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Deterministic progenitor behavior and unitary production of neurons in the neocortex.

Gao P, Postiglione MP, Krieger TG, Hernandez L, Wang C, Han Z, Streicher C, Papusheva E, Insolera R, Chugh K, Kodish O, Huang K, Simons BD, Luo L, Hippenmeyer S, Shi SH - Cell (2014)

Bottom Line: We found that RGPs progress through a coherent program in which their proliferative potential diminishes in a predictable manner.Removal of OTX1, a transcription factor transiently expressed in RGPs, results in both deep- and superficial-layer neuron loss and a reduction in neuronal unit size.These results suggest that progenitor behavior and histogenesis in the mammalian neocortex conform to a remarkably orderly and deterministic program.

View Article: PubMed Central - PubMed

Affiliation: Developmental Biology Program, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY 10065, USA; Graduate Program in Neuroscience, Weill Cornell Medical College, 1300 York Avenue, New York, NY 10065, USA.

ABSTRACT
Radial glial progenitors (RGPs) are responsible for producing nearly all neocortical neurons. To gain insight into the patterns of RGP division and neuron production, we quantitatively analyzed excitatory neuron genesis in the mouse neocortex using Mosaic Analysis with Double Markers, which provides single-cell resolution of progenitor division patterns and potential in vivo. We found that RGPs progress through a coherent program in which their proliferative potential diminishes in a predictable manner. Upon entry into the neurogenic phase, individual RGPs produce ?8-9 neurons distributed in both deep and superficial layers, indicating a unitary output in neuronal production. Removal of OTX1, a transcription factor transiently expressed in RGPs, results in both deep- and superficial-layer neuron loss and a reduction in neuronal unit size. Moreover, ?1/6 of neurogenic RGPs proceed to produce glia. These results suggest that progenitor behavior and histogenesis in the mammalian neocortex conform to a remarkably orderly and deterministic program.

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Related in: MedlinePlus

Clonal Analysis of Neocortical Excitatory Neuron Genesis and Organization Using MADM(A) Serial sectioning and 3D reconstruction of a MADM-labeled P21 brain treated with TM at E10. Colored lines indicate the contours of the brain and colored dots represent the cell bodies of labeled neurons. The x/y/z axes indicate the spatial orientation of the clone with the y axis parallel to the brain midline and pointing dorsally. Similar display is used in subsequent 3D reconstruction images. Hip, hippocampus; Ncx, neocortex.(B) Confocal images of the green/red G2-X clone. Consecutive brain sections were stained with the antibodies against EGFP (green) and tdTomato (red) and with DAPI (blue). Layers are shown to the left. Arrow indicates an excitatory pyramidal neuron with a prominent apical dendrite, and open arrowhead indicates an excitatory stellate neuron. Arrowheads indicate glial cells. High-magnification images of their dendrites with numerous spines are shown in insets. Scale bars, 200 μm and 10 μm.(C) High-magnification 3D reconstruction image of the green/red G2-X clone. Colored lines indicate the layer boundary. WM, white matter.(D) NND analysis of MADM-labeled neurons in the P21-30 neocortex treated with TM at E10. Data are presented as mean ± SEM.(E) Quantification of MADM clone size (P7–P10: E10, n = 24; E11, n = 69; E12, n = 48; E13, n = 28; P21–P30: E10, n = 22; E11, n = 38; E12, n = 47; E13, n = 25).Data are presented as mean ± SEM. (∗p < 0.05, ∗∗∗p < 0.001, and ∗∗∗∗p < 0.0001). See also Figures S1 and S2 and Movies S1 and S2.
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fig1: Clonal Analysis of Neocortical Excitatory Neuron Genesis and Organization Using MADM(A) Serial sectioning and 3D reconstruction of a MADM-labeled P21 brain treated with TM at E10. Colored lines indicate the contours of the brain and colored dots represent the cell bodies of labeled neurons. The x/y/z axes indicate the spatial orientation of the clone with the y axis parallel to the brain midline and pointing dorsally. Similar display is used in subsequent 3D reconstruction images. Hip, hippocampus; Ncx, neocortex.(B) Confocal images of the green/red G2-X clone. Consecutive brain sections were stained with the antibodies against EGFP (green) and tdTomato (red) and with DAPI (blue). Layers are shown to the left. Arrow indicates an excitatory pyramidal neuron with a prominent apical dendrite, and open arrowhead indicates an excitatory stellate neuron. Arrowheads indicate glial cells. High-magnification images of their dendrites with numerous spines are shown in insets. Scale bars, 200 μm and 10 μm.(C) High-magnification 3D reconstruction image of the green/red G2-X clone. Colored lines indicate the layer boundary. WM, white matter.(D) NND analysis of MADM-labeled neurons in the P21-30 neocortex treated with TM at E10. Data are presented as mean ± SEM.(E) Quantification of MADM clone size (P7–P10: E10, n = 24; E11, n = 69; E12, n = 48; E13, n = 28; P21–P30: E10, n = 22; E11, n = 38; E12, n = 47; E13, n = 25).Data are presented as mean ± SEM. (∗p < 0.05, ∗∗∗p < 0.001, and ∗∗∗∗p < 0.0001). See also Figures S1 and S2 and Movies S1 and S2.

