Project description:TWIST1, a basic helix-loop-helix transcription factor is essential for the development of cranial mesoderm and cranial neural crest-derived craniofacial structures. Our previous work showed that, in the absence of TWIST1, some cells within the cranial mesoderm adopt an abnormal epithelial configuration. Here, we show by transcriptome analysis that loss of TWIST1 in the cranial mesoderm is accompanied by a reduction in the expression of genes that are associated with cell-extracellular matrix interactions and the acquisition of mesenchymal characteristics. By comparing the transcriptional profiles of cranial mesoderm-specific Twist1 loss-of-function mutant and control mouse embryos, we identified a set of genes that are both TWIST1-dependent and predominantly expressed in the mesoderm. By ChIP-seq in a cell line model of a TWIST1-dependent mesenchymal state, we identified, among the downstream genes, three direct transcriptional targets of TWIST1: Ddr2, Pcolce and Tgfbi. Our findings show that the mesenchymal properties of the cranial mesoderm is likely to be regulated by a network of TWIST1 targets genes that influence the extracellular matrix and cell-matrix interactions, and collectively they are required for the morphogenesis of the craniofacial structures. Chromatin extracts were subject to chromatin immunoprecipitation with anti TWIST1 monoclonal antibody (ChIP-seq). Input chromatin, not subject to ChIP was used as the negative control. Two independent replicate experiments were performed. Purified, immunoprecipitated DNA was sequenced at Australian Genome Research facility.
Project description:TWIST1, a basic helix-loop-helix transcription factor is essential for the development of cranial mesoderm and cranial neural crest-derived craniofacial structures. Our previous work showed that, in the absence of TWIST1, some cells within the cranial mesoderm adopt an abnormal epithelial configuration. Here, we show by transcriptome analysis that loss of TWIST1 in the cranial mesoderm is accompanied by a reduction in the expression of genes that are associated with cell-extracellular matrix interactions and the acquisition of mesenchymal characteristics. By comparing the transcriptional profiles of cranial mesoderm-specific Twist1 loss-of-function mutant and control mouse embryos, we identified a set of genes that are both TWIST1-dependent and predominantly expressed in the mesoderm. By ChIP-seq in a cell line model of a TWIST1-dependent mesenchymal state, we identified, among the downstream genes, three direct transcriptional targets of TWIST1: Ddr2, Pcolce and Tgfbi. Our findings show that the mesenchymal properties of the cranial mesoderm is likely to be regulated by a network of TWIST1 targets genes that influence the extracellular matrix and cell-matrix interactions, and collectively they are required for the morphogenesis of the craniofacial structures. Cranial neural crest and cranial mesoderm cells were isolated by flow sorting of GFP reporter-labelled cells collected from heads of E9.5 mouse embryos. Three replicates were independently isolated and hybridized to Illumina mouse WG v 2.0 chips
Project description:TWIST1, a basic helix-loop-helix transcription factor is essential for the development of cranial mesoderm and cranial neural crest-derived craniofacial structures. Our previous work showed that, in the absence of TWIST1, some cells within the cranial mesoderm adopt an abnormal epithelial configuration. Here, we show by transcriptome analysis that loss of TWIST1 in the cranial mesoderm is accompanied by a reduction in the expression of genes that are associated with cell-extracellular matrix interactions and the acquisition of mesenchymal characteristics. By comparing the transcriptional profiles of cranial mesoderm-specific Twist1 loss-of-function mutant and control mouse embryos, we identified a set of genes that are both TWIST1-dependent and predominantly expressed in the mesoderm. By ChIP-seq in a cell line model of a TWIST1-dependent mesenchymal state, we identified, among the downstream genes, three direct transcriptional targets of TWIST1: Ddr2, Pcolce and Tgfbi. Our findings show that the mesenchymal properties of the cranial mesoderm is likely to be regulated by a network of TWIST1 targets genes that influence the extracellular matrix and cell-matrix interactions, and collectively they are required for the morphogenesis of the craniofacial structures. For microarray analysis of CM-CKO embryos, embryo heads of four genotypes were collected at E8.5 (5-7 somites) and E9.5 (18- 20 somites): CM-CKO (Twist1flox/del; Mesp1Cre/+), CM-Het (Twist1flox/wt; Mesp1Cre/+), Het (Twist1flox/del; Mesp1+/+) and Control (Twist1flox/wt; Mesp1+/+). Sample sizes for E8.5 embryos were as follows: Control, n=4 CM-CKO, n=4; Het, n=3; CM-Hets, n=3).
