assumptions are often not based on state-of-the-art knowledge of the cis-regulatory code from transcription, developmental genetics, imaging and structural studies. Here I aim to fill this gap by giving a brief historical overview of the field, describing common misconceptions and providing knowledge that might help to guide computational approaches. I will describe the principles and mechanisms involved in the combinatorial requirement of transcription factor binding motifs for enhancer activity, including the role of chromatin accessibility, repressors and low-affinity motifs in the cis-regulatory code. Deciphering the cis-regulatory code would unlock an enormous amount of regulatory information in the genome and would allow us to locate cis-regulatory genetic variants involved in development and disease.
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Affiliation(s)
- Julia Zeitlinger
- Stowers Institute for Medical Research, Kansas City, MO, USA
- The University of Kansas Medical Center, Kansas City, KS, USA
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35
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Stochastic allelic expression as trigger for contractile imbalance in hypertrophic cardiomyopathy. Biophys Rev 2020; 12:1055-1064. [PMID: 32661905 PMCID: PMC7429642 DOI: 10.1007/s12551-020-00719-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Accepted: 07/02/2020] [Indexed: 12/17/2022] Open
Abstract
Hypertrophic cardiomyopathy (HCM), the most common inherited cardiac disease, is caused by several mostly heterozygous mutations in sarcomeric genes. Hallmarks of HCM are cardiomyocyte and myofibrillar disarray and hypertrophy and fibrosis of the septum and the left ventricle. To date, a pathomechanism common to all mutations remains elusive. We have proposed that contractile imbalance, an unequal force generation of neighboring cardiomyocytes, may contribute to development of HCM hallmarks. At the same calcium concentration, we found substantial differences in force generation between individual cardiomyocytes from HCM patients with mutations in β-MyHC (β-myosin heavy chain). Variability among cardiomyocytes was significantly larger in HCM patients as compared with donor controls. We assume that this heterogeneity in force generation among cardiomyocytes may lead to myocardial disarray and trigger hypertrophy and fibrosis. We provided evidence that burst-like transcription of the MYH7-gene, encoding for β-MyHC, is associated with unequal fractions of mutant per wild-type mRNA from cell to cell (cell-to-cell allelic imbalance). This will presumably lead to unequal fractions of mutant per wild-type protein from cell to cell which may underlie contractile imbalance. In this review, we discuss molecular mechanisms of burst-like transcription with regard to contractile imbalance and disease development in HCM.
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36
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Abstract
Transcription in several organisms from certain bacteria to humans has been observed to be stochastic in nature: toggling between active and inactive states. Periods of active nascent RNA synthesis known as bursts represent individual gene activation events in which multiple polymerases are initiated. Therefore, bursting is the single locus illustration of both gene activation and repression. Although transcriptional bursting was originally observed decades ago, only recently have technological advances enabled the field to begin elucidating gene regulation at the single-locus level. In this review, we focus on how biochemical, genomic, and single-cell data describe the regulatory steps of transcriptional bursts.
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Affiliation(s)
- Joseph Rodriguez
- National Institute of Environmental Health Sciences, Durham, North Carolina 27709, USA
| | - Daniel R. Larson
- Center for Cancer Research, National Cancer Institute, Bethesda, Maryland 20892, USA
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37
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Llorà-Batlle O, Tintó-Font E, Cortés A. Transcriptional variation in malaria parasites: why and how. Brief Funct Genomics 2020; 18:329-341. [PMID: 31114839 DOI: 10.1093/bfgp/elz009] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Revised: 02/04/2019] [Accepted: 04/10/2019] [Indexed: 12/24/2022] Open
Abstract
Transcriptional differences enable the generation of alternative phenotypes from the same genome. In malaria parasites, transcriptional plasticity plays a major role in the process of adaptation to fluctuations in the environment. Multiple studies with culture-adapted parasites and field isolates are starting to unravel the different transcriptional alternatives available to Plasmodium falciparum and the underlying molecular mechanisms. Here we discuss how epigenetic variation, directed transcriptional responses and also genetic changes that affect transcript levels can all contribute to transcriptional variation and, ultimately, parasite survival. Some transcriptional changes are driven by stochastic events. These changes can occur spontaneously, resulting in heterogeneity within parasite populations that provides the grounds for adaptation by dynamic natural selection. However, transcriptional changes can also occur in response to external cues. A better understanding of the mechanisms that the parasite has evolved to alter its transcriptome may ultimately contribute to the design of strategies to combat malaria to which the parasite cannot adapt.