Mentions: To specifically label neocortical excitatory neuron progenitors in a temporally controlled manner, we introduced the Emx1-CreERT2 transgene (Kessaris et al., 2006) into the MADM system and induced Cre activity through a single dose of tamoxifen (TM) administered to timed pregnant females at one of the following four embryonic stages: E10, E11, E12, and E13 (Figure S1B). Brains were analyzed at either postnatal day (P)7–P10 or P21– P30. We found no labeling in the absence of TM treatment (n = 5 brains). To ensure unequivocal clonal analysis, we titrated the TM dose to achieve very sparse labeling (see below). To recover all labeled cells, we performed serial sectioning and three-dimensional (3D) reconstruction of individual brains (Figure 1A).


Deterministic progenitor behavior and unitary production of neurons in the neocortex.

Gao P, Postiglione MP, Krieger TG, Hernandez L, Wang C, Han Z, Streicher C, Papusheva E, Insolera R, Chugh K, Kodish O, Huang K, Simons BD, Luo L, Hippenmeyer S, Shi SH - Cell (2014)

Clonal Analysis of Neocortical Excitatory Neuron Genesis and Organization Using MADM(A) Serial sectioning and 3D reconstruction of a MADM-labeled P21 brain treated with TM at E10. Colored lines indicate the contours of the brain and colored dots represent the cell bodies of labeled neurons. The x/y/z axes indicate the spatial orientation of the clone with the y axis parallel to the brain midline and pointing dorsally. Similar display is used in subsequent 3D reconstruction images. Hip, hippocampus; Ncx, neocortex.(B) Confocal images of the green/red G2-X clone. Consecutive brain sections were stained with the antibodies against EGFP (green) and tdTomato (red) and with DAPI (blue). Layers are shown to the left. Arrow indicates an excitatory pyramidal neuron with a prominent apical dendrite, and open arrowhead indicates an excitatory stellate neuron. Arrowheads indicate glial cells. High-magnification images of their dendrites with numerous spines are shown in insets. Scale bars, 200 μm and 10 μm.(C) High-magnification 3D reconstruction image of the green/red G2-X clone. Colored lines indicate the layer boundary. WM, white matter.(D) NND analysis of MADM-labeled neurons in the P21-30 neocortex treated with TM at E10. Data are presented as mean ± SEM.(E) Quantification of MADM clone size (P7–P10: E10, n = 24; E11, n = 69; E12, n = 48; E13, n = 28; P21–P30: E10, n = 22; E11, n = 38; E12, n = 47; E13, n = 25).Data are presented as mean ± SEM. (∗p < 0.05, ∗∗∗p < 0.001, and ∗∗∗∗p < 0.0001). See also Figures S1 and S2 and Movies S1 and S2.
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC4225456&req=5

