Mutations altering the normal function of C/EBPa are frequent in acute myeloid leukaemia with normal karyotype. MYB, a cooperating partner of C/EBPa, is likewise heavily implicated in AML. Here we investigate how the relative requirement for the transcription factor MYB in AML relates to the particular combinations of wild type and mutated alleles of CEBPA. Through knockdown of Myb in murine cell lines modelling the spectrum of CEBPA mutations we show that the consequences of reduced Myb depend on the mutational status of Cebpa. Importantly, Myb knockdown fails to override the block in myeloid differentiation in cells with biallelic N-terminal C/EBPa mutations, demonstrating for the first time that the dependency on Myb observed in AML is much lower in leukaemia with this combination of mutations. By comparing genome-wide analyses of gene expression following Myb knockdown and ChIP-seq data for the binding of C/EBPa isoforms, we provide evidence for a functional cooperation between C/EBPa and Myb in the maintenance of the leukaemia state. This co-dependency breaks down when both alleles of CEBPA harbour N-terminal mutations, as a subset of C/EBPa-regulated genes only bind the short p30 C/EBPa isoform and, unlike other C/EBPa regulated genes, do so without a requirement for Myb. Overall design: Gene expression analysis of FMH9, KL and LL cells with and without Myb knockdown
Dependence on Myb expression is attenuated in myeloid leukaemia with N-terminal CEBPA mutations.
Subject
View SamplesStem samples of wildtype Columbia plants and the wox4-1 mutant (Gabi_462G01) were analyzed in order to draw a connection between general transcriptomic changes during interfascicular formation in the wildtype and WOX4-dependent gene regulation during this process.
WOX4 imparts auxin responsiveness to cambium cells in Arabidopsis.
Specimen part
View SamplesIn-vivo induced establishment and activity of the interfascicular cambium in Arabidopsis thaliana stems under NPA treatments.
WOX4 imparts auxin responsiveness to cambium cells in Arabidopsis.
Specimen part, Treatment
View SamplesWe tamoxifen treated 8-12 week old mice that had floxed alleles of the following: 1) both Apc alleles (giving rise to Apc truncation/inactivation); 2) both Cdx2 alleles (giving rise to Cdx2 inactivation; 3) one Braf allele, that upon Cre-mediated recombination gives a Braf V600E mutant allele (details below), and 4) the combination of both the Cdx2 alleles and the BrafV600E allele. All four of those groups also had a CDX2P-CreERT2 transgene that expresses Cre recombinase fused to a tamoxifen-regulated fragment of the estrogen receptor ligand binding domain. CreERT2 expression occurs only in tissues where the Cdx2 gene is expressed, which is almost exclusively in adult mouse cecum and colon epithelium. A fifth group of mice had the floxed Cdx2 alleles, but no CDX2P-CreERT2 gene. Treating the mice having CDX2P-CreERT2 with tamoxifen permits the Cre recombinase to enter the cell nucleus and recombine the Apc, Braf, and/or Cdx2 alleles containing loxP sequence elements. Mice were treated with intraperitoneal injection of tamoxifen dissolved in corn oil. Three mice per group were used. The control mice did not develop tumors or any morphological or histological changes in their epithelium, but their colons were used to create the 3 control samples. To obtain the BrafV600E allele we used a genetically engineered mouse line previously described by Dankort et al. (Genes Dev 2007, 21:379-84) that can express the BrafV600E mutant protein following Cre-mediated recombination. The Braf(CA) (Braf-Cre-activated) allele mice carry a gene-targeted allele of Braf, where Braf sequences from exons 15-18 are present in the normal mouse Braf intron 14, followed by a mutated exon 15 (carrying the V600E mutation). The exon 15-18 sequence element is flanked by loxP sites. In the absence of Cre-mediated recombination, the Braf(CA) allele expresses a wild type Braf protein. Following Cre-mediated recombination, the Braf exon 15-18 element is removed, and the Braf(CA) allele then encodes the Braf V600E protein (from the introduced mutated exon 15). RNA was purified from tumor or normal tissue, and targets for Affymetrix arrays were synthesized from the mRNAs. We used Affymetrix Mouse Gene 2.1 ST arrays, which hold 41345 probe-sets, but we largely analyzed just those 25216 probe-sets that were mapped to Entrez gene IDs. Raw data was processed with the Robust Multi-array Average algorithm (RMA). Data is log2-transformed transcript abundance estimates. We fit a one-way ANOVA model to the five groups of samples. We supply a supplementary excel workbook that holds the same data as the data matrix file, but also holds the probe-set annotation at the time we analyzed the data, and some simple statistical calculations, which selects subsets of the probe-sets as differentially expressed between pairs of groups, as well as significant Cdx2-/- by Braf V600E interactions. It also gives the homologous human gene IDs we used for enrichment testing, which were 1-to-1 best homologs according to build 68 of NCBI's Homologene. A second supplementary sheet shows the data we enrichment tested after collapsing to distinct human homologs, joins of the results of tests with GSE4045 data and of tests with TCGA data to the mouse genes, and the intersections of selected genes in those data set with our gene selections in mouse. Consumers should consider obtaining more up-to-date probe-set annotation for the array platform.
