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The lysine acetyltransferase activator Brpf1 governs dentate gyrus development through neural stem cells and progenitors.

You L, Yan K, Zou J, Zhou J, Zhao H, Bertos NR, Park M, Wang E, Yang XJ - PLoS Genet. (2015)

Bottom Line: Bromodomain- and PHD finger-containing protein 1 (BRPF1) is a multidomain histone binder and a master activator of three lysine acetyltransferases, MOZ, MORF and HBO1, which are also known as KAT6A, KAT6B and KAT7, respectively.We trace the developmental origin to compromised Sox2+ neural stem cells and Tbr2+ intermediate neuronal progenitors.These results link histone binding and acetylation control to hippocampus development and identify an important epigenetic regulator for patterning the dentate gyrus, a brain structure critical for learning, memory and adult neurogenesis.

View Article: PubMed Central - PubMed

Affiliation: The Rosalind & Morris Goodman Cancer Research Center, McGill University, Montreal, Quebec, Canada; Department of Medicine, McGill University, Montreal, Quebec, Canada.

ABSTRACT
Lysine acetylation has recently emerged as an important post-translational modification in diverse organisms, but relatively little is known about its roles in mammalian development and stem cells. Bromodomain- and PHD finger-containing protein 1 (BRPF1) is a multidomain histone binder and a master activator of three lysine acetyltransferases, MOZ, MORF and HBO1, which are also known as KAT6A, KAT6B and KAT7, respectively. While the MOZ and MORF genes are rearranged in leukemia, the MORF gene is also mutated in prostate and other cancers and in four genetic disorders with intellectual disability. Here we show that forebrain-specific inactivation of the mouse Brpf1 gene causes hypoplasia in the dentate gyrus, including underdevelopment of the suprapyramidal blade and complete loss of the infrapyramidal blade. We trace the developmental origin to compromised Sox2+ neural stem cells and Tbr2+ intermediate neuronal progenitors. We further demonstrate that Brpf1 loss deregulates neuronal migration, cell cycle progression and transcriptional control, thereby causing abnormal morphogenesis of the hippocampus. These results link histone binding and acetylation control to hippocampus development and identify an important epigenetic regulator for patterning the dentate gyrus, a brain structure critical for learning, memory and adult neurogenesis.

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Cell cycle properties and progenitor number in the mutant dentate gyrus.(A-B) After BrdU labeling, E15.5 pregnant mice were sacrificed 1 h later to retrieve fetal brains for subsequent fixing and sectioning. Immunofluorescence microscopy was performed with anti-Ki67 and-BrdU antibodies, with representative images of the hippocampal regions shown in (A) and the quantification of the stained cells in two regions (outlined with dotted lines) presented in (B). The quantification was based on two pairs of control and mutant brains, with 8 matched sections per brain. In the dentate neuroepithelium (dNE), no difference was detected. In the dentate migration stream (dms), the number of BrdU+ progenitors was normal but the Ki67+ cycling cells increased significantly, thereby decreasing the ratio of S-phase (BrdU+) vs proliferating (Ki67+) cells. (C-D) Immunostaining of sections from the same brains as in (A-B) with an antibody specific to phospho-Ser10 of histone H3 (pH3). Representative images of the hippocampal regions are shown in (C) and the quantification of positive cells in two regions (outlined with dashed lines) is presented in (D). No pH3-positive cells were detected in the migration stream. Scale bars: 100 μm; ns, not statistically significant; *p<0.05, **p<0.01.
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pgen.1005034.g008: Cell cycle properties and progenitor number in the mutant dentate gyrus.(A-B) After BrdU labeling, E15.5 pregnant mice were sacrificed 1 h later to retrieve fetal brains for subsequent fixing and sectioning. Immunofluorescence microscopy was performed with anti-Ki67 and-BrdU antibodies, with representative images of the hippocampal regions shown in (A) and the quantification of the stained cells in two regions (outlined with dotted lines) presented in (B). The quantification was based on two pairs of control and mutant brains, with 8 matched sections per brain. In the dentate neuroepithelium (dNE), no difference was detected. In the dentate migration stream (dms), the number of BrdU+ progenitors was normal but the Ki67+ cycling cells increased significantly, thereby decreasing the ratio of S-phase (BrdU+) vs proliferating (Ki67+) cells. (C-D) Immunostaining of sections from the same brains as in (A-B) with an antibody specific to phospho-Ser10 of histone H3 (pH3). Representative images of the hippocampal regions are shown in (C) and the quantification of positive cells in two regions (outlined with dashed lines) is presented in (D). No pH3-positive cells were detected in the migration stream. Scale bars: 100 μm; ns, not statistically significant; *p<0.05, **p<0.01.

