Heterochromatin Protein 1 (HP1) is a major regulator of chromatin structure and function. In animals, the network of proteins interacting with HP1 is mainly associated with constitutive heterochromatin marked by H3K9me3. HP1 physically interacts with the putative orthologue of the SNF2 chromatin remodeler ATRX, which controls deposition of the histone variant H3.3 in mammals. In Arabidopsis thaliana, we show that the orthologue of ATRX participates in H3.3 deposition and characterize the function of conserved domains of plant ATRX. We show that the plant Like HP1 (LHP1) interacts with ATRX through domains that evolved specifically in land plants ancestors. Interaction between ATRX and LHP1 affects the expression of a limited subset of genes controlled by the POLYCOMB REPRESSIVE COMPLEX 2 (PRC2), including the flowering time regulator FLC. In the context of flowering time, ATRX function requires the novel LHP1-interacting domain and the ATPase of the ATRX SNF2 helicase. We conclude that distinct evolutionary pathways led to interaction between ATRX and HP1 in mammals or its counterpart LHP1 in plants, resulting in distinct modes of transcriptional regulation. Overall design: 1 sample (mutant) + 1 reference sample (control)
LHP1 Interacts with ATRX through Plant-Specific Domains at Specific Loci Targeted by PRC2.
Age, Specimen part, Subject
View SamplesWe used microarrays to assess gene expression changes in cells with siRNA-mediated knockdown of OPG compared to normal cells. Furthermore, we used microarrays to assess gene expression in cells treated with either RANKL or TRAIL compared to vehicle-treated cells.
No influence of OPG and its ligands, RANKL and TRAIL, on proliferation and regulation of the calcification process in primary human vascular smooth muscle cells.
Specimen part, Treatment
View SamplesIn Drosophila, PIWI proteins and bound PIWI interacting RNAs (piRNAs) form the core of a small RNA mediated defense system against selfish genetic elements. Within germline cells piRNAs are processed from piRNA clusters and transposons to be loaded into Piwi/Aubergine/AGO3 and a subset of piRNAs undergoes target dependent amplification. In contrast, gonadal somatic support cells express only Piwi, lack signs of piRNA amplification and exhibit primary piRNA biogenesis from piRNA clusters. Neither piRNA processing/loading nor Piwi mediated target silencing is understood at the genetic, cellular or molecular level. We developed an in vivo RNAi assay for the somatic piRNA pathway and identified the RNA helicase Armitage, the Tudor domain containing RNA helicase Yb and the putative nuclease Zucchini as essential factors for primary piRNA biogenesis. Lack of any of these proteins leads to transposon de-silencing, to a collapse in piRNA levels and to a failure in Piwi nuclear accumulation. We show that Armitage and Yb interact physically and co-localize in cytoplasmic Yb-bodies, which flank P-bodies. Loss of Zucchini leads to an accumulation of Piwi and Armitage in Yb-bodies indicating that Yb-bodies are sites of primary piRNA biogenesis. Overall design: small RNA libraries were prepared from Piwi immuno-precipitates of five different genotypes
An in vivo RNAi assay identifies major genetic and cellular requirements for primary piRNA biogenesis in Drosophila.
Subject
View SamplesThe aim of the study was to illucidate how BAFF mediates B cell survival and growth through the identification of BAFF-regulated genes.
BAFF controls B cell metabolic fitness through a PKC beta- and Akt-dependent mechanism.
No sample metadata fields
View SamplesAirway epithelium is the initial point of host-pathogen interaction in Pseudomonas aeruginosa infection, an important pathogen in cystic fibrosis and nosocomial pneumonia. We used global gene expression analysis to determine airway epithelial transcriptional responses dependent on matrilysin (MMP-7) and stromelysin-2 (MMP-10), two matrix metalloproteinases induced by acute P. aeruginosa pulmonary infection. Extraction of Differential Gene Expression (EDGE) analysis of gene expression changes in P. aeruginosa infected organotypic tracheal epithelial cell cultures from wildtype, Mmp7-/-, and Mmp10-/- mice identified 2,089 matrilysin-dependent and 1,628 stromelysin-2-dependent genes that were differentially expressed. Key node network analysis showed that these MMPs controlled distinct gene expression programs involved in proliferation, cell death, immune responses, and signal transduction, among other host defense processes. Our results demonstrate discrete roles for these MMPs in regulating epithelial responses to pseudomonas infection and show that a global genomics strategy can be used to assess MMP function.
Individual matrix metalloproteinases control distinct transcriptional responses in airway epithelial cells infected with Pseudomonas aeruginosa.
No sample metadata fields
View SamplesThis study examines the innate immune response of human pluripotent stem cell derived airway epithelium. Immune challenge was performed with TNF-alpha or bacterial lipopolysaccharide (LPS)
Innate immune response of human pluripotent stem cell-derived airway epithelium.
Specimen part, Treatment
View SamplesTranscript profile of 10 days-old seedlings over expressing miR396
Control of cell proliferation in Arabidopsis thaliana by microRNA miR396.
