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Neural stem and progenitor cells shorten S-phase on commitment to neuron production.

Arai Y, Pulvers JN, Haffner C, Schilling B, Nüsslein I, Calegari F, Huttner WB - Nat Commun (2011)

Bottom Line: We found that G1 lengthening was associated with the transition from stem cell-like apical progenitors to fate-restricted basal (intermediate) progenitors.Comparative genome-wide gene expression analysis of expanding versus committed progenitor cells revealed changes in key factors of cell-cycle regulation, DNA replication and repair and chromatin remodelling.Our findings suggest that expanding neural stem and progenitor cells invest more time during S-phase into quality control of replicated DNA than those committed to neuron production.

View Article: PubMed Central - PubMed

Affiliation: Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, 01307 Dresden, Germany.

ABSTRACT
During mammalian cerebral cortex development, the G1-phase of the cell cycle is known to lengthen, but it has been unclear which neural stem and progenitor cells are affected. In this paper, we develop a novel approach to determine cell-cycle parameters in specific classes of neural stem and progenitor cells, identified by molecular markers rather than location. We found that G1 lengthening was associated with the transition from stem cell-like apical progenitors to fate-restricted basal (intermediate) progenitors. Unexpectedly, expanding apical and basal progenitors exhibit a substantially longer S-phase than apical and basal progenitors committed to neuron production. Comparative genome-wide gene expression analysis of expanding versus committed progenitor cells revealed changes in key factors of cell-cycle regulation, DNA replication and repair and chromatin remodelling. Our findings suggest that expanding neural stem and progenitor cells invest more time during S-phase into quality control of replicated DNA than those committed to neuron production.

No MeSH data available.


Related in: MedlinePlus

Time course of appearance of EdU label in proliferative and neurogenic mitotic APs and BPs.(a–d) Phosphohistone H3 (PH3, blue), Tis21-GFP (green), DAPI (white) and EdU (magenta) staining after cumulative EdU labelling for 1 h (a, c) and 3 h (b, d). Examples of cells in mitosis, as identified by positive PH3 immunostaining (PH3+) plus mitotic appearance on DAPI staining (DAPI-m), are indicated by arrowheads in (a) and (b) and are shown at higher magnification in (c) and (d), respectively; red arrowheads, DAPI-m/PH3+/Tis21-GFP−/EdU− cell (BP); green arrowheads, DAPI-m/PH3+/Tis21-GFP+/EdU− cell (BP); blue arrowheads, DAPI-m/PH3+/Tis21-GFP−/EdU− cell (AP); purple arrowheads, DAPI-m/PH3+/Tis21-GFP+/EdU− cell (AP); red arrows, DAPI-m/PH3+/Tis21-GFP−/EdU+ cell (BP); green arrows, DAPI-m/PH3+/Tis21-GFP+/EdU+ cell (BP); blue arrows, DAPI-m/PH3+/Tis21-GFP−/EdU+ cell (AP); purple arrows, DAPI-m/PH3+/Tis21-GFP+/EdU+ cell (AP). VZ and SVZ are indicated on the left. Scale bars, 50 μm (a, b) and 10 μm (c, d). (e) Proportion of EdU-labelled mitotic cells (mitotic EdU labelling index) after cumulative EdU labelling for the indicated times. The mitotic EdU labelling index was separately determined for proliferative APs (apical Tis21-GFP− mitoses, blue diamonds), BP-genic/neurogenic APs (apical Tis21-GFP+ mitoses, purple squares), proliferative BPs (basal Tis21-GFP− mitoses, red triangles) and neurogenic BPs (basal Tis21-GFP+ mitoses, green crosses). Data are the mean of three (except 2 h: where the mean is of two fields) 450-μm wide fields (sum of two 225-μm fields), each from a different brain and litter; error bars indicate s.e.m. or the range of the two individual values. (f) Diagram showing the duration of the cell-cycle phases in each NPC population (see Table 1). Blue bars, G1-phase; red bars, S-phase; yellow bars, G2-phase; green bars, M-phase.
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f4: Time course of appearance of EdU label in proliferative and neurogenic mitotic APs and BPs.(a–d) Phosphohistone H3 (PH3, blue), Tis21-GFP (green), DAPI (white) and EdU (magenta) staining after cumulative EdU labelling for 1 h (a, c) and 3 h (b, d). Examples of cells in mitosis, as identified by positive PH3 immunostaining (PH3+) plus mitotic appearance on DAPI staining (DAPI-m), are indicated by arrowheads in (a) and (b) and are shown at higher magnification in (c) and (d), respectively; red arrowheads, DAPI-m/PH3+/Tis21-GFP−/EdU− cell (BP); green arrowheads, DAPI-m/PH3+/Tis21-GFP+/EdU− cell (BP); blue arrowheads, DAPI-m/PH3+/Tis21-GFP−/EdU− cell (AP); purple arrowheads, DAPI-m/PH3+/Tis21-GFP+/EdU− cell (AP); red arrows, DAPI-m/PH3+/Tis21-GFP−/EdU+ cell (BP); green arrows, DAPI-m/PH3+/Tis21-GFP+/EdU+ cell (BP); blue arrows, DAPI-m/PH3+/Tis21-GFP−/EdU+ cell (AP); purple arrows, DAPI-m/PH3+/Tis21-GFP+/EdU+ cell (AP). VZ and SVZ are indicated on the left. Scale bars, 50 μm (a, b) and 10 μm (c, d). (e) Proportion of EdU-labelled mitotic cells (mitotic EdU labelling index) after cumulative EdU labelling for the indicated times. The mitotic EdU labelling index was separately determined for proliferative APs (apical Tis21-GFP− mitoses, blue diamonds), BP-genic/neurogenic APs (apical Tis21-GFP+ mitoses, purple squares), proliferative BPs (basal Tis21-GFP− mitoses, red triangles) and neurogenic BPs (basal Tis21-GFP+ mitoses, green crosses). Data are the mean of three (except 2 h: where the mean is of two fields) 450-μm wide fields (sum of two 225-μm fields), each from a different brain and litter; error bars indicate s.e.m. or the range of the two individual values. (f) Diagram showing the duration of the cell-cycle phases in each NPC population (see Table 1). Blue bars, G1-phase; red bars, S-phase; yellow bars, G2-phase; green bars, M-phase.

