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Dll1 maintains quiescence of adult neural stem cells and segregates asymmetrically during mitosis.

Kawaguchi D, Furutachi S, Kawai H, Hozumi K, Gotoh Y - Nat Commun (2013)

Bottom Line: Dll1 protein is induced in activated NSCs and segregates to one daughter cell during mitosis.Dll1-expressing cells reside in close proximity to quiescent NSCs, suggesting a feedback signal for NSC maintenance by their sister cells and progeny.Our data suggest a model in which NSCs produce their own niche cells for their maintenance through asymmetric Dll1 inheritance at mitosis.

View Article: PubMed Central - PubMed

Affiliation: Institute of Molecular and Cellular Biosciences, University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan.

ABSTRACT
Stem cells often divide asymmetrically to produce one stem cell and one differentiating cell, thus maintaining the stem cell pool. Although neural stem cells (NSCs) in the adult mouse subventricular zone have been suggested to divide asymmetrically, intrinsic cell fate determinants for asymmetric NSC division are largely unknown. Stem cell niches are important for stem cell maintenance, but the niche for the maintenance of adult quiescent NSCs has remained obscure. Here we show that the Notch ligand Delta-like 1 (Dll1) is required to maintain quiescent NSCs in the adult mouse subventricular zone. Dll1 protein is induced in activated NSCs and segregates to one daughter cell during mitosis. Dll1-expressing cells reside in close proximity to quiescent NSCs, suggesting a feedback signal for NSC maintenance by their sister cells and progeny. Our data suggest a model in which NSCs produce their own niche cells for their maintenance through asymmetric Dll1 inheritance at mitosis.

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Dll1-EGFP moves to one daughter cell that becomes a neuronal progenitor during asymmetric NSC division.(a) Time-lapse images of dividing NSCs in mouse embryonic neocortical slices. Neocortical NSCs in mouse embryos were transfected with expression plasmids for Dll1-EGFP and histone H2B (H2B)-mCherry by in utero electroporation at E13.5. After development of the embryos for an additional 15–19 h in utero, neocortical slices were prepared, cultured and subjected to time-lapse imaging of EGFP and mCherry fluorescence. Time is indicated relative to the timing of meta-anaphase transition. Broken lines indicate the ventricular surface. The cells are also shown in Supplementary Movie 4. Scale bar, 10 μm. (b) A typical example of dividing NSC sisters. In the left panel, (i) and (ii) indicate Dll1-inheriting and non-Dll1-inheriting sister cells, respectively. The cells are also shown in Supplementary Movie 5. The immunohistofluorescence staining of the corresponding cortical slice is shown in the right panels. (i) and (ii) denote the same sister cells indicated in the left panel. Scale bar, 10 μm. The position and orientation of each daughter cell in the ventricular zone of the cultured slice are also shown in low-magnification images (Supplementary Fig. S2).
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f6: Dll1-EGFP moves to one daughter cell that becomes a neuronal progenitor during asymmetric NSC division.(a) Time-lapse images of dividing NSCs in mouse embryonic neocortical slices. Neocortical NSCs in mouse embryos were transfected with expression plasmids for Dll1-EGFP and histone H2B (H2B)-mCherry by in utero electroporation at E13.5. After development of the embryos for an additional 15–19 h in utero, neocortical slices were prepared, cultured and subjected to time-lapse imaging of EGFP and mCherry fluorescence. Time is indicated relative to the timing of meta-anaphase transition. Broken lines indicate the ventricular surface. The cells are also shown in Supplementary Movie 4. Scale bar, 10 μm. (b) A typical example of dividing NSC sisters. In the left panel, (i) and (ii) indicate Dll1-inheriting and non-Dll1-inheriting sister cells, respectively. The cells are also shown in Supplementary Movie 5. The immunohistofluorescence staining of the corresponding cortical slice is shown in the right panels. (i) and (ii) denote the same sister cells indicated in the left panel. Scale bar, 10 μm. The position and orientation of each daughter cell in the ventricular zone of the cultured slice are also shown in low-magnification images (Supplementary Fig. S2).

Mentions: Asymmetric cell division is often caused by an asymmetric environment that biases the fate of sister cells after cell division. Alternatively, a cell fate determinant might move to one sister cell intrinsically during cell division. To distinguish whether Dll1 asymmetry is established during or after cell division and to determine the fate of Dll1-inheriting daughter cells, we performed time-lapse imaging analysis in organotypic slice cultures. We observed the behaviour of EGFP-tagged Dll1 protein (Dll1-EGFP) during mitosis of NSCs present within embryonic neocortical slice cultures, because similar experiments are hard to perform with adult SVZ slices. Remarkably, time-lapse imaging revealed that most, if not all, Dll1-EGFP migrated to one daughter cell during mitosis (143 out of 157 Dll1+ divisions) (Fig. 6a; Supplementary Movie 4; also see Supplementary Fig. S2). Typically, Dll1-EGFP puncta were clustered around the central spindle and then moved to one daughter cell during anaphase, becoming dispersed within this daughter cell after telophase. We then examined the fate of the daughter cells that inherited or did not inherit Dll1-EGFP using immunohistofluorescence analysis after the time-lapse imaging. In most (9/10) asymmetric divisions that gave rise to one Tbr2+ neuronal progenitor and one Tbr2− undifferentiated cell, the Tbr2+ cell inherited Dll1-EGFP (Fig. 6b; Supplementary Movie 5). The undifferentiated state of Tbr2-negative sister cells was confirmed on the basis of immunostaining for Sox2 or of cell position (in the ventricular zone) (Supplementary Fig. S3). These results suggest that Dll1 inheritance is associated with neuronal differentiation.


