1
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Kiefer L, Gaudin S, Rajkumar SM, Servito GIF, Langen J, Mui MH, Nawsheen S, Canzio D. Tuning cohesin trajectories enables differential readout of the Pcdhα cluster across neurons. Science 2024; 385:eadm9802. [PMID: 39052779 DOI: 10.1126/science.adm9802] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Accepted: 05/16/2024] [Indexed: 07/27/2024]
Abstract
Expression of Protocadherin (Pcdh) genes is critical to the generation of neuron identity and wiring of the nervous system. Pcdhα genes are arranged in clusters and exhibit a range of expression profiles, from stochastic to deterministic. Because Pcdhα promoters have high sequence identity and share distal enhancers, how distinct neurons choose which gene to express remains unclear. We show that the interplay between multiple enhancers, epigenetics, and genome folding orchestrates differential readouts of the locus across neurons. The probability of Pcdhα promoter choice depends on enhancer/promoter encounters catalyzed by cohesin, whose extrusion trajectories determine the likelihood that an individual promoter can "escape" heterochromatin-mediated silencing. We propose that tunable locus-specific regulatory elements and cell type-specific cohesin activity underlie the generation of cellular diversity by Pcdh genes.
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Affiliation(s)
- Lea Kiefer
- Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA 94158, USA
- Department of Neurology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Simon Gaudin
- Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA 94158, USA
- Department of Neurology, University of California, San Francisco, San Francisco, CA 94158, USA
- Department of Biology, Ecole Normale Supérieure de Lyon, 69432 Lyon, France
| | - Sandy M Rajkumar
- Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA 94158, USA
- Department of Neurology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Gabrielle Isabelle F Servito
- Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA 94158, USA
- Department of Neurology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Jennifer Langen
- Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA 94158, USA
- Department of Neurology, University of California, San Francisco, San Francisco, CA 94158, USA
- Neuroscience Graduate Program, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Michael H Mui
- Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA 94158, USA
- Department of Neurology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Shayra Nawsheen
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Daniele Canzio
- Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA 94158, USA
- Department of Neurology, University of California, San Francisco, San Francisco, CA 94158, USA
- Chan-Zuckerberg Biohub Investigator, San Francisco, San Francisco, CA 94158, USA
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2
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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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3
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Pourmorady AD, Bashkirova EV, Chiariello AM, Belagzhal H, Kodra A, Duffié R, Kahiapo J, Monahan K, Pulupa J, Schieren I, Osterhoudt A, Dekker J, Nicodemi M, Lomvardas S. RNA-mediated symmetry breaking enables singular olfactory receptor choice. Nature 2024; 625:181-188. [PMID: 38123679 PMCID: PMC10765522 DOI: 10.1038/s41586-023-06845-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Accepted: 11/07/2023] [Indexed: 12/23/2023]
Abstract
Olfactory receptor (OR) choice provides an extreme example of allelic competition for transcriptional dominance, where every olfactory neuron stably transcribes one of approximately 2,000 or more OR alleles1,2. OR gene choice is mediated by a multichromosomal enhancer hub that activates transcription at a single OR3,4, followed by OR-translation-dependent feedback that stabilizes this choice5,6. Here, using single-cell genomics, we show formation of many competing hubs with variable enhancer composition, only one of which retains euchromatic features and transcriptional competence. Furthermore, we provide evidence that OR transcription recruits enhancers and reinforces enhancer hub activity locally, whereas OR RNA inhibits transcription of competing ORs over distance, promoting transition to transcriptional singularity. Whereas OR transcription is sufficient to break the symmetry between equipotent enhancer hubs, OR translation stabilizes transcription at the prevailing hub, indicating that there may be sequential non-coding and coding mechanisms that are implemented by OR alleles for transcriptional prevalence. We propose that coding OR mRNAs possess non-coding functions that influence nuclear architecture, enhance their own transcription and inhibit transcription from their competitors, with generalizable implications for probabilistic cell fate decisions.
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Affiliation(s)
- Ariel D Pourmorady
- Vagelos College of Physicians and Surgeons, Columbia University New York, New York, NY, USA
- Department of Neuroscience, Columbia University, New York, NY, USA
- Mortimer B. Zuckerman Mind, Brain, and Behavior Institute, Columbia University New York, New York, NY, USA
| | - Elizaveta V Bashkirova
- Mortimer B. Zuckerman Mind, Brain, and Behavior Institute, Columbia University New York, New York, NY, USA
- Integrated Program in Cellular, Molecular and Biomedical Studies, Vagelos College of Physicians and Surgeons, New York, NY, USA
| | - Andrea M Chiariello
- Department of Physics 'Ettore Pancini', University of Naples, and INFN, Napoli, Italy
| | - Houda Belagzhal
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA, USA
| | - Albana Kodra
- Integrated Program in Cellular, Molecular and Biomedical Studies, Vagelos College of Physicians and Surgeons, New York, NY, USA
- Department of Genetics and Development, Vagelos College of Physicians and Surgeons, New York, NY, USA
| | - Rachel Duffié
- Mortimer B. Zuckerman Mind, Brain, and Behavior Institute, Columbia University New York, New York, NY, USA
| | - Jerome Kahiapo
- Department of Molecular Biology & Biochemistry, Rutgers School of Arts and Sciences, Robert Wood Johnson Medical School, Piscataway, NJ, USA
| | - Kevin Monahan
- Department of Molecular Biology & Biochemistry, Rutgers School of Arts and Sciences, Robert Wood Johnson Medical School, Piscataway, NJ, USA
| | - Joan Pulupa
- Mortimer B. Zuckerman Mind, Brain, and Behavior Institute, Columbia University New York, New York, NY, USA
| | - Ira Schieren
- Mortimer B. Zuckerman Mind, Brain, and Behavior Institute, Columbia University New York, New York, NY, USA
| | - Alexa Osterhoudt
- Mortimer B. Zuckerman Mind, Brain, and Behavior Institute, Columbia University New York, New York, NY, USA
- Integrated Program in Cellular, Molecular and Biomedical Studies, Vagelos College of Physicians and Surgeons, New York, NY, USA
| | - Job Dekker
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA, USA
| | - Mario Nicodemi
- Department of Physics 'Ettore Pancini', University of Naples, and INFN, Napoli, Italy
| | - Stavros Lomvardas
- Mortimer B. Zuckerman Mind, Brain, and Behavior Institute, Columbia University New York, New York, NY, USA.
- Department of Biochemistry and Molecular Biophysics, Vagelos College of Physicians and Surgeons, New York, NY, USA.
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4
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Park C, Owusu-Boaitey KE, Valdes GM, Reddien PW. Fate specification is spatially intermingled across planarian stem cells. Nat Commun 2023; 14:7422. [PMID: 37973979 PMCID: PMC10654723 DOI: 10.1038/s41467-023-43267-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Accepted: 11/06/2023] [Indexed: 11/19/2023] Open
Abstract
Regeneration requires mechanisms for producing a wide array of cell types. Neoblasts are stem cells in the planarian Schmidtea mediterranea that undergo fate specification to produce over 125 adult cell types. Fate specification in neoblasts can be regulated through expression of fate-specific transcription factors. We utilize multiplexed error-robust fluorescence in situ hybridization (MERFISH) and whole-mount FISH to characterize fate choice distribution of stem cells within planarians. Fate choices are often made distant from target tissues and in a highly intermingled manner, with neighboring neoblasts frequently making divergent fate choices for tissues of different location and function. We propose that pattern formation is driven primarily by the migratory assortment of progenitors from mixed and spatially distributed fate-specified stem cells and that fate choice involves stem-cell intrinsic processes.
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Affiliation(s)
- Chanyoung Park
- Whitehead Institute for Biomedical Research, Cambridge, MA, USA
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Kwadwo E Owusu-Boaitey
- Whitehead Institute for Biomedical Research, Cambridge, MA, USA
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA
- Harvard/MIT MD-PhD Program, Harvard Medical School, Boston, MA, USA
| | - Giselle M Valdes
- Whitehead Institute for Biomedical Research, Cambridge, MA, USA
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Peter W Reddien
- Whitehead Institute for Biomedical Research, Cambridge, MA, USA.
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA.
- Howard Hughes Medical Institute, Chevy Chase, MD, USA.
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5
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Chakraborty M, Sivan A, Biswas A, Sinha B. Early tension regulation coupled to surface myomerger is necessary for the primary fusion of C2C12 myoblasts. Front Physiol 2022; 13. [PMID: 36277221 PMCID: PMC7613732 DOI: 10.3389/fphys.2022.976715] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Here, we study the time-dependent regulation of fluctuation–tension during myogenesis and the role of the fusogen, myomerger. We measure nanometric height fluctuations of the basal membrane of C2C12 cells after triggering differentiation. Fusion of cells increases fluctuation–tension but prefers a transient lowering of tension (at ∼2–24 h). Cells fail to fuse if early tension is continuously enhanced by methyl-β-cyclodextrin (MβCD). Perturbing tension regulation also reduces fusion. During this pre-fusion window, cells that finally differentiate usually display lower tension than other non-fusing cells, validating early tension states to be linked to fate decision. Early tension reduction is accompanied by low but gradually increasing level of the surface myomerger. Locally too, regions with higher myomerger intensity display lower tension. However, this negative correlation is lost in the early phase by MβCD-based cholesterol depletion or later as differentiation progresses. We find that with tension and surface-myomerger’s enrichment under these conditions, myomerger clusters become pronouncedly diffused. We, therefore, propose that low tension aided by clustered surface-myomerger at the early phase is crucial for fusion and can be disrupted by cholesterol-reducing molecules, implying the potential to affect muscle health.
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6
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A Spacetime Odyssey of Neural Progenitors to Generate Neuronal Diversity. Neurosci Bull 2022; 39:645-658. [PMID: 36214963 PMCID: PMC10073374 DOI: 10.1007/s12264-022-00956-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2022] [Accepted: 06/29/2022] [Indexed: 10/17/2022] Open
Abstract
To understand how the nervous system develops from a small pool of progenitors during early embryonic development, it is fundamentally important to identify the diversity of neuronal subtypes, decode the origin of neuronal diversity, and uncover the principles governing neuronal specification across different regions. Recent single-cell analyses have systematically identified neuronal diversity at unprecedented scale and speed, leaving the deconstruction of spatiotemporal mechanisms for generating neuronal diversity an imperative and paramount challenge. In this review, we highlight three distinct strategies deployed by neural progenitors to produce diverse neuronal subtypes, including predetermined, stochastic, and cascade diversifying models, and elaborate how these strategies are implemented in distinct regions such as the neocortex, spinal cord, retina, and hypothalamus. Importantly, the identity of neural progenitors is defined by their spatial position and temporal patterning factors, and each type of progenitor cell gives rise to distinguishable cohorts of neuronal subtypes. Microenvironmental cues, spontaneous activity, and connectional pattern further reshape and diversify the fate of unspecialized neurons in particular regions. The illumination of how neuronal diversity is generated will pave the way for producing specific brain organoids to model human disease and desired neuronal subtypes for cell therapy, as well as understanding the organization of functional neural circuits and the evolution of the nervous system.
