Project description:Regulation of gene expression is linked to the organization of the genome. With age, chromatin alterations occur on all levels of genome organization, accompanied by changes in the gene expression profile. However, little is known about the changes on the level of transcriptional regulation. Here, we used a multi-omics approach and integrated ATAC-, RNA- and NET-seq to identify age-related changes in the chromatin landscape of murine liver and to investigate how these are linked to transcriptional regulation. We provide the first systematic inventory of the connection between aging, chromatin accessibility and transcriptional regulation in a whole tissue. Aging in murine liver is characterized by an increase in chromatin accessibility at promoter regions, but not in an increase of transcriptional output. Instead, aging is accompanied by a decrease of promoter-proximal pausing of RNA polymerase II (Pol II). We propose that these changes in transcriptional regulation are due to a reduced stability of the pausing complex and may represent a mechanism to compensate for the age-related increase in chromatin accessibility in order to prevent aberrant transcription.
Project description:Acquired drug resistance prevents targeted cancer therapy from achieving stable and complete responses. Emerging evidence implicates a key role for nonmutational mechanisms including changes in cell state during early stages of acquired drug resistance. Targeting nonmutational resistance may therefore present a therapeutic opportunity to eliminate residual surviving tumor cells and impede relapse. A variety of cancer cell lines harbor quiescent, reversibly drug-tolerant âpersisterâ cells which survive cytotoxic drugs including targeted therapies and chemotherapies. These persister cells survive drug through nonmutational mechanisms which are poorly understood. Specifically targeting persister cells is a promising strategy to prevent tumor relapse. We sought to identify therapeutically exploitable vulnerabilities in persister cells using the HER2-amplified breast cancer line BT474 as an experimental model. Similar to other persister cell models, upon treatment with the HER2 inhibitor lapatinib (2uM concentration) for nine or more days, the majority of BT474 cells die, revealing a small population of quiescent surviving persister cells. Removal of lapatinib allows the persister cells to regrow and to re-acquire sensitivity to lapatinib. Subsequent lapatinib treatment re-derives persister cells. The reversibility of persister cell drug resistance indicates a nonmutational resistance mechanism. Here we provide RNAseq gene expression profiling data generated from parental BT474 cells compared to BT474 persister cells generated from nine days of treatment with 2 uM lapatinib. These data can be used to identify genes and pathways which are upregulated in persister cells, revealing potential therapeutic targets. 3 biological replicates of BT474 persister cells, two biological replicates of BT474 parental cells
Project description:To investigate whether changes to chromatin accessibility associated with resistance to lapatinib are a stable or a reversible state, we treated OE19 cells with 500 nM lapatinib for 35 days and then withdrew lapatinib for 1, 2, 3 and 14 days. Control cells treated with DMSO for 1 day and 'resistant' cells treated with 500 nM lapatinib for 35 days were also sequenced.
Project description:"The main goal of the project is to develop a new generation of bioinformatics resources for the integrative analysis of multiple types of omics data. These resources include both novel statistical methodologies as well as user-friendly software implementations. STATegra methods address many aspects of the omics data integration problem such as the design of multiomics experiments, integrative transcriptional and regulatory networks, integrative variable selection, data fusion, integration of public domain data, and integrative pathway analysis. To support method development STATegra uses a model biological system, namely the differentiation process of mouse pre-B-cells. The STATegra consortium generated data focused on a critical step in the differentiation of B lymphocytes, which are key components of the adaptive immune system. Transcription factors of the Ikaros family are central to the normal differentiation of B cell progenitors and their expression increases in response to developmental stage-specific signals to terminate the proliferation of B cell progenitors and to initiate their differentiation. In particular, a novel biological system that models the transition from the pre-BI stage to the pre-BII subsequent stage, where B cell progenitors undergo growth arrest and differentiation, was used. The approach involves a pre-B cell line, B3 , and an inducible version of the Ikaros transcription factor, Ikaros-ERt2. Ikaros factors act to down-regulate genes that drive proliferation and to simultaneously up-regulate the expression of genes that promote the differentiation of B cell progenitors. Hence, in the B3 system, before induction of Ikaros, cells proliferate and their gene expression pattern is similar to proliferating B cell progenitors in vivo. Following Ikaros induction, B3 cells undergo gene expression changes that resemble those that occur in vivo during the transition from cycling to resting pre-B cells, followed by a marked reduction in cellular proliferation and by G1 arrest. On this system the consortium has created a high-quality data collection consisting of a replicated time course using seven different omics platforms: RNA-seq, miRNA-seq, ChIP-seq, DNase-seq, Methyl-seq, proteomics and metabolomics, which is used to assess and to validate STATegra methods."
