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Altbürger C, Rath M, Wehrle J, Driever W. The proneural factors Ascl1a and Ascl1b contribute to the terminal differentiation of dopaminergic GABAergic dual transmitter neurons in zebrafish. Dev Biol 2024; 505:58-74. [PMID: 37931393 DOI: 10.1016/j.ydbio.2023.10.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Revised: 10/06/2023] [Accepted: 10/23/2023] [Indexed: 11/08/2023]
Abstract
The proneural factor Ascl1 is involved in several steps of neurogenesis, from neural progenitor maintenance to initiation of terminal differentiation and neuronal subtype specification. In neural progenitor cells, Ascl1 initiates the cell-cycle exit of progenitors, and contributes to their differentiation into mainly GABAergic neurons. Several catecholaminergic neuron groups in the forebrain of zebrafish use GABA as co-transmitter, but a potential role of the two paralogues Ascl1a and Ascl1b in their neurogenesis is not understood. Here, we show that ascl1a, ascl1b double mutant embryos develop a significantly reduced number of neurons in all GABAergic and catecholaminergic dual transmitter neuron anatomical clusters in the fore- and hindbrain, while glutamatergic catecholaminergic clusters develop normally. However, none of the affected catecholaminergic cell clusters are lost completely, suggesting an impairment in progenitor pools, or a requirement of Ascl1a/b for differentiation of a subset of neurons in each cluster. Early progenitors which are dlx2a+, fezf2 + or emx2 + are not reduced whereas late progenitors and differentiating neurons marked by the expression of dlx5a, isl1 and arxa are severely reduced in ascl1a, ascl1b double mutant embryos. This suggests that Ascl1a and Ascl1b play only a minor or no role in the maintenance of their progenitor pools, but rather contribute to the initiation of terminal differentiation of GABAergic catecholaminergic neurons.
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Affiliation(s)
- Christian Altbürger
- Department of Developmental Biology, Faculty of Biology, Institute Biology 1, Albert Ludwigs University, Freiburg, Hauptstrasse 1, 79104, Freiburg, Germany; CIBSS and BIOSS - Centres for Biological Signalling Studies, University of Freiburg, Schänzlestrasse 18, 79104, Freiburg, Germany
| | - Meta Rath
- Department of Developmental Biology, Faculty of Biology, Institute Biology 1, Albert Ludwigs University, Freiburg, Hauptstrasse 1, 79104, Freiburg, Germany
| | - Johanna Wehrle
- Department of Developmental Biology, Faculty of Biology, Institute Biology 1, Albert Ludwigs University, Freiburg, Hauptstrasse 1, 79104, Freiburg, Germany; MeInBio Research Training Group, University of Freiburg, 79104, Freiburg, Germany
| | - Wolfgang Driever
- Department of Developmental Biology, Faculty of Biology, Institute Biology 1, Albert Ludwigs University, Freiburg, Hauptstrasse 1, 79104, Freiburg, Germany; CIBSS and BIOSS - Centres for Biological Signalling Studies, University of Freiburg, Schänzlestrasse 18, 79104, Freiburg, Germany.
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2
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Mio C, Baldan F, Damante G. NK2 homeobox gene cluster: Functions and roles in human diseases. Genes Dis 2023; 10:2038-2048. [PMID: 37492711 PMCID: PMC10363584 DOI: 10.1016/j.gendis.2022.10.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Revised: 09/15/2022] [Accepted: 10/01/2022] [Indexed: 07/27/2023] Open
Abstract
NK2 genes (NKX2 gene cluster in humans) encode for homeodomain-containing transcription factors that are conserved along the phylogeny. According to the most detailed classifications, vertebrate NKX2 genes are classified into two distinct families, NK2.1 and NK2.2. The former is constituted by NKX2-1 and NKX2-4 genes, which are homologous to the Drosophila scro gene; the latter includes NKX2-2 and NKX2-8 genes, which are homologous to the Drosophila vnd gene. Conservation of these genes is not only related to molecular structure and expression, but also to biological functions. In Drosophila and vertebrates, NK2 genes share roles in the development of ventral regions of the central nervous system. In vertebrates, NKX2 genes have a relevant role in the development of several other organs such as the thyroid, lung, and pancreas. Loss-of-function mutations in NKX2-1 and NKX2-2 are the monogenic cause of the brain-lung-thyroid syndrome and neonatal diabetes, respectively. Alterations in NKX2-4 and NKX2-8 genes may play a role in multifactorial diseases, autism spectrum disorder, and neural tube defects, respectively. NKX2-1, NKX2-2, and NKX2-8 are expressed in various cancer types as either oncogenes or tumor suppressor genes. Several data indicate that evaluation of their expression in tumors has diagnostic and/or prognostic value.