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7
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Abuhashem A, Chivu AG, Zhao Y, Rice EJ, Siepel A, Danko CG, Hadjantonakis AK. RNA Pol II pausing facilitates phased pluripotency transitions by buffering transcription. Genes Dev 2022; 36:gad.349565.122. [PMID: 35981753 PMCID: PMC9480856 DOI: 10.1101/gad.349565.122] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Accepted: 07/18/2022] [Indexed: 01/03/2023]
Abstract
Promoter-proximal RNA Pol II pausing is a critical step in transcriptional control. Pol II pausing has been predominantly studied in tissue culture systems. While Pol II pausing has been shown to be required for mammalian development, the phenotypic and mechanistic details of this requirement are unknown. Here, we found that loss of Pol II pausing stalls pluripotent state transitions within the epiblast of the early mouse embryo. Using Nelfb -/- mice and a NELFB degron mouse pluripotent stem cell model, we show that embryonic stem cells (ESCs) representing the naïve state of pluripotency successfully initiate a transition program but fail to balance levels of induced and repressed genes and enhancers in the absence of NELF. We found an increase in chromatin-associated NELF during transition from the naïve to later pluripotent states. Overall, our work defines the acute and long-term molecular consequences of NELF loss and reveals a role for Pol II pausing in the pluripotency continuum as a modulator of cell state transitions.
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Affiliation(s)
- Abderhman Abuhashem
- Developmental Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, New York 10065, USA
- Weill Cornell/Rockefeller/Sloan Kettering Tri-Institutional MD-PhD Program, New York, New York 10065, USA
- Biochemistry Cell and Molecular Biology Program, Weill Cornell Graduate School of Medical Sciences, Cornell University, New York, New York 10065, USA
| | - Alexandra G Chivu
- Baker Institute for Animal Health, College of Veterinary Medicine, Cornell University, Ithaca, New York 14853, USA
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York 14853, USA
| | - Yixin Zhao
- Simons Center for Quantitative Biology, Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724, USA
| | - Edward J Rice
- Baker Institute for Animal Health, College of Veterinary Medicine, Cornell University, Ithaca, New York 14853, USA
| | - Adam Siepel
- Simons Center for Quantitative Biology, Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724, USA
| | - Charles G Danko
- Baker Institute for Animal Health, College of Veterinary Medicine, Cornell University, Ithaca, New York 14853, USA
- Department of Biomedical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, New York 14853, USA
| | - Anna-Katerina Hadjantonakis
- Developmental Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, New York 10065, USA
- Biochemistry Cell and Molecular Biology Program, Weill Cornell Graduate School of Medical Sciences, Cornell University, New York, New York 10065, USA
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8
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Voortman L, Anderson C, Urban E, Yuan L, Tran S, Neuhaus-Follini A, Derrick J, Gregor T, Johnston RJ. Temporally dynamic antagonism between transcription and chromatin compaction controls stochastic photoreceptor specification in flies. Dev Cell 2022; 57:1817-1832.e5. [PMID: 35835116 PMCID: PMC9378680 DOI: 10.1016/j.devcel.2022.06.016] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Revised: 05/09/2022] [Accepted: 06/20/2022] [Indexed: 01/12/2023]
Abstract
Stochastic mechanisms diversify cell fates during development. How cells randomly choose between two or more fates remains poorly understood. In the Drosophila eye, the random mosaic of two R7 photoreceptor subtypes is determined by expression of the transcription factor Spineless (Ss). We investigated how cis-regulatory elements and trans factors regulate nascent transcriptional activity and chromatin compaction at the ss gene locus during R7 development. The ss locus is in a compact state in undifferentiated cells. An early enhancer drives transcription in all R7 precursors, and the locus opens. In differentiating cells, transcription ceases and the ss locus stochastically remains open or compacts. In SsON R7s, ss is open and competent for activation by a late enhancer, whereas in SsOFF R7s, ss is compact, and repression prevents expression. Our results suggest that a temporally dynamic antagonism, in which transcription drives large-scale decompaction and then compaction represses transcription, controls stochastic fate specification.
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Affiliation(s)
- Lukas Voortman
- Department of Biology, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Caitlin Anderson
- Department of Biology, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Elizabeth Urban
- Department of Biology, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Luorongxin Yuan
- Department of Biology, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Sang Tran
- Department of Biology, Johns Hopkins University, Baltimore, MD 21218, USA
| | | | - Josh Derrick
- Department of Biology, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Thomas Gregor
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ, USA; Joseph Henry Laboratories of Physics, the Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA; Department of Developmental and Stem Cell Biology, UMR3738, Institut Pasteur, 75015 Paris, France
| | - Robert J Johnston
- Department of Biology, Johns Hopkins University, Baltimore, MD 21218, USA.
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9
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Ebrahimi N, Osanlouy M, Bradley CP, Kubke MF, Gerneke DA, Hunter PJ. A method for investigating spatiotemporal growth patterns at cell and tissue levels during C-looping in the embryonic chick heart. iScience 2022; 25:104600. [PMID: 35800755 PMCID: PMC9253367 DOI: 10.1016/j.isci.2022.104600] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Revised: 01/15/2022] [Accepted: 06/08/2022] [Indexed: 11/29/2022] Open
Affiliation(s)
- Nazanin Ebrahimi
- University of Auckland, Auckland Bioengineering Institute, Auckland 1010, New Zealand
- Corresponding author
| | - Mahyar Osanlouy
- University of Auckland, Auckland Bioengineering Institute, Auckland 1010, New Zealand
| | - Chris P. Bradley
- University of Auckland, Auckland Bioengineering Institute, Auckland 1010, New Zealand
| | - M. Fabiana Kubke
- University of Auckland, Anatomy and Medical Imaging, Auckland 1010, New Zealand
| | - Dane A. Gerneke
- University of Auckland, Auckland Bioengineering Institute, Auckland 1010, New Zealand
| | - Peter J. Hunter
- University of Auckland, Auckland Bioengineering Institute, Auckland 1010, New Zealand
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10
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Aydin O, Passaro AP, Raman R, Spellicy SE, Weinberg RP, Kamm RD, Sample M, Truskey GA, Zartman J, Dar RD, Palacios S, Wang J, Tordoff J, Montserrat N, Bashir R, Saif MTA, Weiss R. Principles for the design of multicellular engineered living systems. APL Bioeng 2022; 6:010903. [PMID: 35274072 PMCID: PMC8893975 DOI: 10.1063/5.0076635] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Accepted: 02/02/2022] [Indexed: 12/14/2022] Open
Abstract
Remarkable progress in bioengineering over the past two decades has enabled the formulation of fundamental design principles for a variety of medical and non-medical applications. These advancements have laid the foundation for building multicellular engineered living systems (M-CELS) from biological parts, forming functional modules integrated into living machines. These cognizant design principles for living systems encompass novel genetic circuit manipulation, self-assembly, cell-cell/matrix communication, and artificial tissues/organs enabled through systems biology, bioinformatics, computational biology, genetic engineering, and microfluidics. Here, we introduce design principles and a blueprint for forward production of robust and standardized M-CELS, which may undergo variable reiterations through the classic design-build-test-debug cycle. This Review provides practical and theoretical frameworks to forward-design, control, and optimize novel M-CELS. Potential applications include biopharmaceuticals, bioreactor factories, biofuels, environmental bioremediation, cellular computing, biohybrid digital technology, and experimental investigations into mechanisms of multicellular organisms normally hidden inside the "black box" of living cells.
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Affiliation(s)
| | - Austin P. Passaro
- Regenerative Bioscience Center, University of Georgia, Athens, Georgia 30602, USA
| | - Ritu Raman
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | | | - Robert P. Weinberg
- School of Pharmacy, Massachusetts College of Pharmacy and Health Sciences, Boston, Massachusetts 02115, USA
| | | | - Matthew Sample
- Center for Ethics and Law in the Life Sciences, Leibniz Universität Hannover, 30167 Hannover, Germany
| | - George A. Truskey
- Department of Biomedical Engineering, Duke University, Durham, North Carolina 27708, USA
| | - Jeremiah Zartman
- Department of Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, Indiana 46556, USA
| | - Roy D. Dar
- Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
| | - Sebastian Palacios
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, Massachusetts, 02139, USA
| | - Jason Wang
- Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
| | - Jesse Tordoff
- Computational and Systems Biology Program, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Nuria Montserrat
- Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute of Science and Technology (BIST), 08028 Barcelona, Spain
| | | | - M. Taher A. Saif
- Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
| | - Ron Weiss
- Author to whom correspondence should be addressed:
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11
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Shekhar K, Whitney IE, Butrus S, Peng YR, Sanes JR. Diversification of multipotential postmitotic mouse retinal ganglion cell precursors into discrete types. eLife 2022; 11:e73809. [PMID: 35191836 PMCID: PMC8956290 DOI: 10.7554/elife.73809] [Citation(s) in RCA: 28] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2021] [Accepted: 02/21/2022] [Indexed: 11/13/2022] Open
Abstract
The genesis of broad neuronal classes from multipotential neural progenitor cells has been extensively studied, but less is known about the diversification of a single neuronal class into multiple types. We used single-cell RNA-seq to study how newly born (postmitotic) mouse retinal ganglion cell (RGC) precursors diversify into ~45 discrete types. Computational analysis provides evidence that RGC transcriptomic type identity is not specified at mitotic exit, but acquired by gradual, asynchronous restriction of postmitotic multipotential precursors. Some types are not identifiable until a week after they are generated. Immature RGCs may be specified to project ipsilaterally or contralaterally to the rest of the brain before their type identity emerges. Optimal transport inference identifies groups of RGC precursors with largely nonoverlapping fates, distinguished by selectively expressed transcription factors that could act as fate determinants. Our study provides a framework for investigating the molecular diversification of discrete types within a neuronal class.
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Affiliation(s)
- Karthik Shekhar
- Department of Chemical and Biomolecular Engineering; Helen Wills Neuroscience Institute; Center for Computational Biology; California Institute for Quantitative Biosciences, QB3, University of California, BerkeleyBerkeleyUnited States
- Biological Systems and Engineering Division, Lawrence Berkeley National LaboratoryBerkeleyUnited States
- Broad Institute of Harvard and MITCambridgeUnited States
- Center for Brain Science and Department of Molecular and Cellular Biology, Harvard UniversityCambridgeUnited States
| | - Irene E Whitney
- Center for Brain Science and Department of Molecular and Cellular Biology, Harvard UniversityCambridgeUnited States
| | - Salwan Butrus
- Department of Chemical and Biomolecular Engineering; Helen Wills Neuroscience Institute; Center for Computational Biology; California Institute for Quantitative Biosciences, QB3, University of California, BerkeleyBerkeleyUnited States
| | - Yi-Rong Peng
- Center for Brain Science and Department of Molecular and Cellular Biology, Harvard UniversityCambridgeUnited States
- Department of Ophthalmology, Stein Eye Institute, UCLA David Geffen School of MedicineLos AngelesUnited States
| | - Joshua R Sanes
- Center for Brain Science and Department of Molecular and Cellular Biology, Harvard UniversityCambridgeUnited States
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12
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Voortman L, Johnston RJ. Transcriptional repression in stochastic gene expression, patterning, and cell fate specification. Dev Biol 2022; 481:129-138. [PMID: 34688689 PMCID: PMC8665150 DOI: 10.1016/j.ydbio.2021.10.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2021] [Revised: 10/04/2021] [Accepted: 10/09/2021] [Indexed: 01/03/2023]
Abstract
Development is often driven by signaling and lineage-specific cues, yielding highly uniform and reproducible outcomes. Development also involves mechanisms that generate noise in gene expression and random patterns across tissues. Cells sometimes randomly choose between two or more cell fates in a mechanism called stochastic cell fate specification. This process diversifies cell types in otherwise homogenous tissues. Stochastic mechanisms have been extensively studied in prokaryotes where noisy gene activation plays a pivotal role in controlling cell fates. In eukaryotes, transcriptional repression stochastically limits gene expression to generate random patterns and specify cell fates. Here, we review our current understanding of repressive mechanisms that produce random patterns of gene expression and cell fates in flies, plants, mice, and humans.