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Affiliation(s)
- Oriol Llorà-Batlle
- ISGlobal, Hospital Clínic - Universitat de Barcelona, 08036 Barcelona, Catalonia, Spain
| | - Elisabet Tintó-Font
- ISGlobal, Hospital Clínic - Universitat de Barcelona, 08036 Barcelona, Catalonia, Spain
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38
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Rodrigo G. Ab initio scaling laws between noise and mean of gene expression. Phys Rev E 2020; 100:032415. [PMID: 31640034 DOI: 10.1103/physreve.100.032415] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Indexed: 12/17/2022]
Abstract
Gene expression is inherently noisy due to fluctuations occurring at the molecular level. From a top-down perspective, noise has been traditionally decomposed into an intrinsic component that scales inversely with the mean expression level and an extrinsic component that is constant in absence of regulatory changes. Here, we adopt a bottom-up approach to reveal that extrinsic noise, by itself, can follow the aforementioned decomposition, which entails that one component of it can be confounded with intrinsic noise. Analytical expressions of the noise-mean relationship were derived for different scenarios, which were in part supported by numerical simulations.
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Affiliation(s)
- Guillermo Rodrigo
- Institute for Integrative Systems Biology (I2SysBio), CSIC-University Valencia, 46980 Paterna, Spain
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39
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Abstract
Specificity in transcriptional regulation is imparted by transcriptional activators that bind to specific DNA sequences from which they stimulate transcription. Specificity may be increased by slowing down the kinetics of regulation: by increasing the energy for dissociation of the activator-DNA complex or decreasing activator concentration. In general, higher dissociation energies imply longer DNA dwell times of the activator; the activator-bound gene may not readily turn off again. Lower activator concentrations entail longer pauses between binding events; the activator-unbound gene is not easily turned on again and activated transcription occurs in stochastic bursts. We show that kinetic proofreading of activator-DNA recognition-insertion of an energy-dissipating delay step into the activation pathway for transcription-reconciles high specificity of transcriptional regulation with fast regulatory kinetics. We show that kinetic proofreading results from the stochastic removal and reformation of promoter nucleosomes, at a distance from equilibrium.
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40
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Xu H, Liu JJ, Liu Z, Li Y, Jin YS, Zhang J. Synchronization of stochastic expressions drives the clustering of functionally related genes. SCIENCE ADVANCES 2019; 5:eaax6525. [PMID: 31633028 PMCID: PMC6785257 DOI: 10.1126/sciadv.aax6525] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Accepted: 09/10/2019] [Indexed: 05/18/2023]
Abstract
Functionally related genes tend to be chromosomally clustered in eukaryotic genomes even after the exclusion of tandem duplicates, but the biological significance of this widespread phenomenon is unclear. We propose that stochastic expression fluctuations of neighboring genes resulting from chromatin dynamics are more or less synchronized such that their expression ratio is more stable than that for unlinked genes. Consequently, chromosomal clustering could be advantageous when the expression ratio of the clustered genes needs to stay constant, for example, because of the accumulation of toxic compounds when this ratio is altered. Evidence from manipulative experiments on the yeast GAL cluster, comprising three chromosomally adjacent genes encoding enzymes catalyzing consecutive reactions in galactose catabolism, unequivocally supports this hypothesis and elucidates how disorder in one biological phenomenon-gene expression noise-could prompt the emergence of order in another-genome organization.
