Single cell RNA-seq of WTC-CRISPRi human induced pluripotent stem cells
ABSTRACT: We performed 3' single-cell RNA-seq using the 10X Genomics Chromium (version 1 chemistry) system on ~19,000 undifferentiated human IPSCs to explore the cellular heterogeneity of a seemingly homogeneous cell population.
Project description:Endothelial cells are generated independently in the yolk sac, allantois and embryo proper. We dissected embryos from embryonic day 8.25 and captured individual cells from each of these positions within the embryo to investigate how their transcriptional signatures differ. Single-cell libraries were prepared for sequencing using the Smart-seq2 protocol.
Project description:Seed size is important to crop domestication and natural selection and is affected by the balance of maternal and paternal genomes in endosperm. Endosperm, like placenta in mammals, provides reserves to the developing embryo. Interploidy crosses disrupt the genome balance in endosperm and alter seed size. Specifically, paternal-excess crosses (2 × 4) delay endosperm cellularization (EC) and produce larger seeds, whereas maternal-excess crosses (4 × 2) promote precocious EC and produce smaller seeds. The mechanisms for responding to the parental genome dosage imbalance and for gene expression changes in endosperm are unknown. In plants, RNA polymerase IV (PolIV or p4) encoded by NRPD1a is required for biogenesis of a major class of 24-nt small interfering RNAs (also known as p4-siRNAs), which are predominately expressed in developing endosperm. Here we show that p4-siRNA accumulation depends on the maternal genome dosage, and maternal p4-siRNAs target transposable elements (TEs) and TE-associated genes (TAGs) in seeds. The p4-siRNAs correlate negatively with expression levels of AGAMOUS-LIKE (AGL) genes in endosperm of interploidy crosses. Moreover, disruption of maternal NRPD1a expression is associated with p4-siRNA reduction and AGL up-regulation in endosperm of reciprocal crosses. This is unique genetic evidence for maternal siRNAs in response to parental genome imbalance and in control of transposons and gene expression during endosperm development. 8 samples: 2x X 2x seed,leaf; 4x X 4x seed,leaf; 2x X 4x seed,leaf; 4x X 2x seed,leaf.
Project description:Activation of CD8+ T cells depends exquisitely on the affinity of the T cell receptor (TCR) for a peptide MHC (pMHC) ligand complex. Here, we activated OT-I transgenic CD8+ T cells with pure peptide and examined early activation responses by single-cell RNA-sequencing. T cells were activated with the high affinity OT-I cognate peptide (N4=SIINFEKL) for 1, 3 or 6 hours, or with reduced affinity peptides (T4=SIITFEKL and G4=SIIGFEKL) or the non-binding peptide (NP68=ASNENMDAM) for 6 hours. Cells were then sorted into 96-well plates by FACS and RNA was sequenced following an adapted Smart-Seq2 protocol.
Project description:Adeno-associated viral (AAV) small hairpin (shRNA) expression vectors are a promising therapeutic but can induce severe liver toxicity when delivered at high albeit undefined doses. Using various AAV-shRNA vectors under the high-expressing U6 and low-expressing H1 promoters, we found that dose-limiting toxicity was strongly correlated with an shRNA concentration of >12% of total microRNA levels. Toxicity was associated with a specific reduction in the first synthesized 22nt isoform of miR-122-5p, resulting in the specific de-repression of miR-122 target mRNAs. A causative link between miR-122 reduction and toxicity was established when an AAV-sh-miR-122 vector producing >20% of the total liver miRNAs prevented liver toxicity. Consistent with these results, miR-122 knockout mice, which in part adapt to an absence of miR-122 reduction, also show no toxicity with high dose AAV-shRNA delivery. RNA sequencing of 12 liver samples, 2 receiving H1-shRNAs, 7 with U6-shRNAs and 3 controls; small RNA sequencing of 95 samples including 18 with CMV-driven miR-122 expression in HEK293 cells, 13 in miR-122 knockout mice, 9 samples in mice heterozygous for miR-122, 5 samples with Cre-mediate excision of miR-122, 19 samples immunoprecipitated with Ago2 and 31 additional liver samples (3 control, 11 receiving H1-shRNAs and 17 receiving U6-shRNAs). Small RNA libraries were barcoded (first 4 nucleotides) at the 5' end and ligated to linker-1 (5'-CTGTAGGCACCATCAAT) at the 3' end.
