Project description:total RNAs were extracted from a canine oral malignant melanoma clinical sample (name as 3) and paired normal oral mucosa (name as 3prime) according to the phenol/guanidium thiocyanate method with DNase â treatment. these total RNA were submitted to Filgen, Inc. to perform microRNA microarray.
Project description:Studying a unique case of metastatic melanoma, we observed that cell lines derived from metachronous metastases arising over a decade retained a central core of genetic stability in spite of divergent phenotypes. In the present study we expanded our previous observations comparing these autologous cell lines of clonal derivation with heterologous ones and correlated array Comparative Genomic Hybridization with gene expression profiling to determine their relative contribution to the dynamics of disease progression. aCGH and gene expression profiling were performed on autologous cell lines and heterologous melanoma cell lines originated from other patients. A striking correlation existed between total extent of genetic imbalances, global transcriptional patterns and cellular phenotypes; they did not follow a strict temporal progression but stemmed independently at various time points from a central core of genetic stability best explained according to the cancer stem cell hypothesis; although their contribution was intertwined, genomic imbalances detectable by aCGH contributed only 25% of the transcriptional traits determining autologous tumors distinctiveness. Our study provides important insights about the dynamics of cancer progression and supports the development of targeted anti-cancer therapies against stable genetic factors determining the individuality of each patientâs disease that are maintained throughout the end stage of disease. Keywords: genetic modification design We report the analysis of gene expression profiling of melanoma cell lines obtained from metastsases of a long term survivor melanoma patient and other melanoma cell lines. RNA was amplified and hybridized to 17.5K cDNA arrays.
Project description:Mobilized-peripheral blood hematopoietic stem cells (HSCs) have been used for transplantation, immunotherapy, and cardiovascular regenerative medicine. Agents used for HPC mobilization include G-CSF and the CXCR4 inhibitor AMD3100. The HSCs cells mobilized by each agent may contain different subtypes and have different functions. To characterize mobilized HSCs used for clinical applications, microRNA (miRNA) profiling and gene expression profiling were used to compare AMD3100-mobilized CD133+ cells from 4 subjects, AMD3100 plus G-CSF-mobilized CD133+ cells from 4 subjects and G-CSF-mobilized CD34+ cells from 5 subjects. The HSCs were compared to peripheral blood leukocytes (PBLs) from 7 subjects. Keywords: cell type comparison design gene expression profiling were used to compare AMD3100-mobilized CD133+ cells from 4 subjects, AMD3100 plus G-CSF-mobilized CD133+ cells from 4 subjects and G-CSF-mobilized CD34+ cells from 5 subjects. The HSCs were compared to peripheral blood leukocytes (PBLs) from 7 subjects.
Project description:Active genes on the X chromosome of Drosophila males are upregulated by the Male-specific lethal (MSL) complex containing five MSL proteins and two non-coding roX RNAs. To probe the targeting mechanism, we have solved the structure of the MSL3 chromodomain, designed point mutations in key residues that disrupt putative methyl-lysine recognition, and tested their effect on full length MSL3 function. Transgenic males expressing these site-directed point mutants or MSL3short, a naturally occurring MSL3 form lacking the chromodomain, are unhealthy and developmentally delayed. Genomewide analyses of the binding patterns of these mutants support a two-step model: the first step is chromodomain-independent association with “chromatin entry sites” carrying GA-rich MSL recognition elements (MREs). The second step involves spreading from entry sites to the majority of active genes on the X. Either deleting or introducing point mutations in the MSL3 chromodomain disrupts this second step. In vitro studies demonstrate that chromodomain mutants have diminished interaction with recombinant nucleosomes methylated at H3K36. We propose that MSL spreading depends, to a large extent, on the integrity of the MSL3 chromodomain to interact with lysine-methylated nucleosomes. Chromatin immunoprecipitation using TAP-tag was performed as described previously (Alekseyenko et al., 2006). The immunoprecipitated material was eluted from the beads by adding 10 ?L (100 U) of AcTEV protease into 450 ?L of TEV buffer followed by incubation at 25°C for 1 h. To reverse the cross-links, samples were brought to 0.3M NaCl and 1% SDS and incubated at 65°C for 12 h. The samples were then extracted with phenol/chloroform/isoamyl alcohol followed by chloroform, and precipitated by ethanol in the presence of glycogen. The resulting precipitated DNA and the input DNA were amplified using a DNA linker as described (Strutt et al., 1997). LM-PCR (25 cycles) was performed using Platinum Pfu (Invitrogen). The resulting DNA was labeled and hybridized to arrays by NimbleGen Systems, Inc. Two-channel tiling arrays containing 388,000 probes were designed based on FlyBase 3.2. Chromosomes X and 19.6Mb of 2L were covered. The ChIP sample of interest was hybridized on one channel and genomic DNA was used as the reference on the other channel. Each ChIP-chip experiment was performed in duplicate.