BRAF<sup>V600E</sup> cooperates with CDX2 inactivation to promote serrated colorectal tumorigenesis.
Sex, Treatment
View SamplesThis study compares cardiac induction time-courses using (i) wild-type hESCs subjected to a standard directed differentiation protocol, (ii) EOMES knockout hESCs subjected to the same protocol, and (iii) EOMES KO / TET-ON hESCs subjected to a TET-ON protocol.
Cardiogenic programming of human pluripotent stem cells by dose-controlled activation of EOMES.
Cell line, Time
View SamplesHuman ES cells respond to activation of the BMP and WNT signaling by upregulating target genes. A 4h time-point following signaling factor stimulation was chosen to reveal immediate-early induced genes which are likely to be direct targets.
Cardiogenic programming of human pluripotent stem cells by dose-controlled activation of EOMES.
Cell line, Treatment, Time
View SamplesCurrently there is a lack of effective therapies which result in long-term durable response for patients presenting with advanced and metastatic clear cell renal cell carcinoma (ccRCC). This is due in part to a lack of molecular factors which can be targeted pharmacologically. In order to identify novel tumor-specific targets, we performed high throughput gene array analysis screening numerous patient ccRCC tumor tissues across all stages of disease, and compared their gene expression levels to matched normal kidney. Our results identify a number of genes which demonstrate tumor-specific overexpression, and may present as novel targets for therapy.
Neuronal pentraxin 2 supports clear cell renal cell carcinoma by activating the AMPA-selective glutamate receptor-4.
Specimen part
View SamplesThis study compares directed cardiac differentiation time-courses using (i) HuES6 cells with endogenous ISL1 knockout + inducible ISL1 transgene, and (ii) wild-type HuES6 cells.
Revised roles of ISL1 in a hES cell-based model of human heart chamber specification.
Specimen part, Time
View SamplesIn pluripotential reprogramming, a pluripotent state is established within somatic cells. In this study, we have generated induced pluripotent stem (iPS) cells from bi-maternal (uniparental) parthenogenetic neural stem cells (pNSCs) by transduction with four (Oct4, Klf4, Sox2, and c-Myc) or two (Oct4 and Klf4) transcription factors. The parthenogenetic iPS (piPS) cells directly reprogrammed from pNSCs were able to generate germline-competent himeras, and hierarchical clustering analysis showed that piPS cells were clustered more closer to parthenogenetic ES cells than normal female ES cells. Interestingly, piPS cells showed loss of parthenogenetic-specific imprinting patterns of donor cells. Microarray data also showed that the maternally imprinted genes, which were not expressed in pNSCs, were upregulated in piPS cells, indicating that pluripotential reprogramming lead to induce loss of imprinting as well as re-establishment of various features of pluripotent cells in parthenogenetic somatic cells.
Generation of parthenogenetic induced pluripotent stem cells from parthenogenetic neural stem cells.
Sex, Specimen part
View SamplesThe plasticity of ageing suggests that longevity may be controlled epigenetically by specific alterations in chromatin state. The link between chromatin and ageing has mostly focused on histone deacetylation by the Sir2 family1, 2, but less is known about the role of other histone modifications in longevity. Histone methylation has a crucial role in development and in maintaining stem cell pluripotency in mammals3. Regulators of histone methylation have been associated with ageing in worms4, 5, 6, 7 and flies8, but characterization of their role and mechanism of action has been limited. Here we identify the ASH-2 trithorax complex9, which trimethylates histone H3 at lysine 4 (H3K4), as a regulator of lifespan in Caenorhabditis elegans in a directed RNA interference (RNAi) screen in fertile worms. Deficiencies in members of the ASH-2 complexASH-2 itself, WDR-5 and the H3K4 methyltransferase SET-2extend worm lifespan. Conversely, the H3K4 demethylase RBR-2 is required for normal lifespan, consistent with the idea that an excess of H3K4 trimethylationa mark associated with active chromatinis detrimental for longevity. Lifespan extension induced by ASH-2 complex deficiency requires the presence of an intact adult germline and the continuous production of mature eggs. ASH-2 and RBR-2 act in the germline, at least in part, to regulate lifespan and to control a set of genes involved in lifespan determination. These results indicate that the longevity of the soma is regulated by an H3K4 methyltransferase/demethylase complex acting in the C. elegans germline.
Members of the H3K4 trimethylation complex regulate lifespan in a germline-dependent manner in C. elegans.
Treatment
View Samples