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Dynamic expression of notch signaling genes in neural stem/progenitor cells.

Shimojo H, Ohtsuka T, Kageyama R - Front Neurosci (2011)

Bottom Line: In neural stem/progenitor cells, expression of the Notch effector Hes1, a transcriptional repressor, oscillates with a period of 2-3 h by negative feedback, and Hes1 oscillations induce the oscillatory expression of the proneural gene Neurogenin2 (Ngn2) and the Notch ligand gene Delta-like1 (Dll1).Thus, Ngn2 leads to the maintenance of neural stem/progenitor cells by inducing Dll1 oscillation when its expression oscillates but to neuronal differentiation when its expression is sustained.These results indicate that the different dynamics of Hes1 and Ngn2 lead to different outcomes.

View Article: PubMed Central - PubMed

Affiliation: Institute for Virus Research, Kyoto University Kyoto, Japan.

ABSTRACT
In neural stem/progenitor cells, expression of the Notch effector Hes1, a transcriptional repressor, oscillates with a period of 2-3 h by negative feedback, and Hes1 oscillations induce the oscillatory expression of the proneural gene Neurogenin2 (Ngn2) and the Notch ligand gene Delta-like1 (Dll1). Dll1 oscillation leads to the mutual activation of Notch signaling between neighboring cells, thereby maintaining a group of cells in the undifferentiated state. Not all cells express Hes1 in an oscillatory manner: cells in boundary regions such as the isthmus express Hes1 in a sustained manner, and these cells are rather dormant with regard to proliferation and differentiation. Thus, Hes1 allows cell proliferation and differentiation when its expression oscillates but induces dormancy when its expression is sustained. After Hes1 expression is repressed, Ngn2 is expressed in a sustained manner, promoting neuronal differentiation. Thus, Ngn2 leads to the maintenance of neural stem/progenitor cells by inducing Dll1 oscillation when its expression oscillates but to neuronal differentiation when its expression is sustained. These results indicate that the different dynamics of Hes1 and Ngn2 lead to different outcomes.

No MeSH data available.


Neural stem/progenitor cells and their differentiation. Initially, neuroepithelial cells undergo repeated self-renewal by symmetric division (progenitor expansion phase). As development proceeds, neuroepithelial cells elongate to become radial glial cells, which have cell bodies on the inner side (called the ventricular zone) of the neural tube and radial fibers that reach the outer surface. Radial glial cells gives rise to neurons or basal progenitors (neurogenic phase). After the production of neurons, some radial glial cells give rise to oligodendrocytes and ependymal cells. Radial glial cells finally differentiate into astrocytes (gliogenic phase). Both neuroepithelial cells and radial glial cells are considered embryonic neural stem/progenitor cells.
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Figure 1: Neural stem/progenitor cells and their differentiation. Initially, neuroepithelial cells undergo repeated self-renewal by symmetric division (progenitor expansion phase). As development proceeds, neuroepithelial cells elongate to become radial glial cells, which have cell bodies on the inner side (called the ventricular zone) of the neural tube and radial fibers that reach the outer surface. Radial glial cells gives rise to neurons or basal progenitors (neurogenic phase). After the production of neurons, some radial glial cells give rise to oligodendrocytes and ependymal cells. Radial glial cells finally differentiate into astrocytes (gliogenic phase). Both neuroepithelial cells and radial glial cells are considered embryonic neural stem/progenitor cells.

Mentions: Neuroepithelial cells, which constitute the wall of the neural tube, proliferate by repeating symmetric cell division, where each neuroepithelial cell divides into two neuroepithelial cells (progenitor expansion phase, Figure 1; Alvarez-Buylla et al., 2001; Fishell and Kriegstein, 2003; Fujita, 2003; Götz and Huttner, 2005; Miller and Gauthier, 2007). As the wall of the neural tube becomes thicker, neuroepithelial cells elongate and become radial glial cells, which have cell bodies in the ventricular zone, and radial fibers reaching the pial surface (Figure 1). Radial glial cells were previously thought of as specialized glial cells that guide neuronal migration. Later, it was found that radial glial cells undergo asymmetric cell division, where each radial glial cell divides into two distinct cell types, a radial glial cell and an immature neuron or a basal progenitor (neurogenic phase, Figure 1; Malatesta et al., 2000; Miyata et al., 2001; Noctor et al., 2001). Immature neurons migrate outside of the ventricular zone along radial fibers into the cortical plate, where these cells become mature neurons, whereas basal progenitors migrate into the subventricular zone (SVZ), proliferate further and give rise to more neurons. Radial glial cells give rise to many different types of neurons, initially deep layer neurons and then superficial layer neurons later, by repeating asymmetric cell division. Radial glial cells also give rise to oligodendrocytes and ependymal cells and finally differentiate into astrocytes (gliogenic phase, Figure 1). Both neuroepithelial and radial glial cells are considered neural stem/progenitor cells.


