Classic ‘position effect’ experiments repositioned genes to the telomere to demonstrate that the epigenetic landscape can dramatically alter gene expression. Here we show that systematic gene knockout collections provide an exceptional resource for interrogating position effects, not only at the telomere but at every single genetic locus. Because deleted genes are replaced by the same reporter gene, interrogation of this reporter provides a sensitive probe into many different chromatin environments while controlling for genetic context. Using this approach we find that, whereas replacement of yeast genes with the kanMX marker does not perturb the chromatin landscape, differences due to gene position account for more than 35% of marker gene activity. We observe chromatin influences different from those reported previously, including an antagonistic interaction between histone H3 lysine 36 trimethylation (H3K36me3) and the Rap1 transcriptional activation site in kanMX that is mediated through a Set2-Rpd3-dependent pathway. This interaction explains why some yeast genes have been resistant to deletion and allows successful generation of these deletion strains using a modified transformation procedure. These findings demonstrate that chromatin regulation is not governed by a uniform ‘histone code’, but by specific interactions between chromatin and genetic factors. Overall design: Data included are RNA-Seq data for 4 heterzygous diploid yeast strains and diploid wild-type. Therea re three replicates for each heterzygous strain, and six replicates for wild-type.
Decoupling epigenetic and genetic effects through systematic analysis of gene position.
Subject
View SamplesPurpose: To compare the transcriptomes of IL-21-expressing, IL-21 and IL-4-expressing, and IL-4 expressing follicular helper T (Tfh) cells and Th2 cells in the spleen at 8 days following helminth infection Methods: Cell sorting of the populations was done for CD4+B220-CD44hiCXCR5hiPD-1hi cells of the various types, followed by mRNA purification. Overall design: CD4+Splenic T cell mRNA profiles 8 days post-infection of IL-21/IL-4 dual reporter mice with Nippostrongylus brasiliensis were generated by mRNA sequencing using Illumina HiSeq 2000.
TFH cells progressively differentiate to regulate the germinal center response.
Specimen part, Subject
View SamplesThe clinical course of patients with chronic lymphocytic leukemia (CLL) is heterogeneous. Several prognostic factors have been identified that can stratify patients into groups that differ in their relative tendency for disease progression and/or survival. Here, we pursued a subnetwork-based analysis of gene expression profiles to discriminate between groups of patients with disparate risks for CLL progression.
Subnetwork-based analysis of chronic lymphocytic leukemia identifies pathways that associate with disease progression.
Specimen part
View SamplesTissue repair is a subset of a broad repertoire of IL-4/IL-13-dependent host responses during helminth infections. Here, we show that IL-4/IL-13 alone were not sufficient, but IL-4/IL-13 together with apoptotic cells induced the tissue repair program in macrophages. Genetic ablation of sensors of apoptotic cells impaired the proliferation of tissue-resident macrophages and induction of anti-inflammatory/tissue repair genes in the lung following helminth infection or the damage caused by induction of colitis in the gut. In contrast, recognition of apoptotic cells was dispensable for cytokine-dependent induction of pattern recognition receptor, cell adhesion or chemotaxis genes in macrophages. Detection of apoptotic cells can therefore spatially compartmentalize or prevent premature or ectopic activity of pleiotropic, soluble cytokines, such as IL-4/IL-13. Overall design: RNA sequencing of lung resident macrophages from WT and Axl-/-Mertk-/- mice upon infection with N. brasiliensis
Macrophage function in tissue repair and remodeling requires IL-4 or IL-13 with apoptotic cells.
Age, Specimen part, Cell line, Subject
View SamplesCD4(+) type 1 T regulatory (Tr1) cells are induced in the periphery and have a pivotal role in promoting and maintaining tolerance. The absence of surface markers that uniquely identify Tr1 cells has limited their study and clinical applications. By gene expression profiling of human Tr1 cell clones, we identified the surface markers CD49b and lymphocyte activation gene 3 (LAG-3) as being stably and selectively coexpressed on mouse and human Tr1 cells. We showed the specificity of these markers in mouse models of intestinal inflammation and helminth infection and in the peripheral blood of healthy volunteers. The coexpression of CD49b and LAG-3 enables the isolation of highly suppressive human Tr1 cells from in vitro anergized cultures and allows the tracking of Tr1 cells in the peripheral blood of subjects who developed tolerance after allogeneic hematopoietic stem cell transplantation. The use of these markers makes it feasible to track Tr1 cells in vivo and purify Tr1 cells for cell therapy to induce or restore tolerance in subjects with immune-mediated diseases.
Coexpression of CD49b and LAG-3 identifies human and mouse T regulatory type 1 cells.