No sample metadata fields
View SamplesCraniosynostosis is a disease defined by premature fusion of one or more cranial sutures. The mechanistic pathology of isolated single-suture craniosynostosis is complex and while a number of genetic biomarkers and environmental predispositions have been identified, in many cases the causes remain controversial and inconclusive at best. After controlling for variables contributing to potential bias, FGF7, SFRP4, and VCAM1 emerged as potential genetic biomarkers for single-suture craniosynostosis due to their significantly large changes in gene expression compared to the control population. Furthermore, pathway analysis implicated focal adhesion and extracellular matrix (ECM)-receptor interaction as differentially regulated gene networks when comparing all cases of single-suture synostosis and controls. Lastly, overall gene expression was found to be highly conserved between coronal and metopic cases, as evidenced by the fact that WNT2 and IGFBP2 were the only differentially regulated genes identified in a direct comparison. These results not only confirm the roles of previously reported craniosynostosis-related targets but also introduce novel genetic biomarkers and pathways that may play critical roles in its pathogenesis.
Differential expression of extracellular matrix-mediated pathways in single-suture craniosynostosis.
Sex, Specimen part
View SamplesAnimal mRNAs are regulated by hundreds of RNA binding proteins (RBPs). The identification of RBP targets is crucial for understanding their function. A recent method, PAR-CLIP, uses photoreactive nucleosides to crosslink RBPs to target RNAs in cells prior to immunoprecipitation. Here, we establish iPAR-CLIP (in vivo PAR-CLIP) to determine, at nucleotide resolution, transcriptome-wide target sites of GLD-1, a conserved, germline-specific translational repressor in C. elegans. We identified 439 reproducible targets and demonstrate an excellent dynamic range of target detection by iPAR-CLIP. Upon GLD-1 knock-down, protein but not mRNA expression of the 439 targets was specifically and highly significantly upregulated, demonstrating functionality. Finally, we discovered strongly conserved GLD-1 binding sites nearby the start codon of target genes. We propose that GLD-1 interacts with the translation machinery nearby the start codon, a so far unknown mode of gene regulation in eukaryotes. Overall design: Arrested L1 worms were grown in liquid culture supplemented with 2mM 4SU or 6SG. 250,000 worms were sufficient for one iPAR-CLIP experiment. Living adult worms were transferred to NGM plates and crosslinked on ice using a Stratalinker (Stratagene) with customized 365nm UV-lamps (energy setting: 2J/cm2). Worms were lysed on ice by douncing in NP40 lysis buffer (50 mM HEPES-K pH 7.5, 150 mM KCl, 2 mM EDTA, 0.5% (v/v) NP-40, 0.5 mM DTT, protease inhibitor cocktail (Roche)). Cleared lysates were treated with RNase T1 (Fermentas) (final concentration 1U/?l) for 15 min at 22ºC. GLD-1::GFP::FLAG fusion proteins were immunoprecipitated for 1h at 4ºC using anti-FLAG antibody (Sigma, F3165) coupled to Protein G magnetic beads (Invitrogen). For one iPAR-CLIP experiment (1ml cleared lysate obtained from 250,000 worms), 300µl beads and 150µg antibody were used. Immunoprecipitates were treated with RNase T1 (100U/?l) for exactly 12 min at 22 ºC. Subsequently, PAR-CLIP was carried out as described previously (Hafner et al, 2010). cDNA libraries were sequenced on a Genome Analyzer II (Illumina).
In vivo and transcriptome-wide identification of RNA binding protein target sites.
Cell line, Subject
View SamplesAnimal mRNAs are regulated by hundreds of RNA binding proteins (RBPs). The identification of RBP targets is crucial for understanding their function. A recent method, PAR-CLIP, uses photoreactive nucleosides to crosslink RBPs to target RNAs in cells prior to immunoprecipitation. Here, we establish iPAR-CLIP (in vivo PAR-CLIP) to determine, at nucleotide resolution, transcriptome-wide target sites of GLD-1, a conserved, germline-specific translational repressor in C. elegans. We identified 439 reproducible targets and demonstrate an excellent dynamic range of target detection by iPAR-CLIP. Upon GLD-1 knock-down, protein but not mRNA expression of the 439 targets was specifically and highly significantly upregulated, demonstrating functionality. Finally, we discovered strongly conserved GLD-1 binding sites nearby the start codon of target genes. We propose that GLD-1 interacts with the translation machinery nearby the start codon, a so far unknown mode of gene regulation in eukaryotes. Overall design: PolyA mRNA was extracted from young adult wildtype (N2) worms and young adult germline less worms (glp-4(bn2) TS) to identify and quantify genes expressed in the young adult germline by sequencing. 2x100 paired end sequencing was performed according to the protocol on the Illumina HiSeq 2000.
In vivo and transcriptome-wide identification of RNA binding protein target sites.
Cell line, Subject
View Samples