Project description:MicroRNAs (miRNAs) are small regulatory molecules that cause post-transcriptional gene silencing. Although some miRNAs are known to have region-specific expression patterns in the adult brain, the functional consequences of the region-specificity to the gene regulatory networks of the brain nuclei are not clear. Therefore, we studied miRNA expression patterns by miRNA-seq in two brain regions, frontal cortex (FCx) and hippocampus (HP), which have separate biological functions. We identified 354 miRNA from FCx and 408 from HP. Several miRNA families and clusters were differentially expressed between FCx and HP, including the miR-8 family, miR-182|miR-96|miR-183 cluster, and miR-212|miR-312 cluster overexpressed in FCx and miR-34 family overexpressed in HP. To visualize the clusters, we developed support for viewing genomic alignments of miRNA-seq reads in the Chipster genome browser. We carried out pathway analysis of the predicted target genes of differentially expressed miRNA families and clusters to assess their putative biological functions. Interestingly, specific pathways were identified that are predicted to be regulated by several miRNAs from the same family/cluster. We have developed a miRNA-seq approach with a bioinformatic analysis workflow that is suitable for studying miRNA expression patterns from specific brain nuclei. FCx and HP were shown to have distinct miRNA expression patterns which were reflected in the predicted gene regulatory pathways. This methodology can be applied for the identification of brain region-specific and phenotype-specific miRNA-mRNA-regulatory networks from the adult and developing rodent brain. miRNA-seq of 3 replicates from frontal cortex, 3 replicates from hippocampus, and pooled sequence runs from both
Project description:RNA samples from human tissues (brain and liver) and cell lines (K562 and HL60) were used to assess RNA fragmentation, RNA fractionation, cDNA synthesis, and single versus multiple tag counting. Technical replicates and different cDNA synthesis protocols were compared. Though protocols employing polyA RNA selection generate the highest number of non-ribosomal reads and the most precise measurements for coding transcripts, such protocols were found to detect only a fraction of the non-ribosomal RNA in human cells. PolyA RNA excludes thousands of annotated and even more unannotated transcripts, resulting in an incomplete view of the transcriptome. Ribosomal-depleted RNA provides a more cost-effective method for generating complete transcriptome coverage. Expression measurements using single tag counting provided advantages for assessing gene expression and for detecting short RNAs relative to multi-read protocols. Detection of short RNAs was also hampered by RNA fragmentation. 69 different sequencing channels from a HeliScope Genetic Analysis System and 2 channels from an Illumina machine are included. Some samples were sequenced on multiple channels and some samples include technical replicates.
Project description:BCL6 is crucial for B-cell activation and lymphomagenesis. We used integrative genomics to explore BCL6 mechanism in normal and malignant B-cells. Surprisingly, BCL6 assembled distinct complexes at enhancers vs. promoters. At enhancers BCL6 preferentially recruited SMRT, which mediated H3K27 deacetylation through HDAC3, antagonized p300 activity and repressed transcription, but without decommissioning enhancers. This provides a biochemical basis for toggling enhancers from the active to poised state. Virtually all SMRT was bound with BCL6 suggesting that in B-cells BCL6 uniquely sequesters SMRT from other factors. In promoters BCL6 preferentially recruited BCOR, but most potently repressed promoters where it formed a distinctive ternary complex with SMRT and BCOR. Promoter repression was associated with decreased H3K36me3, H3K79me2 and Pol II elongation, linking BCL6 to transcriptional pausing. We identified the binding patterns of BCL6, SMRT, NCOR and BCOR corepressors in normal germinal center B cells and a DLBCL cell line (OCI-Ly1) using ChIP-seq. Additionally we treated lymphoma cells with siRNA against BCL6 and a non-targeted siRNA (NT control) and performed RNA-seq to identify the genes bound and repressed by BCL6. RNA-seq experiments were performed at 24h and 48h after siRNA treatments. Additional biological triplicate RNA-seq experiments were performed at 48h after BCL6 knockdown. Furthermore, a series of histone mark ChIP-seq and RNA polymerase ChIP-seq (total, Ser5-P and Ser2-P) were preformed to capture the chromatin states associated with the formation of BCL6 corepressor complexes.
Project description:Differentiation into diverse cell lineages requires orchestration of gene regulatory networks guiding cell fate choices. Genetic factors acting through changes in transcriptional levels can contribute to cardiovascular disease risk by impacting early stages of development and have cell type-specific effects. We set out to characterize lineage trajectory progression of subpopulations and identify potential disease-related genes by examining their expression changes in single cells during early stages of cardiac lineage specification. Using 43,168 single-cell transcriptomes, we developed novel classification and trajectory analysis methods to dissect cellular composition and gene networks across five discrete time points underlying lineage derivation of mesoderm, definitive endoderm, vascular endothelium, cardiac precursors, and definitive cell types that comprise cardiomyocytes and a previously unrecognized cardiac outflow tract population.
Project description:Single-cell expression profiling by RNA-Seq promises to exploit cell-to-cell variation in gene expression to reveal regulatory circuitry governing cell differentiation and other biological processes. Here, we describe Monocle, a novel unsupervised algorithm for ordering cells by progress through differentiation that dramatically increases temporal resolution of expression measurements. This reordering unmasks switch-like changes in expression of key regulatory factors, reveals sequentially organized waves of gene regulation, and exposes regulators of cell differentiation. A functional screen confirms that a number of these regulators dramatically alter the efficiency of myoblast differentiation, demonstrating that single-cell expression analysis with Monocle can uncover new regulators even in well-studied systems. We selected primary human myoblasts as a model system of cell differentiation to investigate whether ordering cells by progress revealed new regulators of the process. We sequenced RNA-Seq libraries from each of several hundred cells taken over a time-course of serum-induced differentiation. Please note that this dataset is a single-cell RNA-Seq data set, and each cell comes from a capture plate. Thus, each well of the plate was scored and flagged with several QC criteria prior to library construction, which are provided as sample characteristics; CONTROL indicates that this library is a off-chip tube control library constructed from RNA of approximately 250 cells and 'DEBRIS' indicates that the well contained visible debris (and may or may not include a cell). Libraries marked DEBRIS thus cannot be confirmed to come from a single cell.