Suz12 is essential for mouse development and for EZH2 histone methyltransferase activity

European Institute of Oncology, Milan, Italy.
The EMBO Journal (Impact Factor: 10.75). 11/2004; 23(20):4061-71. DOI: 10.1038/sj.emboj.7600402
Source: PubMed

ABSTRACT SUZ12 is a recently identified Polycomb group (PcG) protein, which together with EZH2 and EED forms different Polycomb repressive complexes (PRC2/3). These complexes contain histone H3 lysine (K) 27/9 and histone H1 K26 methyltransferase activity specified by the EZH2 SET domain. Here we show that mice lacking Suz12, like Ezh2 and Eed mutant mice, are not viable and die during early postimplantation stages displaying severe developmental and proliferative defects. Consistent with this, we demonstrate that SUZ12 is required for proliferation of cells in tissue culture. Furthermore, we demonstrate that SUZ12 is essential for the activity and stability of the PRC2/3 complexes in mouse embryos, in tissue culture cells and in vitro. Strikingly, Suz12-deficient embryos show a specific loss of di- and trimethylated H3K27, demonstrating that Suz12 is indeed essential for EZH2 activity in vivo. In conclusion, our data demonstrate an essential role of SUZ12 in regulating the activity of the PRC2/3 complexes, which are required for regulating proliferation and embryogenesis.

