Plants were grown in growth chambers at 70% humidity and daily cycles of 16 h light and 8 h darkness at 21 C. Plant material used for the experiments was pooled from 12 plants. Stage I and stage II samples contained complete flower buds (stage I) or flowers (stage II). For stage III samples only siliques without withering flower organs were harvested. About 10% of the tissues for each sample were cleared and analyzed by microscopy to ensure that homogenous developmental stages were harvested. The entire experiment was performed twice providing independent biological replicates.
Transcriptional programs of early reproductive stages in Arabidopsis.
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Specimen part
View SamplesAt 3 days after pollination, RNA was extracted from seeds of WT and fis2 mutants, labeled and hybridized to ATH1 arrays.
H3K27me3 profiling of the endosperm implies exclusion of polycomb group protein targeting by DNA methylation.
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Specimen part
View SamplesWild type, pkl, pkr2 and pkl pkr2 plants were grown, and gene expression in roots was compared at the age of 5 days. <br></br>
CHD3 proteins and polycomb group proteins antagonistically determine cell identity in Arabidopsis.
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Age, Specimen part, Time
View SamplesGenomic imprinting is an epigenetic phenomenon causing parental alleles to be active depending on their parent-of-origin. In plants, imprinted genes are mainly confined to the endosperm, an ephemeral tissue supporting embryo development. Differential methylation of histone H3 on lysine 27 (H3K27me3) established by the Polycomb Repressive Complex 2 (PRC2) is a major regulatory mechanism determining activity of paternally expressed imprinted genes (PEGs) in animals and plants. Here, we show that the coding region of many PEGs is marked by an epigenetic signature of H3K27me3, H3K9me2 and CHG methylation and that the combination of these three modifications correlates with paternally-biased gene expression in the endosperm. The maternal alleles of PEGs are marked by CHG methylation in the central cell, indicating that the repressive epigenetic signature of PEGs is established before fertilization. We use the presence of the three modifications to predict novel PEGs and propose that genomic imprinting is substantially more common than previously estimated based on expression data. Overall design: Col × Ler reciprocal crosses were performed using Arabidopsis lines expressing PHE1::NTF and PHE1::BirA. 4DAP siliques were collected and tissue homogenization and nuclei purification were performed from three biological replicates for LerxCol and two for ColxLer using INTACT. Total RNA was extracted from purified nuclei using the mirVana Isolation Kit Protocol (Ambion). mRNA extraction was performed using NEBNext Poly(A) mRNA Magnetic Isolation and the Libraries were prepared with the NEBNext Ultra II RNA Library Prep Kit from Illumina. Samples were sequenced at the National Genomic Infrastructure (NGI) from SciLife Laboratory (Uppsala, Sweden) on an Illumina HiSeq2500 in paired-end 125bp read length.
Epigenetic signatures associated with imprinted paternally expressed genes in the Arabidopsis endosperm.
Specimen part, Subject
View SamplesChromosome dosage plays a significant role in reproductive isolation and speciation in both plants and animals, but underlying mechanisms are largely obscure. Transposable elements can promote hybridity through maternal small RNA, and have been postulated to regulate dosage response via neighboring imprinted genes. Here, we show that a highly conserved microRNA in plants, miR845, targets the tRNAMet primer-binding site (PBS) of LTR-retrotransposons in Arabidopsis pollen, and triggers the accumulation of 21 to 22-nucleotide small RNA in a dose dependent fashion via RNA polymerase IV. We show that these epigenetically activated small-interfering RNAs (easiRNAs) mediate hybridization barriers between diploid seed parents and tetraploid pollen parents (“the triploid block”), and that natural variation for miR845 may account for “endosperm balance” allowing formation of triploid seeds. Targeting the PBS with small RNA is a common mechanism for transposon control in mammals and plants, and provides a uniquely sensitive means to monitor chromosome dosage and imprinting in the developing seed. Overall design: RNA-seq of Arabidopsis pollen
Transposon-derived small RNAs triggered by miR845 mediate genome dosage response in Arabidopsis.
Specimen part, Subject
View SamplesNuclear pore complexes (NPCs) influence gene expression besides their established function in nuclear transport. The TREX-2 complex localizes to the NPC basket and affects gene-NPC interactions, transcription and mRNA export. How TREX-2 regulates the gene expression machinery is unknown. Here, we show that TREX-2 interacts with the Mediator complex, an essential regulator of RNA Polymerase (Pol) II. Structural and biochemical studies identify a conserved region on TREX-2, which directly binds the Mediator Med31/Med7N submodule. TREX-2 regulates assembly of Mediator with its Cdk8 kinase and is required for recruitment and site-specific phosphorylation of Pol II. Transcriptome and phenotypic profiling confirm that TREX-2 and Med31 are functionally interdependent. TREX-2 additionally uses its Mediator-interacting surface to regulate mRNA export suggesting a mechanism for coupling transcription initiation and early steps of mRNA processing at the Mediator level. In sum, we provide insight into how NPC-associated adaptor complexes can access the core transcription machinery. Overall design: RNAseq was performed from WT, sac3?, cdk8? and Sac3 R288D mutant cells. For each strain triplicates were analyzed. WT strain was sac3? transformed with pRS315 SAC3 WT
The Nuclear Pore-Associated TREX-2 Complex Employs Mediator to Regulate Gene Expression.
Subject
View SamplesGene expression profiles from the aortic arch of Ldlr-/-Apob100/100 Mttpflox/flox Mx1-Cre mice at different stages of atherosclerosis development
Transcriptional profiling uncovers a network of cholesterol-responsive atherosclerosis target genes.
Age, Specimen part
View SamplesCNS leukemia is still the major obstacle in treating childhood acute lymphoblastic leukemia (ALL). We have used our NOD/SCID/huALL xenotransplantation model to identify molecular pathways leading to the infiltration of leukemic cells into the CNS compartment.
Central nervous system involvement in acute lymphoblastic leukemia is mediated by vascular endothelial growth factor.
No sample metadata fields
View SamplesPlants with decreased SWC4 expression levels displayed several pleiotropic phenotypic alterations, suggesting that this gene participates in the regulation of different developmental processes. To evaluate genes whose expression was misregulated in SCW4 RNAi line, we performed RNA-seq differential expression analysis.
Arabidopsis SWC4 Binds DNA and Recruits the SWR1 Complex to Modulate Histone H2A.Z Deposition at Key Regulatory Genes.
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Age, Specimen part
View SamplesIt is known that natural killer (NK) cells are a heterogeneous population of functionally distinct NK cell subsets. Here we report on different genomic, phenotypic and functional properties of human NK cell subsets derived from peripheral blood, thymus and bone marrow. NK cell subpopulations were defined via expression of CD56 and CD16.
Specific phenotype and function of CD56-expressing innate immune cell subsets in human thymus.
Specimen part
View Samples