Project description:TWIST1, a basic helix-loop-helix transcription factor is essential for the development of cranial mesoderm and cranial neural crest-derived craniofacial structures. Our previous work showed that, in the absence of TWIST1, some cells within the cranial mesoderm adopt an abnormal epithelial configuration. Here, we show by transcriptome analysis that loss of TWIST1 in the cranial mesoderm is accompanied by a reduction in the expression of genes that are associated with cell-extracellular matrix interactions and the acquisition of mesenchymal characteristics. By comparing the transcriptional profiles of cranial mesoderm-specific Twist1 loss-of-function mutant and control mouse embryos, we identified a set of genes that are both TWIST1-dependent and predominantly expressed in the mesoderm. By ChIP-seq in a cell line model of a TWIST1-dependent mesenchymal state, we identified, among the downstream genes, three direct transcriptional targets of TWIST1: Ddr2, Pcolce and Tgfbi. Our findings show that the mesenchymal properties of the cranial mesoderm is likely to be regulated by a network of TWIST1 targets genes that influence the extracellular matrix and cell-matrix interactions, and collectively they are required for the morphogenesis of the craniofacial structures. For microarray analysis of CM-CKO embryos, embryo heads of four genotypes were collected at E8.5 (5-7 somites) and E9.5 (18- 20 somites): CM-CKO (Twist1flox/del; Mesp1Cre/+), CM-Het (Twist1flox/wt; Mesp1Cre/+), Het (Twist1flox/del; Mesp1+/+) and Control (Twist1flox/wt; Mesp1+/+). Sample sizes for E9.5 were as follows: Control, n=3; CM-CKO, n=4; Het, n=4; CM-Het, n=4). RNA was extracted using the RNeasy Micro kit (Qiagen) and samples sent to the Australian Genome Research Foundation for labelling and hybridization.
Project description:We employ RNA-seq of FACS sorted cell populations to identify genes that are enriched in cranial neural crest in relationship to the trunk. Transcriptional profiling of delaminating cranial and trunk neural crest subpopulations.
Project description:BAF155, as a component of a chromatin remodeling complex, is thought to be involved in the regulation of gene expression. Baf155 knockdown in ES cells results in misregulation of hundreds of genes (Ho et al., 2009). The Baf155msp3 allele presents a unique case for gene expression analysis wherein the BAF complex appears to be intact, in contrast to disruption of the BAF complex when BAF155 function is lost (Chen and Archer, 2005; Sohn et al., 2007). To examine gene expression in the Baf155msp3 mutant at the time of neural tube closure, we performed RNA-Seq and compared gene expression levels between homozygous wildtype and homozygous mutant embryos. After extensive analysis of the RNA-Seq data comparing all 3 mutants to all 3 WT replicates, 78 genes were identified as being upregulated on average in the mutant samples while 22 genes were downregulated. To facilitate an understanding of global gene expression differences, Ingenuity Pathway Analysis (IPA) was used to assign functional categories to the up- and down-regulated genes in the mutants. The most significant molecular and cellular functions of these genes were: 1. cellular movement (1.46E-04>p>4.12E-02), 2. cell death and survival (2.69E-04>p>4.12E-02), and 3. cell growth and proliferation (2.69E-04>p>3.41E-02). Many neuronal genes were significantly misregulated as well. Overall, the RNA-Seq analysis revealed that surprisingly few genes showed altered expression in Baf155 mutant neural tissue, given the broad epigenetic role of the BAF complex, but included genes involved in neural development and cell survival. Moreover, gene expression changes between individual mutants were variable even though the NTD was consistently observed. This suggests that inconsistent gene regulation contributes to failed neural tube closure. RNA was isolated from somite matched (21-23 somites) and phenotype matched cranial tissue of homozygous wildtype and homozygous mutant embryos (3 of each genotype) at E9.5 just after the time of neural tube closure. At E9.5, the vast majority of the embryonic neural tube is comprised of proliferating neural progenitor cells, constituting a relatively homogeneous cell population.