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    • "RING1A, RING1B, and BMI1 are core PRC1 members while SUZ12, EZH2, and EED form core PRC2 members (de Napoles et al., 2004; Surface et al., 2010). Knockout studies of PcG proteins have established their importance during in vivo development (Voncken et al., 2003; Pasini et al., 2004) but their role in lineage specification and differentiation in vitro remains to be completely elucidated. Most studies have shown localization of PcG mediated histone modification (H3K27me3) during differentiation in mouse ES cells (Boyer et al., 2006; Lee et al., 2006; Pasini et al., 2007), while some have shown histone modifications catalyzed by PcG proteins during differentiation into a specific lineage (Hawkins et al., 2010; Xie et al., 2013). "
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    ABSTRACT: Human embryonic (hES) stem cells are excellent model to study lineage specification and differentiation into various cell types. Differentiation necessitates repression of specific genes not required for a particular lineage. Polycomb Group (PcG) proteins are key histone modifiers, whose primary function is gene repression. PcG proteins form complexes called Polycomb Repressive Complexes (PRCs), which catalyze histone modifications such as H2AK119ub1, H3K27me3 and H3K9me3. PcG proteins play a crucial role during differentiation of stem cells. The expression of PcG transcripts during differentiation of hES cells into endoderm, mesoderm and ectoderm lineage is yet to be shown. In-house derived hES cell line KIND1 was differentiated into endoderm, mesoderm and ectoderm lineages; followed by characterized using RT-PCR for HNF4A, CDX2, MEF2C, TBX5, SOX1 and MAP2. qRT-PCR and western blotting was performed to compare expression of PcG transcripts and proteins across all the three lineages. We observed that cells differentiated into endoderm showed upregulation of RING1B, BMI1, EZH2 and EED transcripts. Mesoderm differentiation was characterized by significant downregulation of all PcG transcripts during later stages. BMI1 and RING1B were upregulated while EZH2, SUZ12 and EED remained low during ectoderm differentiation. Western Blotting also showed distinct expression of BMI1 and EZH2 during differentiation into three germ layers. Our study shows that hES cells differentiating into endoderm, mesoderm and ectoderm lineages show distinct PcG expression profile at transcript and protein level. This article is protected by copyright. All rights reserved.
    Cell Biology International 01/2015; 39(5). DOI:10.1002/cbin.10431 · 1.64 Impact Factor
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    • "Although the role of Erk1/2 signaling in lineage priming is a recognized feature of proper ESC differentiation, the functional significance of PRC2 in ESCs is unclear, stemming from an incongruity between its prevalent deposition on developmental genes and the relatively mild defect in self-renewal exhibited by PRC2 mutant ESCs (Chamberlain et al., 2008; Leeb et al., 2010; Pasini et al., 2007; Shen et al., 2008). Instead, PRC2 mutant ESCs exhibit impaired differentiation potential in vitro, which is more consistent with the postimplantation defects observed in vivo (Faust et al., 1995; O'Carroll et al., 2001; Pasini et al., 2004). These genetic studies suggest that PRC2 may play a more important role during lineage commitment. "
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    ABSTRACT: Erk1/2 activation contributes to mouse ES cell pluripotency. We found a direct role of Erk1/2 in modulating chromatin features required for regulated developmental gene expression. Erk2 binds to specific DNA sequence motifs typically accessed by Jarid2 and PRC2. Negating Erk1/2 activation leads to increased nucleosome occupancy and decreased occupancy of PRC2 and poised RNAPII at Erk2-PRC2-targeted developmental genes. Surprisingly, Erk2-PRC2-targeted genes are specifically devoid of TFIIH, known to phosphorylate RNA polymerase II (RNAPII) at serine-5, giving rise to its initiated form. Erk2 interacts with and phosphorylates RNAPII at its serine 5 residue, which is consistent with the presence of poised RNAPII as a function of Erk1/2 activation. These findings underscore a key role for Erk1/2 activation in promoting the primed status of developmental genes in mouse ES cells and suggest that the transcription complex at developmental genes is different than the complexes formed at other genes, offering alternative pathways of regulation.
    Cell 02/2014; 156(4):678-90. DOI:10.1016/j.cell.2014.01.009 · 33.12 Impact Factor
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    • "These processes can regulate the transition from a proliferative NSC to a differentiating cell and a variety of modifying factors that impact transcription have been identified to date (reviewed in Hu et al., 2012). Among these is Suz12, a member of the Polycomb Repressive Complex 2 (PRC2) that serves to regulate histone methylation (Pasini et al., 2004) resulting in direct consequences for transcription of target genes. Suz12 is expressed in the neocortex during development, and heterozygous gene knockout results in neural tube defects and brain malformations (Miro et al., 2009). "
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    ABSTRACT: Regulation of neural stem cell (NSC) fate decisions is critical during the transition from a multicellular mammalian forebrain neuroepithelium to the multi-layered neocortex. Forebrain development requires coordinated vascular investment alongside NSC differentiation. Vascular endothelial growth factor A (Vegf) has proven to be a pleiotrophic gene whose multiple protein isoforms regulate a broad range of effects in neurovascular systems. To test the hypothesis that the Vegf isoforms (120, 164, and 188) are required for normal forebrain development, we analyzed the forebrain transcriptome of mice expressing specific Vegf isoforms, Vegf120, VegfF188, or a combination of Vegf120/188. Transcriptome analysis identified differentially expressed genes in embryonic day (E) 9.5 forebrain, a time point preceding dramatic neuroepithelial expansion and vascular investment in the telencephalon. Meta-analysis identified gene pathways linked to chromosome-level modifications, cell fate regulation, and neurogenesis that were altered in Vegf isoform mice. Based on these gene network shifts, we predicted that NSC populations would be affected in later stages of forebrain development. In the E11.5 telencephalon, we quantified mitotic cells [Phospho-Histone H3 (pHH3)-positive] and intermediate progenitor cells (Tbr2/Eomes-positive), observing quantitative and qualitative shifts in these populations. We observed qualitative shifts in cortical layering at P0, particularly with Ctip2-positive cells in layer V. The results identify a suite of genes and functional gene networks that can be used to further dissect the role of Vegf in regulating NSC differentiation and downstream consequences for NSC fate decisions. © 2013 Wiley Periodicals, Inc. Develop Neurobiol, 2013.
    Developmental Neurobiology 01/2014; 74(1). DOI:10.1002/dneu.22130 · 4.19 Impact Factor
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