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Affiliation(s)
- Catia Mio
- Dipartimento di Area Medica, Università degli Studi di Udine, Udine 33100, Italy
| | - Federica Baldan
- Istituto di Genetica Medica, Azienda Sanitaria Universitaria Friuli Centrale, Udine 33100, Italy
| | - Giuseppe Damante
- Dipartimento di Area Medica, Università degli Studi di Udine, Udine 33100, Italy
- Istituto di Genetica Medica, Azienda Sanitaria Universitaria Friuli Centrale, Udine 33100, Italy
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3
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Altbürger C, Holzhauser J, Driever W. CRISPR/Cas9-based QF2 knock-in at the tyrosine hydroxylase ( th) locus reveals novel th-expressing neuron populations in the zebrafish mid- and hindbrain. Front Neuroanat 2023; 17:1196868. [PMID: 37603776 PMCID: PMC10433395 DOI: 10.3389/fnana.2023.1196868] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Accepted: 06/30/2023] [Indexed: 08/23/2023] Open
Abstract
Catecholaminergic neuron clusters are among the most conserved neuromodulatory systems in vertebrates, yet some clusters show significant evolutionary dynamics. Because of their disease relevance, special attention has been paid to mammalian midbrain dopaminergic systems, which have important functions in motor control, reward, motivation, and cognitive function. In contrast, midbrain dopaminergic neurons in teleosts were thought to be lost secondarily. Here, we generated a CRISPR/Cas9-based knock-in transgene at the th locus, which allows the expression of the Q-system transcription factor QF2 linked to the Tyrosine hydroxylase open reading frame by an E2A peptide. The QF2 knock-in allele still expresses Tyrosine hydroxylase in catecholaminergic neurons. Coexpression analysis of QF2 driven expression of QUAS fluorescent reporter transgenes and of th mRNA and Th protein revealed that essentially all reporter expressing cells also express Th/th. We also observed a small group of previously unidentified cells expressing the reporter gene in the midbrain and a larger group close to the midbrain-hindbrain boundary. However, we detected no expression of the catecholaminergic markers ddc, slc6a3, or dbh in these neurons, suggesting that they are not actively transmitting catecholamines. The identified neurons in the midbrain are located in a GABAergic territory. A coexpression analysis with anatomical markers revealed that Th-expressing neurons in the midbrain are located in the tegmentum and those close to the midbrain-hindbrain boundary are located in the hindbrain. Our data suggest that zebrafish may still have some evolutionary remnants of midbrain dopaminergic neurons.