Dynamic expression of notch signaling genes in neural stem/progenitor cells.

Shimojo H, Ohtsuka T, Kageyama R - Front Neurosci (2011)

Neural stem/progenitor cells and their differentiation. Initially, neuroepithelial cells undergo repeated self-renewal by symmetric division (progenitor expansion phase). As development proceeds, neuroepithelial cells elongate to become radial glial cells, which have cell bodies on the inner side (called the ventricular zone) of the neural tube and radial fibers that reach the outer surface. Radial glial cells gives rise to neurons or basal progenitors (neurogenic phase). After the production of neurons, some radial glial cells give rise to oligodendrocytes and ependymal cells. Radial glial cells finally differentiate into astrocytes (gliogenic phase). Both neuroepithelial cells and radial glial cells are considered embryonic neural stem/progenitor cells.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3116140&req=5

Figure 1: Neural stem/progenitor cells and their differentiation. Initially, neuroepithelial cells undergo repeated self-renewal by symmetric division (progenitor expansion phase). As development proceeds, neuroepithelial cells elongate to become radial glial cells, which have cell bodies on the inner side (called the ventricular zone) of the neural tube and radial fibers that reach the outer surface. Radial glial cells gives rise to neurons or basal progenitors (neurogenic phase). After the production of neurons, some radial glial cells give rise to oligodendrocytes and ependymal cells. Radial glial cells finally differentiate into astrocytes (gliogenic phase). Both neuroepithelial cells and radial glial cells are considered embryonic neural stem/progenitor cells.
Mentions: Neuroepithelial cells, which constitute the wall of the neural tube, proliferate by repeating symmetric cell division, where each neuroepithelial cell divides into two neuroepithelial cells (progenitor expansion phase, Figure 1; Alvarez-Buylla et al., 2001; Fishell and Kriegstein, 2003; Fujita, 2003; Götz and Huttner, 2005; Miller and Gauthier, 2007). As the wall of the neural tube becomes thicker, neuroepithelial cells elongate and become radial glial cells, which have cell bodies in the ventricular zone, and radial fibers reaching the pial surface (Figure 1). Radial glial cells were previously thought of as specialized glial cells that guide neuronal migration. Later, it was found that radial glial cells undergo asymmetric cell division, where each radial glial cell divides into two distinct cell types, a radial glial cell and an immature neuron or a basal progenitor (neurogenic phase, Figure 1; Malatesta et al., 2000; Miyata et al., 2001; Noctor et al., 2001). Immature neurons migrate outside of the ventricular zone along radial fibers into the cortical plate, where these cells become mature neurons, whereas basal progenitors migrate into the subventricular zone (SVZ), proliferate further and give rise to more neurons. Radial glial cells give rise to many different types of neurons, initially deep layer neurons and then superficial layer neurons later, by repeating asymmetric cell division. Radial glial cells also give rise to oligodendrocytes and ependymal cells and finally differentiate into astrocytes (gliogenic phase, Figure 1). Both neuroepithelial and radial glial cells are considered neural stem/progenitor cells.

Bottom Line: In neural stem/progenitor cells, expression of the Notch effector Hes1, a transcriptional repressor, oscillates with a period of 2-3 h by negative feedback, and Hes1 oscillations induce the oscillatory expression of the proneural gene Neurogenin2 (Ngn2) and the Notch ligand gene Delta-like1 (Dll1).Thus, Ngn2 leads to the maintenance of neural stem/progenitor cells by inducing Dll1 oscillation when its expression oscillates but to neuronal differentiation when its expression is sustained.These results indicate that the different dynamics of Hes1 and Ngn2 lead to different outcomes.

View Article: PubMed Central - PubMed

Affiliation: Institute for Virus Research, Kyoto University Kyoto, Japan.

ABSTRACT
In neural stem/progenitor cells, expression of the Notch effector Hes1, a transcriptional repressor, oscillates with a period of 2-3 h by negative feedback, and Hes1 oscillations induce the oscillatory expression of the proneural gene Neurogenin2 (Ngn2) and the Notch ligand gene Delta-like1 (Dll1). Dll1 oscillation leads to the mutual activation of Notch signaling between neighboring cells, thereby maintaining a group of cells in the undifferentiated state. Not all cells express Hes1 in an oscillatory manner: cells in boundary regions such as the isthmus express Hes1 in a sustained manner, and these cells are rather dormant with regard to proliferation and differentiation. Thus, Hes1 allows cell proliferation and differentiation when its expression oscillates but induces dormancy when its expression is sustained. After Hes1 expression is repressed, Ngn2 is expressed in a sustained manner, promoting neuronal differentiation. Thus, Ngn2 leads to the maintenance of neural stem/progenitor cells by inducing Dll1 oscillation when its expression oscillates but to neuronal differentiation when its expression is sustained. These results indicate that the different dynamics of Hes1 and Ngn2 lead to different outcomes.

No MeSH data available.