Roles of bHLH genes in neural stem cell differentiation.
Exp Cell Res
; 306(2): 343-8, 2005 Jun 10.
Article
en En
| MEDLINE
| ID: mdl-15925590
Neural stem cells change their characteristics over time during development: they initially proliferate only and then give rise to neurons first and glial cells later. In the absence of the repressor-type basic helix-loop-helix (bHLH) genes Hes1, Hes3 and Hes5, neural stem cells do not proliferate sufficiently but prematurely differentiate into neurons and become depleted without making the later born cell types such as astrocytes and ependymal cells. Thus, Hes genes are essential for maintenance of neural stem cells to make cells not only in correct numbers but also in full diversity. Hes genes antagonize the activator-type bHLH genes, which include Mash1, Math and Neurogenin. The activator-type bHLH genes promote the neuronal fate determination and induce expression of Notch ligands such as Delta. These ligands activate Notch signaling and upregulate Hes1 and Hes5 expression in neighboring cells, thereby maintaining these cells undifferentiated. Thus, the activator-type and repressor-type bHLH genes regulate each other, allowing only subsets of cells to undergo differentiation while keeping others to stay neural stem cells. This regulation is essential for generation of complex brain structures of appropriate size, shape and cell arrangement.
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Proteínas Represoras
/
Células Madre
/
Secuencias Hélice-Asa-Hélice
/
Proteínas del Tejido Nervioso
/
Neuronas
Límite:
Animals
/
Humans
Idioma:
En
Revista:
Exp Cell Res
Año:
2005
Tipo del documento:
Article
País de afiliación:
Japón
Pais de publicación:
Estados Unidos