Specimen part, Treatment, Time
View SamplesInflammation is a beneficial host response to infection, but it also contributes to inflammatory disease if unregulated. The Th17 lineage of T helper (Th) cells can cause severe human inflammatory diseases. These cells exhibit both instability (i.e., they can cease to express their signature cytokine, IL-17A) and plasticity (i.e., they can start expressing cytokines typical of other lineages) upon in vitro re-stimulation. However technical limitations prevented the transcriptional profiling of pre- and post-conversion Th17 cells ex vivo during immune responses. Thus, it is unknown whether Th17 cell plasticity merely reflects change in expression of a few cytokines, or if Th17 cells physiologically undergo global genetic reprogramming driving their conversion from one T helper cell type to another, a process known as “transdifferentiation”. Furthermore, while Th17 cell instability/plasticity has been associated with pathogenicity, it is unknown whether this could present a therapeutic opportunity, whereby formerly pathogenic Th17 cells could adopt an anti-inflammatory fate. Here we used two novel fate-mapping mouse models to track Th17 cells during immune responses to show that CD4+ T cells that formerly expressed IL-17A go on to acquire an anti-inflammatory phenotype. The transdifferentiation of Th17 into regulatory T cells was illustrated by a global change in their transcriptome and the acquisition of potent regulatory capacity. Comparisons of the transcriptional profiles of pre- and post-conversion Th17 cells also revealed a role for canonical TGF- ß signaling and the aryl hydrocarbon receptor (AhR) in conversion. Thus, Th17 transdifferentiate into regulatory cells, and contribute to the resolution of inflammation. Our data suggest Th17 cell instability and plasticity is a therapeutic opportunity for inflammatory diseases. Overall design: We isolated intestinal lymphocytes from two independent experiments, each using 5 mice injected with anti-CD3 mAb. Th17, exTh17, Tr1 exTh17, Tr1, Foxp3 Treg and Foxp3 IL-10+ Treg cell populations were FACS-sorted from these two independent experiments and the cells of each population were pooled before the analysis. Around 5,000 cells for each population were processed.
Th17 cells transdifferentiate into regulatory T cells during resolution of inflammation.
No sample metadata fields
View SamplesWe have analyzed 2 normal B cells isolated from peripheral blood and 5 CLL specimens with affy 133A microarray for expression.
Aberrant splicing of the E-cadherin transcript is a novel mechanism of gene silencing in chronic lymphocytic leukemia cells.
Specimen part, Disease, Disease stage
View SamplesLung cancers are documented to have remarkable intratumoral genetic heterogeneity. However, little is known about the heterogeneity of biophysical properties, such as cell motility, and its relationship to early disease pathogenesis and micrometastatic dissemination. In this study, we identified and selected a subpopulation of highly migratory premalignant pulmonary epithelial cells that were observed to migrate through microscale constrictions at up to 100-fold the rate of unselected cells. This enhanced migratory capacity was found to be Rac1-dependent and heritable, as evidenced by maintenance of the phenotype through multiple cell divisions continuing more than 8-weeks post-selection. The morphology of this lung epithelial subpopulation was characterized by increased cell protrusion intensity. In a murine model of micrometastatic seeding and pulmonary colonization, the motility-selected premalignant cells exhibit both enhanced survival in short term assays and enhanced outgrowth of premalignant lesions in longer term assays, thus overcoming important aspects of metastatic inefficiency. Overall, our findings indicate that among premalignant pulmonary epithelial cells, subpopulations with heritable motility-related biophysical properties exist, and these may explain micrometastatic seeding occurring early in the pathogenesis of lung cancer. Understanding, targeting, and preventing these critical biophysical traits and their underlying molecular mechanisms may provide a new approach to prevent metastatic behavior.
Identification of a Human Airway Epithelial Cell Subpopulation with Altered Biophysical, Molecular, and Metastatic Properties.
Age, Specimen part
View SamplesPU.1 is a key transcription factor for macrophage differentiation. Novel PU.1 target genes were identified by mRNA profiling of PU.1-deficient progenitor cells (PUER) before and after PU.1 activation. We used two different types of Affymetrix DNA-microarrays (430 2.0 arrays and ST 1.0 exon arrays) to characterize the global PU.1-regulated transcriptional program underlying the early processes of macrophage differentiation.
Transcriptomic profiling identifies a PU.1 regulatory network in macrophages.
No sample metadata fields
View SamplesMecp2 loss-of-function has been associated with altered gene expression in many tissues. We characterized gene expression changes within the hippocampi of 3 different Mecp2 loss-of-function mouse models.
An AT-hook domain in MeCP2 determines the clinical course of Rett syndrome and related disorders.
Age, Specimen part
View Samples