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Affiliation(s)
- Christian Altbürger
- Developmental Biology, Faculty of Biology, Institute of Biology I, Albert Ludwigs University Freiburg, Freiburg, Germany
- CIBSS and BIOSS - Centres for Biological Signalling Studies, Albert Ludwigs University Freiburg, Freiburg, Germany
| | - Jens Holzhauser
- Developmental Biology, Faculty of Biology, Institute of Biology I, Albert Ludwigs University Freiburg, Freiburg, Germany
| | - Wolfgang Driever
- Developmental Biology, Faculty of Biology, Institute of Biology I, Albert Ludwigs University Freiburg, Freiburg, Germany
- CIBSS and BIOSS - Centres for Biological Signalling Studies, Albert Ludwigs University Freiburg, Freiburg, Germany
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4
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Figueroa P, Cheng J, Wang G, Kartchner C, Brito de Andrade D, Watters H, Crispell E, Dorsky RI. otpb functions in a Lef1-dependent transcriptional network required for expression of the stress response inhibitor crhbp in the zebrafish hypothalamus. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.07.544119. [PMID: 37333084 PMCID: PMC10274765 DOI: 10.1101/2023.06.07.544119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/20/2023]
Abstract
The vertebrate hypothalamus regulates physiological and behavioral responses to environmental stimuli through the function of evolutionarily-conserved neuronal subpopulations. Our previous work found that mutation of zebrafish lef1 , which encodes a transcriptional mediator of the Wnt signaling pathway, leads to the loss of hypothalamic neurons and behavioral phenotypes that are both associated with stress-related human mood disorders However, the specific Lef1 target genes that link neurogenesis to behavior remain unknown. One candidate is otpb , which encodes a transcription factor with known roles in hypothalamic development. Here we show that otpb expression in the posterior hypothalamus is Lef1-dependent, and that like lef1 , its function is required for the generation of crhbp + neurons in this region. Transgenic reporter analysis of a crhbp conserved noncoding element suggests that otpb participates in a transcriptional regulatory network with other Lef1 targets. Finally, consistent with a role for crhbp in inhibiting the stress response, zebrafish otpb mutants exhibit decreased exploration in a novel tank diving assay. Together our findings suggest a potential evolutionarily-conserved mechanism for the regulation of innate stress response behaviors through Lef1-mediated hypothalamic neurogenesis.
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Lin CY, Yeh KY, Lai HH, Her GM. AgRP Neuron-Specific Ablation Represses Appetite, Energy Intake, and Somatic Growth in Larval Zebrafish. Biomedicines 2023; 11:biomedicines11020499. [PMID: 36831035 PMCID: PMC9953713 DOI: 10.3390/biomedicines11020499] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 02/01/2023] [Accepted: 02/06/2023] [Indexed: 02/11/2023] Open
Abstract
Neuronal circuits regulating appetite are dominated by arcuate nucleus neurons, which include appetite-promoting and -suppressing neurons that release the orexigenic neuropeptide agouti-related protein (AgRP) and anorexigenic neuropeptide pro-opiomelanocortin, respectively, to compete for melanocortin receptors to modulate feeding behavior. In this study, we expressed novel agrp promoters, including different lengths of the 5' flanking regions of the agrp gene (4749 bp) in the zebrafish genome. We used the agrp promoter to derive the enhanced green fluorescent protein (EGFP)-nitroreductase (NTR) fusion protein, allowing expression of the green fluorescence signal in the AgRP neurons. Then, we treated the transgenic zebrafish AgRP4.7NTR (Tg [agrp-EGFP-NTR]) with metronidazole to ablate the AgRP neurons in the larvae stage and observed a decline in their appetite and growth. The expression of most orexigenic and growth hormone/insulin-like growth factor axis genes decreased, whereas that of several anorexigenic genes increased. Our findings demonstrate that AgRP is a critical regulator of neuronal signaling for zebrafish appetite and energy intake control. Thus, AgRP4.7NTR can be used as a drug-screening platform for therapeutic targets to treat human appetite disorders, including obesity. Furthermore, the unique agrp promoter we identified can be a powerful tool for research on AgRP neurons, especially AgRP neuron-mediated pathways in the hypothalamus, and appetite.