Mentions: We combined EdU labelling with immunostaining for phosphohistone H3 (PH3), an indicator of late G2- and M-phase39, to investigate the duration of G2 and M in the various NPC populations. PH3+ cells, the mitotic state (as opposed to late G2) of which was confirmed by 4,6-diamidino-2-phenylindole (DAPI) staining, were classified as either APs or BPs on the basis of their location at the ventricular surface or in the basal VZ/SVZ, respectively (Fig. 4a,b), and as undergoing proliferative or neurogenic division on the basis of the absence or presence, respectively, of Tis21-GFP (Fig. 4c,d).


Neural stem and progenitor cells shorten S-phase on commitment to neuron production.

Arai Y, Pulvers JN, Haffner C, Schilling B, Nüsslein I, Calegari F, Huttner WB - Nat Commun (2011)

Time course of appearance of EdU label in proliferative and neurogenic mitotic APs and BPs.(a–d) Phosphohistone H3 (PH3, blue), Tis21-GFP (green), DAPI (white) and EdU (magenta) staining after cumulative EdU labelling for 1 h (a, c) and 3 h (b, d). Examples of cells in mitosis, as identified by positive PH3 immunostaining (PH3+) plus mitotic appearance on DAPI staining (DAPI-m), are indicated by arrowheads in (a) and (b) and are shown at higher magnification in (c) and (d), respectively; red arrowheads, DAPI-m/PH3+/Tis21-GFP−/EdU− cell (BP); green arrowheads, DAPI-m/PH3+/Tis21-GFP+/EdU− cell (BP); blue arrowheads, DAPI-m/PH3+/Tis21-GFP−/EdU− cell (AP); purple arrowheads, DAPI-m/PH3+/Tis21-GFP+/EdU− cell (AP); red arrows, DAPI-m/PH3+/Tis21-GFP−/EdU+ cell (BP); green arrows, DAPI-m/PH3+/Tis21-GFP+/EdU+ cell (BP); blue arrows, DAPI-m/PH3+/Tis21-GFP−/EdU+ cell (AP); purple arrows, DAPI-m/PH3+/Tis21-GFP+/EdU+ cell (AP). VZ and SVZ are indicated on the left. Scale bars, 50 μm (a, b) and 10 μm (c, d). (e) Proportion of EdU-labelled mitotic cells (mitotic EdU labelling index) after cumulative EdU labelling for the indicated times. The mitotic EdU labelling index was separately determined for proliferative APs (apical Tis21-GFP− mitoses, blue diamonds), BP-genic/neurogenic APs (apical Tis21-GFP+ mitoses, purple squares), proliferative BPs (basal Tis21-GFP− mitoses, red triangles) and neurogenic BPs (basal Tis21-GFP+ mitoses, green crosses). Data are the mean of three (except 2 h: where the mean is of two fields) 450-μm wide fields (sum of two 225-μm fields), each from a different brain and litter; error bars indicate s.e.m. or the range of the two individual values. (f) Diagram showing the duration of the cell-cycle phases in each NPC population (see Table 1). Blue bars, G1-phase; red bars, S-phase; yellow bars, G2-phase; green bars, M-phase.
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f4: Time course of appearance of EdU label in proliferative and neurogenic mitotic APs and BPs.(a–d) Phosphohistone H3 (PH3, blue), Tis21-GFP (green), DAPI (white) and EdU (magenta) staining after cumulative EdU labelling for 1 h (a, c) and 3 h (b, d). Examples of cells in mitosis, as identified by positive PH3 immunostaining (PH3+) plus mitotic appearance on DAPI staining (DAPI-m), are indicated by arrowheads in (a) and (b) and are shown at higher magnification in (c) and (d), respectively; red arrowheads, DAPI-m/PH3+/Tis21-GFP−/EdU− cell (BP); green arrowheads, DAPI-m/PH3+/Tis21-GFP+/EdU− cell (BP); blue arrowheads, DAPI-m/PH3+/Tis21-GFP−/EdU− cell (AP); purple arrowheads, DAPI-m/PH3+/Tis21-GFP+/EdU− cell (AP); red arrows, DAPI-m/PH3+/Tis21-GFP−/EdU+ cell (BP); green