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Affiliation(s)
- Haiqing Xu
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Jing-Jing Liu
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Zhen Liu
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI 48109, USA
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, China
| | - Ying Li
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Yong-Su Jin
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
- Department of Food Science and Human Nutrition, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Jianzhi Zhang
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI 48109, USA
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41
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Abstract
Numerous studies based on new single-cell and single-gene techniques show that individual genes can be transcribed in short bursts or pulses accompanied by changes in pulsing frequencies. Since so many examples of such discontinuous or fluctuating transcription have been found from prokaryotes to mammals, it now seems to be a common mode of gene expression. In this review we discuss the occurrence of the transcriptional fluctuations, the techniques used for their detection, their putative causes, kinetic characteristics, and probable physiological significance.
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Affiliation(s)
- Evgeny Smirnov
- a Institute of Biology and Medical Genetics , First Faculty of Medicine , Charles University and General University Hospital in Prague , Prague , Czech Republic
| | - Matúš Hornáček
- a Institute of Biology and Medical Genetics , First Faculty of Medicine , Charles University and General University Hospital in Prague , Prague , Czech Republic
| | - Tomáš Vacík
- a Institute of Biology and Medical Genetics , First Faculty of Medicine , Charles University and General University Hospital in Prague , Prague , Czech Republic
| | - Dušan Cmarko
- a Institute of Biology and Medical Genetics , First Faculty of Medicine , Charles University and General University Hospital in Prague , Prague , Czech Republic
| | - Ivan Raška
- a Institute of Biology and Medical Genetics , First Faculty of Medicine , Charles University and General University Hospital in Prague , Prague , Czech Republic
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42
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Sun M, Zhang J. Chromosome-wide co-fluctuation of stochastic gene expression in mammalian cells. PLoS Genet 2019; 15:e1008389. [PMID: 31525198 PMCID: PMC6762216 DOI: 10.1371/journal.pgen.1008389] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Revised: 09/26/2019] [Accepted: 08/28/2019] [Indexed: 12/31/2022] Open
Abstract
Gene expression is subject to stochastic noise, but to what extent and by which means such stochastic variations are coordinated among different genes are unclear. We hypothesize that neighboring genes on the same chromosome co-fluctuate in expression because of their common chromatin dynamics, and verify it at the genomic scale using allele-specific single-cell RNA-sequencing data of mouse cells. Unexpectedly, the co-fluctuation extends to genes that are over 60 million bases apart. We provide evidence that this long-range effect arises in part from chromatin co-accessibilities of linked loci attributable to three-dimensional proximity, which is much closer intra-chromosomally than inter-chromosomally. We further show that genes encoding components of the same protein complex tend to be chromosomally linked, likely resulting from natural selection for intracellular among-component dosage balance. These findings have implications for both the evolution of genome organization and optimal design of synthetic genomes in the face of gene expression noise.
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Affiliation(s)
- Mengyi Sun
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI, United States of America
| | - Jianzhi Zhang
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI, United States of America
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43
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Feed-forward regulation adaptively evolves via dynamics rather than topology when there is intrinsic noise. Nat Commun 2019; 10:2418. [PMID: 31160574 PMCID: PMC6546794 DOI: 10.1038/s41467-019-10388-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Accepted: 05/09/2019] [Indexed: 12/17/2022] Open
Abstract
In transcriptional regulatory networks (TRNs), a canonical 3-node feed-forward loop (FFL) is hypothesized to evolve to filter out short spurious signals. We test this adaptive hypothesis against a novel null evolutionary model. Our mutational model captures the intrinsically high prevalence of weak affinity transcription factor binding sites. We also capture stochasticity and delays in gene expression that distort external signals and intrinsically generate noise. Functional FFLs evolve readily under selection for the hypothesized function but not in negative controls. Interestingly, a 4-node “diamond” motif also emerges as a short spurious signal filter. The diamond uses expression dynamics rather than path length to provide fast and slow pathways. When there is no idealized external spurious signal to filter out, but only internally generated noise, only the diamond and not the FFL evolves. While our results support the adaptive hypothesis, we also show that non-adaptive factors, including the intrinsic expression dynamics, matter. Feed‐forward loops (FFLs) can filter out noise, but whether their overrepresentation in GRNs reflects adaptive evolution for this function is debated. Here, the authors develop a null model of regulatory evolution and find that FFLs evolve readily under selection for the noise filtering function.