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Affiliation(s)
- Chiu-Ya Lin
- Department of Bioscience and Biotechnology, National Taiwan Ocean University, Keelung City 202, Taiwan
- Institute of Biopharmaceutical Sciences, National Yang Ming Chiao Tung University, Taipei 112, Taiwan
| | - Kun-Yun Yeh
- Division of Hemato-Oncology, Department of Internal Medicine, Chang Gung Memorial Hospital, Keelung City 204, Taiwan
| | - Hsin-Hung Lai
- Institute of Biopharmaceutical Sciences, National Yang Ming Chiao Tung University, Taipei 112, Taiwan
| | - Guor Mour Her
- Institute of Biopharmaceutical Sciences, National Yang Ming Chiao Tung University, Taipei 112, Taiwan
- Correspondence: ; Tel.: +886-2-2826-7000 (ext. 67990)
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Wullimann MF. The Neuromeric/Prosomeric Model in Teleost Fish Neurobiology. BRAIN, BEHAVIOR AND EVOLUTION 2022; 97:336-360. [PMID: 35728561 PMCID: PMC9808694 DOI: 10.1159/000525607] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Accepted: 06/08/2022] [Indexed: 01/07/2023]
Abstract
The neuromeric/prosomeric model has been rejuvenated by Puelles and Rubenstein [Trends Neurosci. 1993;16(11):472-9]. Here, its application to the (teleostean) fish brain is detailed, beginning with a historical account. The second part addresses three main issues with particular interest for fish neuroanatomy and looks at the impact of the neuromeric model on their understanding. The first one is the occurrence of four early migrating forebrain areas (M1 through M4) in teleosts and their comparative interpretation. The second issue addresses the complex development and neuroanatomy of the teleostean alar and basal hypothalamus. The third topic is the vertebrate dopaminergic system, with the focus on some teleostean peculiarities. Most of the information will be coming from zebrafish studies, although the general ductus is a comparative one. Throughout the manuscript, comparative developmental and organizational aspects of the teleostean amygdala are discussed. One particular focus is cellular migration streams into the medial amygdala.
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Affiliation(s)
- Mario F. Wullimann
- Division of Neurobiology, Department Biologie II, Ludwig-Maximilians-Universität München (LMU Munich), Martinsried, Germany,Department Genes-Circuits-Behavior, Max-Planck-Institute for Biological Intelligence (i.F.), Martinsried, Germany,*Mario F. Wullimann,
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7
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Magno L, Asgarian Z, Apanaviciute M, Milner Y, Bengoa-Vergniory N, Rubin AN, Kessaris N. Fate mapping reveals mixed embryonic origin and unique developmental codes of mouse forebrain septal neurons. Commun Biol 2022; 5:1137. [PMID: 36302841 PMCID: PMC9613704 DOI: 10.1038/s42003-022-04066-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Accepted: 10/04/2022] [Indexed: 11/08/2022] Open
Abstract
The septum is a key structure at the core of the forebrain that integrates inputs and relays information to other brain areas to support cognition and behaviours such as feeding and locomotion. Underlying these functions is a rich diversity of neuronal types and an intricate complexity of wiring across and within the septal region. We currently have very little understanding of how septal neuronal diversity emerges during development. Using transgenic mice expressing Cre in different subsets of telencephalic precursors we explored the origins of the three main neuronal types of the septal complex: GABAergic, cholinergic and glutamatergic neurons. We find that septal neurons originate from distinct neuroepithelial domains of the developing septum and are born at different embryonic time points. An exception to this is the GABAergic medial septal Parvalbumin-expressing population which is generated outside the septum from surrounding germinal zones. We identify the transcription factor BSX as being expressed in the developing glutamatergic neuron population. Embryonic elimination of BSX in the septum results in a reduction of septal glutamatergic cell numbers and a consequent deficit in locomotion. Further refinement of septal neuron diversity is needed to understand the multiple roles of septal neurons and their contribution to distinct behaviours.
