Project description:Id proteins are dominant negative regulators within the HLH family of proteins. In embryonic stem cells (ESCs), Id1 and Id3 maintain the pluripotent state by preventing neural differentiation. The Id1-interacting protein Zrf1 plays a crucial role as a chromatin-bound factor in specification of the neural fate from ESCs. Here, we show that Id1 blocks Zrf1 recruitment to chromatin, thus preventing the activation of neural genes during ESC differentiation. Moreover, genetic deletion of Id1 in ESCs caused misexpression of more than 6000 genes. Interestingly, the expression of almost half of those genes was restored upon further depletion of Zrf1. We therefore identified Zrf1 as a transcriptional regulator downstream of Id1 in ESCs. In Id1KO mESCs, Zrf1 expression was depleted by using shRNAs. Four replicates corresponding to four independent biological samples per group were collected.
Project description:Id proteins are dominant negative regulators within the HLH family of proteins. In embryonic stem cells (ESCs), Id1 and Id3 maintain the pluripotent state by preventing neural differentiation. The Id1-interacting protein Zrf1 plays a crucial role as a chromatin-bound factor in specification of the neural fate from ESCs. Here, we show that Id1 blocks Zrf1 recruitment to chromatin, thus preventing the activation of neural genes during ESC differentiation. Moreover, genetic deletion of Id1 in ESCs caused misexpression of more than 6000 genes. Interestingly, the expression of almost half of those genes was restored upon further depletion of Zrf1. We therefore identified Zrf1 as a transcriptional regulator downstream of Id1 in ESCs.
Project description:There are no described quality assurance mechanisms for newly formed stem cells. We observed intimate interactions between macrophages and blood stem cells in zebrafish embryos. Stressed stem cells were marked by surface Calreticulin, which stimulates macrophage interaction as an eat me signal. Macrophage-stem cell interactions either lead to removal of cytoplasmic material and stem cell proliferation or resulted in complete stem cell engulfment. Calreticulin knock down or embryonic macrophage depletion reduced the number of stem cell clones into adulthood. Our work supports a model in which embryonic macrophages determine hematopoietic clonality by monitoring stem cell quality.
Project description:Polycomb group (PcG) proteins play important roles in repressing lineage-specific genes and maintaining the undifferentiated state of mouse embryonic stem cells (mESCs). However, the mechanisms by which PcG proteins are recruited to their targets are largely unknown. Here, we show that the histone demethylase Kdm2b is highly expressed in mESCs and regulated by the pluripotent factors Oct4/Sox2 directly. Depletion of Kdm2b in mESCs causes de-repression of lineage-specific genes and induces early differentiation. The function of Kdm2b depends on its CXXC-ZF domain, which mediates Kdm2b’s genome-wide binding to CpG islands (CGIs). Kdm2b interacts with the core components of the Polycomb repressive complex 1 (PRC1) and recruits the complex to the CGIs of early lineage-specific genes. Thus, our study not only reveals a novel Oct4/Sox2-Kdm2b-PRC1-CGI regulatory axis and its function in maintaining undifferentiated state of mESCs, but also demonstrates a critical function of Kdm2b in recruiting PRC1 to the CGIs of lineage-specific genes to repress their expression. In this dataset, we include the ChIP-seq data of Kdm2b, Ezh2 and Ring1b in both control and Kdm2b knock down mouse embryonbic stem cells.