Project description:we utilize Nano-MeDIP-seq for the analysis of the LT-HSC methylome and, for the first time, simultaneously interrogate the methylome and transcriptome of a homogeneous population of primary murine HSCs, in order to define the underlying causes of changes in HSC functionality during normal ageing. We isolated and phenotyped primary LT-HSCs from young, middle-aged and old mice and subjected them to comprehensive methylome (MeDIP-seq) and transcriptome (RNA-seq) analysis.
Project description:Here, we used an isobaric tag for relative and absolute quantitation-based quantitative proteomic analysis to measure changes in protein expression levels during AR formation in Taxodium ‘Zhongshanshan’.
Project description:Study abstract: Axolotl salamanders (Ambystoma mexicanum) remain aquatic in their natural state, during which biomechanical forces on their diarthrodial limb joints are likely reduced relative to salamanders living on land. However, even as sexually mature adults, these amphibians can be induced to metamorphose into a weight-bearing terrestrial stage by environmental stress or the exogenous administration of thyroxine hormone. In some respects, this aquatic to terrestrial transition of axolotl salamanders through metamorphosis may model developmental and changing biomechanical skeletal forces in mammals during the prenatal to postnatal transition at birth and in the early postnatal period. To assess differences in the appendicular skeleton as a function of metamorphosis, anatomical and gene expression parameters were compared in skeletal tissues between aquatic and terrestrial axolotls that were the same age and genetically full siblings. The length of long bones and area of cuboidal bones in the appendicular skeleton, as well as the cellularity of cartilaginous and interzone tissues of femorotibial joints were generally higher in aquatic axolotls compared to their metamorphosed terrestrial siblings. A comparison of steady state mRNA transcripts encoding aggrecan core protein (ACAN), type II collagen (COL2A1), and growth and differentiation factor 5 (GDF5) in femorotibial cartilaginous and interzone tissues did not reveal any significant differences between aquatic and terrestrial axolotls. RNAseq samples: Total RNA was isolated from whole body tissue samples of Mexican axolotl salamanders (Ambystoma mexicanum) at the following developmental stages: Embryo at the tail bud stage, newly hatched larva, larva at the limb bud stage, juvenile at 8.5 centimeters, and adult using variations of guanidinium-based protocols. RNA quantity, purity, and integrity of both the individual samples and the resulting pool were determined with an Agilent 2100 Bioanalyzer using the Eukaryotic Total RNA nano series II analysis kit. The pooled RNA sample was poly-A selected and used for Illumina random priming directional library prep. Four lanes were sequenced only on one end providing single end reads and 4 lanes were sequenced at both ends giving paired-end reads. The library was sequenced on an Illumina HiSeq 2000 for 75bp reads producing 147,248,512 single end reads and 2 x 153,254,667 paired-end reads.
Project description:ChIP-seq for PPARGC1A was performed in OE19 cells to identify genomic binding sites. Cells were treated with 500 nM lapatinib for 48 hours.
Project description:ChIP-seq for HNF4A, PPARGC1A and H3K27ac was performed in OE19 cells to identify genomic binding sites. Cells were treated with DMSO or 500 nM lapatinib for 48 hours.