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Affiliation(s)
- Lukas Voortman
- Department of Biology, Johns Hopkins University, 3400 N. Charles Street, Baltimore, MD, 21218, USA
| | - Robert J Johnston
- Department of Biology, Johns Hopkins University, 3400 N. Charles Street, Baltimore, MD, 21218, USA.
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13
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Abuhashem A, Garg V, Hadjantonakis AK. RNA polymerase II pausing in development: orchestrating transcription. Open Biol 2022; 12:210220. [PMID: 34982944 PMCID: PMC8727152 DOI: 10.1098/rsob.210220] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
The coordinated regulation of transcriptional networks underpins cellular identity and developmental progression. RNA polymerase II promoter-proximal pausing (Pol II pausing) is a prevalent mechanism by which cells can control and synchronize transcription. Pol II pausing regulates the productive elongation step of transcription at key genes downstream of a variety of signalling pathways, such as FGF and Nodal. Recent advances in our understanding of the Pol II pausing machinery and its role in transcription call for an assessment of these findings within the context of development. In this review, we discuss our current understanding of the molecular basis of Pol II pausing and its function during organismal development. By critically assessing the tools used to study this process we conclude that combining recently developed genomics approaches with refined perturbation systems has the potential to expand our understanding of Pol II pausing mechanistically and functionally in the context of development and beyond.
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Affiliation(s)
- Abderhman Abuhashem
- Developmental Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA,Weill Cornell/Rockefeller/Sloan Kettering Tri-Institutional MD-PhD Program, New York, NY 10021, USA,Biochemistry, Cell and Molecular Biology Graduate Program, Weill Cornell Medical College, New York, NY 10021, USA
| | - Vidur Garg
- Developmental Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Anna-Katerina Hadjantonakis
- Developmental Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA,Biochemistry, Cell and Molecular Biology Graduate Program, Weill Cornell Medical College, New York, NY 10021, USA
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14
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Abstract
Within populations, individuals show a variety of behavioral preferences, even in the absence of genetic or environmental variability. Neuromodulators affect these idiosyncratic preferences in a wide range of systems, however, the mechanism(s) by which they do so is unclear. I review the evidence supporting three broad mechanisms by which neuromodulators might affect variability in idiosyncratic behavioral preference: by being a source of variability directly upstream of behavior, by affecting the behavioral output of a circuit in a way that masks or accentuates underlying variability in that circuit, and by driving plasticity in circuits leading to either homeostatic convergence toward a given behavior or divergence from a developmental setpoint. I find evidence for each of these mechanisms and propose future directions to further understand the complex interplay between individual variability and neuromodulators.
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Affiliation(s)
- Ryan T Maloney
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, United States
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15
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Nguyen P, Pease NA, Kueh HY. Scalable control of developmental timetables by epigenetic switching networks. J R Soc Interface 2021; 18:20210109. [PMID: 34283940 DOI: 10.1098/rsif.2021.0109] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
During development, progenitor cells follow timetables for differentiation that span many cell generations. These developmental timetables are robustly encoded by the embryo, yet scalably adjustable by evolution, facilitating variation in organism size and form. Epigenetic switches, involving rate-limiting activation steps at regulatory gene loci, control gene activation timing in diverse contexts, and could profoundly impact the dynamics of gene regulatory networks controlling developmental lineage specification. Here, we develop a mathematical framework to model regulatory networks with genes controlled by epigenetic switches. Using this framework, we show that such epigenetic switching networks uphold developmental timetables that robustly span many cell generations, and enable the generation of differentiated cells in precisely defined numbers and fractions. Changes to epigenetic switching networks can readily alter the timing of developmental events within a timetable, or alter the overall speed at which timetables unfold, enabling scalable control over differentiated population sizes. With their robust, yet flexibly adjustable nature, epigenetic switching networks could represent central targets on which evolution acts to manufacture diversity in organism size and form.
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Affiliation(s)
- Phuc Nguyen
- Molecular Engineering and Sciences Program, University of Washington, Seattle, WA, USA
| | - Nicholas A Pease
- Molecular and Cellular Biology Program, University of Washington, Seattle, WA, USA
| | - Hao Yuan Kueh
- Department of Bioengineering, University of Washington, Seattle, WA, USA.,Institute of Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA, USA
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16
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Thankamony AP, Subbalakshmi AR, Jolly MK, Nair R. Lineage Plasticity in Cancer: The Tale of a Skin-Walker. Cancers (Basel) 2021; 13:3602. [PMID: 34298815 PMCID: PMC8306016 DOI: 10.3390/cancers13143602] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2021] [Revised: 07/04/2021] [Accepted: 07/14/2021] [Indexed: 12/11/2022] Open
Abstract
Lineage plasticity, the switching of cells from one lineage to another, has been recognized as a cardinal property essential for embryonic development, tissue repair and homeostasis. However, such a highly regulated process goes awry when cancer cells exploit this inherent ability to their advantage, resulting in tumorigenesis, relapse, metastasis and therapy resistance. In this review, we summarize our current understanding on the role of lineage plasticity in tumor progression and therapeutic resistance in multiple cancers. Lineage plasticity can be triggered by treatment itself and is reported across various solid as well as liquid tumors. Here, we focus on the importance of lineage switching in tumor progression and therapeutic resistance of solid tumors such as the prostate, lung, hepatocellular and colorectal carcinoma and the myeloid and lymphoid lineage switch observed in leukemias. Besides this, we also discuss the role of epithelial-mesenchymal transition (EMT) in facilitating the lineage switch in biphasic cancers such as aggressive carcinosarcomas. We also discuss the mechanisms involved, current therapeutic approaches and challenges that lie ahead in taming the scourge of lineage plasticity in cancer.
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Affiliation(s)
- Archana P. Thankamony
- Cancer Research Program, Rajiv Gandhi Centre for Biotechnology, Kerala 695014, India;
- Manipal Academy of Higher Education (MAHE), Manipal 576104, India
| | - Ayalur Raghu Subbalakshmi
- Centre for BioSystems Science and Engineering, Indian Institute of Science, Bangalore 560012, India;
| | - Mohit Kumar Jolly
- Centre for BioSystems Science and Engineering, Indian Institute of Science, Bangalore 560012, India;
| | - Radhika Nair
- Cancer Research Program, Rajiv Gandhi Centre for Biotechnology, Kerala 695014, India;
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17
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Gritti N, Oriola D, Trivedi V. Rethinking embryology in vitro: A synergy between engineering, data science and theory. Dev Biol 2021; 474:48-61. [DOI: 10.1016/j.ydbio.2020.10.013] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Revised: 10/21/2020] [Accepted: 10/26/2020] [Indexed: 02/06/2023]
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18
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Xie Q, Brbic M, Horns F, Kolluru SS, Jones RC, Li J, Reddy AR, Xie A, Kohani S, Li Z, McLaughlin CN, Li T, Xu C, Vacek D, Luginbuhl DJ, Leskovec J, Quake SR, Luo L, Li H. Temporal evolution of single-cell transcriptomes of Drosophila olfactory projection neurons. eLife 2021; 10:e63450. [PMID: 33427646 PMCID: PMC7870145 DOI: 10.7554/elife.63450] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Accepted: 01/05/2021] [Indexed: 12/18/2022] Open
Abstract
Neurons undergo substantial morphological and functional changes during development to form precise synaptic connections and acquire specific physiological properties. What are the underlying transcriptomic bases? Here, we obtained the single-cell transcriptomes of Drosophila olfactory projection neurons (PNs) at four developmental stages. We decoded the identity of 21 transcriptomic clusters corresponding to 20 PN types and developed methods to match transcriptomic clusters representing the same PN type across development. We discovered that PN transcriptomes reflect unique biological processes unfolding at each stage-neurite growth and pruning during metamorphosis at an early pupal stage; peaked transcriptomic diversity during olfactory circuit assembly at mid-pupal stages; and neuronal signaling in adults. At early developmental stages, PN types with adjacent birth order share similar transcriptomes. Together, our work reveals principles of cellular diversity during brain development and provides a resource for future studies of neural development in PNs and other neuronal types.
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Affiliation(s)
- Qijing Xie
- Department of Biology, Howard Hughes Medical Institute, Stanford UniversityStanfordUnited States
- Neurosciences Graduate Program, Stanford UniversityStanfordUnited States
| | - Maria Brbic
- Department of Computer Science, Stanford UniversityStanfordUnited States
| | - Felix Horns
- Department of Bioengineering, Stanford UniversityStanfordUnited States
- Biophysics Graduate Program, Stanford UniversityStanfordUnited States
| | | | - Robert C Jones
- Department of Bioengineering, Stanford UniversityStanfordUnited States
| | - Jiefu Li
- Department of Biology, Howard Hughes Medical Institute, Stanford UniversityStanfordUnited States
| | - Anay R Reddy
- Department of Biology, Howard Hughes Medical Institute, Stanford UniversityStanfordUnited States
| | - Anthony Xie
- Department of Biology, Howard Hughes Medical Institute, Stanford UniversityStanfordUnited States
| | - Sayeh Kohani
- Department of Biology, Howard Hughes Medical Institute, Stanford UniversityStanfordUnited States
| | - Zhuoran Li
- Department of Biology, Howard Hughes Medical Institute, Stanford UniversityStanfordUnited States
| | - Colleen N McLaughlin
- Department of Biology, Howard Hughes Medical Institute, Stanford UniversityStanfordUnited States
| | - Tongchao Li
- Department of Biology, Howard Hughes Medical Institute, Stanford UniversityStanfordUnited States
| | - Chuanyun Xu
- Department of Biology, Howard Hughes Medical Institute, Stanford UniversityStanfordUnited States
| | - David Vacek
- Department of Biology, Howard Hughes Medical Institute, Stanford UniversityStanfordUnited States
| | - David J Luginbuhl
- Department of Biology, Howard Hughes Medical Institute, Stanford UniversityStanfordUnited States
| | - Jure Leskovec
- Department of Computer Science, Stanford UniversityStanfordUnited States
| | - Stephen R Quake
- Department of Bioengineering, Stanford UniversityStanfordUnited States
- Department of Applied Physics, Stanford UniversityStanfordUnited States
- Chan Zuckerberg BiohubStanfordUnited States
| | - Liqun Luo
- Department of Biology, Howard Hughes Medical Institute, Stanford UniversityStanfordUnited States
| | - Hongjie Li
- Department of Biology, Howard Hughes Medical Institute, Stanford UniversityStanfordUnited States
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19
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Kuwahara H, Gao X. Stable maintenance of hidden switches as a strategy to increase the gene expression stability. NATURE COMPUTATIONAL SCIENCE 2021; 1:62-70. [PMID: 38217152 DOI: 10.1038/s43588-020-00001-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2020] [Accepted: 11/02/2020] [Indexed: 01/15/2024]
Abstract
In response to severe genetic and environmental perturbations, wild-type organisms can express hidden alternative phenotypes adaptive to such adverse conditions. While our theoretical understanding of the population-level fitness advantage and evolution of phenotypic switching under variable environments has grown, the mechanism by which these organisms maintain phenotypic switching capabilities under static environments remains to be elucidated. Here, using computational simulations, we analyzed the evolution of gene circuits under natural selection and found that different strategies evolved to increase the gene expression stability near the optimum level. In a population comprising bistable individuals, a strategy of maintaining bistability and raising the potential barrier separating the bistable regimes was consistently taken. Our results serve as evidence that hidden bistable switches can be stably maintained during environmental stasis-an essential property enabling the timely release of adaptive alternatives with small genetic changes in the event of substantial perturbations.