Project description:The TET family of FE(II) and 2-oxoglutarate-dependent enzymes (Tet1/2/3) promote DNA demethylation by converting 5-methylcytosine to 5-hydroxymethylcytosine (5hmC), which they further oxidize into 5-formylcytosine and 5-carboxylcytosine. Tet1 is robustly expressed in mouse embryonic stem cells (mESCs) and has been implicated in mESC maintenance. Here we demonstrate that, unlike genetic deletion, RNAi-mediated depletion of Tet1 in mESCs led to a significant reduction in 5hmC and loss of mESC identity. The differentiation phenotype due to Tet1 depletion positively correlated with the extent of 5hmC loss. Meta-analyses of genomic datasets suggested interaction between Tet1 and leukemia inhibitory factor (LIF) signaling. LIF signaling is known to promote self-renewal and pluripo-tency in mESCs partly by opposing MAPK/ERK mediated differentiation. Withdrawal of LIF leads to differentiation of mESCs. We discovered that Tet1 depletion impaired LIF-dependent Stat3-mediated gene activation by affecting Stat3's ability to bind to its target sites on chromatin. Nanog overexpression or inhibition of MAPK/ERK signaling, both known to maintain mESCs in the absence of LIF, rescued Tet1 depletion, further supporting the dependence of LIF/Stat3 signaling on Tet1. These data support the conclusion that analysis of mESCs in the hours/days immediately following efficient Tet1 depletion reveals Tet1M-bM-^@M-^Ys normal physiological role in maintaining the pluripotent state that may be subject to homeostatic compensation in genetic models. Genome-wide mapping of 5hmC and microarray gene expression profiling in E14Tg2a mESCs after transfection with indicated siRNAs: Tet1 siRNA #1 (Invitrogen, MSS284895), Tet1 siRNA #2 (Invitrogen, MSS284897), and Control siRNA duplex targeting firefly luciferase.
Project description:The TET family of FE(II) and 2-oxoglutarate-dependent enzymes (Tet1/2/3) promote DNA demethylation by converting 5-methylcytosine to 5-hydroxymethylcytosine (5hmC), which they further oxidize into 5-formylcytosine and 5-carboxylcytosine. Tet1 is robustly expressed in mouse embryonic stem cells (mESCs) and has been implicated in mESC maintenance. Here we demonstrate that, unlike genetic deletion, RNAi-mediated depletion of Tet1 in mESCs led to a significant reduction in 5hmC and loss of mESC identity. The differentiation phenotype due to Tet1 depletion positively correlated with the extent of 5hmC loss. Meta-analyses of genomic datasets suggested interaction between Tet1 and leukemia inhibitory factor (LIF) signaling. LIF signaling is known to promote self-renewal and pluripo-tency in mESCs partly by opposing MAPK/ERK mediated differentiation. Withdrawal of LIF leads to differentiation of mESCs. We discovered that Tet1 depletion impaired LIF-dependent Stat3-mediated gene activation by affecting Stat3's ability to bind to its target sites on chromatin. Nanog overexpression or inhibition of MAPK/ERK signaling, both known to maintain mESCs in the absence of LIF, rescued Tet1 depletion, further supporting the dependence of LIF/Stat3 signaling on Tet1. These data support the conclusion that analysis of mESCs in the hours/days immediately following efficient Tet1 depletion reveals Tet1’s normal physiological role in maintaining the pluripotent state that may be subject to homeostatic compensation in genetic models. Genome-wide mapping of 5hmC and microarray gene expression profiling in E14Tg2a mESCs after transfection with indicated siRNAs: Tet1 siRNA #1 (Invitrogen, MSS284895), Tet1 siRNA #2 (Invitrogen, MSS284897), and Control siRNA duplex targeting firefly luciferase.
Project description:The transforming growth factor beta (TGF-β) superfamily proteins are potent regulators of cellular development and differentiation. Long non-coding RNAs (lncRNAs) play widespread roles in spatial-temporal regulation of early development. However, the roles of lncRNAs regulated by nodal/TGF-β signaling is still elusive. Here, we showed a nodal-driven Smad induced lncRNA in mouse embryonic stem cells (mESCs), lncRNA-Smad7, which is divergently transcribed to Smad7, regulates cell fate determination through repressing Bmp2. Depletion of lncRNA-Smad7 dramatically impairs cardiomyocyte differentiation in mESCs. Moreover, LncRNA-Smad7 represses Bmp2 expression and binds at the promoter region of Bmp2. Importantly, knock-down Bmp2 rescues the defect of cardiomyocyte differentiation. Hence, we showed that lncRNA-Smad7 is antagonistic to BMP signaling in mESCs. Furthermore, lncRNA-Smad7 regulates cell fate determination between osteocytes and myocytes formation in C2C12 cells by repressing Bmp2. Thus, we provide new insights regarding the antagonistic effects between nodal/TGF-β and BMP signaling via lncRNA-Smad7.
