Single-cell transcriptome profiling of Sox2-low iPS cells
Ontology highlight
ABSTRACT: Single-cell RNA-seq was performed on homozygous Sox2 knockout induced pluripotent stem (iPS) cells, where residual Sox2 expression is observed from incompletely silenced retroviral transgenes. These were compared to Sox2-low iPS cells rescued by exogenous Sox2 transgenic expression, and wild-type iPS cells to assess the lineage expression profile of Sox2-low cells and degree of transcriptional heterogeneity in each population.
Project description:A simple method is presented to reset human pluripotent cells to a naive state via transient histone deacetylase inhibition and maintenance in chemically-defined naive stem cell culture media. Cells can be reset without transgenes and expanded continuously either on feeders or alternative substrates in feeder-free conditions. Multiple cell lines of varying origin were reset and characterised in parallel with conventionally cultured counterparts.
Project description:Transfer of somatic cell nuclei to enucleated eggs or ectopic expression of specific transcription factors are two different reprogramming strategies used to generate pluripotent cells from differentiated cells. However, they are poorly efficient and other unknown factors might be required to increase their success rate. Here, we show that Xenopus egg extracts at the metaphase stage (M phase) have a strong reprogramming activity on mouse embryonic fibroblasts (MEFs). First, they reset replication properties of MEF nuclei toward a replication profile characteristic of early development and they erase several epigenetic marks, such as trimethylation of H3K9, H3K4 and H4K20. Second, when MEFs are reversibly permeabilized in the presence of M phase Xenopus egg extracts, they show a transient increase in cell proliferation, form colonies and start to express specific pluripotency markers. Finally, transient exposure of MEF nuclei to M phase Xenopus egg extracts increases the success of nuclear transfer to enucleated mouse oocytes and strongly synergize with the production of pluripotent stem cells by ectopic expression of transcription factors. The mitotic stage of the egg extract is crucial as neither of these effects is detected when using interphasic Xenopus egg extracts. Our data demonstrate that mitosis is essential to make mammalian somatic nuclei prone to reprogramming and that, surprisingly, the heterologous Xenopus system has features that are conserved enough to remodel mammalian nuclei. MEF cells were infected by retroviruses encoding for Oct4, Sox2, Klf4 and c-Myc and, then reversibly permeabilized and treated with Xenopus M-phase extract. All samples of each cell type (e.g. untreated MEF, ES cells and M-iPS cells) were made in triplicates. Total RNAs were extracted with RNeasy kit and hybridized on Nimblegen MM9 microarrays.
Project description:We found that MCF7 and ZR751 Sox2-expressing breast cancer cell lines comprise of cells with heterogeneous Sox2 transcription activity reporter response. A small subset of Sox2 reporter responsive cells are more tumourigenic than the bulk Sox2 reporter unresponsive cells. We questioned whether Sox2 exhibit differential gene promoter occupancies in the two cell subsets to govern differential gene expression patterns. Sox2 ChIP in reporter unresponsive (RU) and reporter responsive (RR) cells (duplicate samples) were compared. IgG ChIP in RU and RR cells served as the negative controls.
Project description:Glioblastomas type A cell line (U-2987) was transfected with pLEX-blast-V5-YFP (control), and pLEX-blast-V5-SFRP2 (SFRP2), and type B cell culture (U-2982, U-343 MG) were transfected with pLEX-blast-V5-YFP (control), and pLEX-blast-V5-SOX2 (SOX2). Then RNA-seq was performed and used to analyse their regulation in the gene expression level.