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Affiliation(s)
- Hiroyuki Kuwahara
- Computational Bioscience Research Center (CBRC), Computer, Electrical and Mathematical Sciences and Engineering (CEMSE) Division, King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
| | - Xin Gao
- Computational Bioscience Research Center (CBRC), Computer, Electrical and Mathematical Sciences and Engineering (CEMSE) Division, King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia.
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20
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Miller AC, Urban EA, Lyons EL, Herman TG, Johnston RJ. Interdependent regulation of stereotyped and stochastic photoreceptor fates in the fly eye. Dev Biol 2020; 471:89-96. [PMID: 33333066 PMCID: PMC7856283 DOI: 10.1016/j.ydbio.2020.12.008] [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: 08/14/2020] [Revised: 12/07/2020] [Accepted: 12/09/2020] [Indexed: 12/14/2022]
Abstract
Diversification of neuronal subtypes often requires stochastic gene regulatory mechanisms. How stochastically expressed transcription factors interact with other regulators in gene networks to specify cell fates is poorly understood. The random mosaic of color-detecting R7 photoreceptor subtypes in Drosophila is controlled by the stochastic on/off expression of the transcription factor Spineless (Ss). In SsON R7s, Ss induces expression of Rhodopsin 4 (Rh4), whereas in SsOFF R7s, the absence of Ss allows expression of Rhodopsin 3 (Rh3). Here, we find that the transcription factor Runt, which is initially expressed in all R7s, is sufficient to promote stochastic Ss expression. Later, as R7s develop, Ss negatively feeds back onto Runt to prevent repression of Rh4 and ensure proper fate specification. Together, stereotyped and stochastic regulatory inputs are integrated into feedforward and feedback mechanisms to control cell fate.
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Affiliation(s)
- Adam C Miller
- Institute of Molecular Biology, University of Oregon, Eugene, OR, 97403, USA
| | - Elizabeth A Urban
- Department of Biology, Johns Hopkins University, 3400 N Charles Street, Baltimore, MD, 21218-2685, USA
| | - Eric L Lyons
- Institute of Molecular Biology, University of Oregon, Eugene, OR, 97403, USA
| | - Tory G Herman
- Institute of Molecular Biology, University of Oregon, Eugene, OR, 97403, USA.
| | - Robert J Johnston
- Department of Biology, Johns Hopkins University, 3400 N Charles Street, Baltimore, MD, 21218-2685, USA.
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21
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Ferreira Castro A, Baltruschat L, Stürner T, Bahrami A, Jedlicka P, Tavosanis G, Cuntz H. Achieving functional neuronal dendrite structure through sequential stochastic growth and retraction. eLife 2020; 9:e60920. [PMID: 33241995 PMCID: PMC7837678 DOI: 10.7554/elife.60920] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Accepted: 11/15/2020] [Indexed: 02/06/2023] Open
Abstract
Class I ventral posterior dendritic arborisation (c1vpda) proprioceptive sensory neurons respond to contractions in the Drosophila larval body wall during crawling. Their dendritic branches run along the direction of contraction, possibly a functional requirement to maximise membrane curvature during crawling contractions. Although the molecular machinery of dendritic patterning in c1vpda has been extensively studied, the process leading to the precise elaboration of their comb-like shapes remains elusive. Here, to link dendrite shape with its proprioceptive role, we performed long-term, non-invasive, in vivo time-lapse imaging of c1vpda embryonic and larval morphogenesis to reveal a sequence of differentiation stages. We combined computer models and dendritic branch dynamics tracking to propose that distinct sequential phases of stochastic growth and retraction achieve efficient dendritic trees both in terms of wire and function. Our study shows how dendrite growth balances structure-function requirements, shedding new light on general principles of self-organisation in functionally specialised dendrites.
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Affiliation(s)
- André Ferreira Castro
- Frankfurt Institute for Advanced StudiesFrankfurt am MainGermany
- Ernst Strüngmann Institute (ESI) for Neuroscience in cooperation with Max Planck SocietyFrankfurt am MainGermany
- Center for Neurodegenerative Diseases (DZNE)BonnGermany
| | | | - Tomke Stürner
- Center for Neurodegenerative Diseases (DZNE)BonnGermany
- Department of Zoology, University of CambridgeCambridgeUnited Kingdom
| | | | - Peter Jedlicka
- Frankfurt Institute for Advanced StudiesFrankfurt am MainGermany
- Faculty of Medicine, ICAR3R – Interdisciplinary Centre for 3Rs in Animal Research, Justus Liebig University GiessenGiessenGermany
- Neuroscience Center, Institute of Clinical Neuroanatomy, Goethe UniversityFrankfurt am MainGermany
| | - Gaia Tavosanis
- Center for Neurodegenerative Diseases (DZNE)BonnGermany
- LIMES Institute, University of BonnBonnGermany
| | - Hermann Cuntz
- Frankfurt Institute for Advanced StudiesFrankfurt am MainGermany
- Ernst Strüngmann Institute (ESI) for Neuroscience in cooperation with Max Planck SocietyFrankfurt am MainGermany
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22
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Llorca A, Marín O. Orchestrated freedom: new insights into cortical neurogenesis. Curr Opin Neurobiol 2020; 66:48-56. [PMID: 33096393 DOI: 10.1016/j.conb.2020.09.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Revised: 08/03/2020] [Accepted: 09/02/2020] [Indexed: 11/17/2022]
Abstract
In mammals, the construction of the cerebral cortex involves the coordinated output of large populations of apical progenitor cells. Cortical progenitor cells use intrinsic molecular programs and complex regulatory mechanisms to generate a large diversity of excitatory projection neurons in appropriate numbers. In this review, we summarize recent findings regarding the neurogenic behavior of cortical progenitors during neurogenesis. We describe alternative models explaining the generation of neuronal diversity among excitatory projection neurons and the role of intrinsic and extrinsic signals in the modulation of the individual output of apical progenitor cells.
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Affiliation(s)
- Alfredo Llorca
- Centre for Developmental Neurobiology, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London SE1 1UL, United Kingdom; MRC Centre for Neurodevelopmental Disorders, King's College London, London SE1 1UL, United Kingdom
| | - Oscar Marín
- Centre for Developmental Neurobiology, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London SE1 1UL, United Kingdom; MRC Centre for Neurodevelopmental Disorders, King's College London, London SE1 1UL, United Kingdom.
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23
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Theoretical study of the impact of adaptation on cell-fate heterogeneity and fractional killing. Sci Rep 2020; 10:17429. [PMID: 33060729 PMCID: PMC7562916 DOI: 10.1038/s41598-020-74238-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Accepted: 09/22/2020] [Indexed: 02/07/2023] Open
Abstract
Fractional killing illustrates the cell propensity to display a heterogeneous fate response over a wide range of stimuli. The interplay between the nonlinear and stochastic dynamics of biochemical networks plays a fundamental role in shaping this probabilistic response and in reconciling requirements for heterogeneity and controllability of cell-fate decisions. The stress-induced fate choice between life and death depends on an early adaptation response which may contribute to fractional killing by amplifying small differences between cells. To test this hypothesis, we consider a stochastic modeling framework suited for comprehensive sensitivity analysis of dose response curve through the computation of a fractionality index. Combining bifurcation analysis and Langevin simulation, we show that adaptation dynamics enhances noise-induced cell-fate heterogeneity by shifting from a saddle-node to a saddle-collision transition scenario. The generality of this result is further assessed by a computational analysis of a detailed regulatory network model of apoptosis initiation and by a theoretical analysis of stochastic bifurcation mechanisms. Overall, the present study identifies a cooperative interplay between stochastic, adaptation and decision intracellular processes that could promote cell-fate heterogeneity in many contexts.
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24
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Bayer EA, Sun H, Rafi I, Hobert O. Temporal, Spatial, Sexual and Environmental Regulation of the Master Regulator of Sexual Differentiation in C. elegans. Curr Biol 2020; 30:3604-3616.e3. [DOI: 10.1016/j.cub.2020.06.060] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Revised: 05/04/2020] [Accepted: 06/17/2020] [Indexed: 12/23/2022]
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25
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Fields C, Levin M. Scale-Free Biology: Integrating Evolutionary and Developmental Thinking. Bioessays 2020; 42:e1900228. [PMID: 32537770 DOI: 10.1002/bies.201900228] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Revised: 04/24/2020] [Indexed: 12/16/2022]
Abstract
When the history of life on earth is viewed as a history of cell division, all of life becomes a single cell lineage. The growth and differentiation of this lineage in reciprocal interaction with its environment can be viewed as a developmental process; hence the evolution of life on earth can also be seen as the development of life on earth. Here, in reviewing this field, some potentially fruitful research directions suggested by this change in perspective are highlighted. Variation and selection become, for example, bidirectional information flows between scales, while the notions of "cooperation" and "competition" become scale relative. The language of communication, inference, and information processing becomes more useful than the language of causation to describe the interactions of both homogeneous and heterogeneous living systems at any scale. Emerging scale-free theoretical frameworks such as predictive coding and active inference provide conceptual tools for reconceptualizing biology as the study of a unified, multiscale dynamical system.
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Affiliation(s)
- Chris Fields
- 23 Rue des Lavandieres, 11160 Caunes Minervois, France
| | - Michael Levin
- Allen Discovery Center at Tufts University, Medford, MA, 02155, USA
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26
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Abstract
The cerebellum is a pivotal centre for the integration and processing of motor and sensory information. Its extended development into the postnatal period makes this structure vulnerable to a variety of pathologies, including neoplasia. These properties have prompted intensive investigations that reveal not only developmental mechanisms in common with other regions of the neuraxis but also unique strategies to generate neuronal diversity. How the phenotypically distinct cell types of the cerebellum emerge rests on understanding how gene expression differences arise in a spatially and temporally coordinated manner from initially homogeneous cell populations. Increasingly sophisticated fate mapping approaches, culminating in genetic-induced fate mapping, have furthered the understanding of lineage relationships between early- versus later-born cells. Tracing the developmental histories of cells in this way coupled with analysis of gene expression patterns has provided insight into the developmental genetic programmes that instruct cellular heterogeneity. A limitation to date has been the bulk analysis of cells, which blurs lineage relationships and obscures gene expression differences between cells that underpin the cellular taxonomy of the cerebellum. This review emphasises recent discoveries, focusing mainly on single-cell sequencing in mouse and parallel human studies that elucidate neural progenitor developmental trajectories with unprecedented resolution. Complementary functional studies of neural repair after cerebellar injury are challenging assumptions about the stability of postnatal cellular identities. The result is a wealth of new information about the developmental mechanisms that generate cerebellar neural diversity, with implications for human evolution.