Project description:The Wnt/β-catenin signalling pathway is a key regulator of embryonic stem cell self-renewal and differentiation. Constitutive activation of this pathway has been shown to significantly increase mouse embryonic stem cell (mESC) self-renewal and pluripotency marker expression. In this study, we generated a novel β-catenin knock-out model in mESCs by using CRISPR/Cas9 technology to delete putatively functional N-terminally truncated isoforms observed in previous knock-out models. While we showed that aberrant N-terminally truncated isoforms are not functional in mESCS, we observed that canonical Wnt signalling is not active in mESCs, as β-catenin ablation does not alter mESC transcriptional profile in LIF-enriched culture conditions; on the other hand, Wnt signalling activation represses mESC spontaneous differentiation. We also showed that transcriptionally silent β-catenin (ΔC) isoforms can rescue β-catenin knock-out self-renewal defects in mESCs, cooperating with TCF1 and LEF1 in the inhibition of mESC spontaneous differentiation in a Gsk3 dependent manner.
Project description:The TET family of FE(II) and 2-oxoglutarate-dependent enzymes (Tet1/2/3) promote DNA demethylation by converting 5-methylcytosine to 5-hydroxymethylcytosine (5hmC), which they further oxidize into 5-formylcytosine and 5-carboxylcytosine. Tet1 is robustly expressed in mouse embryonic stem cells (mESCs) and has been implicated in mESC maintenance. Here we demonstrate that, unlike genetic deletion, RNAi-mediated depletion of Tet1 in mESCs led to a significant reduction in 5hmC and loss of mESC identity. The differentiation phenotype due to Tet1 depletion positively correlated with the extent of 5hmC loss. Meta-analyses of genomic datasets suggested interaction between Tet1 and leukemia inhibitory factor (LIF) signaling. LIF signaling is known to promote self-renewal and pluripo-tency in mESCs partly by opposing MAPK/ERK mediated differentiation. Withdrawal of LIF leads to differentiation of mESCs. We discovered that Tet1 depletion impaired LIF-dependent Stat3-mediated gene activation by affecting Stat3's ability to bind to its target sites on chromatin. Nanog overexpression or inhibition of MAPK/ERK signaling, both known to maintain mESCs in the absence of LIF, rescued Tet1 depletion, further supporting the dependence of LIF/Stat3 signaling on Tet1. These data support the conclusion that analysis of mESCs in the hours/days immediately following efficient Tet1 depletion reveals Tet1’s normal physiological role in maintaining the pluripotent state that may be subject to homeostatic compensation in genetic models.
Project description:The TET family of FE(II) and 2-oxoglutarate-dependent enzymes (Tet1/2/3) promote DNA demethylation by converting 5-methylcytosine to 5-hydroxymethylcytosine (5hmC), which they further oxidize into 5-formylcytosine and 5-carboxylcytosine. Tet1 is robustly expressed in mouse embryonic stem cells (mESCs) and has been implicated in mESC maintenance. Here we demonstrate that, unlike genetic deletion, RNAi-mediated depletion of Tet1 in mESCs led to a significant reduction in 5hmC and loss of mESC identity. The differentiation phenotype due to Tet1 depletion positively correlated with the extent of 5hmC loss. Meta-analyses of genomic datasets suggested interaction between Tet1 and leukemia inhibitory factor (LIF) signaling. LIF signaling is known to promote self-renewal and pluripo-tency in mESCs partly by opposing MAPK/ERK mediated differentiation. Withdrawal of LIF leads to differentiation of mESCs. We discovered that Tet1 depletion impaired LIF-dependent Stat3-mediated gene activation by affecting Stat3's ability to bind to its target sites on chromatin. Nanog overexpression or inhibition of MAPK/ERK signaling, both known to maintain mESCs in the absence of LIF, rescued Tet1 depletion, further supporting the dependence of LIF/Stat3 signaling on Tet1. These data support the conclusion that analysis of mESCs in the hours/days immediately following efficient Tet1 depletion reveals Tet1’s normal physiological role in maintaining the pluripotent state that may be subject to homeostatic compensation in genetic models.