Project description:To study the composition of mRNPs containing TcDhh1, we carried out immunoprecipitation assays with anti-TcDhh1 and epimastigotes lysates. Pre-immune serum was used as control. We also carried out a ribonomic approach to identify the mRNAs present within the TcDhh1 immunoprecipitated complexes. For this purpose, competitive microarray hibridizations were performed against negative controls, the non-precipitated fraction.
Project description:Evaluation of differential gene expression during the metacyclogenesis process in Trypanosoma cruzi, comparing three stages (epimastigotes, stressed epimastigotes and 24h adhered epimastigotes in differentiation) and using both total and polysomal mRNA.
Project description:Using the Deep Seq transcriptome sequencing we characterized the heme induced transcriptome of epimastigotes and determined that most of the upregulated genes were related to glucose metabolism inside the glycosomes.
Project description:Sub2, part of the mRNA QC system, was knocked down using RNAi. Total RNA was extracted and sequenced at BGI at three timepoints; zero, 24 and 48 hours post induction.
Project description:T. cruzi epimastigotes in the logarithmic growth phase (3×106 cells mL-1) were incubated for 12h with bortezomib (1.8 µM), GNF6702 (2.9 µM) or compound 1 (24 µM), equivalent to 8× the EC50 values of each compound. Controls were incubated in the presence of diluent (DMSO). Cells were harvested by centrifugation (1912g, 15 min, 4 °C) and washed with ice-cold PBS (1912g, 5 min, 4 °C), and finally, the cell pellets were resuspended in 1.5 mL of ice-cold lysis buffer (1 mM EDTA, 1 mM DTT, 100 μM TLCK, and 1× Roche EDTA-free cOmplete protease inhibitor cocktail in 50 mM potassium phosphate buffer, pH 7.4). Cell suspensions were submitted to 3 freeze–thaw cycles in a dry ice/ethanol bath to biologically inactivate the parasites and then lysed using the One ShotTM Cell disruptor (Constant Systems, UK) at 30 kpsi.
Project description:We investigated the composition of chromatin protein network around endogenous androgen receptor (AR) in VCaP castration resistant prostate cancer cells using recently developed chromatin-directed proteomic approach called ChIP-SICAP . The androgen-induced AR chromatin protein network contained expected TFs, e.g. HOXB13, chromatin remodeling proteins, e.g. SMARCA4, and several novel candidates not previously associated with AR, e.g. prostate cancer biomarker SIM2. Based on these findings, the role of SMARCA4 and SIM2 was further characterized at AR chromatin domains . Silencing of SIM2 altered chromatin accessibility at a similar number of AR-binding sites as SMARCA4, an established ATPase subunit of the BAF chromatin remodeling complex, often aberrantly expressed in prostate cancer. Despite the wide co-occurrence on chromatin of SMARCA4 and AR, depletion of SMARCA4 influenced chromatin accessibility and expression of a restricted set of AR target genes, in particular those involved in cell morphogenetic changes in epithelial-mesenchymal transition. Silencing of SIM2, in turn, affected the expression of a much larger group of androgen-regulated genes, e.g. those involved in cellular responses to external stimuli and steroid hormone stimulus. The silencing also reduced proliferation of VCaP cells and tumor size in chick embryo chorioallantoic membrane assay, further suggesting the importance of SIM2 in the regulation prostate cancer cells.
Project description:Background: The platinum compounds cisplatin and carboplatin are the mainstay of chemotherapy for lung cancer; however, treatment failure remains a critical issue since about 60% of all non-small cell lung cancer (NSCLC) patients display intrinsic platinum resistance. Methods: We analyzed global gene expression profiles in NSCLC clones surviving a pulse treatment with cisplatin by microarray and mapped deregulated signaling networks in silico by Ingenuity Pathway Analysis (IPA). Results: Cisplatin-surviving NSCLC clones were demonstrated to have heterogeneous gene expression patterns both in terms of the number and the identity of the altered genes. Genes involved in Wnt signaling pathway (DKK1), DNA repair machinery (XRCC2) and cell-cell/ cell-matrix interaction (FMN1 and LGALS9) were among the top deregulated genes by microarray and were subsequently validated by q-RT-PCR. We focused on DKK1, which was previously reported to be overexpressed in NSCLC. IPA network analysis revealed coordinate up-regulation of several DKK1 transcriptional regulators (TCF4, EZH2, DNAJB6 and HDAC2) in cisplatin-surviving clones. Knockdown of DKK1 by siRNA sensitized untreated NSCLC cells to cisplatin, illustrating a putative role of DKK1 in intrinsic platinum resistance. Conclusions: Gene expression analysis identified DKK1 as a putative cisplatin resistance marker and a potential novel therapeutic target to overcome platinum resistance in NSCLC. U1810 cells were sparsely seeded for clonogenic survival assay in three separate experiments (replicate 1-3), left untreated or treated with cisplatin for 1 h and then kept for 9 days to assay long-term effects of a single pulse treatment.
Project description:The structure of chromatin is critical for many aspects of cellular physiology and is considered to be the primary medium to store epigenetic information. It is defined by the histone molecules that constitute the nucleosome, the positioning of the nucleosomes along the DNA and the non-histone proteins that associate with it. These factors help to establish and maintain a largely DNA sequence-independent but surprisingly stable structure. Chromatin is extensively disassembled and reassembled during DNA replication, repair, recombination or transcription in order to allow the necessary factors to gain access to their substrate. Despite such constant interference with chromatin structure, the epigenetic information is generally well maintained. Surprisingly, the mechanisms that coordinate chromatin assembly and ensure proper assembly are not particularly well understood. Here, we use SWATH-MS to describe the kinetics of in vitro assembled chromatin supported by an embryo extract prepared from preblastoderm Drosophila melanogaster embryos. This system allows easy manipulation of distinct aspects of chromatin assembly such as post-translational histone modifications, the levels of histone chaperones and the concentration of distinct DNA binding factors. Our findings support the idea that chromatin assembly factors and factors important for chromatin structure bind chromatin in an ordered manner, which is -at least in part- regulated by histone deacetylation. We are able to identify functional clusters of proteins based on their different binding kinetics. Whereas many proteins bind exclusively during the onset of chromatin assembly, a few proteins show a clear tendency towards matured chromatin.
Project description:Organoid technology provides the possibility to culture human colontissue and patient-derived colorectal cancers (CRC) while maintainingall functional and phenotypic characteristics. Labeling of human colonstem cells (CoSCs), especially in normal and benign tumor organoids, ischallenging and therefore limits usability of multi-patient organoidlibraries for CoSC research. Here, we developed STAR (STem cell Ascl2Reporter), a minimal enhancer/promoter element that reportstranscriptional activity of ASCL2, a master regulator of LGR5+ CoSCfate. Among others via lentiviral infection, STAR minigene labels stemcells in normal as well as in multiple engineered and patient-derivedCRC organoids of different stage and genetic make-up. STAR revealed thatstem cell driven differentiation hierarchies and the capacity of cellfate plasticity (de-differentiation) are present at all stages of humanCRC development. The flexible and user-friendly nature of STARapplications in combination with organoid technology will facilitatebasic research on human adult stem cell biology.