Project description:Cardiac development arises from two sources of mesoderm progenitors, the first (FHF) and the second heart field (SHF). Mesp1 has been proposed to mark the most primitive multipotent cardiac progenitors common for both heart fields. Here, using clonal analysis of the earliest prospective cardiovascular progenitors in a temporally controlled manner during the early gastrulation, we found that Mesp1 progenitors consist of two temporally distinct pools of progenitors restricted to either the FHF or the SHF. FHF progenitors were unipotent, while SHF progenitors, were either uni- or bipotent. Microarray and single cell RT-PCR analysis of Mesp1 progenitors revealed the existence of molecularly distinct populations of Mesp1 progenitors, consistent with their lineage and regional contribution. Altogether, these results provide evidence that heart development arises from distinct populations of unipotent and bipotent cardiac progenitors that independently express Mesp1 at different time points during their specification, revealing that the regional segregation and lineage restriction of cardiac progenitors occurs very early during gastrulation. We used microarrays to characterize the molecular mechanisms that control Mesp1 progenitor specification and lineage segregation during the early stage of cardiac mesoderm formation, 50 Mesp1 H2B-GFP+ or Mesp1 H2B-GFP- cells at E6.5 or E7.5 from mouse embryos were sorted for RNA extraction, amplification and hybridization on Affimetrix microarrays. Microaarrays were performed on Mouse Genome 430 PM strip Affymetrix array. The overall design was repeated in two different biological samples.
Project description:Specification to primordial germ cells (PGCs) occurs under the mesoderm induction signals during gastrulation. Here, we found that Akt activation in embryonic stem (ES) cells generated self-renewing spheres during mesodermal differentiation induction and that the differentiation status of the sphere cells was in between ES cells and PGCs. Essential regulators for PGC specification and their downstream germ cell-specific genes were expressed in the spheres, showing that the cells of the sphere commenced the differentiation to germ lineage. However, the spheres could not proceed to spermatogenesis after transplantation to testes. Meanwhile, the transfer of the spheres to the original feeder-free ES cell culture conditions induced chaotic differentiation. In contrast, when the spheres were cultured on mouse embryonic fibroblasts or in the presence of ERK-cascade and GSK3 inhibitors, the reversion to the ES cell-like cell states was induced. These results indicate that the Akt signaling brings about a novel metastable and pluripotent state between ES cells and PGCs. Five samples were analyzed, which included the Akt-Mer-expressing ES cell (ESC) line #21 treated with or without 4OHT (4-hydroxytamoxifen), the #21 ESC-derived primordial germ cell (PGC)-like sphere cells and the ESC-like cells reverted from #21 PGC-like sphere cells. The PGC-like sphere cells derived from another Akt-Mer ESC line #42 was also examined.
Project description:In order to gain a more global view of the activity of histone demethylases we report here studies of the two fission yeast SWIRM and polyamine oxidase domain homologues of mammalian LSD1. Consistent with previous work (Nicolas et al., 2006) we find that the two S. pombe proteins, which we name Swm1 and Swm2 (after SWIRM1 and SWIRM2), associate together in a complex. We find that this complex specifically demethylates lysine 9 in histone H3 (H3K9) to up- and down-regulate expression of different genes. Using chromatin-immunoprecipitation, to isolate fragments of chromatin containing either H3K4me2 or H3K9me2, and DNA microarray analysis (ChIP-chip), we have studied genome-wide changes in patterns of histone methylation, and their correlation with gene expression, upon deletion of the swm1+ gene. Using hyper-geometric probability comparisons we uncover links between lysine specific demethylases, the histone deacetylase Clr6, and the chromatin remodeller Hrp1. Keywords: chip on chip Genome-wide studies of histone demethylation catalysed by the fission yeast SWIRM and polyamine oxidase domain homologues of mammalian LSD1
Project description:The Sin3/HDAC complex is highly conserved from yeast to humans. Sin3 provides the scaffolding needed to coordinate DNA binding proteins with various chromatin modifying enzymes, most often histone deacetylases, to establish chromatin environments important both for correct gene regulation and genome stability (reviewed in [1]). Three Sin3 homologs are present. Here we explore Pst3, the most ancient of the Sin3 molecules, in Schizosaccharomyces pombe. In contrast to Pst1 [2] and Pst2 [3], Pst3 occupies the entire nuclear space, including the nucleolus. The deletion of pst3+ causes general genome instability including chomosome mis-segregation, gross sporulation defects, rampant anneuploidy, and distended nucleoli. Genome-wide expression analysis indicated a role in both gene repression and gene activation. Interestingly, highly expressed genes encoding ribosomal and nucleolar proteins were positively regulated by Pst3. Genome wide binding analysis for Pst3-GFP indicated that Pst3 is bound both to intergenic and coding regions, and could be correlated with expression data. Proteins previously identified as part of the Clr6/Pst2 complex co-immunopercipitated with Pst3-TAP. Additionally, Snf59, the kinase Ssp1, and the Dead-Box helicase Dbp10 were identified as Pst3 interaction partners. Taken together this data suggests that Pst3 has a direct role in the structure and function of the nucleolus. Keywords: Expression profiling Expression profiling experiments were performed and quantified according to (Xue et al., 2004).