To understand the population genetics of structural variants (SVs), and their effects on phenotypes, we developed an approach to mapping SVs, particularly transpositions, segregating in a sequenced population, and which avoids calling SVs directly. The evidence for a potential SV at a locus is indicated by variation in the counts of short-reads that map anomalously to the locus. These SV traits are treated as quantitative traits and mapped genetically, analogously to a gene expression study. Association between an SV trait at one locus and genotypes at a distant locus indicate the origin and target of a transposition. Using ultra-low-coverage (0.3x) population sequence data from 488 recombinant inbred Arabidopsis genomes, we identified 6,502 segregating SVs. Remarkably, 25% of these were transpositions. Whilst many SVs cannot be delineated precisely, PCR validated 83% of 44 predicted transposition breakpoints. We show that specific SVs may be causative for quantitative trait loci for germination, fungal disease resistance and other phenotypes. Further we show that the phenotypic heritability attributable to sequence anomalies differs from, and in the case of time to germination and bolting, exceeds that due to standard genetic variation. Gene expression within SVs is also more likely to be silenced or dysregulated, as inferred from RNA-seq data collected from a subset of just over 200 of the MAGIC lines. This approach is generally applicable to large populations sequenced at low-coverage, and complements the prevalent strategy of SV discovery in fewer individuals sequenced at high coverage. Overall design: 209 samples consisting of different inbred lines from the Multiparent Advance Generation InterCross (MAGIC) population in the reference plant, Arabidopsis thaliana. For each sample, RNA was collected from the aerial shoot at the 4th true leaf stage, and Illumina mRNA-seq libraries were constructed (a single library was constructed with each line; that is, each MAGIC line is represented by one biological replicate). Using these libraries, which were non-stranded, paired-end 100 bp RNA-seq Illumina reads were generated for each sample, and used to quantify gene expresison in each MAGIC line. The resulting expression phenotypes are suitable for describing the impacts of genetic variation in the MAGIC line founders on the control of gene expression.
Genomic Rearrangements in <i>Arabidopsis</i> Considered as Quantitative Traits.
Subject
View SamplesSplenic innate-like marginal zone B (MZB) cells are strategically positioned at the interface between the circulating blood and lymphoid tissue, where they initiate rapid immune responses to blood-borne antigens. Here, we find that selective genetic deletion of MZB cells substantially increases the follicular helper T (Tfh) cell and germinal center (GC) response to high cholesterol diet (HCD), which leads to T cell-dependent acceleration of atherosclerosis. We show that MZB cells activate a homeostatic program in response to HCD, in which upregulation of the transcription factor Atf3 plays a determinant regulatory role. Shuttling of MZB cells to the follicle is dispensable for their regulatory properties on Tfh cells. Instead, HCD promotes increased interaction between MZB and (pre-)Tfh cells outside the follicle, and upregulates MZB cell expression of Cd274 in an Atf3-dependent manner. Interaction between MZB and Tfh cells leads to Cd274-mediated suppression of Tfh cell motility, limits Tfh cell accumulation in the follicle and suppresses the pro-atherogenic Tfh/GC response. Our findings reveal a previously unsuspected role for MZB cells in the control of Tfh/GC response to a cholesterol diet, and uncover a new mechanism through which MZB cells can couple their unique metabolic and innate immune properties and use them to maintain a tolerogenic state. The results may have broad (patho)physiological implications. Overall design: Transcriptomic comparision between high-fat diet and standard chow in LDLr -/- splenic marginal zone B cells
Marginal zone B cells control the response of follicular helper T cells to a high-cholesterol diet.
No sample metadata fields
View SamplesGlucocorticoids (GC) are used as first line therapies for generalized suppression of inflammation (e.g. allergies or autoimmune diseases), but their long-term use is limited by severe side effects. Our previous work has revealed that GC induced a stable anti-inflammatory phenotype in monocytes, the glucocorticoid-stimulated monocytes (GCsM) that we now exploited for targeted GC-mediated therapeutic effects.
Immune suppression via glucocorticoid-stimulated monocytes: a novel mechanism to cope with inflammation.
Specimen part, Treatment
View SamplesPhospholamban R14del mutazion (PLN-R14del) has been identified in a large family pedigree in which heterozygous carriers exhibited inherited dilated cardiomyopathy (DCM) and death by middle age. To better understand the causal link between the mutations in PLN and DCM pathology, we derived induced pluripotent stem cells from a DCM patient carrying the PLN R14del mutation. We showed that iPSC-derived cardiomyocytes recapitulated the DCM-specific phenotype and demonstrated that either TALEN-mediated genetic correction or combinatorial gene therapy resulted in phenotypic rescue. Our findings offer novel insights into the pathogenesis caused by mutant PLN and point to the development of potential new therapeutics of pathogenic genetic variants associated with inherited cardiomyopathies. Overall design: iPSCs were derived from a female patient carrying a heterozygous mutation (R14del) in the PLN gene. Tree samples were analyzed: Cardiomyocytes derived from PLN-R41del iPSC cells (R14del-CM); R14del-CMs infected with AAV6-EGFP-miR-PLN and R14del-CMs infected with AAV6-EGFP-miR-luc used as a negative control
Correction of human phospholamban R14del mutation associated with cardiomyopathy using targeted nucleases and combination therapy.
