Project description:We developed a system to study the DNA replication-independent turnover nucleosomes containing the histone variant H3.3 in mammalian cells. By measuring the genome-wide incorporation of H3.3 at different time points following epitope-tagged H3.3 expression, we find three categories of H3.3-nucleosome turnover in vivo: rapid turnover, intermediate turnover and, specifically at telomeres, slow turnover. Our data indicate that H3.3-containing nucleosomes at enhancers and promoters undergo a rapid turnover that is associated with active histone modification marks including H3K4me1, H3K4me3, H3K9ac, H3K27ac and the histone variant H2A.Z. The rate of turnover is negatively correlated with H3K27me3 at regulatory regions and with H3K36me3 at gene bodies. Examination of incorporation dynamics of histone variant H3.3
Project description:Purpose: We identified KPC1 as the ubiquitin ligase that binds to the p105 precursor of NF-kB, ubiquitinates it and mediates its proteasomal processing to generate the p50 active subunit of the transcription factor. Using U87-MG human glioblastoma xenografts, we observed that overexpression of KPC1 results in strong inhibition of tumor growth mediated via excessive generation of p50.The goal of this RNASeq study was to analyze the profile of gene expression in xenografts overexpressing control (V0), KPC1 or p50 vectors, and to further understand how the altered gene expression patterns can explain the tumor suppressive effect we observed. Results:Transcript analysis of U87-MG xenografts overexpressing control (V0), KPC1 or p50 vector mapped to the human genome revealed: • A strong similarity between overexpression of p50 and KPC1 (correlation of 0.51, p-value<10-300 ) • A specific signature of NF-kB targets [21 of the consistently changed genes are known to be regulated by NF-kB (p-value<3.4×10-9 )] • A significant (p-value<1.4×10-18) increase in the expression of 40 tumor suppressor genes, with no significant change in other classes. • A significant down regulation of a cluster of genes including LIN28B, IL-6, HMAGA2 and VEGFA. This finding links well to an established regulatory axis involving LIN28B, Let-7 microRNA, and IL-6 in inflammation and cell transformation that is regulated by NF-kB. Exponentially growing U87-MG cells were stably transfected with an empty vector (V0) or vectors coding for Myc-KPC1 or Flag-p50. Cells were dissociated with trypsin, washed with PBS, and brought to a concentration of 50×10^6 cells/ml. Cell suspension (5×10^6/0.1 ml) was inoculated subcutaneously at the right flank of 7-weeks old male Balb/C nude mice (n=7). Following 21 days, mRNA from U87-MG xenografts was isolated using an RNA purification kit, and analyzed using the Illumina HiSeq 2500 sequencer. The RNASeq analysis experiment was repeated twice independently. Run1 included a total of 7 samples. Samples 1-3 were isolated from V0 – control tumors (3 different tumors), samples 4-5 were isolated from KPC1-expressing tumors (2 different pools of 3 tumors each due to small tumor size), and samples 6-7 were isolated from p50-expressing tumors for (2 different pools of 2-3 tumors each, due to very small tumor size). Run2 included a total of 5 samples. Samples 8-10 were isolated from V0 (control) tumors (3 different tumors), samples 11-12 were isolated from KPC1 tumors (2 different pools of 3 tumors each due to small tumor size). Several repeated attempts to extract RNA from the p50-expressing tumors did not yield any results, as the tumors were miniscule.
Project description:We used microarrays to detail the global gene expression in stably transfected HEK 293T cells of the over-expression of truncated FMRP containing 295 amino acid residues, which were compared with control (stably transfected HEK 293T cells of empty lentiviral vector (pLEX-MCS). Stably transfected HEK 293T cells of empty lentiviral vector (pLEX-MCS) and the over-expression of truncated FMRP were for RNA extraction and hybridization on Affymetrix microarrays.
Project description:A non-functional myosin Vb motor in duodenal enterocytes results in disruption of epithelial cell polarity characterized by complete loss of microvilli and mislocalization of apical brush border proteins in the cytoplasm which finally cause a devastating disease in neonates with severe malabsorption defects accompanied by protracted diarrhea during infancy, classified as microvillus inclusion disease (MVID). The exact mechanisms how loss-of-function of MYO5B induces polarity loss are not completely understood in MVID pathogenesis. Obtaining better insights in cell polarity defects caused by loss of MYO5B, we performed microarray- in combination with protein expression-analysis in an inducible CaCo2 MYO5B RNAi cell system. Surprisingly, in MYO5B-depleted CaCo2 cells, CDH1 coding for the cell adhesion protein E-Cadherin and important for cell adhesion and therefore maintenance of cell polarity, was significantly downregulated. Interestingly, mesenchymal cell markers, specifically Vimentin and N-Cadherin, physiologically not expressed in differentiated epithelium, were upregulated and accompanied by increased phospho-c-jun levels in the nucleus. Importantly phospho-c-jun was also found in nuclei of duodenal enterocytes in MVID patients, indicating loss of MYO5B induces epithelial cell scattering in enterocytes. 3 Myosin 5B KD versus 3 control samples
Project description:Here we performed a microarray experiment on samples of adherent cultures of Human Glioblastoma Cancer Stem Like Cells (NCH421K cell line) expressing a shRNA targeting the transcription factor ZEB1 (shZEB1) or a control shRNA targeting GFP 72 hours after lentiviral infection. This resulted in the generation of a genome-wide mRNA expression pattern and quantification for these cells in the two conditions.
Project description:mRNA expression profile modified by stable transfection of microRNA mir-517a (MIR517A) in a human hepatocellular carcinoma cell line Huh-7 Keywords: Hepatocellular carcinoma, Expression array, microRNA microRNA mir-517a (MIR517A) was transfected to Huh-7 cells using GFP-expressing lentiviral vector. Infected cells were selected using flow cytometry and subjected to mRNA expression microarray experiment. The profiles were compared to controls cells infected with only GFP protein.
Project description:E2F transcription factors are central regulators of cell cycle progression and cell fate decisions in mammalian cells. E2F4 is a transcriptional repressor implicated in cell cycle arrest and whose repressive activity depends on its interaction with members of the RB family. E2F4 often represents the predominant E2F activity in cells. Here we show that E2F4 is important for the proliferation and the survival of mouse embryonic stem cells. In these cells, E2F4 acts in part as a transcriptional activator that promotes the expression of cell cycle genes. Importantly, this role for E2F4 is completely independent of the RB family. Accordingly, an unbiased analysis of the E2F4 interactome shows that E2F4 functionally interacts with chromatin regulators associated with gene activation in RB family-mutant cells. Taken together, our findings uncover a non-canonical role for E2F4 that reveal novel insights into the biology of rapidly dividing cell types.
Project description:Oral squamous cell carcinoma cell line Cal27 was transfected with lentiviral shIL-1beta or scrambled shRNA. We used microarrays to detail the global program of gene expression during this process. IL-1beta was identified as one of the key node genes in oral carainogenesis in our preveious in vitro study. This in vivo study was designed to confirm the role of IL-1 beta and explore some more detail about the evolvment of IL-1 in malignant transformation.