arrows, DAPI-m/PH3+/Tis21-GFP+/EdU+ cell (BP); blue arrows, DAPI-m/PH3+/Tis21-GFP−/EdU+ cell (AP); purple arrows, DAPI-m/PH3+/Tis21-GFP+/EdU+ cell (AP). VZ and SVZ are indicated on the left. Scale bars, 50 μm (a, b) and 10 μm (c, d). (e) Proportion of EdU-labelled mitotic cells (mitotic EdU labelling index) after cumulative EdU labelling for the indicated times. The mitotic EdU labelling index was separately determined for proliferative APs (apical Tis21-GFP− mitoses, blue diamonds), BP-genic/neurogenic APs (apical Tis21-GFP+ mitoses, purple squares), proliferative BPs (basal Tis21-GFP− mitoses, red triangles) and neurogenic BPs (basal Tis21-GFP+ mitoses, green crosses). Data are the mean of three (except 2 h: where the mean is of two fields) 450-μm wide fields (sum of two 225-μm fields), each from a different brain and litter; error bars indicate s.e.m. or the range of the two individual values. (f) Diagram showing the duration of the cell-cycle phases in each NPC population (see Table 1). Blue bars, G1-phase; red bars, S-phase; yellow bars, G2-phase; green bars, M-phase.
Mentions: We combined EdU labelling with immunostaining for phosphohistone H3 (PH3), an indicator of late G2- and M-phase39, to investigate the duration of G2 and M in the various NPC populations. PH3+ cells, the mitotic state (as opposed to late G2) of which was confirmed by 4,6-diamidino-2-phenylindole (DAPI) staining, were classified as either APs or BPs on the basis of their location at the ventricular surface or in the basal VZ/SVZ, respectively (Fig. 4a,b), and as undergoing proliferative or neurogenic division on the basis of the absence or presence, respectively, of Tis21-GFP (Fig. 4c,d).

Bottom Line: We found that G1 lengthening was associated with the transition from stem cell-like apical progenitors to fate-restricted basal (intermediate) progenitors.Comparative genome-wide gene expression analysis of expanding versus committed progenitor cells revealed changes in key factors of cell-cycle regulation, DNA replication and repair and chromatin remodelling.Our findings suggest that expanding neural stem and progenitor cells invest more time during S-phase into quality control of replicated DNA than those committed to neuron production.

View Article: PubMed Central - PubMed

Affiliation: Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, 01307 Dresden, Germany.

ABSTRACT
During mammalian cerebral cortex development, the G1-phase of the cell cycle is known to lengthen, but it has been unclear which neural stem and progenitor cells are affected. In this paper, we develop a novel approach to determine cell-cycle parameters in specific classes of neural stem and progenitor cells, identified by molecular markers rather than location. We found that G1 lengthening was associated with the transition from stem cell-like apical progenitors to fate-restricted basal (intermediate) progenitors. Unexpectedly, expanding apical and basal progenitors exhibit a substantially longer S-phase than apical and basal progenitors committed to neuron production. Comparative genome-wide gene expression analysis of expanding versus committed progenitor cells revealed changes in key factors of cell-cycle regulation, DNA replication and repair and chromatin remodelling. Our findings suggest that expanding neural stem and progenitor cells invest more time during S-phase into quality control of replicated DNA than those committed to neuron production.

No MeSH data available.


Related in: MedlinePlus