Tumors driven by activation of the transcription factor Myc generally show oncogene addiction. However, the gene-expression programs that depend upon sustained Myc activity in those tumors remain unknown. We have addressed this issue in a model of liver carcinoma driven by a reversible tet-Myc transgene, combining gene expression profiling with the mapping of Myc and RNA Polymerase II on chromatin. Switching off the oncogene in advanced carcinomas revealed that Myc is required for the continuous activation and repression of distinct sets of genes, constituting no more than half of those deregulated during tumor progression, and an even smaller subset of all Myc-bound genes. We further showed that a Myc mutant unable to associate with the co-repressor protein Miz1 is defective in the initiation of liver tumorigenesis. Altogether, our data provide the first detailed analysis of a Myc-dependent transcriptional program in a fully developed carcinoma, revealing that the critical effectors of Myc in tumor maintenance must be included within defined subsets (ca. 1,300 each) of activated and repressed genes. Overall design: RNAseq samples of control liver (n=11), tet-Myc tumors (n=16), tet-Myc tumors with short-term Myc inactivation (n=8), tet-MycVD tumors (n=11)
Identification of MYC-Dependent Transcriptional Programs in Oncogene-Addicted Liver Tumors.
Specimen part, Cell line, Subject
View SamplesThe role of on-CG methylation in seed development and dormancy remains unknown. There are four genes in charge of non-CG methylation in Arabidopsis: drm1, drm2, cmt2 and cmt3. The majority of non-CG methylation in vegetative tissues, leaf, is gone in homozygous ddcc mutant line (Hume et al., 2014). To uncover the possible role of non-CG DNA methylation in seed development and dormancy, we characterized the transcriptome of ddcc mutant in Arabidopsis post-mature green seeds using Illumina sequencing. Meanwhile, post-mature green seeds from wild type were used as control. Overall design: Illumina sequencing of transcripts from post-mature green seeds of ddcc mutant and wild type. Two biological replicates were collected.
Similarity between soybean and <i>Arabidopsis</i> seed methylomes and loss of non-CG methylation does not affect seed development.
Specimen part, Subject
View SamplesDetailed analysis comparing hiPSC lines that were newly generated and compared them to already established hiPSC lines
Molecular analyses of human induced pluripotent stem cells and embryonic stem cells.
Specimen part, Cell line
View SamplesThe ATP-dependent DExH/D-box helicase DHX9 is a key participant in a number of gene regulatory steps, including transcriptional, translational, microRNA-mediated control, DNA replication, and maintenance of genomic stability. DHX9 has also been implicated in maintenance of the tumorigenic process and in drug response. Here, we report that inhibition of DHX9 expression is lethal to multiple human and mouse cancer cell lines. In contrast, using a novel conditional shDHX9 mouse model, we demonstrate that sustained and prolonged suppression of DHX9 is well tolerated at the organismal level. Our results demonstrate a robust tolerance for DHX9 knockdown in non-transformed cells and supports the targeting of DHX9 as an effective and specific chemotherapeutic approach.
Tumor cell survival dependence on the DHX9 DExH-box helicase.
Specimen part
View SamplesPost-traumatic stress disorder is a concerning psycho behavioral disorder thought to emerge from the complex interaction between genetic and environmental factors. For soldiers exposed to combat, the risk of developing this disorder is two-fold and diagnosis is often late, when much sequela has set in. To be able to identify and diagnose in advance those at “risk” of developing PTSD, would greatly taper the gap between late sequelae and treatment. Therefore, this study sought to test the hypothesis that the transcriptome can be used to track the development of PTSD in this unique and susceptible cohort of individuals. Gene expression levels in peripheral blood samples from 85 Canadian infantry soldiers (n = 58 subjects negative for PTSD symptoms and n = 27 subjects with PTSD symptoms) were determined by RNA sequencing technology following their return from deployment to Afghanistan. Count-based gene expression quantification, normalization and differential analysis (with thorough correction for confounders) revealed significant differences in two genes, LRP8 and GOLM1 . These preliminary results provide a proof-of-principle for the diagnostic utility of blood-based gene expression profiles for tracking symptoms of post-traumatic stress disorder in soldiers returning from tour. It is also the first to report transcriptome-wide expression profiles alongside a post-traumatic symptom checklist. Overall design: Peripheral blood samples from 85 Canadian infantry soldiers (n = 58 subjects negative for PTSD symptoms and n = 27 subjects with PTSD symptoms)
Using Next-Generation Sequencing Transcriptomics To Determine Markers of Post-traumatic Symptoms: Preliminary Findings from a Post-deployment Cohort of Soldiers.