Mentions: At both P10 and P24, Ki67+ neuronal precursors virtually disappeared in the subgranular zone of the mutant dentate gyri (Fig. 3D-E). To substantiate this, we performed BrdU labeling and sacrificed the pups 1 h later. Different from the birthdating analysis just described above (Fig. 7A-B), this short labeling protocol was to assess cells with active DNA synthesis. As shown in Fig. 7C-D, this protocol identified dramatic reduction of BrdU+ cells at the mutant subgranular zone at P12. In addition, immunostaining for cleaved caspase 3 failed to evident apoptosis in the wild-type or mutant dentate gyrus. Together, these results indicate that Brpf1 impairs cell cycle progression. To investigate this further, we analyzed cell cycle progression of the progenitors. E15.5 pregnant mice were sacrificed after 1 h pulse of BrdU labeling to retrieve the fetal brain for immunofluorescence microscopy with anti-Ki67 and-BrdU antibodies. Representative images of the hippocampal regions are shown in Fig. 8A and the quantification of the immunostained cells in two regions (outlined with dotted lines) is presented in Fig. 8B. In the dentate neuroepithelium, no difference was detected (Fig. 8B, left). In the dentate migration stream, the number of BrdU+ progenitors was normal but the Ki67+ cycling cell population (at G1, S, G2 and M, but not G0) increased significantly, thereby decreasing the ratio of S-phase (BrdU+) over proliferating (Ki67+) cells (Fig. 7B, right). Moreover, immunostaining analysis of the related sections with an antibody specific to phospho-Ser10 of histone H3 revealed no difference between the wild-type and mutant (Fig. 8C-D), indicating that the M phase of the cell cycle is normal in the mutant. These results indicate that Brpf1 loss impairs cell cycle progression of the dentate migration stream at E15.5, most likely through the G1 phase. Notably, the defects at E15.5 (Fig. 8) were smaller than those at or after P10 (Figs. 3D-E & 7C-D). Consistent with difference, Brpf1 expression in the developing hippocampus was low at E14.5 and E17.5, but increased dramatically after P3 (Fig. 1).


The lysine acetyltransferase activator Brpf1 governs dentate gyrus development through neural stem cells and progenitors.

You L, Yan K, Zou J, Zhou J, Zhao H, Bertos NR, Park M, Wang E, Yang XJ - PLoS Genet. (2015)

Cell cycle properties and progenitor number in the mutant dentate gyrus.(A-B) After BrdU labeling, E15.5 pregnant mice were sacrificed 1 h later to retrieve fetal brains for subsequent fixing and sectioning. Immunofluorescence microscopy was performed with anti-Ki67 and-BrdU antibodies, with representative images of the hippocampal regions shown in (A) and the quantification of the stained cells in two regions (outlined with dotted lines) presented in (B). The quantification was based on two pairs of control and mutant brains, with 8 matched sections per brain. In the dentate neuroepithelium (dNE), no difference was detected. In the dentate migration stream (dms), the number of BrdU+ progenitors was normal but the Ki67+ cycling cells increased significantly, thereby decreasing the ratio of S-phase (BrdU+) vs proliferating (Ki67+) cells. (C-D) Immunostaining of sections from the same brains as in (A-B) with an antibody specific to phospho-Ser10 of histone H3 (pH3). Representative images of the hippocampal regions are shown in (C) and the quantification of positive cells in two regions (outlined with dashed lines) is presented in (D). No pH3-positive cells were detected in the migration stream. Scale bars: 100 μm; ns, not statistically significant; *p<0.05, **p<0.01.
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Related In: Results  -  Collection

