38 research outputs found

    Histone modifications form a cell-type-specific chromosomal bar code that persists through the cell cycle.

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    Chromatin configuration influences gene expression in eukaryotes at multiple levels, from individual nucleosomes to chromatin domains several Mb long. Post-translational modifications (PTM) of core histones seem to be involved in chromatin structural transitions, but how remains unclear. To explore this, we used ChIP-seq and two cell types, HeLa and lymphoblastoid (LCL), to define how changes in chromatin packaging through the cell cycle influence the distributions of three transcription-associated histone modifications, H3K9ac, H3K4me3 and H3K27me3. We show that chromosome regions (bands) of 10-50 Mb, detectable by immunofluorescence microscopy of metaphase (M) chromosomes, are also present in G1 and G2. They comprise 1-5 Mb sub-bands that differ between HeLa and LCL but remain consistent through the cell cycle. The same sub-bands are defined by H3K9ac and H3K4me3, while H3K27me3 spreads more widely. We found little change between cell cycle phases, whether compared by 5 Kb rolling windows or when analysis was restricted to functional elements such as transcription start sites and topologically associating domains. Only a small number of genes showed cell-cycle related changes: at genes encoding proteins involved in mitosis, H3K9 became highly acetylated in G2M, possibly because of ongoing transcription. In conclusion, modified histone isoforms H3K9ac, H3K4me3 and H3K27me3 exhibit a characteristic genomic distribution at resolutions of 1 Mb and below that differs between HeLa and lymphoblastoid cells but remains remarkably consistent through the cell cycle. We suggest that this cell-type-specific chromosomal bar-code is part of a homeostatic mechanism by which cells retain their characteristic gene expression patterns, and hence their identity, through multiple mitoses

    Transition to naïve human pluripotency mirrors pan-cancer DNA hypermethylation.

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    Epigenetic reprogramming is a cancer hallmark, but how it unfolds during early neoplastic events and its role in carcinogenesis and cancer progression is not fully understood. Here we show that resetting from primed to naïve human pluripotency results in acquisition of a DNA methylation landscape mirroring the cancer DNA methylome, with gradual hypermethylation of bivalent developmental genes. We identify a dichotomy between bivalent genes that do and do not become hypermethylated, which is also mirrored in cancer. We find that loss of H3K4me3 at bivalent regions is associated with gain of methylation. Additionally, we observe that promoter CpG island hypermethylation is not restricted solely to emerging naïve cells, suggesting that it is a feature of a heterogeneous intermediate population during resetting. These results indicate that transition to naïve pluripotency and oncogenic transformation share common epigenetic trajectories, which implicates reprogramming and the pluripotency network as a central hub in cancer formation

    Resetting transcription factor control circuitry toward ground-state pluripotency in human.

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    Current human pluripotent stem cells lack the transcription factor circuitry that governs the ground state of mouse embryonic stem cells (ESC). Here, we report that short-term expression of two components, NANOG and KLF2, is sufficient to ignite other elements of the network and reset the human pluripotent state. Inhibition of ERK and protein kinase C sustains a transgene-independent rewired state. Reset cells self-renew continuously without ERK signaling, are phenotypically stable, and are karyotypically intact. They differentiate in vitro and form teratomas in vivo. Metabolism is reprogrammed with activation of mitochondrial respiration as in ESC. DNA methylation is dramatically reduced and transcriptome state is globally realigned across multiple cell lines. Depletion of ground-state transcription factors, TFCP2L1 or KLF4, has marginal impact on conventional human pluripotent stem cells but collapses the reset state. These findings demonstrate feasibility of installing and propagating functional control circuitry for ground-state pluripotency in human cells.This research was supported by the UK Medical Research Council, the Japan Science and Technology agency (JST, PRESTO), the Genome Biology Unit of the European Molecular Biology Laboratory, European Commission projects PluriMes, BetaCellTherapy, EpiGeneSys, and Blueprint, and the Wellcome Trust. Y.T. was a University of Cambridge Herchel Smith Fellow. A.S. is a Medical Research Council Professor

    Analisis Pengaruh Budaya Organisasi Dan Kompensasi Terhadap Kinerja Karyawan Dengan Motivasi Sebagai Variabel Intervening (Studi Kasus Pada PT. Lg Bagian Penjualan Indonesia Semarang)

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    The problems that occurred in the employee portion of sales LG Indonesia Semarang is adecline in performance is indicated by not achieving the target for 2015. The employeeperformance and motivation is also thought to be influenced by factors of organizationalculture and also compensation deemed not feasible by most employees. This study aimedto analyze the influence of organizational culture on the motivation and compensationand employee performance parts sales LG Indonesia Semarang. The population used inthis study were all employees of LG Indonesia Semarang. The sampling technique usedwas purposive sampling. Criteria samples taken were all employees of the salesdepartment LG Indonesia Semarang who have worked more than two years are 71nurses. The method of collecting the data in this study using questionnaires andinterviews. Methods of data analysis using path analysis. Based on the research,organizational culture and compensation have a positive effect on motivation andperformance, while motivation is also a positive effect on performance. Based on theresults Sobel Test to determine whether there is mediating the relationship between theindependent and dependent variables, it is known that motivation mediates the effect ofcompensation and organizational culture on performance

