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DeHaro-Arbona FJ, Roussos C, Baloul S, Townson J, Gómez Lamarca MJ, Bray S. Dynamic modes of Notch transcription hubs conferring memory and stochastic activation revealed by live imaging the co-activator Mastermind. eLife 2024; 12:RP92083. [PMID: 38727722 PMCID: PMC11087053 DOI: 10.7554/elife.92083] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/12/2024] Open
Abstract
Developmental programming involves the accurate conversion of signalling levels and dynamics to transcriptional outputs. The transcriptional relay in the Notch pathway relies on nuclear complexes containing the co-activator Mastermind (Mam). By tracking these complexes in real time, we reveal that they promote the formation of a dynamic transcription hub in Notch ON nuclei which concentrates key factors including the Mediator CDK module. The composition of the hub is labile and persists after Notch withdrawal conferring a memory that enables rapid reformation. Surprisingly, only a third of Notch ON hubs progress to a state with nascent transcription, which correlates with polymerase II and core Mediator recruitment. This probability is increased by a second signal. The discovery that target-gene transcription is probabilistic has far-reaching implications because it implies that stochastic differences in Notch pathway output can arise downstream of receptor activation.
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Affiliation(s)
- F Javier DeHaro-Arbona
- Department of Physiology Development and Neuroscience, University of CambridgeCambridgeUnited Kingdom
| | - Charalambos Roussos
- Department of Physiology Development and Neuroscience, University of CambridgeCambridgeUnited Kingdom
| | - Sarah Baloul
- Department of Physiology Development and Neuroscience, University of CambridgeCambridgeUnited Kingdom
| | - Jonathan Townson
- Department of Physiology Development and Neuroscience, University of CambridgeCambridgeUnited Kingdom
| | - María J Gómez Lamarca
- Department of Physiology Development and Neuroscience, University of CambridgeCambridgeUnited Kingdom
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocıo/CSIC/Universidad de Sevilla, Departamento de Biologıa CelularSevilleSpain
| | - Sarah Bray
- Department of Physiology Development and Neuroscience, University of CambridgeCambridgeUnited Kingdom
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Cucun G, Köhler M, Pfitsch S, Rastegar S. Insights into the mechanisms of neuron generation and specification in the zebrafish ventral spinal cord. FEBS J 2024; 291:646-662. [PMID: 37498183 DOI: 10.1111/febs.16913] [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: 05/02/2023] [Revised: 06/20/2023] [Accepted: 07/25/2023] [Indexed: 07/28/2023]
Abstract
The vertebrate nervous system is composed of a wide range of neurons and complex synaptic connections, raising the intriguing question of how neuronal diversity is generated. The spinal cord provides an excellent model for exploring the mechanisms governing neuronal diversity due to its simple neural network and the conserved molecular processes involved in neuron formation and specification during evolution. This review specifically examines two distinct progenitor domains present in the zebrafish ventral spinal cord: the lateral floor plate (LFP) and the p2 progenitor domain. The LFP is responsible for the production of GABAergic Kolmer-Agduhr neurons (KA″), glutamatergic V3 neurons, and intraspinal serotonergic neurons, while the p2 domain generates V2 precursors that subsequently differentiate into three unique subpopulations of V2 neurons, namely glutamatergic V2a, GABAergic V2b, and glycinergic V2s. Based on recent findings, we will examine the fundamental signaling pathways and transcription factors that play a key role in the specification of these diverse neurons and neuronal subtypes derived from the LFP and p2 progenitor domains.
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Affiliation(s)
- Gokhan Cucun
- Institute for Biological and Chemical Systems - Biological Information Processing (IBCS-BIP), Karlsruhe Institute of Technology (KIT), Eggenstein-Leopoldshafen, Germany
| | - Melina Köhler
- Institute for Biological and Chemical Systems - Biological Information Processing (IBCS-BIP), Karlsruhe Institute of Technology (KIT), Eggenstein-Leopoldshafen, Germany
| | - Sabrina Pfitsch
- Institute for Biological and Chemical Systems - Biological Information Processing (IBCS-BIP), Karlsruhe Institute of Technology (KIT), Eggenstein-Leopoldshafen, Germany
| | - Sepand Rastegar
- Institute for Biological and Chemical Systems - Biological Information Processing (IBCS-BIP), Karlsruhe Institute of Technology (KIT), Eggenstein-Leopoldshafen, Germany
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3
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Wyart C, Carbo-Tano M, Cantaut-Belarif Y, Orts-Del'Immagine A, Böhm UL. Cerebrospinal fluid-contacting neurons: multimodal cells with diverse roles in the CNS. Nat Rev Neurosci 2023; 24:540-556. [PMID: 37558908 DOI: 10.1038/s41583-023-00723-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/26/2023] [Indexed: 08/11/2023]
Abstract
The cerebrospinal fluid (CSF) is a complex solution that circulates around the CNS, and whose composition changes as a function of an animal's physiological state. Ciliated neurons that are bathed in the CSF - and thus referred to as CSF-contacting neurons (CSF-cNs) - are unusual polymodal interoceptive neurons. As chemoreceptors, CSF-cNs respond to variations in pH and osmolarity and to bacterial metabolites in the CSF. Their activation during infections of the CNS results in secretion of compounds to enhance host survival. As mechanosensory neurons, CSF-cNs operate together with an extracellular proteinaceous polymer known as the Reissner fibre to detect compression during spinal curvature. Once activated, CSF-cNs inhibit motor neurons, premotor excitatory neurons and command neurons to enhance movement speed and stabilize posture. At longer timescales, CSF-cNs instruct morphogenesis throughout life via the release of neuropeptides that act over long distances on skeletal muscle. Finally, recent evidence suggests that mouse CSF-cNs may act as neural stem cells in the spinal cord, inspiring new paths of investigation for repair after injury.