Project description:Pluripotency can be induced in murine and human fibroblast by transduction of four transcription factors (Oct4, Sox2, Klf4 and c-Myc). Previously we reported that two factors (Oct4 and Klf4) are sufficient for reprogramming adult mouse neural stem cells (NSCs) to a pluripotent state. However, although NSCs endogenously express the factors Sox2, c-Myc, and Klf4, our previous report does not elucidate why exogenous expression of either Klf4 or c-Myc is still required for reprogramming. Here we report that exogenous expression of Oct4 is sufficient to generate one-factor induced pluripotent stem (1F iPS) cells without any oncogenic factors, such as c-Myc and Klf4, from mouse adult NSCs, which endogenously express Sox2, c-Myc, and Klf4, and also intermediate reprogramming markers alkaline phosphatase (AP), stage-specific embryonic antigen-1 (SSEA-1). These results extend our previous report proposing that somatic cells can be reprogrammed to a pluripotent state with a reducing number of reprogramming factors when the complementing factors are endogenously expressed in the somatic cells. Experiment Overall Design: 10 hybridizations in total. Experiment Overall Design: NSC-derived iPS cells by one-factor (Oct4) in triplicate: Experiment Overall Design: - NSC_1F_iPS_1 Experiment Overall Design: - NSC_1F_iPS_2 Experiment Overall Design: - NSC_1F_iPS_3 Experiment Overall Design: One-factor (Oct4) iPS cell-derived NSC in triplicate: Experiment Overall Design: - 1F_iPS_NSC_1 Experiment Overall Design: - 1F_iPS_NSC_2 Experiment Overall Design: - 1F_iPS_NSC_3 Experiment Overall Design: Neural stem cell (NSC) derived from brain of OG2/Rosa26 mice: Experiment Overall Design: - NSC_1 Experiment Overall Design: - NSC_2 Experiment Overall Design: - NSC_3 Experiment Overall Design: - NSC_4
Project description:Rabbit embryos, as in humans, develop as bilaminar discs at gastrulation and unlike egg cylinders as in rodents. Mammalian primordial germ cells (PGCs) in all species originate during gastrulation. We sequence the transcriptomes of rabbit embryos during gastrulation, and show that rabbit PGC (rbPGC) specification occurs at the posterior epiblast at the onset of gastrulation
Project description:Primitive neural stem cells (NSCs) could be derived from pluripotent mouse embryonic stem (ES) cells, and then differentiate into definitive-type neural stem cells which resemble NSCs obtained from the central nervous system. Hence, primitive NSCs define an early stage of neural induction and provide a model to understand the mechanism that controls initial neural commitment. In this study, we performed microarray assay to analyze the global transcriptional profiles in mouse ES cell-derived primitive and definitive NSCs and to depict the molecular changes during the multi-staged neural differentiation process. Primitive NSCs derived directly from ESCs in Lif (p-NSC_L), primitive NSCs that were sub-cultured in the presence of Lif and FGF (p-NSC_LF), as well as definitive NSCs derived from primitive NSCs in medium containing FGF and EGF, were collected for RNA extraction and hybridization on Affymetrix microarrays. Mouse ESCs and NSCs obtained from mouse embryonic brain (E11.5) were included for controls. For each cell type, we collected two biological replicate samples for microarray analysis.
Project description:Mouse embryonic stem cells (i.e., mESCs; line ESC 129-B13) were genetically modified using CRISPR-Cas9 to mutate the H3f3b locus, in order to carry homozygous lysine-to-alanine substitution of residues K9, K27 or K79. Two control mESC lines carrying knock-out of the H3f3a gene were used as background for the editing. Low-coverage whole-genome sequencing (~0.8/0.9X) was performed to assess the chromosomal integrity of the edited lines. Genomic DNA was extracted from each mutant and control mESC line and sonicated to obtain fragments of ~150-200bp on average. Fragmented DNA (~0.5-1 ug) was used for library preparation using the NEBNext Ultra II DNA library preparation kit (New England Biolabs). Sequencing was performed on a NextSeq500 platform in single-end mode (75bp reads).
Project description:Induced pluripotent stem (iPS) cell reprogramming is a gradual epigenetic process that reactivates the pluripotent transcriptional network by erasing and establishing heterochromatin marks. Here, we characterize the physical structure of heterochromatin domains in full and partial mouse iPS cells by correlative Electron Spectroscopic Imaging (ESI). In somatic and partial iPS cells, constitutive heterochromatin marked by H3K9me3 is highly compartmentalized into chromocenter structures of densely packed 10 nm chromatin fibers. In contrast, chromocenter boundaries are poorly defined in pluripotent ES and full iPS cells, and are characterized by unusually dispersed 10 nm heterochromatin fibers in high Nanog-expressing cells, including pluripotent cells of the mouse blastocyst prior to differentiation. This heterochromatin reorganization accompanies retroviral silencing during conversion of partial iPS cells by Mek/Gsk3 2i inhibitor treatment. Thus, constitutive heterochromatin reorganization serves as a novel biomarker with retroviral silencing for identifying iPS cells in the very late stages of reprogramming. We compared the expression profiles of partially and fully reprogrammed iPS cell lines derived from CD1 mouse embryonic fibroblasts (MEFSs) by retroviral reprogramming (pMX-Oct4, pMX-Klf4 and pMX-Sox2). to the differentiated MEFS and the J1 embryonic stem cell line. We also studied the effect of a 2i cocktail treatment in partially reprogrammed iPS cells.