fig1: Clonal Analysis of Neocortical Excitatory Neuron Genesis and Organization Using MADM(A) Serial sectioning and 3D reconstruction of a MADM-labeled P21 brain treated with TM at E10. Colored lines indicate the contours of the brain and colored dots represent the cell bodies of labeled neurons. The x/y/z axes indicate the spatial orientation of the clone with the y axis parallel to the brain midline and pointing dorsally. Similar display is used in subsequent 3D reconstruction images. Hip, hippocampus; Ncx, neocortex.(B) Confocal images of the green/red G2-X clone. Consecutive brain sections were stained with the antibodies against EGFP (green) and tdTomato (red) and with DAPI (blue). Layers are shown to the left. Arrow indicates an excitatory pyramidal neuron with a prominent apical dendrite, and open arrowhead indicates an excitatory stellate neuron. Arrowheads indicate glial cells. High-magnification images of their dendrites with numerous spines are shown in insets. Scale bars, 200 μm and 10 μm.(C) High-magnification 3D reconstruction image of the green/red G2-X clone. Colored lines indicate the layer boundary. WM, white matter.(D) NND analysis of MADM-labeled neurons in the P21-30 neocortex treated with TM at E10. Data are presented as mean ± SEM.(E) Quantification of MADM clone size (P7–P10: E10, n = 24; E11, n = 69; E12, n = 48; E13, n = 28; P21–P30: E10, n = 22; E11, n = 38; E12, n = 47; E13, n = 25).Data are presented as mean ± SEM. (∗p < 0.05, ∗∗∗p < 0.001, and ∗∗∗∗p < 0.0001). See also Figures S1 and S2 and Movies S1 and S2.
Mentions: To specifically label neocortical excitatory neuron progenitors in a temporally controlled manner, we introduced the Emx1-CreERT2 transgene (Kessaris et al., 2006) into the MADM system and induced Cre activity through a single dose of tamoxifen (TM) administered to timed pregnant females at one of the following four embryonic stages: E10, E11, E12, and E13 (Figure S1B). Brains were analyzed at either postnatal day (P)7–P10 or P21– P30. We found no labeling in the absence of TM treatment (n = 5 brains). To ensure unequivocal clonal analysis, we titrated the TM dose to achieve very sparse labeling (see below). To recover all labeled cells, we performed serial sectioning and three-dimensional (3D) reconstruction of individual brains (Figure 1A).

Bottom Line: We found that RGPs progress through a coherent program in which their proliferative potential diminishes in a predictable manner.Removal of OTX1, a transcription factor transiently expressed in RGPs, results in both deep- and superficial-layer neuron loss and a reduction in neuronal unit size.These results suggest that progenitor behavior and histogenesis in the mammalian neocortex conform to a remarkably orderly and deterministic program.

View Article: PubMed Central - PubMed

Affiliation: Developmental Biology Program, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY 10065, USA; Graduate Program in Neuroscience, Weill Cornell Medical College, 1300 York Avenue, New York, NY 10065, USA.

ABSTRACT
Radial glial progenitors (RGPs) are responsible for producing nearly all neocortical neurons. To gain insight into the patterns of RGP division and neuron production, we quantitatively analyzed excitatory neuron genesis in the mouse neocortex using Mosaic Analysis with Double Markers, which provides single-cell resolution of progenitor division patterns and potential in vivo. We found that RGPs progress through a coherent program in which their proliferative potential diminishes in a predictable manner. Upon entry into the neurogenic phase, individual RGPs produce ?8-9 neurons distributed in both deep and superficial layers, indicating a unitary output in neuronal production. Removal of OTX1, a transcription factor transiently expressed in RGPs, results in both deep- and superficial-layer neuron loss and a reduction in neuronal unit size. Moreover, ?1/6 of neurogenic RGPs proceed to produce glia. These results suggest that progenitor behavior and histogenesis in the mammalian neocortex conform to a remarkably orderly and deterministic program.

Show MeSH
Related in: MedlinePlus