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Affiliation(s)
- Lorenza Magno
- Wolfson Institute for Biomedical Research and Department of Cell and Developmental Biology, University College London, WC1E 6BT, London, UK.
| | - Zeinab Asgarian
- Wolfson Institute for Biomedical Research and Department of Cell and Developmental Biology, University College London, WC1E 6BT, London, UK
| | - Migle Apanaviciute
- Wolfson Institute for Biomedical Research and Department of Cell and Developmental Biology, University College London, WC1E 6BT, London, UK
| | - Yasmin Milner
- Wolfson Institute for Biomedical Research and Department of Cell and Developmental Biology, University College London, WC1E 6BT, London, UK
| | - Nora Bengoa-Vergniory
- Wolfson Institute for Biomedical Research and Department of Cell and Developmental Biology, University College London, WC1E 6BT, London, UK
| | - Anna Noren Rubin
- Wolfson Institute for Biomedical Research and Department of Cell and Developmental Biology, University College London, WC1E 6BT, London, UK
| | - Nicoletta Kessaris
- Wolfson Institute for Biomedical Research and Department of Cell and Developmental Biology, University College London, WC1E 6BT, London, UK.
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8
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Annona G, Ferran JL, De Luca P, Conte I, Postlethwait JH, D’Aniello S. Expression Pattern of nos1 in the Developing Nervous System of Ray-Finned Fish. Genes (Basel) 2022; 13:918. [PMID: 35627303 PMCID: PMC9140475 DOI: 10.3390/genes13050918] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Revised: 05/04/2022] [Accepted: 05/14/2022] [Indexed: 12/04/2022] Open
Abstract
Fish have colonized nearly all aquatic niches, making them an invaluable resource to understand vertebrate adaptation and gene family evolution, including the evolution of complex neural networks and modulatory neurotransmitter pathways. Among ancient regulatory molecules, the gaseous messenger nitric oxide (NO) is involved in a wide range of biological processes. Because of its short half-life, the modulatory capability of NO is strictly related to the local activity of nitric oxide synthases (Nos), enzymes that synthesize NO from L-arginine, making the localization of Nos mRNAs a reliable indirect proxy for the location of NO action domains, targets, and effectors. Within the diversified actinopterygian nos paralogs, nos1 (alias nnos) is ubiquitously present as a single copy gene across the gnathostome lineage, making it an ideal candidate for comparative studies. To investigate variations in the NO system across ray-finned fish phylogeny, we compared nos1 expression patterns during the development of two well-established experimental teleosts (zebrafish and medaka) with an early branching holostean (spotted gar), an important evolutionary bridge between teleosts and tetrapods. Data reported here highlight both conserved expression domains and species-specific nos1 territories, confirming the ancestry of this signaling system and expanding the number of biological processes implicated in NO activities.
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Affiliation(s)
- Giovanni Annona
- Biology and Evolution of Marine Organisms (BEOM), Stazione Zoologica Anton Dohrn, 80121 Napoli, Italy
- Research Infrastructure for Marine Biological Resources Department (RIMAR), Stazione Zoologica Anton Dohrn, 80121 Napoli, Italy;
| | - José Luis Ferran
- Department of Human Anatomy and Psychobiology, Faculty of Medicine, University of Murcia, 30120 Murcia, Spain;
- Institute of Biomedical Research of Murcia—IMIB, Virgen de la Arrixaca University Hospital, 30120 Murcia, Spain
| | - Pasquale De Luca
- Research Infrastructure for Marine Biological Resources Department (RIMAR), Stazione Zoologica Anton Dohrn, 80121 Napoli, Italy;
| | - Ivan Conte
- Telethon Institute of Genetics and Medicine, 80078 Pozzuoli, Italy;
- Department of Biology, University of Napoli Federico II, 80126 Napoli, Italy
| | | | - Salvatore D’Aniello
- Biology and Evolution of Marine Organisms (BEOM), Stazione Zoologica Anton Dohrn, 80121 Napoli, Italy
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9
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Carstensen MB, Medvetzky A, Weinberger A, Driever W, Gothilf Y, Rath MF. Genetic ablation of the Bsx homeodomain transcription factor in zebrafish: Impact on mature pineal gland morphology and circadian behavior. J Pineal Res 2022; 72:e12795. [PMID: 35249239 PMCID: PMC9285933 DOI: 10.1111/jpi.12795] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Revised: 03/01/2022] [Accepted: 03/02/2022] [Indexed: 11/30/2022]
