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microRNAs(miRNAs)是一类内源性非编码小RNA,通过调控基因表达来参与生命过程中的一系列重要进程。越来越多的证据表明,miRNAs参与了几乎所有生物代谢过程,其胚胎干细胞的自我更新与分化和在多能干细胞(iPSCs)中的诱导调节作用也日益受到关注。该文介绍了miRNAs的生成、检测方法以及miRNAs对胚胎干细胞(ESCs)及诱导多能性干细胞的调控作用,并对miRNAs的应用前景进行了展望。  相似文献   

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Induced pluripotent stem (iPS) cells derived from terminally differentiated human fibroblasts are reprogrammed to possess stem cell like properties. However, the extent to which iPS cells exhibit unique properties of the human embryonic stem (hES) cell cycle remains to be established. hES cells are characterized by an abbreviated G1 phase (~ 2.5 h) and accelerated organization of subnuclear domains that mediate the assembly of regulatory machinery for histone gene expression [i.e., histone locus bodies (HLBs)]. We therefore examined cell cycle parameters of iPS cells in comparison to hES cells. Analysis of DNA synthesis [5-bromo-2'-deoxy-uridine (BrdU) incorporation], cell cycle distribution (FACS analysis and Ki67 staining) and subnuclear organization of HLBs [immunofluorescence microscopy and fluorescence in situ hybridization (FISH)] revealed that human iPS cells have a short G1 phase (~ 2.5 h) and an abbreviated cell cycle (16-18 h). Furthermore, HLBs are formed and reorganized rapidly after mitosis (within 1.5-2 h). Thus, reprogrammed iPS cells have cell cycle kinetics and dynamic subnuclear organization of regulatory machinery that are principal properties of pluripotent hES cells. Our findings support the concept that the abbreviated cell cycle of hES and iPS cells is functionally linked to pluripotency.  相似文献   

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The embryonic stem cell-specific cell cycle-regulating (ESCC) family of microRNAs (miRNAs) enhances reprogramming of mouse embryonic fibroblasts to induced pluripotent stem cells. Here we show that the human ESCC miRNA orthologs hsa-miR-302b and hsa-miR-372 promote human somatic cell reprogramming. Furthermore, these miRNAs repress multiple target genes, with downregulation of individual targets only partially recapitulating the total miRNA effects. These targets regulate various cellular processes, including cell cycle, epithelial-mesenchymal transition (EMT), epigenetic regulation and vesicular transport. ESCC miRNAs have a known role in regulating the unique embryonic stem cell cycle. We show that they also increase the kinetics of mesenchymal-epithelial transition during reprogramming and block TGFβ-induced EMT of human epithelial cells. These results demonstrate that the ESCC miRNAs promote dedifferentiation by acting on multiple downstream pathways. We propose that individual miRNAs generally act through numerous pathways that synergize to regulate and enforce cell fate decisions.  相似文献   

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Over the last years, the microRNA (miRNA) pathway has emerged as a key component of the regulatory network of pluripotency. Although clearly distinct states of pluripotency have been described in vivo and ex vivo, differences in miRNA expression profiles associated with the developmental modulation of pluripotency have not been extensively studied so far. Here, we performed deep sequencing to profile miRNA expression in naive (embryonic stem cell [ESC]) and primed (epiblast stem cell [EpiSC]) pluripotent stem cells derived from mouse embryos of identical genetic background. We developed a graphical representation method allowing the rapid identification of miRNAs with an atypical profile including mirtrons, a small nucleolar RNA (snoRNA)-derived miRNA, and miRNAs whose biogenesis may differ between ESC and EpiSC. Comparison of mature miRNA profiles revealed that ESCs and EpiSCs exhibit very different miRNA signatures with one third of miRNAs being differentially expressed between the two cell types. Notably, differential expression of several clusters, including miR290-295, miR17-92, miR302/367, and a large repetitive cluster on chromosome 2, was observed. Our analysis also showed that differentiation priming of EpiSC compared to ESC is evidenced by changes in miRNA expression. These dynamic changes in miRNAs signature are likely to reflect both redundant and specific roles of miRNAs in the fine-tuning of pluripotency during development.  相似文献   

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