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pgen.1005034.g008: Cell cycle properties and progenitor number in the mutant dentate gyrus.(A-B) After BrdU labeling, E15.5 pregnant mice were sacrificed 1 h later to retrieve fetal brains for subsequent fixing and sectioning. Immunofluorescence microscopy was performed with anti-Ki67 and-BrdU antibodies, with representative images of the hippocampal regions shown in (A) and the quantification of the stained cells in two regions (outlined with dotted lines) presented in (B). The quantification was based on two pairs of control and mutant brains, with 8 matched sections per brain. In the dentate neuroepithelium (dNE), no difference was detected. In the dentate migration stream (dms), the number of BrdU+ progenitors was normal but the Ki67+ cycling cells increased significantly, thereby decreasing the ratio of S-phase (BrdU+) vs proliferating (Ki67+) cells. (C-D) Immunostaining of sections from the same brains as in (A-B) with an antibody specific to phospho-Ser10 of histone H3 (pH3). Representative images of the hippocampal regions are shown in (C) and the quantification of positive cells in two regions (outlined with dashed lines) is presented in (D). No pH3-positive cells were detected in the migration stream. Scale bars: 100 μm; ns, not statistically significant; *p<0.05, **p<0.01.
Mentions: At both P10 and P24, Ki67+ neuronal precursors virtually disappeared in the subgranular zone of the mutant dentate gyri (Fig. 3D-E). To substantiate this, we performed BrdU labeling and sacrificed the pups 1 h later. Different from the birthdating analysis just described above (Fig. 7A-B), this short labeling protocol was to assess cells with active DNA synthesis. As shown in Fig. 7C-D, this protocol identified dramatic reduction of BrdU+ cells at the mutant subgranular zone at P12. In addition, immunostaining for cleaved caspase 3 failed to evident apoptosis in the wild-type or mutant dentate gyrus. Together, these results indicate that Brpf1 impairs cell cycle progression. To investigate this further, we analyzed cell cycle progression of the progenitors. E15.5 pregnant mice were sacrificed after 1 h pulse of BrdU labeling to retrieve the fetal brain for immunofluorescence microscopy with anti-Ki67 and-BrdU antibodies. Representative images of the hippocampal regions are shown in Fig. 8A and the quantification of the immunostained cells in two regions (outlined with dotted lines) is presented in Fig. 8B. In the dentate neuroepithelium, no difference was detected (Fig. 8B, left). In the dentate migration stream, the number of BrdU+ progenitors was normal but the Ki67+ cycling cell population (at G1, S, G2 and M, but not G0) increased significantly, thereby decreasing the ratio of S-phase (BrdU+) over proliferating (Ki67+) cells (Fig. 7B, right). Moreover, immunostaining analysis of the related sections with an antibody specific to phospho-Ser10 of histone H3 revealed no difference between the wild-type and mutant (Fig. 8C-D), indicating that the M phase of the cell cycle is normal in the mutant. These results indicate that Brpf1 loss impairs cell cycle progression of the dentate migration stream at E15.5, most likely through the G1 phase. Notably, the defects at E15.5 (Fig. 8) were smaller than those at or after P10 (Figs. 3D-E & 7C-D). Consistent with difference, Brpf1 expression in the developing hippocampus was low at E14.5 and E17.5, but increased dramatically after P3 (Fig. 1).

Bottom Line: Bromodomain- and PHD finger-containing protein 1 (BRPF1) is a multidomain histone binder and a master activator of three lysine acetyltransferases, MOZ, MORF and HBO1, which are also known as KAT6A, KAT6B and KAT7, respectively.We trace the developmental origin to compromised Sox2+ neural stem cells and Tbr2+ intermediate neuronal progenitors.These results link histone binding and acetylation control to hippocampus development and identify an important epigenetic regulator for patterning the dentate gyrus, a brain structure critical for learning, memory and adult neurogenesis.

View Article: PubMed Central - PubMed

Affiliation: The Rosalind & Morris Goodman Cancer Research Center, McGill University, Montreal, Quebec, Canada; Department of Medicine, McGill University, Montreal, Quebec, Canada.

ABSTRACT
Lysine acetylation has recently emerged as an important post-translational modification in diverse organisms, but relatively little is known about its roles in mammalian development and stem cells. Bromodomain- and PHD finger-containing protein 1 (BRPF1) is a multidomain histone binder and a master activator of three lysine acetyltransferases, MOZ, MORF and HBO1, which are also known as KAT6A, KAT6B and KAT7, respectively. While the MOZ and MORF genes are rearranged in leukemia, the MORF gene is also mutated in prostate and other cancers and in four genetic disorders with intellectual disability. Here we show that forebrain-specific inactivation of the mouse Brpf1 gene causes hypoplasia in the dentate gyrus, including underdevelopment of the suprapyramidal blade and complete loss of the infrapyramidal blade. We trace the developmental origin to compromised Sox2+ neural stem cells and Tbr2+ intermediate neuronal progenitors. We further demonstrate that Brpf1 loss deregulates neuronal migration, cell cycle progression and transcriptional control, thereby causing abnormal morphogenesis of the hippocampus. These results link histone binding and acetylation control to hippocampus development and identify an important epigenetic regulator for patterning the dentate gyrus, a brain structure critical for learning, memory and adult neurogenesis.

Show MeSH
Related in: MedlinePlus