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44
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Donovan BT, Huynh A, Ball DA, Patel HP, Poirier MG, Larson DR, Ferguson ML, Lenstra TL. Live-cell imaging reveals the interplay between transcription factors, nucleosomes, and bursting. EMBO J 2019; 38:embj.2018100809. [PMID: 31101674 DOI: 10.15252/embj.2018100809] [Citation(s) in RCA: 140] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Revised: 04/12/2019] [Accepted: 04/25/2019] [Indexed: 12/19/2022] Open
Abstract
Transcription factors show rapid and reversible binding to chromatin in living cells, and transcription occurs in sporadic bursts, but how these phenomena are related is unknown. Using a combination of in vitro and in vivo single-molecule imaging approaches, we directly correlated binding of the Gal4 transcription factor with the transcriptional bursting kinetics of the Gal4 target genes GAL3 and GAL10 in living yeast cells. We find that Gal4 dwell time sets the transcriptional burst size. Gal4 dwell time depends on the affinity of the binding site and is reduced by orders of magnitude by nucleosomes. Using a novel imaging platform called orbital tracking, we simultaneously tracked transcription factor binding and transcription at one locus, revealing the timing and correlation between Gal4 binding and transcription. Collectively, our data support a model in which multiple RNA polymerases initiate transcription during one burst as long as the transcription factor is bound to DNA, and bursts terminate upon transcription factor dissociation.
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Affiliation(s)
- Benjamin T Donovan
- Biophysics Graduate Program, The Ohio State University, Columbus, OH, USA
| | - Anh Huynh
- Department of Physics, Boise State University, Boise, ID, USA
| | - David A Ball
- Laboratory of Receptor Biology and Gene Expression, National Cancer Institute, NIH, Bethesda, MD, USA
| | - Heta P Patel
- Division of Gene Regulation, The Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - Michael G Poirier
- Biophysics Graduate Program, The Ohio State University, Columbus, OH, USA.,Departments of Physics, Chemistry & Biochemistry, Ohio State Biochemistry Program, The Ohio State University, Columbus, OH, USA
| | - Daniel R Larson
- Laboratory of Receptor Biology and Gene Expression, National Cancer Institute, NIH, Bethesda, MD, USA
| | - Matthew L Ferguson
- Department of Physics, Boise State University, Boise, ID, USA .,Biomolecular Sciences, Boise State University, Boise, ID, USA
| | - Tineke L Lenstra
- Division of Gene Regulation, The Netherlands Cancer Institute, Amsterdam, The Netherlands
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45
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de Jong TV, Moshkin YM, Guryev V. Gene expression variability: the other dimension in transcriptome analysis. Physiol Genomics 2019; 51:145-158. [DOI: 10.1152/physiolgenomics.00128.2018] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Transcriptome sequencing is a powerful technique to study molecular changes that underlie the differences in physiological conditions and disease progression. A typical question that is posed in such studies is finding genes with significant changes between sample groups. In this respect expression variability is regarded as a nuisance factor that is primarily of technical origin and complicates the data analysis. However, it is becoming apparent that the biological variation in gene expression might be an important molecular phenotype that can affect physiological parameters. In this review we explore the recent literature on technical and biological variability in gene expression, sources of expression variability, (epi-)genetic hallmarks, and evolutionary constraints in genes with robust and variable gene expression. We provide an overview of recent findings on effects of external cues, such as diet and aging, on expression variability and on other biological phenomena that can be linked to it. We discuss metrics and tools that were developed for quantification of expression variability and highlight the importance of future studies in this direction. To assist the adoption of expression variability analysis, we also provide a detailed description and computer code, which can easily be utilized by other researchers. We also provide a reanalysis of recently published data to highlight the value of the analysis method.