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Affiliation(s)
- Max J. van Essen
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Samuel Nayler
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Esther B. E. Becker
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - John Jacob
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
- * E-mail:
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27
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Naoki H, Matsui T. Somite boundary determination in normal and clock-less vertebrate embryos. Dev Growth Differ 2020; 62:177-187. [PMID: 32108939 DOI: 10.1111/dgd.12655] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2019] [Revised: 01/31/2020] [Accepted: 02/01/2020] [Indexed: 12/21/2022]
Abstract
Vertebrate segments called somites are generated by periodic segmentation of the presomitic mesoderm (PSM). In the most accepted theoretical model for somite segmentation, the clock and wavefront (CW) model, a clock that ticks to determine particular timings and a wavefront that moves posteriorly are presented in the PSM, and somite positions are determined when the clock meets the posteriorly moving wavefront somewhere in the PSM. Over the last two decades, it has been revealed that the molecular mechanism of the clock and wavefront in vertebrates is based on clock genes including Hes family transcription factors and Notch effectors that oscillate within the PSM to determine particular timings and fibroblast growth factor (FGF) gradients, acting as the posteriorly moving wavefront to determine the position of somite segmentation. A clock-less condition in the CW model was predicted to form no somites; however, irregularly sized somites were still formed in mice and zebrafish, suggesting that this was one of the limitations of the CW model. Recently, we performed interdisciplinary research of experimental and theoretical biological studies and revealed the mechanisms of somite boundary determination in normal and clock-less conditions by characterization of the FGF/extracellular signal-regulated kinase (ERK) activity dynamics. Since features of the molecular clock have already been described in-depth in several reviews, we summarized recent findings regarding the role of FGF/ERK signaling in somite boundary formation and described our current understanding of how FGF/ERK signaling contributes to somitogenesis in normal and clock-less conditions in this review.
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Affiliation(s)
- Honda Naoki
- Laboratory of Theoretical Biology, Research Center for Dynamic Living Systems, Graduate School of Biostudies, Kyoto University, Sakyo, Kyoto, Japan
| | - Takaaki Matsui
- Gene Regulation Research, Division of Biological Science, Nara Institute of Science and Technology, Takayama, Nara, Japan
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28
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Kroll JR, Tsiaxiras J, van Zon JS. Variability in β-catenin pulse dynamics in a stochastic cell fate decision in C. elegans. Dev Biol 2020; 461:110-123. [PMID: 32032579 PMCID: PMC7203549 DOI: 10.1016/j.ydbio.2020.02.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Revised: 01/31/2020] [Accepted: 02/02/2020] [Indexed: 11/30/2022]
Abstract
During development, cell fate decisions are often highly stochastic, but with the frequency of the different possible fates tightly controlled. To understand how signaling networks control the cell fate frequency of such random decisions, we studied the stochastic decision of the Caenorhabditis elegans P3.p cell to either fuse to the hypodermis or assume vulva precursor cell fate. Using time-lapse microscopy to measure the single-cell dynamics of two key inhibitors of cell fusion, the Hox gene LIN-39 and Wnt signaling through the β-catenin BAR-1, we uncovered significant variability in the dynamics of LIN-39 and BAR-1 levels. Most strikingly, we observed that BAR-1 accumulated in a single, 1–4 h pulse at the time of the P3.p cell fate decision, with strong variability both in pulse slope and time of pulse onset. We found that the time of BAR-1 pulse onset was delayed relative to the time of cell fusion in mutants with low cell fusion frequency, linking BAR-1 pulse timing to cell fate outcome. Overall, a model emerged where animal-to-animal variability in LIN-39 levels and BAR-1 pulse dynamics biases cell fate by modulating their absolute level at the time cell fusion is induced. Our results highlight that timing of cell signaling dynamics, rather than its average level or amplitude, could play an instructive role in determining cell fate. The fate of the C. elegans P3.p cell is stochastic. β-catenin (BAR-1) accumulated in P3.p at the time of the cell fate decision. There is variability in dynamics of Hox and β-catenin levels during the decision. BAR-1 accumulated with variable pulse slope and time of pulse onset. Pulse dynamics bias cell fate at the time of the cell fate decision.
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Affiliation(s)
- Jason R Kroll
- Department of Living Matter, AMOLF, 1098 XG, Amsterdam, the Netherlands
| | - Jasonas Tsiaxiras
- Department of Living Matter, AMOLF, 1098 XG, Amsterdam, the Netherlands
| | - Jeroen S van Zon
- Department of Living Matter, AMOLF, 1098 XG, Amsterdam, the Netherlands.
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29
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Peng YR, James RE, Yan W, Kay JN, Kolodkin AL, Sanes JR. Binary Fate Choice between Closely Related Interneuronal Types Is Determined by a Fezf1-Dependent Postmitotic Transcriptional Switch. Neuron 2019; 105:464-474.e6. [PMID: 31812516 DOI: 10.1016/j.neuron.2019.11.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2019] [Revised: 10/07/2019] [Accepted: 10/30/2019] [Indexed: 02/08/2023]
Abstract
Many neuronal types occur as pairs that are similar in most respects but differ in a key feature. In some pairs of retinal neurons, called paramorphic, one member responds to increases and the other to decreases in luminance (ON and OFF responses). Here, we focused on one such pair, starburst amacrine cells (SACs), to explore how closely related neuronal types diversify. We find that ON and OFF SACs are transcriptionally distinct prior to their segregation, dendritic outgrowth, and synapse formation. The transcriptional repressor Fezf1 is selectively expressed by postmitotic ON SACs and promotes the ON fate and gene expression program while repressing the OFF fate and program. The atypical Rho GTPase Rnd3 is selectively expressed by OFF SACs and regulates their migration but is repressed by Fezf1 in ON SACs, enabling differential positioning of the two types. These results define a transcriptional program that controls diversification of a paramorphic pair.
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Affiliation(s)
- Yi-Rong Peng
- Center for Brain Science and Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA
| | - Rebecca E James
- Solomon H. Snyder Department of Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Wenjun Yan
- Center for Brain Science and Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA
| | - Jeremy N Kay
- Departments of Ophthalmology and Neurobiology, Duke University Medical Center, Durham, NC, USA
| | - Alex L Kolodkin
- Solomon H. Snyder Department of Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
| | - Joshua R Sanes
- Center for Brain Science and Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA.
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30
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A universal transportin protein drives stochastic choice of olfactory neurons via specific nuclear import of a sox-2-activating factor. Proc Natl Acad Sci U S A 2019; 116:25137-25146. [PMID: 31767767 DOI: 10.1073/pnas.1908168116] [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] [Indexed: 02/07/2023] Open
Abstract
Stochastic neuronal cell fate choice involving notch-independent mechanisms is a poorly understood biological process. The Caenorhabditis elegans AWC olfactory neuron pair asymmetrically differentiates into the default AWCOFF and induced AWCON subtypes in a stochastic manner. Stochastic choice of the AWCON subtype is established using gap junctions and SLO BK potassium channels to repress a calcium-activated protein kinase pathway. However, it is unknown how the potassium channel-repressed calcium signaling is translated into the induction of the AWCON subtype. Here, we identify a detailed working mechanism of how the homeodomain-like transcription factor NSY-7, previously described as a repressor in the maintenance of AWC asymmetry, couples SLO BK potassium channels to transactivation of sox-2 expression for the induction of the AWCON subtype through the identification of a unique imb-2 (transportin 1) allele. imb-2 loss-of-function mutants are not viable; however, we identify a viable imb-2 allele from an unbiased forward genetic screen that reveals a specific role of imb-2 in AWC olfactory neuron asymmetry. IMB-2 specifically drives nuclear import of NSY-7 within AWC neurons to transactivate the expression of the high mobility group (HMG)-box transcription factor SOX-2 for the specification of the AWCON subtype. This study provides mechanistic insight into how NSY-7 couples SLO BK potassium channels to transactivation of sox-2 expression for the induction of the AWCON subtype. Our findings also provide structure-function insight into a conserved amino acid residue of transportins in brain development and suggest its dysfunction may lead to human neurological disorders.
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31
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Courgeon M, Desplan C. Coordination between stochastic and deterministic specification in the Drosophila visual system. Science 2019; 366:science.aay6727. [PMID: 31582524 DOI: 10.1126/science.aay6727] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Accepted: 09/18/2019] [Indexed: 01/05/2023]
Abstract
Sensory systems use stochastic fate specification to increase their repertoire of neuronal types. How these stochastic decisions are coordinated with the development of their targets is unknown. In the Drosophila retina, two subtypes of ultraviolet-sensitive R7 photoreceptors are stochastically specified. In contrast, their targets in the brain are specified through a deterministic program. We identified subtypes of the main target of R7, the Dm8 neurons, each specific to the different subtypes of R7s. Dm8 subtypes are produced in excess by distinct neuronal progenitors, independently from R7. After matching with their cognate R7, supernumerary Dm8s are eliminated by apoptosis. Two interacting cell adhesion molecules, Dpr11 and DIPγ, are essential for the matching of one of the synaptic pairs. These mechanisms allow the qualitative and quantitative matching of R7 and Dm8 and thereby permit the stochastic choice made in R7 to propagate to the brain.
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Affiliation(s)
| | - Claude Desplan
- Department of Biology, New York University, New York, NY 10003, USA.
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32
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Attner MA, Keil W, Benavidez JM, Greenwald I. HLH-2/E2A Expression Links Stochastic and Deterministic Elements of a Cell Fate Decision during C. elegans Gonadogenesis. Curr Biol 2019; 29:3094-3100.e4. [PMID: 31402303 DOI: 10.1016/j.cub.2019.07.062] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Revised: 07/08/2019] [Accepted: 07/19/2019] [Indexed: 11/20/2022]
Abstract
Stochastic mechanisms diversify cell fate in organisms ranging from bacteria to humans [1-4]. In the anchor cell/ventral uterine precursor cell (AC/VU) fate decision during C. elegans gonadogenesis, two "α cells," each with equal potential to be an AC or a VU, interact via LIN-12/Notch and its ligand LAG-2/DSL [5, 6]. This LIN-12/Notch-mediated interaction engages feedback mechanisms that amplify a stochastic initial difference between the two α cells, ensuring that the cell with higher lin-12 activity becomes the VU while the other becomes the AC [7-9]. The initial difference between the α cells was originally envisaged as a random imbalance from "noise" in lin-12 expression/activity [6]. However, subsequent evidence that the relative birth order of the α cells biases their fates suggested other factors may be operating [7]. Here, we investigate the nature of the initial difference using high-throughput lineage analysis [10]; GFP-tagged endogenous LIN-12, LAG-2, and HLH-2, a conserved transcription factor that orchestrates AC/VU development [7, 11]; and tissue-specific hlh-2 null alleles. We identify two stochastic elements: relative birth order, which largely originates at the beginning of the somatic gonad lineage three generations earlier, and onset of HLH-2 expression, such that the α cell whose parent expressed HLH-2 first is biased toward the VU fate. We find that these elements are interrelated, because initiation of HLH-2 expression is linked to the birth of the parent cell. Finally, we provide a potential deterministic mechanism for the HLH-2 expression bias by showing that hlh-2 is required for LIN-12 expression in the α cells.
