Project description:Polycomb-mediated gene repression plays an important role in adult stem cell maintenance. We knocked out (using the inducible AhCre-LoxP system) Polycomb genes Eed and Ezh2 in the intestine for 6 weeks, after which crypts - the small intestinal stem cell zone - were harvested and RNA sequenced. We found Wnt, Notch and cell cycle pathways to be affected in Eed knockout (KO) but not Ezh2 KO crypts. Direct targets of Eed were determined by comparing this data with ChIP-sequencing.
Project description:Polycomb-mediated gene repression plays an important role in adult stem cell maintenance. We knocked out (using the inducible AhCre-LoxP system) Polycomb genes Eed and Ezh2 in the intestine for 6 weeks, after which crypts - the small intestinal stem cell zone - were harvested and RNA sequenced. We found Wnt, Notch and cell cycle pathways to be affected in Eed knockout (KO) but not Ezh2 KO crypts. Direct targets of Eed were determined by comparing this data with ChIP-sequencing. Small intestinal crypt mRNA profiles of 6 weeks-induced 12 weeks old Eed KO, Ezh2 KO and WT mice (all triplicates) as well as 10 days-induced Eed KO and WT organoids (duplicates) were generated by RNA sequencing over two runs and using IlluminaHiseq2000 and Hiseq2500.
Project description:Purpose: We aimed to investigate the effect of several anti-leukemia drugs in combination with decitabine (DAC) on the proliferation of myeloid leukemia cells in vitro and in vivo, to select the most efficient combination group and explore associated mechanisms of these combination therapies. Experimental Design: After comparing with five anti-leukemia drugs in several different kinds of cell lines, the combination effect of idarubicin (IDA) with DAC was best. In vivo, by using microPET, TUNEL, and transmission electron microscopy, the inhibitory effects obtained by sequentially combining DAC with IDA, evidenced by evaluating tumor cell proliferation and cell apoptosis. Molecular studies were conducted using gene chip, which was used to explore associated pathways, and real-time quantitative reverse transcription-PCR, western blot and immunohistochemistry (IHC), used to assess regulation of Wnt/β-catenin pathway. Results: The sequential combination of DAC and IDA showed synergistic induction of cell death in U937, HEL, SKM-1 and cells isolated from AML patients. Importantly, the inhibition of tumor growth in the sequential combination group was found to be significantly higher than that of single drug group or control group in vivo. Moreover, sequential treatment with DAC and IDA induced apoptosis and depression of the Wnt/β-catenin pathway in both culture and animal studies. Conclusions: Our findings showed that sequentially combining decitabine with idarubicin had a synergistic anti-leukemia effect. These findings were attributed to demethylation of Wnt pathway inhibitors and downregulation of Wnt pathway nuclear targets observed in vitro and in vivo. After comparing with five anti-leukemia drugs in several different kinds of cell lines, the combination effect of idarubicin (IDA) with DAC was best. In vivo, by using microPET, TUNEL, and transmission electron microscopy, the inhibitory effects obtained by sequentially combining DAC with IDA, evidenced by evaluating tumor cell proliferation and cell apoptosis. Molecular studies were conducted using gene chip, which was used to explore associated pathways, and real-time quantitative reverse transcription-PCR, western blot and immunohistochemistry (IHC), used to assess regulation of Wnt/β-catenin pathway.