Abstract
The pineal gland is a neuroendocrine structure in the brain, which produces and secretes the hormone melatonin at nighttime and is considered a key element in the circadian clock system. Early morphogenesis of the gland is controlled by a number of transcription factors, some of which remain active in adult life. One of these is the brain-specific homeobox (Bsx), a highly conserved homeodomain transcription factor with a developmental role in the pineal gland of several species, including zebrafish, and regulatory roles in mature pinealocytes of the rat. To determine the role of Bsx in circadian biology, we here examined the effects of a bsx loss-of-function mutation on the pineal gland in adult zebrafish and on behavioral circadian rhythms in larvae. In pineal cell type-specific Gfp/Egfp reporter zebrafish lines, we did not detect fluorescence signals in the pineal area of homozygous (bsx-/- ) mutants. Interestingly, a nonpigmented area on the dorsal surface of the head above the gland, known as the pineal window, was pigmented in the homozygous mutants. Furthermore, a structure corresponding to the pineal gland was not detectable in the midline of the adult brain in histological sections analyzed by Nissl staining and S-antigen immunohistochemistry. Moreover, the levels of pineal transcripts were greatly reduced in bsx-/- mutants, as revealed by quantitative real-time polymerase chain reaction analysis. Notably, analysis of locomotor activity at the larval stage revealed altered circadian rhythmicity in the bsx mutants with periods and phases similar to wildtype, but severely reduced amplitudes in locomotor activity patterns. Thus, Bsx is essential for full development of the pineal gland, with its absence resulting in a phenotype of morphological pineal gland ablation and disrupted circadian behavior.
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Affiliation(s)
- Mikkel Bloss Carstensen
- Department of Neuroscience, Faculty of Health and Medical SciencesUniversity of CopenhagenCopenhagenDenmark
- School of Neurobiology, Biochemistry and Biophysics, Faculty of Life SciencesTel Aviv UniversityTel AvivIsrael
| | - Adar Medvetzky
- School of Neurobiology, Biochemistry and Biophysics, Faculty of Life SciencesTel Aviv UniversityTel AvivIsrael
| | - Alon Weinberger
- School of Neurobiology, Biochemistry and Biophysics, Faculty of Life SciencesTel Aviv UniversityTel AvivIsrael
| | - Wolfgang Driever
- Developmental Biology, Institute Biology, Faculty of BiologyAlbert Ludwig University of FreiburgFreiburgGermany
| | - Yoav Gothilf
- School of Neurobiology, Biochemistry and Biophysics, Faculty of Life SciencesTel Aviv UniversityTel AvivIsrael
- Sagol School of NeuroscienceTel Aviv UniversityTel AvivIsrael
| | - Martin Fredensborg Rath
- Department of Neuroscience, Faculty of Health and Medical SciencesUniversity of CopenhagenCopenhagenDenmark
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10
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Choi JH, Duboue ER, Macurak M, Chanchu JM, Halpern ME. Specialized neurons in the right habenula mediate response to aversive olfactory cues. eLife 2021; 10:e72345. [PMID: 34878403 PMCID: PMC8691842 DOI: 10.7554/elife.72345] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Accepted: 12/07/2021] [Indexed: 12/27/2022] Open
Abstract
Hemispheric specializations are well studied at the functional level but less is known about the underlying neural mechanisms. We identified a small cluster of cholinergic neurons in the dorsal habenula (dHb) of zebrafish, defined by their expression of the lecithin retinol acyltransferase domain containing 2 a (lratd2a) gene and their efferent connections with a subregion of the ventral interpeduncular nucleus (vIPN). The lratd2a-expressing neurons in the right dHb are innervated by a subset of mitral cells from both the left and right olfactory bulb and are activated upon exposure to the odorant cadaverine that is repellent to adult zebrafish. Using an intersectional strategy to drive expression of the botulinum neurotoxin specifically in these neurons, we find that adults no longer show aversion to cadaverine. Mutants with left-isomerized dHb that lack these neurons are also less repelled by cadaverine and their behavioral response to alarm substance, a potent aversive cue, is diminished. However, mutants in which both dHb have right identity appear more reactive to alarm substance. The results implicate an asymmetric dHb-vIPN neural circuit in the processing of repulsive olfactory cues and in modulating the resultant behavioral response.