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Affiliation(s)
- Tristan V. de Jong
- European Research Institute for the Biology of Ageing, University of Groningen, University Medical Centre Groningen, Groningen, The Netherlands
| | - Yuri M. Moshkin
- Institute of Cytology and Genetics, Siberian Branch of RAS, Novosibirsk, Russia
- Institute of Molecular and Cellular Biology, Siberian Branch of RAS, Novosibirsk, Russia
| | - Victor Guryev
- European Research Institute for the Biology of Ageing, University of Groningen, University Medical Centre Groningen, Groningen, The Netherlands
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46
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Nikopoulou C, Parekh S, Tessarz P. Ageing and sources of transcriptional heterogeneity. Biol Chem 2019; 400:867-878. [DOI: 10.1515/hsz-2018-0449] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Accepted: 03/27/2019] [Indexed: 12/14/2022]
Abstract
Abstract
Cellular heterogeneity is an important contributor to biological function and is employed by cells, tissues and organisms to adapt, compensate, respond, defend and/or regulate specific processes. Research over the last decades has revealed that transcriptional noise is a major driver for cell-to-cell variability. In this review we will discuss sources of transcriptional variability, in particular bursting of gene expression and how it could contribute to cellular states and fate decisions. We will highlight recent developments in single cell sequencing technologies that make it possible to address cellular heterogeneity in unprecedented detail. Finally, we will review recent literature, in which these new technologies are harnessed to address pressing questions in the field of ageing research, such as transcriptional noise and cellular heterogeneity in the course of ageing.
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Affiliation(s)
- Chrysa Nikopoulou
- Max Planck Research Group ‘Chromatin and Ageing’ , Max Planck Institute for Biology of Ageing , Joseph-Stelzmann-Str. 9b , D-50931 Cologne , Germany
| | - Swati Parekh
- Max Planck Research Group ‘Chromatin and Ageing’ , Max Planck Institute for Biology of Ageing , Joseph-Stelzmann-Str. 9b , D-50931 Cologne , Germany
| | - Peter Tessarz
- Max Planck Research Group ‘Chromatin and Ageing’ , Max Planck Institute for Biology of Ageing , Joseph-Stelzmann-Str. 9b , D-50931 Cologne , Germany
- Cluster of Excellence in Cellular Stress Responses in Aging-Associated Diseases (CECAD) , University of Cologne , Joseph-Stelzmann-Str. 26 , D-50931 Cologne , Germany
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47
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Bernheim-Groswasser A, Gov NS, Safran SA, Tzlil S. Living Matter: Mesoscopic Active Materials. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2018; 30:e1707028. [PMID: 30256463 DOI: 10.1002/adma.201707028] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2017] [Revised: 03/27/2018] [Indexed: 06/08/2023]
Abstract
An introduction to the physical properties of living active matter at the mesoscopic scale (tens of nanometers to micrometers) and their unique features compared with "dead," nonactive matter is presented. This field of research is increasingly denoted as "biological physics" where physics includes chemical physics, soft matter physics, hydrodynamics, mechanics, and the related engineering sciences. The focus is on the emergent properties of these systems and their collective behavior, which results in active self-organization and how they relate to cellular-level biological function. These include locomotion (cell motility and migration) forces that give rise to cell division, the growth and form of cellular assemblies in development, the beating of heart cells, and the effects of mechanical perturbations such as shear flow (in the bloodstream) or adhesion to other cells or tissues. An introduction to the fundamental concepts and theory with selected experimental examples related to the authors' own research is presented, including red-blood-cell membrane fluctuations, motion of the nucleus within an egg cell, self-contracting acto-myosin gels, and structure and beating of heart cells (cardiomyocytes), including how they can be driven by an oscillating, mechanical probe.
