Project description:In differentiated mouse ESCs, most of the nodal/activin responsive genes are dependent on both Smad4 and Trim33, some are solely dependent on Smad4, and some are dependent on Trim33.
Project description:In differentiated mouse ESCs, most of the nodal/activin responsive genes are dependent on both Smad4 and Trim33, some are solely dependent on Smad4, and some are dependent on Trim33. Ebs at Day2.5 from WT, Smad4 null, and Trim33 knock-down ESCs, were treated with activin or SB 431542 for 2 h.
Project description:Graded levels of molecular oxygen (O2) exist within developing mammalian embryos and can differentially regulate cellular specification pathways. During differentiation, cells acquire distinct epigenetic landscapes, which determine their function, however the mechanisms which regulate this are poorly understood. The demethylation of 5-methylcytosine (5mC ) is achieved via successive oxidation reactions catalysed by the Ten-Eleven-Translocation (Tet) enzymes, yielding the 5-hydroxymethylcytosine (5hmC ) intermediate. These require O2 as a co-factor, and hence may link epigenetic processes directly to O2 gradients during development. We demonstrate that the activities of Tet enzymes are differentially dependent upon [O2], and that Tet1 activity, specifically, is inhibited by low levels of O2 which are physiologically relevant in embryogenesis. Further, embryonic stem cells, induced to differentiate, displayed a transient burst of 5hmC, which was both dependent upon Tet1 and inhibited by low (1%) [O2]. A GC-rich promoter region within the Tet3 locus was identified as a significant target of this 5mC-hydroxylation. Further, this region was shown to associate with Tet1, and display the histone epigenetic marks, H3K4me3 and H3K27me3, which are characteristic of a bivalent, developmentally “poised” promoter. We conclude that Tet1 activity, determined by [O2] may play a critical role in regulating cellular differentiation and fate in embryogenesis
Project description:The role of Striatin Interacting Protein 2 (Strip2) in differentiation of embryonic stem cells (ESCs) is still under debate. Strip2 silenced (KD) ESCs were differentiated for 4, 8, 12, and 16 days. We show that Strip2 is distributed in the perinucleus or nuclei of wild type (WT) undifferentiated ESCs, but is localized in high-density nuclear bodies in differentiated cells. CellNet analysis of microarray gene expression data for KD and scrambled control (SCR) embryoid bodies (EBs), as well as immunostainings of key pluripotent factors, demonstrated that KD ESCs remain undifferentiated. This occurs even in 16-day old EBs, which possessed a high tumorigenic potential. Correlated with very high expression levels of epigenetic regulator genes, Hat1 and Dnmt3, enzymatic activities of the histone acetyltransferase type B (HAT1) and DNA (cytosine-5)-methyltransferase 3 beta (DNMT3b) were higher in differentiated 16-day old KD EBs than in SCR or WT EBs. The expression levels of let-7, 290 and 302 microRNA families were opposed in KD ESCs, while KD EBs had levels comparable to WT and SCR ESCs during differentiation. This demonstrates that Strip2 is critical to the onset of differentiation, regulating expression of epigenetic regulators, HAT1 and DNMT3b, as well as microRNAs involved in pluripotency. For a more comprehensive understanding of the potential effects of miRNA for heart development, we carried out the first study of time-resolved parallel profiling of mRNA and miRNA levels in the developing and adult (10 weeks old) as well as old (14 months old) murine heart and identify the dynamical activation or repression of numerous biological processes and signalling pathways
Project description:TET1 maintains hypomethylation at bivalent promoters through its catalytic activity in embryonic stem cells (ESCs). However, whether and how TET1 exerts catalytic activity-independent functions in regulating bivalent genes is not well understood. Therefore, we mapped the TET1 interactome in mouse ESCs using a SILAC IP-MS proteomics approach.
Project description:The role of Striatin Interacting Protein 2 (Strip2) in differentiation of embryonic stem cells (ESCs) is still under debate. Strip2 silenced (KD) ESCs were differentiated for 4, 8, 12, and 16 days. We show that Strip2 is distributed in the perinucleus or nuclei of wild type (WT) undifferentiated ESCs, but is localized in high-density nuclear bodies in differentiated cells. CellNet analysis of microarray gene expression data for KD and scrambled control (SCR) embryoid bodies (EBs), as well as immunostainings of key pluripotent factors, demonstrated that KD ESCs remain undifferentiated. This occurs even in 16-day old EBs, which possessed a high tumorigenic potential. Correlated with very high expression levels of epigenetic regulator genes, Hat1 and Dnmt3, enzymatic activities of the histone acetyltransferase type B (HAT1) and DNA (cytosine-5)-methyltransferase 3 beta (DNMT3b) were higher in differentiated 16-day old KD EBs than in SCR or WT EBs. The expression levels of let-7, 290 and 302 microRNA families were opposed in KD ESCs, while KD EBs had levels comparable to WT and SCR ESCs during differentiation. This demonstrates that Strip2 is critical to the onset of differentiation, regulating expression of epigenetic regulators, HAT1 and DNMT3b, as well as microRNAs involved in pluripotency.
Project description:RNA helicases are involved in multiple steps of RNA metabolism to direct their roles in gene expression, yet their functions in pluripotency control remain largely unexplored. Starting from an RNAi screen of RNA helicases, we identified that eIF4A3, a DEAD-box (Ddx) helicase component of the exon junction complex (EJC), is essential for the maintenance of embryonic stem cells (ESCs). We mapped the eIF4A3 interactomes in mouse ESCs, revealing that eIF4A3 is widely involved in the post-transcriptional regulation of gene expression. Mechanistically, we show that eIF4A3 post-transcriptionally controls the pluripotency-related cell cycle regulators and that its depletion causes cellular differentiation via cell cycle dysregulation. Specifically, eIF4A3 is required for the efficient nuclear export of Ccnb1 mRNA, which encodes Cyclin B1, a key component of the pluripotency-promoting pathway during cell cycle progression of ESCs. Our results reveal a previously unappreciated role of eIF4A3 and its associated EJC in the post-transcriptional cell cycle control in maintaining stem cell pluripotency.
Project description:Mouse 129-B13 ESCs were genetically modified using CRISPR-Cas9 with two guides to remove exon 5 of Phf14, single-cell sorted and expanded to establish modified cell lines (2). Samples were differentiated from mouse ESCs (Day 0) to embryoid bodies (Day 4), neural progenitor cells (Day 8) and glutamatergic neurons (Day 12). Additionally, the parental 129-B13 ESC wild-type cells were split into two and differentiated separately as controls. NEBNext Poly(A) mRNA Magnetic Isolation Module was used to enrich mRNA. Nonsense-mediated decay was observed in Phf14 ex 5 KOs and no Phf14 protein expression was detected by western blot in these cells.