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Affiliation(s)
- Jung-Hwa Choi
- Carnegie Institution for Science, Department of EmbryologyBaltimoreUnited States
| | - Erik R Duboue
- Jupiter Life Science Initiative, Florida Atlantic UniversityJupiterUnited States
- Wilkes Honors College, Florida Atlantic UniversityJupiterUnited States
| | - Michelle Macurak
- Carnegie Institution for Science, Department of EmbryologyBaltimoreUnited States
| | - Jean-Michel Chanchu
- Carnegie Institution for Science, Department of EmbryologyBaltimoreUnited States
| | - Marnie E Halpern
- Carnegie Institution for Science, Department of EmbryologyBaltimoreUnited States
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11
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Borba C, Kourakis MJ, Schwennicke S, Brasnic L, Smith WC. Fold Change Detection in Visual Processing. Front Neural Circuits 2021; 15:705161. [PMID: 34497492 PMCID: PMC8419522 DOI: 10.3389/fncir.2021.705161] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Accepted: 07/30/2021] [Indexed: 11/13/2022] Open
Abstract
Visual processing transforms the complexities of the visual world into useful information. Ciona, an invertebrate chordate and close relative of the vertebrates, has one of the simplest nervous systems known, yet has a range of visuomotor behaviors. This simplicity has facilitated studies linking behavior and neural circuitry. Ciona larvae have two distinct visuomotor behaviors - a looming shadow response and negative phototaxis. These are mediated by separate neural circuits that initiate from different clusters of photoreceptors, with both projecting to a CNS structure called the posterior brain vesicle (pBV). We report here that inputs from both circuits are processed to generate fold change detection (FCD) outputs. In FCD, the behavioral response scales with the relative fold change in input, but is invariant to the overall magnitude of the stimulus. Moreover, the two visuomotor behaviors have fundamentally different stimulus/response relationships - indicative of differing circuit strategies, with the looming shadow response showing a power relationship to fold change, while the navigation behavior responds linearly. Pharmacological modulation of the FCD response points to the FCD circuits lying outside of the visual organ (the ocellus), with the pBV being the most likely location. Consistent with these observations, the connectivity and properties of pBV interneurons conform to known FCD circuit motifs, but with different circuit architectures for the two circuits. The negative phototaxis circuit forms a putative incoherent feedforward loop that involves interconnecting cholinergic and GABAergic interneurons. The looming shadow circuit uses the same cholinergic and GABAergic interneurons, but with different synaptic inputs to create a putative non-linear integral feedback loop. These differing circuit architectures are consistent with the behavioral outputs of the two circuits. Finally, while some reports have highlighted parallels between the pBV and the vertebrate midbrain, suggesting a common origin for the two, others reports have disputed this, suggesting that invertebrate chordates lack a midbrain homolog. The convergence of visual inputs at the pBV, and its putative role in visual processing reported here and in previous publications, lends further support to the proposed common origin of the pBV and the vertebrate midbrain.
