Project description:Increasing evidence supports a role for altered gene expression in mediating the lasting effects of cocaine on the brain, and recent work has demonstrated the involvement of chromatin modifications in these alterations. However, all such studies to date have been restricted by their reliance on microarray technologies which have intrinsic limitations. Here, we used advanced sequencing methods, RNA-seq and ChIP-seq, to obtain an unprecedented view of cocaine-induced changes in gene expression and associated adaptations in numerous modes of chromatin regulation in the nucleus accumbens, a key brain reward region. We identify unique combinations of chromatin changes, or signatures, that accompany cocaine’s regulation of gene expression, including the dramatic involvement of pre-mRNA alternative splicing in cocaine action. Together, this delineation of the cocaine-induced epigenome in the nucleus accumbens reveals several novel modes of drug regulation, thereby providing new insight into the biological basis of cocaine addiction. More broadly, the combinatorial chromatin and transcriptional approaches that we describe serve as an important resource for the field, as they can be applied to other systems to reveal novel transcriptional and epigenetic mechanisms of neuronal regulation. ChIP-seq of 6 marks (H3K27me3, H3K36me3, H3K4me1, H3K4me3, H3K9me2, RNApolII) were done on mouse nucleus accumbens 24 hr after 7 day daily cocaine ip injection with saline as control. Three replicates for each condition.
Project description:In a previous study, we found that H2S alleviates salinity stress in cucumber by maintaining the Na+/K+ balance and by regulating H2S metabolism and the oxidative stress response. However, little is known about the molecular mechanisms behind H2S-regulated salt-stress tolerance in cucumber. Here, an integrated transcriptomic and proteomic analysis based on RNA-seq and 2-DE was used to investigate the global mechanism underlying H2S-regulated salt-stress tolerance. In total, 11 761 differentially expressed genes (DEGs) and 61 differentially expressed proteins (DEPs) were identified. Analysis of the pathways associated with the DEGs showed that salt stress enriched expression of genes in primary and energy metabolism, such as photosynthesis, carbon metabolism and biosynthesis of amino acids. Application of H2S significantly decreased these DEGs but enriched DEGs related to plant-pathogen interaction, sulfur-containing metabolism, cell defense and signal transduction pathways. Notably, changes related to sulfur-containing metabolism and cell defense were also observed through proteome analysis, such as Cysteine synthase 1, Glutathione S-transferase U25-like, Protein disulfide-isomerase and Peroxidase 2. We present the first global analysis of the mechanism underlying H2S regulation of salt-stress tolerance in cucumber through tracking changes in the expression of specific proteins and genes.
Project description:Increasing evidence supports a role for altered gene expression in mediating the lasting effects of cocaine on the brain, and recent work has demonstrated the involvement of chromatin modifications in these alterations. However, all such studies to date have been restricted by their reliance on microarray technologies which have intrinsic limitations. Here, we used advanced sequencing methods, RNA-seq and ChIP-seq, to obtain an unprecedented view of cocaine-induced changes in gene expression and associated adaptations in numerous modes of chromatin regulation in the nucleus accumbens, a key brain reward region. We identify unique combinations of chromatin changes, or signatures, that accompany cocaineM-bM-^@M-^Ys regulation of gene expression, including the dramatic involvement of pre-mRNA alternative splicing in cocaine action. Together, this delineation of the cocaine-induced epigenome in the nucleus accumbens reveals several novel modes of drug regulation, thereby providing new insight into the biological basis of cocaine addiction. More broadly, the combinatorial chromatin and transcriptional approaches that we describe serve as an important resource for the field, as they can be applied to other systems to reveal novel transcriptional and epigenetic mechanisms of neuronal regulation. Total RNA was isolated from mouse nucleus accumbens 24 hr after 7 day daily cocaine or saline control ip injection for mRNA sequencing by following illumina RNA seq kit protocol. Another batch of acute cocaine RNA-seq was performed using the same parameters except the treatment group was given 6 days of saline injection followed by 1 day of cocaine injection. The acute cocaine batch serves as control experiments.