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Affiliation(s)
- Claire Wyart
- Institut du Cerveau (ICM), INSERM U1127, UMR CNRS 7225 Paris, Sorbonne Université, Paris, France.
| | - Martin Carbo-Tano
- Institut du Cerveau (ICM), INSERM U1127, UMR CNRS 7225 Paris, Sorbonne Université, Paris, France
| | - Yasmine Cantaut-Belarif
- Institut du Cerveau (ICM), INSERM U1127, UMR CNRS 7225 Paris, Sorbonne Université, Paris, France
| | | | - Urs L Böhm
- NeuroCure Cluster of Excellence, Charité Universitätsmedizin Berlin, Berlin, Germany
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Chen F, Köhler M, Cucun G, Takamiya M, Kizil C, Cosacak MI, Rastegar S. sox1a:eGFP transgenic line and single-cell transcriptomics reveal the origin of zebrafish intraspinal serotonergic neurons. iScience 2023; 26:107342. [PMID: 37529101 PMCID: PMC10387610 DOI: 10.1016/j.isci.2023.107342] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Revised: 06/03/2023] [Accepted: 07/06/2023] [Indexed: 08/03/2023] Open
Abstract
Sox transcription factors are crucial for vertebrate nervous system development. In zebrafish embryo, sox1 genes are expressed in neural progenitor cells and neurons of ventral spinal cord. Our recent study revealed that the loss of sox1a and sox1b function results in a significant decline of V2 subtype neurons (V2s). Using single-cell RNA sequencing, we analyzed the transcriptome of sox1a lineage progenitors and neurons in the zebrafish spinal cord at four time points during embryonic development, employing the Tg(sox1a:eGFP) line. In addition to previously characterized sox1a-expressing neurons, we discovered the expression of sox1a in late-developing intraspinal serotonergic neurons (ISNs). Developmental trajectory analysis suggests that ISNs arise from lateral floor plate (LFP) progenitor cells. Pharmacological inhibition of the Notch signaling pathway revealed its role in negatively regulating LFP progenitor cell differentiation into ISNs. Our findings highlight the zebrafish LFP as a progenitor domain for ISNs, alongside known Kolmer-Agduhr (KA) and V3 interneurons.
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Affiliation(s)
- Fushun Chen
- Institute of Biological and Chemical Systems-Biological Information Processing (IBCS-BIP), Karlsruhe Institute of Technology (KIT), Campus North, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
| | - Melina Köhler
- Institute of Biological and Chemical Systems-Biological Information Processing (IBCS-BIP), Karlsruhe Institute of Technology (KIT), Campus North, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
| | - Gokhan Cucun
- Institute of Biological and Chemical Systems-Biological Information Processing (IBCS-BIP), Karlsruhe Institute of Technology (KIT), Campus North, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
| | - Masanari Takamiya
- Institute of Biological and Chemical Systems-Biological Information Processing (IBCS-BIP), Karlsruhe Institute of Technology (KIT), Campus North, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
| | - Caghan Kizil
- German Center for Neurodegenerative Diseases (DZNE) Dresden, Helmholtz Association, Tatzberg 41, 01307 Dresden, Germany
- Department of Neurology and the Taub Institute for Research on Alzheimer’s Disease and the Aging Brain, Columbia University Irving Medical Center, 630 W 168th Street, New York, NY 10032, USA
| | - Mehmet Ilyas Cosacak
- German Center for Neurodegenerative Diseases (DZNE) Dresden, Helmholtz Association, Tatzberg 41, 01307 Dresden, Germany
| | - Sepand Rastegar
- Institute of Biological and Chemical Systems-Biological Information Processing (IBCS-BIP), Karlsruhe Institute of Technology (KIT), Campus North, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
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Bello-Rojas S, Bagnall MW. Clonally related, Notch-differentiated spinal neurons integrate into distinct circuits. eLife 2022; 11:83680. [PMID: 36580075 PMCID: PMC9799969 DOI: 10.7554/elife.83680] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Accepted: 11/24/2022] [Indexed: 12/30/2022] Open
Abstract
Shared lineage has diverse effects on patterns of neuronal connectivity. In mammalian cortex, excitatory sister neurons assemble into shared microcircuits. In Drosophila, in contrast, sister neurons with different levels of Notch expression (NotchON/NotchOFF) develop distinct identities and diverge into separate circuits. Notch-differentiated sister neurons have been observed in vertebrate spinal cord and cerebellum, but whether they integrate into shared or distinct circuits remains unknown. Here, we evaluate how sister V2a (NotchOFF)/V2b (NotchON) neurons in the zebrafish integrate into spinal circuits. Using an in vivo labeling approach, we identified pairs of sister V2a/b neurons born from individual Vsx1+ progenitors and observed that they have somata in close proximity to each other and similar axonal trajectories. However, paired whole-cell electrophysiology and optogenetics revealed that sister V2a/b neurons receive input from distinct presynaptic sources, do not communicate with each other, and connect to largely distinct targets. These results resemble the divergent connectivity in Drosophila and represent the first evidence of Notch-differentiated circuit integration in a vertebrate system.
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Affiliation(s)
- Saul Bello-Rojas
- Department of Neuroscience, Washington University in St. LouisSt. LouisUnited States
| | - Martha W Bagnall
- Department of Neuroscience, Washington University in St. LouisSt. LouisUnited States
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