Project description:In Drosophila, X chromosome dosage compensation requires the male-specific lethal (MSL) complex, which associates with actively transcribed genes on the single male X chromosome to upregulate transcription approximately 2-fold. We found that on the male X chromosome, or when MSL complex is ectopically localized to an autosome, histone H3K36 trimethylation (H3K36me3) is a strong predictor of MSL binding. We isolated mutants lacking Set2, the H3K36me3 methyltransferase, and found that Set2 is an essential gene in both sexes of Drosophila. In set2 mutant males, MSL complex maintains X specificity but exhibits reduced binding to target genes. Furthermore, recombinant MSL3 protein preferentially binds nucleosomes marked by H3K36me3 in vitro. Our results support a model in which MSL complex uses high-affinity sites to initially recognize the X chromosome and then associates with many of its targets through sequence-independent features of transcribed genes. Keywords: ChIP-chip ChIP-chip experiments were performed on custom Nimblegen arrays (GPL5636). Each array contained 388,000 oligonucleotide probes covering all of the X and the 2L chromosomes, with a 100 bp resolution (50mer probes with 50 bp gaps). The design was based on FlyBase 3.2. For the superspreading experiments, an additional array was used that contains the entire X chromosome and 3R (GPL5660). MSL complex binding sites on both arrays are the same and signal on the 3R chromosome was at background level.
Project description:The Drosophila MSL complex mediates dosage compensation by increasing transcription of the single X chromosome in males approximately two-fold. This is accomplished through recognition of the X chromosome and subsequent acetylation of histone H4K16 on X-linked genes. Initial binding to the X is thought to occur at a subset of sites. However, the consensus sequence motif of entry sites (M-bM-^@M-^\MSL recognition elementM-bM-^@M-^] or MRE) is only slightly enriched on the X (~2 fold), and only a fraction of them is utilized by the MSL complex. Here we ask whether chromatin context could distinguish between utilized and non-utilized copies of the motif, by comparing their relative enrichment for histone modifications and chromosomal proteins mapped in the NHGRI modENCODE project. Through a comparative analysis of the chromatin features in male S2 cells, which contain MSL complex, and female Kc cells, which lack the complex, we find that the presence of active chromatin modifications, together with an elevated local GC content in surrounding sequence, has strong predictive value for functional MSL entry sites, independent of MSL binding. We tested these sites for function in Kc cells by RNAi knockdown of Sxl, resulting in induction of MSL complex. We show that ectopic MSL expression in Kc cells leads to H4K16 acetylation around these sites, and a relative increase in X chromosome transcription. Collectively, our results support a model in which a pre-existing active chromatin environment, coincident with H3K36me3, contributes to MSL entry site selection. The consequences of MSL targeting of the male X chromosome include increase in nucleosome lability, enrichment for H4K16 acetylation and JIL-1 kinase, and depletion of linker histone H1 on active X-linked genes. Our finding serves as a model to understand how chromatin and local sequence features are involved in the selection of functional protein binding sites in the genome. The key Drosophila female sex determinant protein, SXL, represses dosage compensation by inhibiting MSL2 translation. Loss of SXL results in the expression, stabilization, and targetting of the MSL complex in female cells. Therefore, depletion of SXL by RNA interference (RNAi) in female Kc cells will lead to a MSL2-dependent increase in transcription from the female X chromosomes, consistent with the induction of dosage compensation. In this experiment, we generated ChIP-chip profiles of H4K16 acetylation (H4K16ac) in Kc cells of control (GFP) and Sxl RNAi. For ChIP, we used Upstate (now Millipore) anti-H4K16ac antibody, catalog # 07-329, lot #JBC1355376.
Project description:Human embryonic stem (hES) cells have unique features: self-renewal ability and pluripotency. They can be continuously cultured in undifferentiated state and give rise to cells and tissues of all three germ layers. Thus hES cells provide a resource not only for cell replacement therapy but also for studying human developmental biology. However, much work needs to be done to understand the molecular mechanisms responsible for the maintenance of the undifferentiatiation state and the differentiation process of human embryonic stem cells. Keywords: cell type comparison design We performed gene expression profiling on 3 separate passages from 3 different hES cell lines (WA09 (H9), TE06 (I6) and BG01v), EBs samples derived from WA09 cells at 3 different time points, and 5 types of adult cells (HUVEC, HMVEC, UASMC NHA, and LFB).
Project description:We describe here transcripts induced after intraperitoneal injection of rainbow trout with 2 different viruses, both belonging to strain 23.75 of viral hemorrhagic septicemia virus (VHSV): a deleted Nv gene (dNV) virus and a wild type (wt) virus. Two days after infection, differentially expressed transcript levels from selected immune-related trout genes were studied in internal organs (spleen and head kidney). Fishes were divided in two groups (3 fishes per group). The first group was intraperitoneally injected with 100000 pfu per trout of dNV VHSV, while the second group was injected with 100000 pfu/trout of wt VHSV. All fishes were sacrificed two days post infection.