Project description:We used genome-wide sequencing methods to study stimulus-dependent enhancer function in neurons. We identified ~12,000 neuronal activity-regulated enhancers that are bound by the general transcriptional co-activator CBP in an activity-dependent manner. A function of CBP at enhancers may be to recruit RNA polymerase II (RNAPII), as we also observed activity-regulated RNAPII binding to thousands of enhancers. Remarkably, RNAPII at enhancers transcribes bi-directionally a novel class of enhancer RNAs (eRNAs) within enhancer domains defined by the presence of histone H3 that is mono-methylated at lysine 4 (H3K4me1). The level of eRNA expression at neuronal enhancers positively correlates with the level of mRNA synthesis at nearby genes, suggesting that eRNA synthesis occurs specifically at enhancers that are actively engaged in promoting mRNA synthesis. These findings reveal that a widespread mechanism of enhancer activation involves RNAPII binding and eRNA synthesis. Examination of genome-wide binding of three types of modified histones, four transcription factors, and RNA polymerase II (ChIP-Seq), as well as RNA expression (RNA-Seq) before and after membrane depolarization via application of extracellular potassium.
Project description:We used an immature mouse T cell line engineered to express a biotinylated form of the cleaved form of Notch1 (ICN1). ICN1-bound sites were precipitated with streptavidin-coated beads and subjected to ChIP-sequencing. Beko cells correspond to a spontaneous T lymphoma immature cell line derived from a TCRb deficient mouse. These cells were engineered to express a biotin-tagged-ICN1 and the bacterial biotin ligase BirA (Bio-ICN1) or just BirA as a control (Bio). Chromatin from both cell lines was subjected to strepatavidin-mediated precipitation and subjected to sequencing with the Illumina GAII sequencer as single end 36 base pair reads.
Project description:The transcription factor Ikaros represses Notch signaling. Since Ikaros and Notch treanscriptional mediator RBPJ both recognize sequences that contain the same core TGGGAA motif, it was hypothesized that Ikaros represses Notch signaling by targeting Notch response elements and competing with RBPJ for their binding. Here we used the mouse T-cell leukemia cell line T29 to compare the genomic binding profiles of Ikaros and RBPJ by ChIP-seq. The T29 cell line is derived from a Ikaros-deficient T-cell leukemia (Dumortier et al, MCB 26, 209-220, 2006) and exhibits strong Notch activation. We performed two chip-seq experiments with an anti-RBPJ antibody to map RBPJ binding sites. To map Ikaros binding sites, we engineered a T29-derived cell line that expresses a fusion protein between Ikaros and the ligand binding domain of the estrogen receptor (Ik1-ER) which is activated by addition of 4-hydroxy-tamoxifen (4OHT). We used an anti-Ikaros antibody to map the sites bound by Ik1-ER after treatment of the cells with 4OHT. Sequencing were performed with the Illumina GAII sequencer as as single end 36 base pair reads.
Project description:The nuclear receptor HNF4A regulates embryonic and post-natal hepatocyte gene expression. Using hepatocyte-specific inactivation in mice, we show that the TAF4 subunit of TFIID acts as a cofactor for HNF4A in vivo and that HNF4A interacts directly with the TAF4-TAF12 heterodimer in vitro. In vivo, TAF4 is required to maintain HNF4A-directed embryonic gene expression at post-natal stages and for HNF4A-directed activation of post-natal gene expression. TAF4 promotes HNF4A occupancy of functional cis-regulatory elements located adjacent to the transcription start sites of post-natal expressed genes and for pre-initiation complex formation required for their expression. Promoter-proximal HNF4A-TFIID interactions are therefore required for pre-initiation complex formation and stable HNF4A occupancy of regulatory elements as two concomitant mutually dependent processes. Examination of PIC, H3k4me3, Ctcf and Hnf4a occupancy in wild-type and Taf4-/- livers by deep sequencing