Ontology highlight
ABSTRACT:
PROVIDER: PRJNA295060 | ENA |
REPOSITORIES: ENA
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Project description:Cellular differentiation involves profound changes in the chromatic landscape, yet the mechanisms by which somatic cell identity is subsequently maintained remain incompletely understood. To further elucidate regulatory pathways that safeguard the somatic state, we performed two comprehensive RNAi screens targeting chromatin factors during transcription factor-mediated reprogramming of mouse fibroblasts to induced pluripotent stem cells (iPSCs). Remarkably, subunits of the chromatin assembly factor-1 (CAF-1) complex emerged as the most prominent hits from both screens, followed by modulators of lysine sumoylation and heterochromatin maintenance. Suppression of CAF-1 increased reprogramming efficiency by several orders of magnitude and facilitated iPSC formation in as little as 4 days. Mechanistically, CAF-1 suppression led to a more accessible chromatin structure at enhancer elements early during reprogramming. These changes were accompanied by a decrease in somatic heterochromatin domains, increased binding of Sox2 to pluripotency-specific targets and activation of associated genes. Notably, suppression of CAF-1 also enhanced the direct conversion of B cells into macrophages and fibroblasts into neurons. Together, our findings reveal the histone chaperone CAF-1 as a novel regulator of somatic cell identity during transcription factor-induced cell fate transitions and provide a potential strategy to modulate cellular plasticity in a regenerative setting. Gene expression analysis in CAF-1 knockdown and Renilla control during early OKSM-induced reprogramming by microarray
2015-12-10 | E-GEOD-72741 | biostudies-arrayexpress
Project description:CAF-1 safeguards somatic cell identity during factor-induced reprogramming
| PRJNA294797 | ENA
Project description:During development, specialized cell lineages are generated through the establishment of cell type-specific transcriptional patterns and epigenetic programs. However, the precise mechanisms and regulators that maintain these specialized cell states remain largely elusive. To identify molecules that safeguard somatic cell identity, we performed two comprehensive RNAi screens targeting known and predicted chromatin regulators during transcription factor-mediated reprogramming of mouse fibroblasts to induced pluripotent stem cells (iPSCs). Remarkably, subunits of the chromatin assembly factor-1 (CAF-1) complex emerged as the most prominent hits from both screens, followed by modulators of lysine sumoylation, DNA methylation and heterochromatin maintenance. Suppression of CAF-1 increased reprogramming efficiencies by several orders of magnitude and generated iPSCs two to three times faster compared to controls without affecting cell proliferation. We demonstrate that suppression of CAF-1 leads to a more accessible chromatin structure specifically at enhancer elements early during reprogramming. These changes were accompanied by increased binding of the reprogramming factor Sox2 to ESC-specific regulatory elements and earlier activation of pluripotency-associated genes. Notably, suppression of CAF-1 also enhanced iPSC formation from blood progenitors as well as the direct conversion of B cells into macrophages and fibroblasts into neurons. Together, our findings reveal the histone chaperone CAF-1 as an unanticipated regulator of somatic cell identity and provide a potential strategy to modulate cellular plasticity in a regenerative setting. Keywords: Genome binding/occupancy profiling by high throughput sequencing Chromatin accessibility and Sox2 bindings in CAF-1 knockdown and Renilla control during early OKSM reprogramming by high throughput sequencing
2015-12-10 | E-GEOD-72744 | biostudies-arrayexpress
Project description:Cellular differentiation involves profound changes in the chromatic landscape, yet the mechanisms by which somatic cell identity is subsequently maintained remain incompletely understood. To further elucidate regulatory pathways that safeguard the somatic state, we performed two comprehensive RNAi screens targeting chromatin factors during transcription factor-mediated reprogramming of mouse fibroblasts to induced pluripotent stem cells (iPSCs). Remarkably, subunits of the chromatin assembly factor-1 (CAF-1) complex emerged as the most prominent hits from both screens, followed by modulators of lysine sumoylation and heterochromatin maintenance. Suppression of CAF-1 increased reprogramming efficiency by several orders of magnitude and facilitated iPSC formation in as little as 4 days. Mechanistically, CAF-1 suppression led to a more accessible chromatin structure at enhancer elements early during reprogramming. These changes were accompanied by a decrease in somatic heterochromatin domains, increased binding of Sox2 to pluripotency-specific targets and activation of associated genes. Notably, suppression of CAF-1 also enhanced the direct conversion of B cells into macrophages and fibroblasts into neurons. Together, our findings reveal the histone chaperone CAF-1 as a novel regulator of somatic cell identity during transcription factor-induced cell fate transitions and provide a potential strategy to modulate cellular plasticity in a regenerative setting.