Dll1 maintains quiescence of adult neural stem cells and segregates asymmetrically during mitosis.

Kawaguchi D, Furutachi S, Kawai H, Hozumi K, Gotoh Y - Nat Commun (2013)

Dll1-EGFP moves to one daughter cell that becomes a neuronal progenitor during asymmetric NSC division.(a) Time-lapse images of dividing NSCs in mouse embryonic neocortical slices. Neocortical NSCs in mouse embryos were transfected with expression plasmids for Dll1-EGFP and histone H2B (H2B)-mCherry by in utero electroporation at E13.5. After development of the embryos for an additional 15–19 h in utero, neocortical slices were prepared, cultured and subjected to time-lapse imaging of EGFP and mCherry fluorescence. Time is indicated relative to the timing of meta-anaphase transition. Broken lines indicate the ventricular surface. The cells are also shown in Supplementary Movie 4. Scale bar, 10 μm. (b) A typical example of dividing NSC sisters. In the left panel, (i) and (ii) indicate Dll1-inheriting and non-Dll1-inheriting sister cells, respectively. The cells are also shown in Supplementary Movie 5. The immunohistofluorescence staining of the corresponding cortical slice is shown in the right panels. (i) and (ii) denote the same sister cells indicated in the left panel. Scale bar, 10 μm. The position and orientation of each daughter cell in the ventricular zone of the cultured slice are also shown in low-magnification images (Supplementary Fig. S2).
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Related In: Results  -  Collection

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f6: Dll1-EGFP moves to one daughter cell that becomes a neuronal progenitor during asymmetric NSC division.(a) Time-lapse images of dividing NSCs in mouse embryonic neocortical slices. Neocortical NSCs in mouse embryos were transfected with expression plasmids for Dll1-EGFP and histone H2B (H2B)-mCherry by in utero electroporation at E13.5. After development of the embryos for an additional 15–19 h in utero, neocortical slices were prepared, cultured and subjected to time-lapse imaging of EGFP and mCherry fluorescence. Time is indicated relative to the timing of meta-anaphase transition. Broken lines indicate the ventricular surface. The cells are also shown in Supplementary Movie 4. Scale bar, 10 μm. (b) A typical example of dividing NSC sisters. In the left panel, (i) and (ii) indicate Dll1-inheriting and non-Dll1-inheriting sister cells, respectively. The cells are also shown in Supplementary Movie 5. The immunohistofluorescence staining of the corresponding cortical slice is shown in the right panels. (i) and (ii) denote the same sister cells indicated in the left panel. Scale bar, 10 μm. The position and orientation of each daughter cell in the ventricular zone of the cultured slice are also shown in low-magnification images (Supplementary Fig. S2).
Mentions: Asymmetric cell division is often caused by an asymmetric environment that biases the fate of sister cells after cell division. Alternatively, a cell fate determinant might move to one sister cell intrinsically during cell division. To distinguish whether Dll1 asymmetry is established during or after cell division and to determine the fate of Dll1-inheriting daughter cells, we performed time-lapse imaging analysis in organotypic slice cultures. We observed the behaviour of EGFP-tagged Dll1 protein (Dll1-EGFP) during mitosis of NSCs present within embryonic neocortical slice cultures, because similar experiments are hard to perform with adult SVZ slices. Remarkably, time-lapse imaging revealed that most, if not all, Dll1-EGFP migrated to one daughter cell during mitosis (143 out of 157 Dll1+ divisions) (Fig. 6a; Supplementary Movie 4; also see Supplementary Fig. S2). Typically, Dll1-EGFP puncta were clustered around the central spindle and then moved to one daughter cell during anaphase, becoming dispersed within this daughter cell after telophase. We then examined the fate of the daughter cells that inherited or did not inherit Dll1-EGFP using immunohistofluorescence analysis after the time-lapse imaging. In most (9/10) asymmetric divisions that gave rise to one Tbr2+ neuronal progenitor and one Tbr2− undifferentiated cell, the Tbr2+ cell inherited Dll1-EGFP (Fig. 6b; Supplementary Movie 5). The undifferentiated state of Tbr2-negative sister cells was confirmed on the basis of immunostaining for Sox2 or of cell position (in the ventricular zone) (Supplementary Fig. S3). These results suggest that Dll1 inheritance is associated with neuronal differentiation.

Bottom Line: Dll1 protein is induced in activated NSCs and segregates to one daughter cell during mitosis.Dll1-expressing cells reside in close proximity to quiescent NSCs, suggesting a feedback signal for NSC maintenance by their sister cells and progeny.Our data suggest a model in which NSCs produce their own niche cells for their maintenance through asymmetric Dll1 inheritance at mitosis.

View Article: PubMed Central - PubMed

Affiliation: Institute of Molecular and Cellular Biosciences, University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan.

ABSTRACT
Stem cells often divide asymmetrically to produce one stem cell and one differentiating cell, thus maintaining the stem cell pool. Although neural stem cells (NSCs) in the adult mouse subventricular zone have been suggested to divide asymmetrically, intrinsic cell fate determinants for asymmetric NSC division are largely unknown. Stem cell niches are important for stem cell maintenance, but the niche for the maintenance of adult quiescent NSCs has remained obscure. Here we show that the Notch ligand Delta-like 1 (Dll1) is required to maintain quiescent NSCs in the adult mouse subventricular zone. Dll1 protein is induced in activated NSCs and segregates to one daughter cell during mitosis. Dll1-expressing cells reside in close proximity to quiescent NSCs, suggesting a feedback signal for NSC maintenance by their sister cells and progeny. Our data suggest a model in which NSCs produce their own niche cells for their maintenance through asymmetric Dll1 inheritance at mitosis.

Show MeSH