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Reyes-Pinto R, Ferrán JL, Vega-Zuniga T, González-Cabrera C, Luksch H, Mpodozis J, Puelles L, Marín GJ. Change in the neurochemical signature and morphological development of the parvocellular isthmic projection to the avian tectum. J Comp Neurol 2021; 530:553-573. [PMID: 34363623 DOI: 10.1002/cne.25229] [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: 05/04/2021] [Revised: 07/27/2021] [Accepted: 07/30/2021] [Indexed: 11/05/2022]
Abstract
Neurons can change their classical neurotransmitters during ontogeny, sometimes going through stages of dual release. Here, we explored the development of the neurotransmitter identity of neurons of the avian nucleus isthmi parvocellularis (Ipc), whose axon terminals are retinotopically arranged in the optic tectum (TeO) and exert a focal gating effect upon the ascending transmission of retinal inputs. Although cholinergic and glutamatergic markers are both found in Ipc neurons and terminals of adult pigeons and chicks, the mRNA expression of the vesicular acetylcholine transporter, VAChT, is weak or absent. To explore how the Ipc neurotransmitter identity is established during ontogeny, we analyzed the expression of mRNAs coding for cholinergic (ChAT, VAChT, and CHT) and glutamatergic (VGluT2 and VGluT3) markers in chick embryos at different developmental stages. We found that between E12 and E18, Ipc neurons expressed all cholinergic mRNAs and also VGluT2 mRNA; however, from E16 through posthatch stages, VAChT mRNA expression was specifically diminished. Our ex vivo deposits of tracer crystals and intracellular filling experiments revealed that Ipc axons exhibit a mature paintbrush morphology late in development, experiencing marked morphological transformations during the period of presumptive dual vesicular transmitter release. Additionally, although ChAT protein immunoassays increasingly label the growing Ipc axon, this labeling was consistently restricted to sparse portions of the terminal branches. Combined, these results suggest that the synthesis of glutamate and acetylcholine, and their vesicular release, is complexly linked to the developmental processes of branching, growing and remodeling of these unique axons.
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Affiliation(s)
- Rosana Reyes-Pinto
- Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
| | - José L Ferrán
- Department of Human Anatomy and Psychobiology and IMIB-Arrixaca Institute, University of Murcia, Murcia, Spain
| | - Tomas Vega-Zuniga
- Lehrstuhl für Zoologie, Technical University of Munich, Freising, Germany.,Institute of Science and Technology Austria (IST Austria), Klosterneuburg, Austria
| | | | - Harald Luksch
- Lehrstuhl für Zoologie, Technical University of Munich, Freising, Germany
| | - Jorge Mpodozis
- Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
| | - Luis Puelles
- Department of Human Anatomy and Psychobiology and IMIB-Arrixaca Institute, University of Murcia, Murcia, Spain
| | - Gonzalo J Marín
- Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago, Chile.,Facultad de Medicina, Universidad Finis Terrae, Santiago, Chile
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Abstract
To elucidate a gene function, in vivo analysis is indispensable. We can carry out gain and loss of function experiment of a gene of interest by electroporation in ovo and ex ovo culture system on early-stage and advanced-stage chick embryos, respectively. In this section, we introduce in/ex ovo electroporation methods for the development of the chick central nervous system and visual system investigation.
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Affiliation(s)
- Hidekiyo Harada
- Genetics and Development Division, Krembil Research Institute, University of Toronto, 60 Leonard St., Toronto, ON, Canada.
- Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, ON, Canada.
| | - Minoru Omi
- Department of Anatomy I, School of Medicine, Fujita Health University, Toyoake, Aichi, Japan
| | - Harukazu Nakamura
- Frontier Research Institute for Interdisciplinary Science (FRIS), Tohoku University, Aoba-ku, Sendai, Japan
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ϒ-secretase and LARG mediate distinct RGMa activities to control appropriate layer targeting within the optic tectum. Cell Death Differ 2015; 23:442-53. [PMID: 26292756 PMCID: PMC5072438 DOI: 10.1038/cdd.2015.111] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2014] [Revised: 07/11/2015] [Accepted: 07/02/2015] [Indexed: 11/15/2022] Open
Abstract
While a great deal of progress has been made in understanding the molecular mechanisms that regulate retino-tectal mapping, the determinants that target retinal projections to specific layers of the optic tectum remain elusive. Here we show that two independent RGMa-peptides, C- and N-RGMa, activate two distinct intracellular pathways to regulate axonal growth. C-RGMa utilizes a Leukemia-associated RhoGEF (LARG)/Rho/Rock pathway to inhibit axonal growth. N-RGMa on the other hand relies on ϒ-secretase cleavage of the intracellular portion of Neogenin to generate an intracellular domain (NeICD) that uses LIM-only protein 4 (LMO4) to block growth. In the developing tectum (E18), overexpression of C-RGMa and dominant-negative LARG (LARG-PDZ) induced overshoots in the superficial tectal layer but not in deeper tectal layers. In younger embryos (E12), C-RGMa and LARG-PDZ prevented ectopic projections toward deeper tectal layers, indicating that C-RGMa may act as a barrier to descending axons. In contrast both N-RGMa and NeICD overexpression resulted in aberrant axonal-paths, all of which suggests that it is a repulsive guidance molecule. Thus, two RGMa fragments activate distinct pathways resulting in different axonal responses. These data reveal how retinal projections are targeted to the appropriate layer in their target tissue.
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Krabichler Q, Vega-Zuniga T, Morales C, Luksch H, Marín GJ. The visual system of a Palaeognathous bird: Visual field, retinal topography and retino-central connections in the Chilean Tinamou (Nothoprocta perdicaria). J Comp Neurol 2014; 523:226-50. [DOI: 10.1002/cne.23676] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2014] [Revised: 09/05/2014] [Accepted: 09/09/2014] [Indexed: 02/05/2023]
Affiliation(s)
- Quirin Krabichler
- Chair of Zoology, Technische Universität München; Freising-Weihenstephan Germany
| | - Tomas Vega-Zuniga
- Chair of Zoology, Technische Universität München; Freising-Weihenstephan Germany
| | - Cristian Morales
- Laboratorio de Neurobiología y Biología del Conocer; Departamento de Biología; Facultad de Ciencias; Universidad de Chile; Santiago de Chile Chile
| | - Harald Luksch
- Chair of Zoology, Technische Universität München; Freising-Weihenstephan Germany
| | - Gonzalo J. Marín
- Laboratorio de Neurobiología y Biología del Conocer; Departamento de Biología; Facultad de Ciencias; Universidad de Chile; Santiago de Chile Chile
- Facultad de Medicina; Universidad Finis Terrae; Santiago de Chile Chile
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