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E-proteins orchestrate the progression of neural stem cell differentiation in the postnatal forebrain

BACKGROUND: Neural stem cell (NSC) differentiation is a complex multistep process that persists in specific regions of the postnatal forebrain and requires tight regulation throughout life. The transcriptional control of NSC proliferation and specification involves Class II (proneural) and Class V (...

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Autores principales: Fischer, Bruno, Azim, Kasum, Hurtado-Chong, Anahí, Ramelli, Sandra, Fernández, María, Raineteau, Olivier
Formato: Online Artículo Texto
Lenguaje:English
Publicado: BioMed Central 2014
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4274746/
https://www.ncbi.nlm.nih.gov/pubmed/25352248
http://dx.doi.org/10.1186/1749-8104-9-23
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author Fischer, Bruno
Azim, Kasum
Hurtado-Chong, Anahí
Ramelli, Sandra
Fernández, María
Raineteau, Olivier
author_facet Fischer, Bruno
Azim, Kasum
Hurtado-Chong, Anahí
Ramelli, Sandra
Fernández, María
Raineteau, Olivier
author_sort Fischer, Bruno
collection PubMed
description BACKGROUND: Neural stem cell (NSC) differentiation is a complex multistep process that persists in specific regions of the postnatal forebrain and requires tight regulation throughout life. The transcriptional control of NSC proliferation and specification involves Class II (proneural) and Class V (Id1-4) basic helix-loop-helix (bHLH) proteins. In this study, we analyzed the pattern of expression of their dimerization partners, Class I bHLH proteins (E-proteins), and explored their putative role in orchestrating postnatal subventricular zone (SVZ) neurogenesis. RESULTS: Overexpression of a dominant-negative form of the E-protein E47 (dnE47) confirmed a crucial role for bHLH transcriptional networks in postnatal neurogenesis by dramatically blocking SVZ NSC differentiation. In situ hybridization was used in combination with RT-qPCR to measure and compare the level of expression of E-protein transcripts (E2-2, E2A, and HEB) in the neonatal and adult SVZ as well as in magnetic affinity cell sorted progenitor cells and neuroblasts. Our results evidence that E-protein transcripts, in particular E2-2 and E2A, are enriched in the postnatal SVZ with expression levels increasing as cells engage towards neuronal differentiation. To investigate the role of E-proteins in orchestrating lineage progression, both in vitro and in vivo gain-of-function and loss-of-function experiments were performed for individual E-proteins. Overexpression of E2-2 and E2A promoted SVZ neurogenesis by enhancing not only radial glial cell differentiation but also cell cycle exit of their progeny. Conversely, knock-down by shRNA electroporation resulted in opposite effects. Manipulation of E-proteins and/or Ascl1 in SVZ NSC cultures indicated that those effects were Ascl1 dependent, although they could not solely be attributed to an Ascl1-induced switch from promoting cell proliferation to triggering cell cycle arrest and differentiation. CONCLUSIONS: In contrast to former concepts, suggesting ubiquitous expression and subsidiary function for E-proteins to foster postnatal neurogenesis, this work unveils E-proteins as being active players in the orchestration of postnatal SVZ neurogenesis.
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spelling pubmed-42747462014-12-24 E-proteins orchestrate the progression of neural stem cell differentiation in the postnatal forebrain Fischer, Bruno Azim, Kasum Hurtado-Chong, Anahí Ramelli, Sandra Fernández, María Raineteau, Olivier Neural Dev Research Article BACKGROUND: Neural stem cell (NSC) differentiation is a complex multistep process that persists in specific regions of the postnatal forebrain and requires tight regulation throughout life. The transcriptional control of NSC proliferation and specification involves Class II (proneural) and Class V (Id1-4) basic helix-loop-helix (bHLH) proteins. In this study, we analyzed the pattern of expression of their dimerization partners, Class I bHLH proteins (E-proteins), and explored their putative role in orchestrating postnatal subventricular zone (SVZ) neurogenesis. RESULTS: Overexpression of a dominant-negative form of the E-protein E47 (dnE47) confirmed a crucial role for bHLH transcriptional networks in postnatal neurogenesis by dramatically blocking SVZ NSC differentiation. In situ hybridization was used in combination with RT-qPCR to measure and compare the level of expression of E-protein transcripts (E2-2, E2A, and HEB) in the neonatal and adult SVZ as well as in magnetic affinity cell sorted progenitor cells and neuroblasts. Our results evidence that E-protein transcripts, in particular E2-2 and E2A, are enriched in the postnatal SVZ with expression levels increasing as cells engage towards neuronal differentiation. To investigate the role of E-proteins in orchestrating lineage progression, both in vitro and in vivo gain-of-function and loss-of-function experiments were performed for individual E-proteins. Overexpression of E2-2 and E2A promoted SVZ neurogenesis by enhancing not only radial glial cell differentiation but also cell cycle exit of their progeny. Conversely, knock-down by shRNA electroporation resulted in opposite effects. Manipulation of E-proteins and/or Ascl1 in SVZ NSC cultures indicated that those effects were Ascl1 dependent, although they could not solely be attributed to an Ascl1-induced switch from promoting cell proliferation to triggering cell cycle arrest and differentiation. CONCLUSIONS: In contrast to former concepts, suggesting ubiquitous expression and subsidiary function for E-proteins to foster postnatal neurogenesis, this work unveils E-proteins as being active players in the orchestration of postnatal SVZ neurogenesis. BioMed Central 2014-10-29 /pmc/articles/PMC4274746/ /pubmed/25352248 http://dx.doi.org/10.1186/1749-8104-9-23 Text en Copyright © 2014 Fischer et al.; licensee BioMed Central Ltd. http://creativecommons.org/licenses/by/4.0 This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.
spellingShingle Research Article
Fischer, Bruno
Azim, Kasum
Hurtado-Chong, Anahí
Ramelli, Sandra
Fernández, María
Raineteau, Olivier
E-proteins orchestrate the progression of neural stem cell differentiation in the postnatal forebrain
title E-proteins orchestrate the progression of neural stem cell differentiation in the postnatal forebrain
title_full E-proteins orchestrate the progression of neural stem cell differentiation in the postnatal forebrain
title_fullStr E-proteins orchestrate the progression of neural stem cell differentiation in the postnatal forebrain
title_full_unstemmed E-proteins orchestrate the progression of neural stem cell differentiation in the postnatal forebrain
title_short E-proteins orchestrate the progression of neural stem cell differentiation in the postnatal forebrain
title_sort e-proteins orchestrate the progression of neural stem cell differentiation in the postnatal forebrain
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4274746/
https://www.ncbi.nlm.nih.gov/pubmed/25352248
http://dx.doi.org/10.1186/1749-8104-9-23
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