Project description:Approximately 60-70% of patients with 22q11.2 deletion syndrome (22q11.2DS; velo-cardio-facial syndrome/DiGeorge syndrome) have cardiac outflow tract anomalies including persistent truncus arteriosus (PTA) as the most severe defect. Among the genes in the 22q11.2 region, TBX1, encoding a T-box transcription factor is a major candidate for cardiovascular malformations and its inactivation in mice results in a PTA. To identify novel signaling mechanisms that function downstream, we found that Tbx1 restricts canonical Wnt signaling in the pharyngeal apparatus. To test for tissue specificity within the pharyngeal apparatus, we inactivated Tbx1 in the anterior portion of the secondary heart field (AHF) mesoderm using the Mef2c-AHF-Cre allele and observed a full penetrant PTA (n = 30). Tbx1 promotes progenitor cells but restricts differentiation whereas Wnt signaling, in the AHF, promotes cardiomyocyte differentiation. To determine whether Tbx1 and canonical Wnt signaling act in opposing pathways, both alleles of Tbx1 and one β-catenin allele were inactivated in the AHF and 85% of them (n = 35) showed partial or complete rescue. The antagonistic function of the two pathways was further confirmed by gene expression profiling, indicating that these two pathways provide a key balance in the AHF to prevent premature differentiation of progenitor cells prior to reaching the cardiac outflow tract. We inactivatedTbx1 and beta-catenin allele to identify function of Tbx1 and beta-catenin in the anterior portion of the secondary heart field (AHF) mesoderm. We also inactivated both alleles of Tbx1 and one β-catenin alleles (rescue design) to determine whether Tbx1 and canonical Wnt signaling act in opposing pathways
Project description:During animal development, signals determine and organize a vast number of complex tissues using a very small number of signal transduction pathways. These developmental signaling pathways determine cell fates through a coordinated transcriptional response that remains poorly understood. The Wnt pathway is involved in a variety of these cellular functions, and its signals are transmitted in part through a β-catenin/TCF transcriptional complex. Here we report an in vivo Drosophila assay that we used to distinguish between activation, de-repression and repression of transcriptional responses, separating upstream and downstream pathway activation and canonical/non-canonical Wnt signals in embryos. We find a specific set of genes downstream of both β-catenin and TCF with an additional group of genes regulated by Wnt. The non-canonical Wnt4 regulates a separate cohort of genes. We correlate transcriptional changes with phenotypic outcomes of cell differentiation and embryo size, showing our model can be used to characterize developmental signaling compartmentalization in vivo.
Project description:The Wnt/β-catenin signaling pathway plays crucial roles in nearly all parts of embryonic development and adult stem cell homeostasis. Its aberrant activation has been linked to many diseases such as developmental irregularities and various severe forms of cancer, with colorectal cancer (CRC) as a prime example. While much work has been dedicated to uncovering effective therapeutics to block oncogenic Wnt signaling, such interventions have not proven trivial because of the broad activity of Wnt throughout the adult body and the difficulty in finding suitable molecular targets. We have previously identified the developmental transcription factor TBX3 as a participant of the Wnt-mediated transcriptional regulation. Here, we performed Cap-Analysis Gene Expression sequencing (CAGE-seq) to assess the genome-wide transcriptional consequences upon TBX3 overexpression in the human colorectal cancer cell line HCT116.
Project description:The MS data of Protein Lysine 43 Methylation by EZH1 Promotes AML1-ETO Transcriptional Repression Protein Lysine 43 Methylation by EZH1 Promotes AML1-ETO Transcriptional Repression
Project description:Wnt/β-catenin signaling is a highly organized biochemical cascade that triggers a gene expression program in the signal-receiving cell. The Wnt/β-catenin-driven transcriptional response is involved in virtually all cellular processes during development, homeostasis, and its deregulation causes human disease. However, outstanding questions remain unanswered. Here, we combined RNA sequencing with CUT&RUN-LoV-U against β-catenin to assess the correlation between β-catenin recruitment to target loci and its effect on target gene expression. To this end, we performed a bulk RNA sequencing analysis on human embryonic stem cells (hESCs) treated with the the GSK3 inhibitor/Wnt activator CHIR99021 (10 mM) for 3 days, and compared them to untreated hESCs. We then correlated the observed gene expression changes with β-catenin binding events identified from a separate experiment (see “Related Accession Number”). We observed that β-catenin binding is associated with both activation and repression of cell-specific gene expression programs, underscoring how Wnt/b-catenin drives complex cell behaviors.