No sample metadata fields
View SamplesThe differentiated state of somatic cells provides barriers for the efficient derivation of induced pluripotent stem cells (iPSCs). To address why some cell types reprogram more readily than others, we studied the effect of combined modulation of cellular signaling pathways. This revealed that inhibition of TGF together with activation of Wnt signaling in presence of ascorbic acid allows >80% of murine fibroblasts to acquire pluripotency after one week of reprogramming factor expression. In contrast, hepatic progenitors and blood progenitors predominantly required only TGF inhibition or canonical Wnt activation, respectively, to reprogram at efficiencies approaching 100%. Strikingly, blood progenitors reactivated endogenous pluripotency loci in a highly synchronous manner. We further demonstrate that expression of specific chromatin-modifying enzymes and reduced TGF/MAP kinase activity are intrinsic properties associated with the unique reprogramming response of these cells. Together, our observations define novel cell type-specific requirements for the rapid and synchronous reprogramming of somatic cells.
Combinatorial modulation of signaling pathways reveals cell-type-specific requirements for highly efficient and synchronous iPSC reprogramming.
Specimen part, Time
View SamplesCharacterization of the transcriptome of normal and abnormal embryos. Overall design: Gene expression profiling of every mono and trisomy.
Human blastocysts of normal and abnormal karyotypes display distinct transcriptome profiles.
Specimen part, Subject
View SamplesThe regional specificity and timing of gene activation following chemotherapy, and how this relates to subsequent mucositis development is currently unknown. The aim of the study was therefore to determine the early time course of gene expression changes along the gastrointestinal tract (GIT) of the DA rat following irinotecan treatment, so as to provide an insight into the genetic component of mucositis.
Gene expression analysis of multiple gastrointestinal regions reveals activation of common cell regulatory pathways following cytotoxic chemotherapy.
Sex, Age
View SamplesThe human steroid receptor RNA activator (SRA) gene encodes both non-coding RNAs (ncRNAs) and protein-generating isoforms. However, the breadth of endogenous target genes that might be regulated by SRA RNAs remains largely unknown. To address this, we depleted SRA RNA in two human cancer cell lines (HeLa and MCF-7) with small interfering RNAs, then assayed for changes in gene expression by microarray analyses using Affymetrix HGU133+2 arrays. We also tested if SRA depletion affects estradiol-regulated genes in MCF-7 breast cancer cells.
Research resource: expression profiling reveals unexpected targets and functions of the human steroid receptor RNA activator (SRA) gene.
Cell line
View SamplesSimilar to the bone marrow, the mammary gland contains a distinct population of Hoechst-effluxing side population cells, MG-SPs. To better characterize MG-SPs, their microarray gene profiles were compared to the remaining cells, which retain Hoechst dye (MG-NSPs). For analysis, gene ontology (GO) that describes genes in terms of biological processes and ontology traverser (OT) that performs enrichment analysis were utilized. OT showed that MG-SP specific genes were enriched in the GO categories of cell cycle regulation and checkpoints, multi-drug resistant transporters, organogenesis, and vasculogenesis. The MG-NSP upregulated genes were enriched in the GO category of cellular organization and biogenesis which includes basal epithelial markers, p63, smooth muscle actin (SMA), myosin, alpha-6 integrin, cytokeratin (CK) 14, as well as luminal markers, CK8 and CD24. Additional studies showed that a higher percentage of MG-SPs exist in the G1 phase of the cell cycle compared to the MG-NSPs. G1 cell cycle block of MG-SPs may be explained by higher expression of cell cycle negative regulatory genes such as TGF-beta2 (transforming growth factor-beta2), IGFBP-5 (insulin like growth factor binding protein-5), P18 INK4C and Wnt-5a (wingless-5a). Accordingly, a smaller percentage of MG-SPs expressed nuclear b-catenin, possibly as a consequence of the higher expression of Wnt-5a. In conclusion, microarray gene profiling suggests that MG-SPs are a lineage deficient mammary gland sub-population expressing key genes involved in cell cycle regulation, development and angiogenesis.
Transcriptional profiling of mammary gland side population cells.
No sample metadata fields
View SamplesMicrocystin-LR (MC-LR), the most toxic member of microcystin family, inhibits protein phosphatase PP2A, triggers oxidative stress and induces hepatotoxicity. Gene expression profiling of MC-LR treated larvae using DNA microarray analysis revealed effects in the retinal visual cycle and pigmentation synthesis pathways that have not been previously associated with MC-LR. Liver-related genes were also differentially expressed. The microarray data were confirmed by quantitative real-time PCR. Our findings provide new evidence that microcystin-LR exposure of zebrafish larvae modulates the retinal visual cycle and pigmentation synthesis pathways and ultimately alter larval zebrafish behavior
Transcriptional and Behavioral Responses of Zebrafish Larvae to Microcystin-LR Exposure.
Specimen part
View Samples