2015-12-10 | GSE72741 | GEO
Project description:During development, specialized cell lineages are generated through the establishment of cell type-specific transcriptional patterns and epigenetic programs. However, the precise mechanisms and regulators that maintain these specialized cell states remain largely elusive. To identify molecules that safeguard somatic cell identity, we performed two comprehensive RNAi screens targeting known and predicted chromatin regulators during transcription factor-mediated reprogramming of mouse fibroblasts to induced pluripotent stem cells (iPSCs). Remarkably, subunits of the chromatin assembly factor-1 (CAF-1) complex emerged as the most prominent hits from both screens, followed by modulators of lysine sumoylation, DNA methylation and heterochromatin maintenance. Suppression of CAF-1 increased reprogramming efficiencies by several orders of magnitude and generated iPSCs two to three times faster compared to controls without affecting cell proliferation. We demonstrate that suppression of CAF-1 leads to a more accessible chromatin structure specifically at enhancer elements early during reprogramming. These changes were accompanied by increased binding of the reprogramming factor Sox2 to ESC-specific regulatory elements and earlier activation of pluripotency-associated genes. Notably, suppression of CAF-1 also enhanced iPSC formation from blood progenitors as well as the direct conversion of B cells into macrophages and fibroblasts into neurons. Together, our findings reveal the histone chaperone CAF-1 as an unanticipated regulator of somatic cell identity and provide a potential strategy to modulate cellular plasticity in a regenerative setting. Keywords: Genome binding/occupancy profiling by high throughput sequencing
2015-12-10 | GSE72744 | GEO
Project description:Transcription factor-induced reprogramming of somatic cells to pluripotency is a very inefficient process, probably due to the existence of important epigenetic barriers that are imposed during differentiation and that contribute to preserve cell identity. In an effort to decipher the molecular nature of these barriers, we followed a genome-wide approach, in which we identified macro histone variants (macroH2A) as highly expressed in human somatic cells but downregulated after reprogramming to pluripotency, as well as strongly induced during differentiation. Knock down of macro histone variants in human keratinocytes increased the efficiency of reprogramming to pluripotency, while overexpression had opposite effects. Genome-wide occupancy profiles show that in human keratinocytes macroH2A.1 preferentially occupies genes that are expressed at low levels and are marked with H3K27me3, including pluripotency-related genes and bivalent developmental regulators, at which its presence prevents the regain of H3K4me2 during reprogramming, over imposing an additional layer of repression that preserves cell identity. Gemone wide occupancy of HA:macroH2A.1 in human keratinocytes
2013-04-03 | E-GEOD-44400 | biostudies-arrayexpress
Project description:Despite rapid progress in characterizing transcription factor-driven reprogramming of somatic cells to an induced pluripotent stem (iPS) cell state, many mechanistic questions still remain. To gain insight into the earliest events in the reprogramming process, we systematically analyzed the transcriptional and epigenetic changes that occur during early factor induction after discrete numbers of divisions. We observed rapid, genome-wide changes in the euchromatic histone modification, H3K4me2, at more than a thousand loci including large subsets of pluripotency or developmentally related gene promoters and enhancers. In contrast, patterns of the repressive H3K27me3 modification remained largely unchanged except for focused depletion specifically at positions where H3K4 methylation is gained. These chromatin regulatory events precede transcriptional changes within the corresponding loci. Our data provide evidence for an early, organized, and population-wide epigenetic response to ectopic reprogramming factors that clarify the temporal order through which somatic identity is reset during reprogramming. Covalent histone modifications were measured by ChIP-Seq during the initial phase in the reprogramming of mouse embryonic fibroblasts.
2011-01-03 | E-GEOD-26099 | biostudies-arrayexpress
Project description:Despite rapid progress in characterizing transcription factor-driven reprogramming of somatic cells to an induced pluripotent stem (iPS) cell state, many mechanistic questions still remain. To gain insight into the earliest events in the reprogramming process, we systematically analyzed the transcriptional and epigenetic changes that occur during early factor induction after discrete numbers of divisions. We observed rapid, genome-wide changes in the euchromatic histone modification, H3K4me2, at more than a thousand loci including large subsets of pluripotency or developmentally related gene promoters and enhancers. In contrast, patterns of the repressive H3K27me3 modification remained largely unchanged except for focused depletion specifically at positions where H3K4 methylation is gained. These chromatin regulatory events precede transcriptional changes within the corresponding loci. Our data provide evidence for an early, organized, and population-wide epigenetic response to ectopic reprogramming factors that clarify the temporal order through which somatic identity is reset during reprogramming. Gene expression was measured by Affymetric microarrays during the initial phase of the reprogramming of mouse embryonic fibroblasts.
2011-01-03 | E-GEOD-26096 | biostudies-arrayexpress
Project description:Despite rapid progress in characterizing transcription factor-driven reprogramming of somatic cells to an induced pluripotent stem (iPS) cell state, many mechanistic questions still remain. To gain insight into the earliest events in the reprogramming process, we systematically analyzed the transcriptional and epigenetic changes that occur during early factor induction after discrete numbers of divisions. We observed rapid, genome-wide changes in the euchromatic histone modification, H3K4me2, at more than a thousand loci including large subsets of pluripotency or developmentally related gene promoters and enhancers. In contrast, patterns of the repressive H3K27me3 modification remained largely unchanged except for focused depletion specifically at positions where H3K4 methylation is gained. These chromatin regulatory events precede transcriptional changes within the corresponding loci. Our data provide evidence for an early, organized, and population-wide epigenetic response to ectopic reprogramming factors that clarify the temporal order through which somatic identity is reset during reprogramming. Genome-scale DNA methylation was measured by reduced representation bisulfite sequencing (RRBS) during the initial phase in the reprogramming of mouse embryonic fibroblasts.
2011-01-03 | E-GEOD-26098 | biostudies-arrayexpress
Project description:Transcription factor-induced reprogramming of somatic cells to pluripotency is a very inefficient process, probably due to the existence of important epigenetic barriers that are imposed during differentiation and that contribute to preserve cell identity. In an effort to decipher the molecular nature of these barriers, we followed a genome-wide approach, in which we identified macro histone variants (macroH2A) as highly expressed in human somatic cells but downregulated after reprogramming to pluripotency, as well as strongly induced during differentiation. Knock down of macro histone variants in human keratinocytes increased the efficiency of reprogramming to pluripotency, while overexpression had opposite effects. Genome-wide occupancy profiles show that in human keratinocytes macroH2A.1 preferentially occupies genes that are expressed at low levels and are marked with H3K27me3, including pluripotency-related genes and bivalent developmental regulators, at which its presence prevents the regain of H3K4me2 during reprogramming, over imposing an additional layer of repression that preserves cell identity.
2013-04-03 | GSE44400 | GEO