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Affiliation(s)
- Anne Bernheim-Groswasser
- Department of Chemical Engineering and Ilse Katz Institute for Nanoscale Science and Technology, Ben Gurion University of the Negev, Beer-Sheva, 84105, Israel
| | - Nir S Gov
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot, 7610001, Israel
| | - Samuel A Safran
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot, 7610001, Israel
| | - Shelly Tzlil
- Department of Mechanical Engineering, Technion, Haifa, 3200003, Israel
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Pichon X, Lagha M, Mueller F, Bertrand E. A Growing Toolbox to Image Gene Expression in Single Cells: Sensitive Approaches for Demanding Challenges. Mol Cell 2018; 71:468-480. [DOI: 10.1016/j.molcel.2018.07.022] [Citation(s) in RCA: 126] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Revised: 07/19/2018] [Accepted: 07/20/2018] [Indexed: 12/21/2022]
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Nicolas D, Zoller B, Suter DM, Naef F. Modulation of transcriptional burst frequency by histone acetylation. Proc Natl Acad Sci U S A 2018; 115:7153-7158. [PMID: 29915087 PMCID: PMC6142243 DOI: 10.1073/pnas.1722330115] [Citation(s) in RCA: 100] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Many mammalian genes are transcribed during short bursts of variable frequencies and sizes that substantially contribute to cell-to-cell variability. However, which molecular mechanisms determine bursting properties remains unclear. To probe putative mechanisms, we combined temporal analysis of transcription along the circadian cycle with multiple genomic reporter integrations, using both short-lived luciferase live microscopy and single-molecule RNA-FISH. Using the Bmal1 circadian promoter as our model, we observed that rhythmic transcription resulted predominantly from variations in burst frequency, while the genomic position changed the burst size. Thus, burst frequency and size independently modulated Bmal1 transcription. We then found that promoter histone-acetylation level covaried with burst frequency, being greatest at peak expression and lowest at trough expression, while remaining unaffected by the genomic location. In addition, specific deletions of ROR-responsive elements led to constitutively elevated histone acetylation and burst frequency. We then investigated the suggested link between histone acetylation and burst frequency by dCas9p300-targeted modulation of histone acetylation, revealing that acetylation levels influence burst frequency more than burst size. The correlation between acetylation levels at the promoter and burst frequency was also observed in endogenous circadian genes and in embryonic stem cell fate genes. Thus, our data suggest that histone acetylation-mediated control of transcription burst frequency is a common mechanism to control mammalian gene expression.
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Affiliation(s)
- Damien Nicolas
- Institute of Bioengineering, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, Lausanne CH-1015, Switzerland
| | - Benjamin Zoller
- Institute of Bioengineering, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, Lausanne CH-1015, Switzerland
| | - David M Suter
- Institute of Bioengineering, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, Lausanne CH-1015, Switzerland
| | - Felix Naef
- Institute of Bioengineering, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, Lausanne CH-1015, Switzerland
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Bameta T, Das D, Padinhateeri R. Coupling of replisome movement with nucleosome dynamics can contribute to the parent-daughter information transfer. Nucleic Acids Res 2018; 46:4991-5000. [PMID: 29850895 PMCID: PMC6007630 DOI: 10.1093/nar/gky207] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Accepted: 03/09/2018] [Indexed: 01/09/2023] Open
Abstract
Positioning of nucleosomes along the genomic DNA is crucial for many cellular processes that include gene regulation and higher order packaging of chromatin. The question of how nucleosome-positioning information from a parent chromatin gets transferred to the daughter chromatin is highly intriguing. Accounting for experimentally known coupling between replisome movement and nucleosome dynamics, we propose a model that can obtain de novo nucleosome assembly similar to what is observed in recent experiments. Simulating nucleosome dynamics during replication, we argue that short pausing of the replication fork, associated with nucleosome disassembly, can be a event crucial for communicating nucleosome positioning information from parent to daughter. We show that the interplay of timescales between nucleosome disassembly (τp) at the replication fork and nucleosome sliding behind the fork (τs) can give rise to a rich ‘phase diagram’ having different inherited patterns of nucleosome organization. Our model predicts that only when τp ≥ τs the daughter chromatin can inherit nucleosome positioning of the parent.
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Affiliation(s)
- Tripti Bameta
- UM-DAE Centre for Excellence in Basic Sciences, University of Mumbai, Vidhyanagari Campus, Mumbai 400098, India
- To whom correspondence should be addressed. Tel: +91 22 25767761; Fax: +91 22 25767760; . Correspondence may also be addressed to Tripti Bameta.
| | - Dibyendu Das
- Department of Physics, Indian Institute of Technology Bombay, Mumbai 400076, India
| | - Ranjith Padinhateeri
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai 400076, India
- To whom correspondence should be addressed. Tel: +91 22 25767761; Fax: +91 22 25767760; . Correspondence may also be addressed to Tripti Bameta.
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