High-throughput sequencing of mouse liver transcriptome in Clock mutant animals
ABSTRACT: Circadian profile of polyA RNA by RNA-Seq, collected from ClockΔ19 mouse liver at CT22, CT28, CT34, CT40. RNA from three livers pooled per time point. 4 Clock mutant samples with no replicates
Project description:Circadian profile of polyA RNA by RNA-Seq, collected from mouse liver at CT23, CT29, CT35, CT41, CT47, CT53, CT59, CT65. RNA from three livers pooled per time point. 8 wildtype samples with no replicates.
Project description:The interior of the neuronal cell nucleus is a highly organized 3-dimensional (3D) structure in which regions of the genome that are millions of bases apart participate in specialized sub-structures with dedicated functions. To investigate neuronal chromatin organization and dynamics in vivo, we generated bitransgenic mice that express histone GFP-tagged H2B in principal neurons of the forebrain. Surprisingly, the expression of this chimeric histone in mature neurons causes chromocenter declustering and disrupts the association of heterochromatin with the nuclear lamina. The loss of these structures does not affect neuronal viability but is associated with specific transcriptional and behavioral deficits related to serotonergic dysfunction. Overall, our results demonstrate that the 3D-organization of chromatin in the neuronal nucleus supports an additional level of epigenetic regulation of gene expression that critically influences neuronal function and indicate that some loci associated with neuropsychiatric disorders may be particularly sensitive to changes in chromatin architecture. Genome-wide profiling by high throughput sequencing of H3K27me3 in the adult hippocampus of CaMKII-tTA/tetO-H2BGFP (H2BGFP) and their wild-type littermates mice (WT). Chromatin immunoprecipitation (ChIP) was carried out using pooled hippocampal tissue from 3 mice (one hippocampus per mouse). One DNA library was constructed per genotype. Each DNA library was prepared from pooled immunoprecipitated DNA from 4 independent ChIP assays. In total, tissue from 12 different mice was used to prepare each DNA library. 60% of a lane was used to perform single end (1x50bp) multiplex sequencing in HiSeq 2500 apparatus (Illumina). Each library, was sequenced in duplicate (in two independent sequencing runs. Technical replicates).
Project description:The interior of the eukaryotic cell nucleus is a highly organized 3D structure. In mature hippocampal and cortical pyramidal neurons, transcriptionally silent DNA is typically compacted in a few clusters referred to as chromocenters that are strongly stained with DNA intercalating agents like DAPI and whose function is still uncertain. We found that this 3D structure was severely disrupted by the incorporation of the chimeric histone H2BGFP into neuronal chromatin. Experiments in inducible and forebrain restricted bitransgenic mice demonstrated that the expression of this histone alters the higher-order organization of neuronal heterochromatin and causes a complex behavioral phenotype that includes hyperactivity, and social interaction, prepulse inhibition and cognitive defects. This phenotype was associated with highly specific transcriptional deficits that affected several serotonin receptor genes located at the edge of gene desert regions. Pharmacological and electrophysiological experiments indicate that this epigenetically-induced hyposerotonergic state may underlie the behavioral defects. Our results suggest a new role for perinuclear heterochromatin and chromocenter organization in the epigenetic regulation of neuronal gene expression and mental illness. We used microarrays to detect differential gene expression in transgenic mice expressing histone H2BGFP in the forebrain. We obtained triplicate samples (biological replicates) of either genotype (wild-type and H2BGFP mice). Each sample contained pooled total RNA from the hippocampi of 2 three-month old genotype-matched mice.
Project description:Background RNA sequencing (RNA-seq) is a powerful technique for identifying and quantifying transcription and splicing events, both known and novel. However, given its recent development and the proliferation of library construction methods, understanding the bias it introduces is incomplete but critical to realizing its value. Results Here we present a method, in vitro transcription sequencing (IVT-seq), for identifying and assessing the technical biases in RNA-seq library generation and sequencing at scale. We created a pool of > 1000 in vitro transcribed (IVT) RNAs from a full-length human cDNA library and sequenced them with poly-A and total RNA-seq, the most common protocols. Because each cDNA is full length and we show IVT is incredibly processive, each base in each transcript should be equivalently represented. However, with common RNA-seq applications and platforms, we find ~50% of transcripts have > 2-fold and ~10% have > 10-fold differences in within-transcript sequence coverage. Strikingly, we also find > 6% of transcripts have regions of high, unpredictable sequencing coverage, where the same transcript varies dramatically in coverage between samples, confounding accurate determination of their expression. To get at causal factors, we used a combination of experimental and computational approaches to show that rRNA depletion is responsible for the most significant variability in coverage and that several sequence determinants also strongly influence representation. Conclusions In sum, these results show the utility of IVT-seq in promoting better understanding of bias introduced by RNA-seq and suggest caution in its interpretation. Furthermore, we find that rRNA-depletion is responsible for substantial, unappreciated biases in coverage. Perhaps most importantly, these coverage biases introduced during library preparation suggest exon level expression analysis may be inadvisable. 5 rRNA-depleted samples with duplicates, 1 polyA selected, 1 total RNA, and 1 plasmid library all without replicates.
Project description:The hallmark of human cancer is heterogeneity, mirroring the complexity of genetic and epigenetic alterations acquired during oncogenesis. We extracted DNA of 14 cultured human ovarian carcinoma cell lines subjected to pooled shRNA screen using TRC 1.0 library, and performed DNAseq. 14 ovarian carcinoma cell lines DNAseq data.
Project description:ChIP-seq was performed using Drosophila Kc167 cells using antibodies against the two isoforms of Fs(1)h, the Brd4 homologue. Differences in binding patterns between the two isoforms are described. We examined the differences in Fs(1)h isoform binding across the genome and describe the short isoform to be correlated with transcription at enhancers and promoters. The long isoform is found predominately at insulator binding sites where multiple insulators are bound.
Project description:Here we map the localization of Mod(mdg4), including Mod(mdg4)2.2 specific and Mod(mdg4) common to all isoforms, to chromatin insulators, as well as the lethal-3 malignant brain tumor protein in Drosophila Kc cells. examination of genomic occupancy for Mod(mdg4)2.2, Mod(mdg4)BTB (all isoforms), and L(3)mbt, control samples used for Drosophila Kc were previously described (Wood, Van Bortle et al., 2011 GSE30740)
Project description:Here we map the localization of H3K27me3 in Drosophila Kc cells, as well as in Drosophila Kc cells wherein dCTCF is knock down. examination of genomic occupancy for H3K27me3, control samples used for Drosophila Kc were previously described (Wood, Van Bortle et al., 2011 GSE30740)