Sex, Subject
View SamplesThe sensation of hunger after a period of fasting and the sensation of satiety after eating is crucial to behavioral regulation of food intake, but the biological mechanisms regulating these sensations are incompletely understood. We studied the behavioral and physiological adaptation to fasting in the vinegar fly (Drosophila melanogaster). Here we show that flies demonstrated increased behavioral attraction to food odor when food-deprived with no corresponding increase in sensitivity in the peripheral olfactory system. Flies increased their food intake transiently in the post-fasted state, but returned to a stable baseline feeding level within 24 hr after return to food. This modulation in feeding was accompanied by a significant increase in the size of the crop organ of the digestive system, suggesting that fasted flies responded both by increasing their food intake and storing reserve food in their crop. The post-fasting feeding response was observed in both male and female flies of diverse genetic backgrounds. Expression profiling of head, body, and chemosensory tissues by microarray analysis revealed several hundred genes that are regulated by feeding state, including 247 genes in the fly head. We performed RNA interference-mediated knockdown of, takeout, one of the genes strongly downregulated by fasting in multiple tissues. When takeout was knocked down in all neurons the post-fasting feeding response was abolished. These observations suggest that a coordinated transcriptional response to internal physiological state may regulate both ingestive behaviors and chemosensory perception of food
Post-fasting olfactory, transcriptional, and feeding responses in Drosophila.
Specimen part, Treatment, Time
View SamplesTranscriptome analysis of RNA extracted from human induced pluripotent stem cell (hipsc)-derived neurons exposed to botulinum neurotoxin type A1 (BoNT/A1) and an atoxic derivative, BoNT/A ad.
Analysis of gene expression in induced pluripotent stem cell-derived human neurons exposed to botulinum neurotoxin A subtype 1 and a type A atoxic derivative.
Specimen part
View SamplesPurpose: Communication between growth cones and their environment plays a central role in assembling neural circuits. We use Tandemly-Tagged Ribosome Affinity Purification (T-TRAP) of mRNA from R cells followed by RNA-seq for multiple time points during development to follow gene expression during target selection and synapse formation. Methods: We chose a ribosome trap method by modifying the N-terminus of the Drosophila ribosomal protein RpL10 with two tandemly arranged epitopes, 3X FLAG and GFP, separated by the Tobacco Etch Virus (TEV) protease site and expressed this in specific cell types using the GAL4/UAS system. cDNA libraries were prepared from mRNA associated with the affinity purified ribosomes and sequenced using an Illumina HiSeq 2000. We mapped raw reads to the D. melanogaster reference genome (release FB2013_01) with the gapped aligner Tophat. Only reads uniquely aligned were collected.Transcript expression levels were quantified using RPKM units using customized scripts written in Perl. Results: In this study, we observed massive changes in expression of cell surface proteins over short time scales (i.e. 5 fold differences in the expression of many hundreds of genes over 5 hr intervals) as R cell growth cones encounter the processes of many different neurons during their conversion from growth cones to synaptic terminals. In addition, to changes in transcripts encoding cell surface proteins, other mRNAs changed significantly as did non-coding RNAs (lincRNAs) associated with ribosomes. Although dramatic changes in transcript levels of presynaptic proteins were not observed preceding the onset of synapse formation, marked changes in the 3''-untranslated regions of these transcripts were seen. Conclusions: These studies provide a step towards merging traditional genetic and global genomic approaches to understanding cellular recognition underlying the assembly of neural circuits. Overall design: We chose 7 time points for RNA-seq analysis of R cells during pupal development corresponding to 24, 35, 40, 45, 53, 65 and 96 hrs after pupal formation (APF).
Rapid Changes in the Translatome during the Conversion of Growth Cones to Synaptic Terminals.
Age, Specimen part, Subject
View SamplesATFS-1 has been shown to regulate transcription of mitochondrial chaperone genes such as mtHsp70/hsp-6 and hsp-60 in response to mitocondrial stress. To identify the entire ATFS-1-mediated response, we compared the transcript profiles from wild-type and atfs-1(tm4525) worms raised in the absence and presence of mitochondrial stress.
Mitochondrial import efficiency of ATFS-1 regulates mitochondrial UPR activation.
Specimen part
View SamplesLeptin binding to the leptin receptor (LepR) causes rapid signaling to the nucleus. We investigated the early (2 hr) transcriptional response to acute leptin injectio (intracerebroventricular)
Ancient origins and evolutionary conservation of intracellular and neural signaling pathways engaged by the leptin receptor.
Specimen part, Treatment
View Samples