The rate of cell differentiation is tightly controlled and critical for normal development and stem cell differentiation. However, so far it has been difficult to control the rate of ESCs differentiation. Here we report the acceleration of the differentiation rate due to the activation of protein kinase A (PKA) and the associated early loss of embryonic stem cells (ESCs) pluripotency markers and the early appearance of mesodermal and other germ layer cell markers.
Protein kinase A accelerates the rate of early stage differentiation of pluripotent stem cells.
Time
View SamplesThe forced expression of Yamanaka factors (Oct3/4, Sox2, Klf4, and c-Myc) reprograms cells into induced pluripotent stem cells (iPSCs) through a series of sequential cell fate conversions. The order and robustness of gene expression changes are highly depended on the Yamanaka factor stoichiometry. We specifically focused on two different reprogramming paths induced by high- and low-Klf4 stoichiometry, which were accomplished by introducing OK+9MS or OKMS polycistronic cassettes, respectively, into mouse embryonic fibroblasts. By comparing these reprograming intermediates with embryonic stem cells (ESCs) and primary keratinocytes, we identified high-Klf4 specific, transiently up-regulated epithelial genes. We found that expression of these epithelial genes was enriched in a TROP2-positive cell population. Moreover, we identified a set of transcription factors which are candidates for the regulation of transiently expressed epithelial genes, and revealed their connection to high-Klf4-specific reprogramming hallmarks.
OVOL1 Influences the Determination and Expansion of iPSC Reprogramming Intermediates.
Specimen part, Treatment
View SamplesOct3/4, Sox2, Klf4, and c-Myc re-wire somatic cells to achieve induced pluripotency (iPS cells). However, subtle differences in reprogramming methodology may confound comparative studies of reprogramming-induced gene expression changes. We specifically focused on the design of polycistronic reprogramming constructs, which encode all four factors linked with 2A peptides. Notably, publically available cassettes were found to employ one of two Klf4 variants (Klf4S and Klf4L; GenBank Accession Nos: AAC52939.1 and AAC04892.1), differing only by nine N-terminal amino acids. In a polycistronic context, these two variants generated dissimilar protein stoichiometry, where Klf4L vectors produced more Klf4 protein than those encoding Klf4S.
KLF4 N-terminal variance modulates induced reprogramming to pluripotency.
Sex, Specimen part
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Srf destabilizes cellular identity by suppressing cell-type-specific gene expression programs.
Specimen part
View SamplesMulticellular organisms consist of multiple cell types, whose identities are maintained appropriately at locations where they are reside. The identity of each cell type is primarily maintained by cell-type-specific gene expression programs, but mechanisms that suppress these programs are poorly defined. Here we show that serum response factor (Srf), a transcription factor that is activated by various extracellular stimuli, can repress cell-type-specific genes and promote cellular reprogramming to pluripotency. Manipulations that decrease -actin monomer resulted in nuclear accumulation of Mkl1 and the activation of Srf, which downregulated cell-type-specific genes and altered epigenetics in enhancers and chromatin organization. Mice overexpressing Srf exhibited various pathologies including an ulcerative colitis-like symptom and a metaplasia-like phenotype in the pancreas. Our results demonstrate an unexpected function of Srf via a mechanism by which extracellular stimuli actively destabilize cell identity and suggest Srf involvement in a wide range of diseases.
Srf destabilizes cellular identity by suppressing cell-type-specific gene expression programs.
Specimen part
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Differentiation-defective phenotypes revealed by large-scale analyses of human pluripotent stem cells.
Specimen part
View SamplesIt remains controversial whether human induced pluripotent stem cells (hiPSCs) are distinct from human embryonic stem cells (hESCs) in their molecular signatures and differentiation properties. We examined the gene expression and DNA methylation of 49 hiPSC and 10 hESC lines and identified no molecular signatures that distinguished hiPSCs from hESCs. Comparisons of the in vitro directed neural differentiation of 40 hiPSC and four hESC lines showed that most hiPSC clones were comparable to hESCs. However, in seven hiPSC clones, significant amount of undifferentiated cells persisted even after neural differentiation and resulted in teratoma formation when transplantated into mouse brains. These differentiation-defective hiPSC clones were marked by higher expression of several genes, including those expressed from long terminal repeats of human endogenous retroviruses. These data demonstrated that many hiPSC clones are indistinguishable from hESCs, while some defective hiPSC clones need to be eliminated prior to their application for regenerative medicine.
Differentiation-defective phenotypes revealed by large-scale analyses of human pluripotent stem cells.
Specimen part
View SamplesSpecification of germ cell fate is fundamental in development. With a highly representative single-cell microarray and rigorous quantitative-PCR analysis, we defined the genome-wide transcription dynamics that create primordial germ cells (PGCs) from the epiblast, a process that exclusively segregates them from their somatic neighbors. We also analyzed the effect of the loss of Blimp1, a key transcriptional regulator, on these dynamics. Our analysis revealed that PGC specification involves complex, yet highly ordered regulation of a large number of genes, proceeding under the strong influence of mesoderm induction with active repression of specific programs such as epithelial-mesenchymal transition, Hox gene activation, cell-cycle progression and DNA methyltransferase machinery. Remarkably, Blimp1 is essential for repressing nearly all the genes normally down-regulated in PGCs relative to their somatic neighbors, whereas it is dispensable for the activation of approximately half of the genes up-regulated in PGCs.
Complex genome-wide transcription dynamics orchestrated by Blimp1 for the specification of the germ cell lineage in mice.
No sample metadata fields
View SamplesMany organisms acquired circadian clock system to adapt daily and seasonal environmental changes. Mammals have the master clock in the brains suprachiasmatic nucleus (SCN) that synchronizes other circadian clocks in the peripheral tissues or organs. Plants also have circadian clock in their bodies, but the presence of the tissue-specific functions of circadian clock is remained elusive. The aim of this experiment is to compare tissue-specific gene expression profile using gene expression Microarray.
Tissue-specific clocks in Arabidopsis show asymmetric coupling.
Specimen part, Time
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Induction of mouse germ-cell fate by transcription factors in vitro.
Sex, Specimen part
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