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Affiliation(s)
- Michelle A Attner
- Department of Biological Sciences, Columbia University, 1212 Amsterdam Avenue, New York, NY 10027, USA
| | - Wolfgang Keil
- Center for Studies in Physics and Biology, The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA; Laboratoire Physico Chimie Curie, Institut Curie, PSL Research University, CNRS UMR168, 26 rue d'Ulm, 75248 Paris Cedex 05, France
| | - Justin M Benavidez
- Department of Biological Sciences, Columbia University, 1212 Amsterdam Avenue, New York, NY 10027, USA
| | - Iva Greenwald
- Department of Biological Sciences, Columbia University, 1212 Amsterdam Avenue, New York, NY 10027, USA.
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Borowsky R, Luk A, Kim RS. Sperm swimming behaviors are correlated with sperm haploid genetic variability in the Mexican tetra, Astyanax mexicanus. PLoS One 2019; 14:e0218538. [PMID: 31242252 PMCID: PMC6594619 DOI: 10.1371/journal.pone.0218538] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2018] [Accepted: 06/04/2019] [Indexed: 12/11/2022] Open
Abstract
The diploid genotypes of males are widely thought to determine sperm phenotypes, yet recent work shows that the haploid genetics of the individual sperm cell also contributes significantly. We tested seven sperm phenotypes, flagellar length and six behaviors, looking for correlations between genetic and phenotypic variability. While flagellar length appears to be controlled by the diploid genotype of the source, variation in three of the behavioral phenotypes, linearity, wobble, and progression are significantly correlated with the heterozygosity of the male producer. Because males that are more genetically variable produce a sperm set that is more diverse in its haploid genotypes, we suggest that the correlations may reflect significant haploid genetic control of sperm swimming behaviors.
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Affiliation(s)
- Richard Borowsky
- Department of Biology, New York University, New York, New York, United States of America
- * E-mail:
| | - Alissa Luk
- Department of Biology, New York University, New York, New York, United States of America
| | - Rebecca S. Kim
- Department of Environmental Medicine, Langone Center, New York University, New York, New York, United States of America
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34
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Riedemann S, Sutor B, Bergami M, Riedemann T. Gad1-promotor-driven GFP expression in non-GABAergic neurons of the nucleus endopiriformis in a transgenic mouse line. J Comp Neurol 2019; 527:2215-2232. [PMID: 30847931 DOI: 10.1002/cne.24673] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Revised: 03/04/2019] [Accepted: 03/04/2019] [Indexed: 01/22/2023]
Abstract
Transgenic animals have become a widely used model to identify and study specific cell types in whole organs. Promotor-driven reporter gene labeling of the cells under investigation has promoted experimental efficacy to a large degree. However, rigorous assessment of transgene expression specificity in these animal models is highly recommended to validate cellular identity and to isolate potentially mislabeled cell populations. Here, we report on one such mislabeled neuron population in a widely used transgenic mouse line in which GABAergic somatostatin-expressing interneurons (SOMpos INs) are labeled by eGFP (so-called GIN mouse, FVB-Tg(GadGFP)45704Swn/J). These neurons represent a subpopulation of all SOMpos INs. However, we report here on GFP labeling of non-GABAergic neurons in the nucleus endopiriformis of this mouse line.
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Affiliation(s)
- Sophie Riedemann
- Department of Physiological Genomics, Biomedical Center, Ludwig-Maximilians-University, Munich, Germany
| | - Bernd Sutor
- Department of Physiological Genomics, Biomedical Center, Ludwig-Maximilians-University, Munich, Germany
| | - Matteo Bergami
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD) and University Hospital of Cologne, Cologne, Germany.,Center for Molecular Medicine (CMMC), University of Cologne, Cologne, Germany
| | - Therese Riedemann
- Department of Physiological Genomics, Biomedical Center, Ludwig-Maximilians-University, Munich, Germany
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35
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Allen NC, Philip NH, Hui L, Zhou X, Franklin RA, Kong Y, Medzhitov R. Desynchronization of the molecular clock contributes to the heterogeneity of the inflammatory response. Sci Signal 2019; 12:12/571/eaau1851. [PMID: 30837303 DOI: 10.1126/scisignal.aau1851] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Heterogeneity in the behavior of genetically and developmentally equivalent cells is becoming increasingly appreciated. There are several sources of cellular heterogeneity, including both intrinsic and extrinsic noise. We found that some aspects of heterogeneity in the response of macrophages to bacterial lipopolysaccharide (LPS) were due to intercellular desynchronization of the molecular clock, a cell-intrinsic oscillator. We found that the ratio of the relative expression of two clock genes, Nfil3 and Dbp, expressed in opposite phases of the clock, determined the fraction of cells that produced the cytokine IL-12p40 in response to LPS. The clock can be entrained by various environmental stimuli, making it a mechanism by which population-level heterogeneity and the inflammatory response can be regulated.
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Affiliation(s)
- Nancy C Allen
- Department of Immunobiology, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Naomi H Philip
- Department of Immunobiology, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Lucy Hui
- Department of Immunobiology, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Xu Zhou
- Department of Immunobiology, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Ruth A Franklin
- Department of Immunobiology, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Yong Kong
- Department of Immunobiology, Yale University School of Medicine, New Haven, CT 06510, USA.,Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Ruslan Medzhitov
- Howard Hughes Medical Institute, Department of Immunobiology, Yale University School of Medicine, New Haven, CT 06510, USA.
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36
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Urban EA, Johnston RJ. Buffering and Amplifying Transcriptional Noise During Cell Fate Specification. Front Genet 2018; 9:591. [PMID: 30555516 PMCID: PMC6282114 DOI: 10.3389/fgene.2018.00591] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2018] [Accepted: 11/15/2018] [Indexed: 11/29/2022] Open
Abstract
The molecular processes that drive gene transcription are inherently noisy. This noise often manifests in the form of transcriptional bursts, producing fluctuations in gene activity over time. During cell fate specification, this noise is often buffered to ensure reproducible developmental outcomes. However, sometimes noise is utilized as a “bet-hedging” mechanism to diversify functional roles across a population of cells. Studies of bacteria, yeast, and cultured cells have provided insights into the nature and roles of noise in transcription, yet we are only beginning to understand the mechanisms by which noise influences the development of multicellular organisms. Here we discuss the sources of transcriptional noise and the mechanisms that either buffer noise to drive reproducible fate choices or amplify noise to randomly specify fates.
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Affiliation(s)
- Elizabeth A Urban
- Department of Biology, Johns Hopkins University, Baltimore, MD, United States
| | - Robert J Johnston
- Department of Biology, Johns Hopkins University, Baltimore, MD, United States
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37
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Ebadi H, Perry M, Short K, Klemm K, Desplan C, Stadler PF, Mehta A. Patterning the insect eye: From stochastic to deterministic mechanisms. PLoS Comput Biol 2018; 14:e1006363. [PMID: 30439954 PMCID: PMC6264902 DOI: 10.1371/journal.pcbi.1006363] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Revised: 11/29/2018] [Accepted: 07/16/2018] [Indexed: 01/09/2023] Open
Abstract
While most processes in biology are highly deterministic, stochastic mechanisms are sometimes used to increase cellular diversity. In human and Drosophila eyes, photoreceptors sensitive to different wavelengths of light are distributed in stochastic patterns, and one such patterning system has been analyzed in detail in the Drosophila retina. Interestingly, some species in the dipteran family Dolichopodidae (the “long legged” flies, or “Doli”) instead exhibit highly orderly deterministic eye patterns. In these species, alternating columns of ommatidia (unit eyes) produce corneal lenses of different colors. Occasional perturbations in some individuals disrupt the regular columns in a way that suggests that patterning occurs via a posterior-to-anterior signaling relay during development, and that specification follows a local, cellular-automaton-like rule. We hypothesize that the regulatory mechanisms that pattern the eye are largely conserved among flies and that the difference between unordered Drosophila and ordered dolichopodid eyes can be explained in terms of relative strengths of signaling interactions rather than a rewiring of the regulatory network itself. We present a simple stochastic model that is capable of explaining both the stochastic Drosophila eye and the striped pattern of Dolichopodidae eyes and thereby characterize the least number of underlying developmental rules necessary to produce both stochastic and deterministic patterns. We show that only small changes to model parameters are needed to also reproduce intermediate, semi-random patterns observed in another Doli species, and quantification of ommatidial distributions in these eyes suggests that their patterning follows similar rules. A simple model is able to account for a diversity of photoreceptor patterns in different fly species, ranging from highly deterministic to fully random.
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Affiliation(s)
- Haleh Ebadi
- Bioinformatics, Institute for Computer Science, Leipzig University, Leipzig, Germany
- * E-mail:
| | - Michael Perry
- Department of Biology, New York University, New York, New York, United States of America
| | - Keith Short
- Department of Biology, New York University, New York, New York, United States of America
| | - Konstantin Klemm
- Department of Computer Science, School of Science and Technology, Nazarbayev University, Astana, Republic of Kazakhstan
- Instituto de Física Interdisciplinar y Sistemas Complejos, Palma de Mallorca, Spain
| | - Claude Desplan
- Department of Biology, New York University, New York, New York, United States of America
| | - Peter F. Stadler
- Bioinformatics, Institute for Computer Science, Leipzig University, Leipzig, Germany
- Max Planck Institute for Mathematics in the Sciences, Leipzig, Germany
- Santa Fe Institute, Santa Fe, New Mexico, United States of America
| | - Anita Mehta
- Max Planck Institute for Mathematics in the Sciences, Leipzig, Germany
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38
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La Manno G, Soldatov R, Zeisel A, Braun E, Hochgerner H, Petukhov V, Lidschreiber K, Kastriti ME, Lönnerberg P, Furlan A, Fan J, Borm LE, Liu Z, van Bruggen D, Guo J, He X, Barker R, Sundström E, Castelo-Branco G, Cramer P, Adameyko I, Linnarsson S, Kharchenko PV. RNA velocity of single cells. Nature 2018; 560:494-498. [PMID: 30089906 PMCID: PMC6130801 DOI: 10.1038/s41586-018-0414-6] [Citation(s) in RCA: 1977] [Impact Index Per Article: 329.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2017] [Accepted: 07/03/2018] [Indexed: 11/09/2022]
Abstract
RNA abundance is a powerful indicator of the state of individual cells. Single-cell RNA sequencing can reveal RNA abundance with high quantitative accuracy, sensitivity and throughput1. However, this approach captures only a static snapshot at a point in time, posing a challenge for the analysis of time-resolved phenomena such as embryogenesis or tissue regeneration. Here we show that RNA velocity-the time derivative of the gene expression state-can be directly estimated by distinguishing between unspliced and spliced mRNAs in common single-cell RNA sequencing protocols. RNA velocity is a high-dimensional vector that predicts the future state of individual cells on a timescale of hours. We validate its accuracy in the neural crest lineage, demonstrate its use on multiple published datasets and technical platforms, reveal the branching lineage tree of the developing mouse hippocampus, and examine the kinetics of transcription in human embryonic brain. We expect RNA velocity to greatly aid the analysis of developmental lineages and cellular dynamics, particularly in humans.
