Specification 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.
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Many 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, TimeView Samples
Spermatogonial stem cells (SSCs) have pluripotent potential. However, frequency of pluripotent cell derivation is low and the mechanism of culture-induced reprogramming remains unknown. Here we report that epigenetic instability of germline stem (GS) cells, cultured SSCs, induces pluripotent cell derivation. GS cells undergo DNA demethylation in H19 differentially methylated region under low-density culture. When H19 demethylation was induced by Dnmt1 depletion, they converted into embryonic stem (ES)-like cells. Dnmt1 depletion downregulated Dmrt1 expression, whose depletion also induced pluripotency. Functional screening of Dmrt1 target gene revealed that Dmrt1 depletion upregulates Sox2, the key molecule responsible for generating induced pluripotent stem cells. Although Sox2 transfection upregulated Oct4 and produced pluripotent cells, this conversion was inhibited by Oct1 overexpression, suggesting that the balance of Oct proteins maintains SSC identity. These results suggest that culture-induced reprogramming is caused by unstable DNA methylation, and that Dmrt1-Sox2 cascade is critical for regulating pluripotency in SSCs.
Regulation of pluripotency in male germline stem cells by Dmrt1.
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This SuperSeries is composed of the SubSeries listed below.
Identification of MMP1 as a novel risk factor for intracranial aneurysms in ADPKD using iPSC models.
Sex, Specimen part, Disease stage, SubjectView Samples
Comparison of gene expressions among FOP- or resFOP-iMSCs after chondrogenic differentiation with Activin-A, BMP-7 or TGF-B3
Activin-A enhances mTOR signaling to promote aberrant chondrogenesis in fibrodysplasia ossificans progressiva.
Specimen partView Samples
The germ cell lineage ensures the continuity of life through the generation of male and female gametes, which unite to form a totipotent zygote. We have established a culture system that recapitulates the mouse germ-cell specification pathway: Using cytokines, embryonic stem cells (ESCs)/induced pluripotent stem cells (iPSCs) are induced into epiblast-like cells (EpiLCs) and then into primordial germ cell-like cells (PGCLCs) with capacity both for spermatogenesis and oogenesis, creating an opportunity for understanding and regulating mammalian germ cell development in both sexes in vitro. Here we show that, without cytokines, simultaneous over-expression of three transcription factors (TFs), Blimp1 (also known as Prdm1), Prdm14 and Tfap2c (also known as AP2), directs EpiLCs, but not ESCs, swiftly and highly efficiently into a PGC state with endogenous transcription circuitry. The induction of the PGC state on EpiLCs minimally requires Prdm14 but not Blimp1 or Tfap2c. The TF-induced PGC state reconstitutes key transcriptome and epigenetic reprogramming in PGCs, but bypasses a mesodermal program that accompanies PGC specification in vivo and in vitro by cytokines including BMP4. Importantly, the TF-induced PGC-like cells robustly contribute to spermatogenesis and fertile offspring. Our findings provide not only a novel insight into the transcriptional logic that creates a germ cell state, but also a foundation for the TF-based reconstitution and regulation of mammalian gametogenesis.
Induction of mouse germ-cell fate by transcription factors in vitro.
Sex, Specimen partView Samples
Global gene expression profiling of human iPSC and the iPSC-derived presomitic mesoderm(PSM), somite(SM), and the derivatives, dermomyotome(DM), dermatome(D), myotome(MYO), sclerotome(SCL) and syndetome(SYN).
Modeling human somite development and fibrodysplasia ossificans progressiva with induced pluripotent stem cells.
Specimen part, TimeView Samples