    Kajian Pengelolaan Lahan Subdas Secang Kulonprogo YOGYAKARTA

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    Penelitian ini bertujuan untuk mengevaluasi kemampuan lahan, menyusun arahan penggunaanlahan dan mengkaji pengelolaan lahan SubDAS Secang. Metode yang digunakan dalam penelitianadalah sampel terpilih pada 48 satuan lahan. Penelitian menunjukkan bahwa kemampuan lahanSubDAS Secang terdiri atas kelas lahan I seluas 187 ha, kelas lahan II seluas 147 ha, kelas lahan IIIseluas 515,2 ha, kelas lahan IV seluas 1522,7 ha, kelas lahan V seluas 7,3 ha dan kelas lahan VI seluas1223,2 ha. Arahan penggunaan lahan SubDAS Secang berupa pertanian lahan basah seluas 326,85 ha,kawasan permukiman dan budidaya tanaman semusim seluas 200,55 ha, kawasan budidaya tanamanlahan kering seluas 525,81 ha, kawasan budidaya tanaman tahunan seluas 1981,31 ha, kawasanpenyangga seluas 716,54 ha. Pengelolaan lahan memberikan pedoman pemanfaatan lahan; daerah hilirsebagai daerah pemanfaatan untuk pertanian irigasi; daerah tengah diperuntukan permukiman danpembudidayaan tanaman lahan kering; serta daerah hulu sebagai daerah imbuhan diperuntukkanwanatani dan hutan penyangga

    FGF Signaling Inhibition in ESCs Drives Rapid Genome-wide Demethylation to the Epigenetic Ground State of Pluripotency

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    SummaryGenome-wide erasure of DNA methylation takes place in primordial germ cells (PGCs) and early embryos and is linked with pluripotency. Inhibition of Erk1/2 and Gsk3β signaling in mouse embryonic stem cells (ESCs) by small-molecule inhibitors (called 2i) has recently been shown to induce hypomethylation. We show by whole-genome bisulphite sequencing that 2i induces rapid and genome-wide demethylation on a scale and pattern similar to that in migratory PGCs and early embryos. Major satellites, intracisternal A particles (IAPs), and imprinted genes remain relatively resistant to erasure. Demethylation involves oxidation of 5-methylcytosine (5mC) to 5-hydroxymethylcytosine (5hmC), impaired maintenance of 5mC and 5hmC, and repression of the de novo methyltransferases (Dnmt3a and Dnmt3b) and Dnmt3L. We identify a Prdm14- and Nanog-binding cis-acting regulatory region in Dnmt3b that is highly responsive to signaling. These insights provide a framework for understanding how signaling pathways regulate reprogramming to an epigenetic ground state of pluripotency

    Retinol and ascorbate drive erasure of epigenetic memory and enhance reprogramming to naïve pluripotency by complementary mechanisms

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    Epigenetic memory, in particular DNA methylation, is established during development in differentiating cells and must be erased to create naïve (induced) pluripotent stem cells. The ten-eleven translocation (TET) enzymes can catalyze the oxidation of 5-methylcytosine (5mC) to 5-hydroxymethylcytosine (5hmC) and further oxidized derivatives, thereby actively removing this memory. Nevertheless, the mechanism by which the TET enzymes are regulated, and the extent to which they can be manipulated, are poorly understood. Here we report that retinoic acid (RA) or retinol (vitamin A) and ascorbate (vitamin C) act as modulators of TET levels and activity. RA or retinol enhances 5hmC production in naïve embryonic stem cells by activation of TET2 and TET3 transcription, whereas ascorbate potentiates TET activity and 5hmC production through enhanced Fe2+ recycling, and not as a cofactor as reported previously. We find that both ascorbate and RA or retinol promote the derivation of induced pluripotent stem cells synergistically and enhance the erasure of epigenetic memory. This mechanistic insight has significance for the development of cell treatments for regenenerative medicine, and enhances our understanding of how intrinsic and extrinsic signals shape the epigenome

    Epifania, recriação e ressentimento: fragmentos narrativos sobre a experiência da viagem na imigração italiana no Brasil

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    L'expérience du voyage dans le processus de l'immigration marque le premier contact avec l'inconnu. L'aventure de la traversée de l'océan signifie par conséquent l'abandon du seul monde tangible. Le nouveau monde va se dévoiler à l'émigrant au fur et à mesure que le navire avance en mer, en un mélange de représentations produites avant le départ et de nouvelles “idées-images” que l'expérience elle-même du voyage contribue à élaborer en continu. Au cours de ce processus, la lecture de "Sull'Oceano" d’Edmondo De Amicis permet une immersion dans ce monde fragmentaire d'images et des récits que l'émigrant va produire. Il tente par ce biais de comprendre sa propre expérience et son existence, en un monde entrecroisé de différentes expressions de la sensibilité. Lê nouveau monde se révèle, souvenir tout à la fois d’une terre que l’on a abandonnée et recréation d'une représentation pacificatrice

    The Influence of Hydroxylation on Maintaining CpG Methylation Patterns: A Hidden Markov Model Approach

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    German Research Council (DFG) as part of the Collaborative Research Center "Physical modeling of non-equilibrium processes in biological systems" (SFB 1027) and the Cluster of Excellence on Multimodal Computing and Interaction at Saarland Universit
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