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Affiliation(s)
- Cezar Borba
- Department of Molecular, Cell and Developmental Biology, University of California, Santa Barbara, Santa Barbara, CA, United States
| | - Matthew J Kourakis
- Neuroscience Research Institute, University of California, Santa Barbara, Santa Barbara, CA, United States
| | - Shea Schwennicke
- College of Creative Studies, University of California, Santa Barbara, Santa Barbara, CA, United States
| | - Lorena Brasnic
- Department of Molecular, Cell and Developmental Biology, University of California, Santa Barbara, Santa Barbara, CA, United States.,Faculty of Life Sciences and Medicine, King's College London, London, United Kingdom
| | - William C Smith
- Department of Molecular, Cell and Developmental Biology, University of California, Santa Barbara, Santa Barbara, CA, United States.,College of Creative Studies, University of California, Santa Barbara, Santa Barbara, CA, United States
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12
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Soengas JL. Integration of Nutrient Sensing in Fish Hypothalamus. Front Neurosci 2021; 15:653928. [PMID: 33716662 PMCID: PMC7953060 DOI: 10.3389/fnins.2021.653928] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Accepted: 01/26/2021] [Indexed: 12/13/2022] Open
Abstract
The knowledge regarding hypothalamic integration of metabolic and endocrine signaling resulting in regulation of food intake is scarce in fish. Available studies pointed to a network in which the activation of the nutrient-sensing (glucose, fatty acid, and amino acid) systems would result in AMP-activated protein kinase (AMPK) inhibition and activation of protein kinase B (Akt) and mechanistic target of rapamycin (mTOR). Changes in these signaling pathways would control phosphorylation of transcription factors cAMP response-element binding protein (CREB), forkhead box01 (FoxO1), and brain homeobox transcription factor (BSX) leading to food intake inhibition through changes in the expression of neuropeptide Y (NPY), agouti-related peptide (AgRP), pro-opio melanocortin (POMC), and cocaine and amphetamine-related transcript (CART). The present mini-review summarizes information on the topic and identifies gaps for future research.
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Affiliation(s)
- José L Soengas
- Laboratorio de Fisioloxía Animal, Departamento de Bioloxía Funcional e Ciencias da Saúde, Facultade de Bioloxía and Centro de Investigación Mariña, Universidade de Vigo, Vigo, Spain
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Hutcheson DA, Xie Y, Figueroa P, Dorsky RI. A transgene targeted to the zebrafish nkx2.4b locus drives specific green fluorescent protein expression and disrupts thyroid development. Dev Dyn 2020; 249:1387-1393. [PMID: 32644242 DOI: 10.1002/dvdy.224] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Revised: 06/25/2020] [Accepted: 07/02/2020] [Indexed: 11/09/2022] Open
Abstract
BACKGROUND With the goal of labeling and manipulating the zebrafish hypothalamus, we sought to target a green fluorescent protein (gfp) transgene to the expression domains of nkx2.4b, a gene expressed during hypothalamic and thyroid development. We combined transcription activator-like effector nucleases (TALENs)-mediated mutagenesis with a targeting construct to enable insertion of a gfp transgene into the endogenous nkx2.4b genomic locus. RESULTS Injection of TALENs targeted to the first exon of nkx2.4b created a predicted null allele, and homozygous mutant embryos displayed loss of thyroid markers. From embryos injected with both TALENs and a targeting construct carrying a gfp transgene, we recovered a line in which GFP was expressed specifically in the hypothalamus and thyroid. Fish homozygous for this allele lacked exon 1 of nkx2.4b and exhibited hypothyroid phenotypes. CONCLUSIONS By combining TALENs injections with a targeting construct that contained a gfp transgene, we were able to recover an allele in which GFP is expressed in the nkx2.4b expression domains, with homozygous phenotypes suggesting the creation of a loss-of-function transgenic line. These results demonstrate the creation of a useful tool for studying hypothalamus and thyroid development.
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Affiliation(s)
- David A Hutcheson
- Department of Neurobiology and Anatomy, University of Utah, Salt Lake City, Utah, USA
| | - Yuanyuan Xie
- Department of Molecular, Cellular and Developmental Biology, BioFrontiers Institute, University of Colorado, Boulder, Colorado, USA
| | - Priscilla Figueroa
- Department of Neurobiology and Anatomy, University of Utah, Salt Lake City, Utah, USA
| | - Richard I Dorsky
- Department of Neurobiology and Anatomy, University of Utah, Salt Lake City, Utah, USA
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