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Affiliation(s)
- Gioele La Manno
- Laboratory of Molecular Neurobiology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
- Science for Life Laboratory, Solna, Sweden
| | - Ruslan Soldatov
- Department of Biomedical Informatics, Harvard Medical School, Boston, MA, USA
| | - Amit Zeisel
- Laboratory of Molecular Neurobiology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
- Science for Life Laboratory, Solna, Sweden
| | - Emelie Braun
- Laboratory of Molecular Neurobiology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
- Science for Life Laboratory, Solna, Sweden
| | - Hannah Hochgerner
- Laboratory of Molecular Neurobiology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
- Science for Life Laboratory, Solna, Sweden
| | - Viktor Petukhov
- Department of Biomedical Informatics, Harvard Medical School, Boston, MA, USA
- Department of Applied Mathematics, Peter The Great St. Petersburg Polytechnic University, St, Petersburg, Russia
| | - Katja Lidschreiber
- Department of Biosciences and Nutrition, Karolinska Institutet, Stockholm, Sweden
| | - Maria E Kastriti
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Peter Lönnerberg
- Laboratory of Molecular Neurobiology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
- Science for Life Laboratory, Solna, Sweden
| | - Alessandro Furlan
- Laboratory of Molecular Neurobiology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - Jean Fan
- Department of Biomedical Informatics, Harvard Medical School, Boston, MA, USA
| | - Lars E Borm
- Laboratory of Molecular Neurobiology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
- Science for Life Laboratory, Solna, Sweden
| | - Zehua Liu
- Department of Biomedical Informatics, Harvard Medical School, Boston, MA, USA
| | - David van Bruggen
- Laboratory of Molecular Neurobiology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - Jimin Guo
- Department of Biomedical Informatics, Harvard Medical School, Boston, MA, USA
| | - Xiaoling He
- John van Geest Centre for Brain Repair, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
| | - Roger Barker
- John van Geest Centre for Brain Repair, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
| | - Erik Sundström
- Division of Neurodegeneration, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Stockholm, Sweden
| | - Gonçalo Castelo-Branco
- Laboratory of Molecular Neurobiology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - Patrick Cramer
- Department of Biosciences and Nutrition, Karolinska Institutet, Stockholm, Sweden
- Max Planck Institute for Biophysical Chemistry, Department of Molecular Biology, Göttingen, Germany
| | - Igor Adameyko
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Sten Linnarsson
- Laboratory of Molecular Neurobiology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden.
- Science for Life Laboratory, Solna, Sweden.
| | - Peter V Kharchenko
- Department of Biomedical Informatics, Harvard Medical School, Boston, MA, USA.
- Harvard Stem Cell Institute, Cambridge, MA, USA.
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39
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Simon CS, Hadjantonakis AK, Schröter C. Making lineage decisions with biological noise: Lessons from the early mouse embryo. WILEY INTERDISCIPLINARY REVIEWS-DEVELOPMENTAL BIOLOGY 2018; 7:e319. [PMID: 29709110 DOI: 10.1002/wdev.319] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2017] [Revised: 02/09/2018] [Accepted: 03/13/2018] [Indexed: 12/18/2022]
Abstract
Understanding how individual cells make fate decisions that lead to the faithful formation and homeostatic maintenance of tissues is a fundamental goal of contemporary developmental and stem cell biology. Seemingly uniform populations of stem cells and multipotent progenitors display a surprising degree of heterogeneity, primarily originating from the inherent stochastic nature of molecular processes underlying gene expression. Despite this heterogeneity, lineage decisions result in tissues of a defined size and with consistent proportions of differentiated cell types. Using the early mouse embryo as a model we review recent developments that have allowed the quantification of molecular intercellular heterogeneity during cell differentiation. We first discuss the relationship between these heterogeneities and developmental cellular potential. We then review recent theoretical approaches that formalize the mechanisms underlying fate decisions in the inner cell mass of the blastocyst stage embryo. These models build on our extensive knowledge of the genetic control of fate decisions in this system and will become essential tools for a rigorous understanding of the connection between noisy molecular processes and reproducible outcomes at the multicellular level. We conclude by suggesting that cell-to-cell communication provides a mechanism to exploit and buffer intercellular variability in a self-organized process that culminates in the reproducible formation of the mature mammalian blastocyst stage embryo that is ready for implantation into the maternal uterus. This article is categorized under: Gene Expression and Transcriptional Hierarchies > Cellular Differentiation Establishment of Spatial and Temporal Patterns > Regulation of Size, Proportion, and Timing Gene Expression and Transcriptional Hierarchies > Gene Networks and Genomics Gene Expression and Transcriptional Hierarchies > Quantitative Methods and Models.
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Affiliation(s)
- Claire S Simon
- Developmental Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, New York
| | - Anna-Katerina Hadjantonakis
- Developmental Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, New York
| | - Christian Schröter
- Department of Systemic Cell Biology, Max Planck Institute of Molecular Physiology, Dortmund, Germany
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40
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Li H, Shuster SA, Li J, Luo L. Linking neuronal lineage and wiring specificity. Neural Dev 2018; 13:5. [PMID: 29653548 PMCID: PMC5899351 DOI: 10.1186/s13064-018-0102-0] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Accepted: 03/14/2018] [Indexed: 02/01/2023] Open
Abstract
Brain function requires precise neural circuit assembly during development. Establishing a functional circuit involves multiple coordinated steps ranging from neural cell fate specification to proper matching between pre- and post-synaptic partners. How neuronal lineage and birth timing influence wiring specificity remains an open question. Recent findings suggest that the relationships between lineage, birth timing, and wiring specificity vary in different neuronal circuits. In this review, we summarize our current understanding of the cellular, molecular, and developmental mechanisms linking neuronal lineage and birth timing to wiring specificity in a few specific systems in Drosophila and mice, and review different methods employed to explore these mechanisms.
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Affiliation(s)
- Hongjie Li
- Department of Biology and Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305, USA
| | - S. Andrew Shuster
- Department of Biology and Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305, USA
- Neurosciences Graduate Program, Stanford University, Stanford, CA 94305 USA
| | - Jiefu Li
- Department of Biology and Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305, USA
| | - Liqun Luo
- Department of Biology and Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305, USA
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41
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Anderson C, Reiss I, Zhou C, Cho A, Siddiqi H, Mormann B, Avelis CM, Deford P, Bergland A, Roberts E, Taylor J, Vasiliauskas D, Johnston RJ. Natural variation in stochastic photoreceptor specification and color preference in Drosophila. eLife 2017; 6:29593. [PMID: 29251595 PMCID: PMC5745083 DOI: 10.7554/elife.29593] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Accepted: 12/15/2017] [Indexed: 11/25/2022] Open
Abstract
Each individual perceives the world in a unique way, but little is known about the genetic basis of variation in sensory perception. In the fly eye, the random mosaic of color-detecting R7 photoreceptor subtypes is determined by stochastic on/off expression of the transcription factor Spineless (Ss). In a genome-wide association study, we identified a naturally occurring insertion in a regulatory DNA element in ss that lowers the ratio of SsON to SsOFF cells. This change in photoreceptor fates shifts the innate color preference of flies from green to blue. The genetic variant increases the binding affinity for Klumpfuss (Klu), a zinc finger transcriptional repressor that regulates ss expression. Klu is expressed at intermediate levels to determine the normal ratio of SsON to SsOFF cells. Thus, binding site affinity and transcription factor levels are finely tuned to regulate stochastic expression, setting the ratio of alternative fates and ultimately determining color preference.
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Affiliation(s)
- Caitlin Anderson
- Department of Biology, Johns Hopkins University, Baltimore, United States
| | - India Reiss
- Department of Biology, Johns Hopkins University, Baltimore, United States
| | - Cyrus Zhou
- Department of Biology, Johns Hopkins University, Baltimore, United States
| | - Annie Cho
- Department of Biology, Johns Hopkins University, Baltimore, United States
| | - Haziq Siddiqi
- Department of Biology, Johns Hopkins University, Baltimore, United States
| | - Benjamin Mormann
- Center for Developmental Genetics, Department of Biology, New York University, New York, United States
| | - Cameron M Avelis
- Department of Biophysics, Johns Hopkins University, Baltimore, United States
| | - Peter Deford
- Department of Biology, Johns Hopkins University, Baltimore, United States
| | - Alan Bergland
- Department of Biology, University of Virginia, Charlottesville, United States
| | - Elijah Roberts
- Department of Biophysics, Johns Hopkins University, Baltimore, United States
| | - James Taylor
- Department of Biology, Johns Hopkins University, Baltimore, United States
| | - Daniel Vasiliauskas
- Paris-Saclay Institute of Neuroscience, Université Paris Sud, Centre National de la Recherche Scientifque, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Robert J Johnston
- Department of Biology, Johns Hopkins University, Baltimore, United States
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Alqadah A, Hsieh YW, Xiong R, Chuang CF. Stochastic left-right neuronal asymmetry in Caenorhabditis elegans. Philos Trans R Soc Lond B Biol Sci 2017; 371:rstb.2015.0407. [PMID: 27821536 DOI: 10.1098/rstb.2015.0407] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/20/2016] [Indexed: 12/28/2022] Open
Abstract
Left-right asymmetry in the nervous system is observed across species. Defects in left-right cerebral asymmetry are linked to several neurological diseases, but the molecular mechanisms underlying brain asymmetry in vertebrates are still not very well understood. The Caenorhabditis elegans left and right amphid wing 'C' (AWC) olfactory neurons communicate through intercellular calcium signalling in a transient embryonic gap junction neural network to specify two asymmetric subtypes, AWCOFF (default) and AWCON (induced), in a stochastic manner. Here, we highlight the molecular mechanisms that establish and maintain stochastic AWC asymmetry. As the components of the AWC asymmetry pathway are highly conserved, insights from the model organism C. elegans may provide a window onto how brain asymmetry develops in humans.This article is part of the themed issue 'Provocative questions in left-right asymmetry'.
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Affiliation(s)
- Amel Alqadah
- Department of Biological Sciences, University of Illinois at Chicago, IL 60607, USA
| | - Yi-Wen Hsieh
- Department of Biological Sciences, University of Illinois at Chicago, IL 60607, USA
| | - Rui Xiong
- Department of Biological Sciences, University of Illinois at Chicago, IL 60607, USA
| | - Chiou-Fen Chuang
- Department of Biological Sciences, University of Illinois at Chicago, IL 60607, USA
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Yan J, Anderson C, Viets K, Tran S, Goldberg G, Small S, Johnston RJ. Regulatory logic driving stable levels of defective proventriculus expression during terminal photoreceptor specification in flies. Development 2017; 144:844-855. [PMID: 28126841 DOI: 10.1242/dev.144030] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2016] [Accepted: 01/02/2017] [Indexed: 12/13/2022]
Abstract
How differential levels of gene expression are controlled in post-mitotic neurons is poorly understood. In the Drosophila retina, expression of the transcription factor Defective Proventriculus (Dve) at distinct cell type-specific levels is required for terminal differentiation of color- and motion-detecting photoreceptors. Here, we find that the activities of two cis-regulatory enhancers are coordinated to drive dve expression in the fly eye. Three transcription factors act on these enhancers to determine cell-type specificity. Negative autoregulation by Dve maintains expression from each enhancer at distinct homeostatic levels. One enhancer acts as an inducible backup ('dark' shadow enhancer) that is normally repressed but becomes active in the absence of the other enhancer. Thus, two enhancers integrate combinatorial transcription factor input, feedback and redundancy to generate cell type-specific levels of dve expression and stable photoreceptor fate. This regulatory logic may represent a general paradigm for how precise levels of gene expression are established and maintained in post-mitotic neurons.
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Affiliation(s)
- Jenny Yan
- Department of Biology, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218-2685, USA
| | - Caitlin Anderson
- Department of Biology, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218-2685, USA
| | - Kayla Viets
- Department of Biology, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218-2685, USA
| | - Sang Tran
- Department of Biology, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218-2685, USA
| | - Gregory Goldberg
- Center for Developmental Genetics, Department of Biology, New York University, 100 Washington Square East, New York, NY 10003-6688, USA
| | - Stephen Small
- Center for Developmental Genetics, Department of Biology, New York University, 100 Washington Square East, New York, NY 10003-6688, USA
| | - Robert J Johnston
- Department of Biology, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218-2685, USA
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Plavskin Y, Nagashima A, Perroud PF, Hasebe M, Quatrano RS, Atwal GS, Timmermans MCP. Ancient trans-Acting siRNAs Confer Robustness and Sensitivity onto the Auxin Response. Dev Cell 2016; 36:276-89. [PMID: 26859352 DOI: 10.1016/j.devcel.2016.01.010] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2015] [Revised: 12/03/2015] [Accepted: 01/11/2016] [Indexed: 11/29/2022]
Abstract
Novel developmental programs often evolve via cooption of existing genetic networks. To understand this process, we explored cooption of the TAS3 tasiRNA pathway in the moss Physcomitrella patens. We find an ancestral function for this repeatedly redeployed pathway in the spatial regulation of a conserved set of Auxin Response Factors. In moss, this results in stochastic patterning of the filamentous protonemal tissue. Through modeling and experimentation, we demonstrate that tasiRNA regulation confers sensitivity and robustness onto the auxin response. Increased auxin sensitivity parallels increased developmental sensitivity to nitrogen, a key environmental signal. We propose that the properties lent to the auxin response network, along with the ability to stochastically modulate development in response to environmental cues, have contributed to repeated cooption of the tasiRNA-ARF module during evolution. The signaling properties of a genetic network, and not just its developmental output, are thus critical to understanding evolution of multicellular forms.
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Affiliation(s)
- Yevgeniy Plavskin
- Watson School of Biological Sciences, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA
| | - Akitomo Nagashima
- National Institute for Basic Biology, Okazaki 444-8585, Japan; Exploratory Research for Advanced Technology, Japan Science and Technology Agency, Okazaki 444-8585, Japan
| | | | - Mitsuyasu Hasebe
- National Institute for Basic Biology, Okazaki 444-8585, Japan; Exploratory Research for Advanced Technology, Japan Science and Technology Agency, Okazaki 444-8585, Japan
| | - Ralph S Quatrano
- Department of Biology, Washington University, St. Louis, MO 63130, USA
| | - Gurinder S Atwal
- Watson School of Biological Sciences, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA
| | - Marja C P Timmermans
- Watson School of Biological Sciences, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA; Center for Plant Molecular Biology, University of Tübingen, 72076 Tübingen, Germany.
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Mestek Boukhibar L, Barkoulas M. The developmental genetics of biological robustness. ANNALS OF BOTANY 2016; 117:699-707. [PMID: 26292993 PMCID: PMC4845795 DOI: 10.1093/aob/mcv128] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2015] [Revised: 05/07/2015] [Accepted: 06/29/2015] [Indexed: 05/10/2023]
Abstract
BACKGROUND Living organisms are continuously confronted with perturbations, such as environmental changes that include fluctuations in temperature and nutrient availability, or genetic changes such as mutations. While some developmental systems are affected by such challenges and display variation in phenotypic traits, others continue consistently to produce invariable phenotypes despite perturbation. This ability of a living system to maintain an invariable phenotype in the face of perturbations is termed developmental robustness. Biological robustness is a phenomenon observed across phyla, and studying its mechanisms is central to deciphering the genotype-phenotype relationship. Recent work in yeast, animals and plants has shown that robustness is genetically controlled and has started to reveal the underlying mechinisms behind it. SCOPE AND CONCLUSIONS Studying biological robustness involves focusing on an important property of developmental traits, which is the phenotypic distribution within a population. This is often neglected because the vast majority of developmental biology studies instead focus on population aggregates, such as trait averages. By drawing on findings in animals and yeast, this Viewpoint considers how studies on plant developmental robustness may benefit from strict definitions of what is the developmental system of choice and what is the relevant perturbation, and also from clear distinctions between gene effects on the trait mean and the trait variance. Recent advances in quantitative developmental biology and high-throughput phenotyping now allow the design of targeted genetic screens to identify genes that amplify or restrict developmental trait variance and to study how variation propagates across different phenotypic levels in biological systems. The molecular characterization of more quantitative trait loci affecting trait variance will provide further insights into the evolution of genes modulating developmental robustness. The study of robustness mechanisms in closely related species will address whether mechanisms of robustness are evolutionarily conserved.
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Affiliation(s)
- Lamia Mestek Boukhibar
- Imperial College London, Department of Life Sciences, Sir Alexander Fleming Building, South Kensington Campus, London SW7 2AZ, UK
| | - Michalis Barkoulas
- Imperial College London, Department of Life Sciences, Sir Alexander Fleming Building, South Kensington Campus, London SW7 2AZ, UK
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Stoeger T, Battich N, Pelkmans L. Passive Noise Filtering by Cellular Compartmentalization. Cell 2016; 164:1151-1161. [DOI: 10.1016/j.cell.2016.02.005] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2015] [Indexed: 12/30/2022]
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Vogt G. Stochastic developmental variation, an epigenetic source of phenotypic diversity with far-reaching biological consequences. J Biosci 2015; 40:159-204. [PMID: 25740150 DOI: 10.1007/s12038-015-9506-8] [Citation(s) in RCA: 77] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
This article reviews the production of different phenotypes from the same genotype in the same environment by stochastic cellular events, nonlinear mechanisms during patterning and morphogenesis, and probabilistic self-reinforcing circuitries in the adult life. These aspects of phenotypic variation are summarized under the term 'stochastic developmental variation' (SDV) in the following. In the past, SDV has been viewed primarily as a nuisance, impairing laboratory experiments, pharmaceutical testing, and true-to-type breeding. This article also emphasizes the positive biological effects of SDV and discusses implications for genotype-to-phenotype mapping, biological individuation, ecology, evolution, and applied biology. There is strong evidence from experiments with genetically identical organisms performed in narrowly standardized laboratory set-ups that SDV is a source of phenotypic variation in its own right aside from genetic variation and environmental variation. It is obviously mediated by molecular and higher-order epigenetic mechanisms. Comparison of SDV in animals, plants, fungi, protists, bacteria, archaeans, and viruses suggests that it is a ubiquitous and phylogenetically old phenomenon. In animals, it is usually smallest for morphometric traits and highest for life history traits and behaviour. SDV is thought to contribute to phenotypic diversity in all populations but is particularly relevant for asexually reproducing and genetically impoverished populations, where it generates individuality despite genetic uniformity. In each generation, SDV produces a range of phenotypes around a well-adapted target phenotype, which is interpreted as a bet-hedging strategy to cope with the unpredictability of dynamic environments. At least some manifestations of SDV are heritable, adaptable, selectable, and evolvable, and therefore, SDV may be seen as a hitherto overlooked evolution factor. SDV is also relevant for husbandry, agriculture, and medicine because most pathogens are asexuals that exploit this third source of phenotypic variation to modify infectivity and resistance to antibiotics. Since SDV affects all types of organisms and almost all aspects of life, it urgently requires more intense research and a better integration into biological thinking.
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Affiliation(s)
- Günter Vogt
- Faculty of Biosciences, University of Heidelberg, Im Neuenheimer Feld 230, D-69120, Heidelberg, Germany,
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Guo M, Wang H, Potter SS, Whitsett JA, Xu Y. SINCERA: A Pipeline for Single-Cell RNA-Seq Profiling Analysis. PLoS Comput Biol 2015; 11:e1004575. [PMID: 26600239 PMCID: PMC4658017 DOI: 10.1371/journal.pcbi.1004575] [Citation(s) in RCA: 215] [Impact Index Per Article: 23.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2015] [Accepted: 09/30/2015] [Indexed: 01/15/2023] Open
Abstract
A major challenge in developmental biology is to understand the genetic and cellular processes/programs driving organ formation and differentiation of the diverse cell types that comprise the embryo. While recent studies using single cell transcriptome analysis illustrate the power to measure and understand cellular heterogeneity in complex biological systems, processing large amounts of RNA-seq data from heterogeneous cell populations creates the need for readily accessible tools for the analysis of single-cell RNA-seq (scRNA-seq) profiles. The present study presents a generally applicable analytic pipeline (SINCERA: a computational pipeline for SINgle CEll RNA-seq profiling Analysis) for processing scRNA-seq data from a whole organ or sorted cells. The pipeline supports the analysis for: 1) the distinction and identification of major cell types; 2) the identification of cell type specific gene signatures; and 3) the determination of driving forces of given cell types. We applied this pipeline to the RNA-seq analysis of single cells isolated from embryonic mouse lung at E16.5. Through the pipeline analysis, we distinguished major cell types of fetal mouse lung, including epithelial, endothelial, smooth muscle, pericyte, and fibroblast-like cell types, and identified cell type specific gene signatures, bioprocesses, and key regulators. SINCERA is implemented in R, licensed under the GNU General Public License v3, and freely available from CCHMC PBGE website, https://research.cchmc.org/pbge/sincera.html.
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Affiliation(s)
- Minzhe Guo
- The Perinatal Institute, Section of Neonatology, Perinatal and Pulmonary Biology, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, United States of America
- Department of Electrical Engineering and Computing Systems, College of Engineering and Applied Science, University of Cincinnati, Cincinnati, Ohio, United States of America
| | - Hui Wang
- The Perinatal Institute, Section of Neonatology, Perinatal and Pulmonary Biology, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, United States of America
| | - S. Steven Potter
- Division of Developmental Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, United States of America
| | - Jeffrey A. Whitsett
- The Perinatal Institute, Section of Neonatology, Perinatal and Pulmonary Biology, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, United States of America
| | - Yan Xu
- The Perinatal Institute, Section of Neonatology, Perinatal and Pulmonary Biology, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, United States of America
- Division of Biomedical Informatics, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, United States of America
- * E-mail:
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Kuwahara H, Arold ST, Gao X. Beyond initiation-limited translational bursting: the effects of burst size distributions on the stability of gene expression. Integr Biol (Camb) 2015; 7:1622-32. [DOI: 10.1039/c5ib00107b] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Affiliation(s)
- Hiroyuki Kuwahara
- Computational Bioscience Research Center, King Abdullah University of Science and Technology, Thuwal, 23955, Saudi Arabia
- Computer, Electrical and Mathematical Sciences and Engineering Division, King Abdullah University of Science and Technology, Thuwal, 23955, Saudi Arabia
| | - Stefan T. Arold
- Computational Bioscience Research Center, King Abdullah University of Science and Technology, Thuwal, 23955, Saudi Arabia
- Biological and Environmental Science and Engineering Division, King Abdullah University of Science and Technology, Thuwal, 23955, Saudi Arabia
| | - Xin Gao
- Computational Bioscience Research Center, King Abdullah University of Science and Technology, Thuwal, 23955, Saudi Arabia
- Computer, Electrical and Mathematical Sciences and Engineering Division, King Abdullah University of Science and Technology, Thuwal, 23955, Saudi Arabia
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