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Differences in the epigenetic and reprogramming properties of pluripotent and extra-embryonic stem cells implicate chromatin remodelling as an important early event in the developing mouse embryo.

Santos J, Pereira CF, Di-Gregorio A, Spruce T, Alder O, Rodriguez T, Azuara V, Merkenschlager M, Fisher AG - Epigenetics Chromatin (2010)

Bottom Line: We found that many lineage-specific genes replicate early in ES, TS and XEN cells, which was consistent with a broadly 'accessible' chromatin that was reported previously for multiple ES cell lines.A comparative analysis of modified histones at the promoters of individual genes showed that in TS and ES cells many lineage-specific regulator genes are co-marked with modifications associated with active (H4ac, H3K4me2, H3K9ac) and repressive (H3K27me3) chromatin.Consistent with TS and XEN having a restricted developmental potential, we show that these cells selectively reprogramme somatic cells to induce the de novo expression of genes associated with extraembryonic differentiation.

View Article: PubMed Central - HTML - PubMed

Affiliation: Lymphocyte Development Group, MRC Clinical Sciences Centre, Imperial College School of Medicine, Hammersmith Campus, Du Cane Road, London W12 0NN, UK.

ABSTRACT

Background: During early mouse development, two extra-embryonic lineages form alongside the future embryo: the trophectoderm (TE) and the primitive endoderm (PrE). Epigenetic changes known to take place during these early stages include changes in DNA methylation and modified histones, as well as dynamic changes in gene expression.

Results: In order to understand the role and extent of chromatin-based changes for lineage commitment within the embryo, we examined the epigenetic profiles of mouse embryonic stem (ES), trophectoderm stem (TS) and extra-embryonic endoderm (XEN) stem cell lines that were derived from the inner cell mass (ICM), TE and PrE, respectively. As an initial indicator of the chromatin state, we assessed the replication timing of a cohort of genes in each cell type, based on data that expressed genes and acetylated chromatin domains, generally, replicate early in S-phase, whereas some silent genes, hypoacetylated or condensed chromatin tend to replicate later. We found that many lineage-specific genes replicate early in ES, TS and XEN cells, which was consistent with a broadly 'accessible' chromatin that was reported previously for multiple ES cell lines. Close inspection of these profiles revealed differences between ES, TS and XEN cells that were consistent with their differing lineage affiliations and developmental potential. A comparative analysis of modified histones at the promoters of individual genes showed that in TS and ES cells many lineage-specific regulator genes are co-marked with modifications associated with active (H4ac, H3K4me2, H3K9ac) and repressive (H3K27me3) chromatin. However, in XEN cells several of these genes were marked solely by repressive modifications (such as H3K27me3, H4K20me3). Consistent with TS and XEN having a restricted developmental potential, we show that these cells selectively reprogramme somatic cells to induce the de novo expression of genes associated with extraembryonic differentiation.

Conclusions: These data provide evidence that the diversification of defined embryonic and extra-embryonic lineages is accompanied by chromatin remodelling at specific loci. Stem cell lines from the ICM, TE and PrE can each dominantly reprogramme somatic cells but reset gene expression differently, reflecting their separate lineage identities and increasingly restricted developmental potentials.

No MeSH data available.


Related in: MedlinePlus

Embryo-derived stem cell lines respectively express lineage-associated markers. (A) Brief schematic representation of mouse pre-implantation development and origin of lineage-derived stem cells. Embryonic stem (ES), trophectoderm stem (TS) and extra-embryonic endoderm (XEN) can be derived from the inner cell mass (yellow), trophectoderm (blue) and primitive endoderm (red) of mouse blastocysts. (B) Reverse transcription polymerase chain reaction expression analysis of ESOS25, TSB1 and XENIM8A1 cells lines. RNA was isolated and cDNA prepared from all three embryo-derived stem cell lines cells and analysed using primers for Oct4, Nanog, Sox2, Fgf4, Rex1, Cdx2, Eomes, Esrrb, Hand1, Gata4, Gata6, Foxa2, Hnf4 and Gapdh as a loading control. +/- indicates presence or absence of reverse transcriptase; H2O, water control.
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Figure 1: Embryo-derived stem cell lines respectively express lineage-associated markers. (A) Brief schematic representation of mouse pre-implantation development and origin of lineage-derived stem cells. Embryonic stem (ES), trophectoderm stem (TS) and extra-embryonic endoderm (XEN) can be derived from the inner cell mass (yellow), trophectoderm (blue) and primitive endoderm (red) of mouse blastocysts. (B) Reverse transcription polymerase chain reaction expression analysis of ESOS25, TSB1 and XENIM8A1 cells lines. RNA was isolated and cDNA prepared from all three embryo-derived stem cell lines cells and analysed using primers for Oct4, Nanog, Sox2, Fgf4, Rex1, Cdx2, Eomes, Esrrb, Hand1, Gata4, Gata6, Foxa2, Hnf4 and Gapdh as a loading control. +/- indicates presence or absence of reverse transcriptase; H2O, water control.

Mentions: Recently, data from two different sources has provided important insights into how lineage potential is regulated at the earliest stages of mammalian development. Studies comparing DNA methylation at gene promoters in embryonic stem (ES) versus trophectoderm stem (TS) cells, germ cells and fibroblasts identified novel factors that act as 'gatekeepers' for the specification of extra-embryonic tissue [17] and showed that epigenetic reprogramming, essential for the transmission of pluripotency, occurs within the germline prior to fertilization [18]. Another set of reports, in which the chromatin profile of ES cells, somatic stem cells and their differentiated progeny were contrasted, provided collective evidence that many developmental regulators genes in ES cells are primed for future expression, being marked with histone modifications associated with both active and repressed chromatin [19,20]. In this study we have examined the epigenetic status of other blastocyst-derived lineages required for the successful development of the early mammalian embryo, using stem cells lines isolated from the TE [21] and PrE [22] that self-renew and differentiate into defined extra embryonic tissues (Figure 1A). Our results demonstrate that, following lineage specification to the ICM, TE and PrE, there are predictable changes in the temporal replication and chromatin structure of lineage-determining genes, as reflected in the stem cell lines analysed here. We also show that extra-embryonic endoderm (XEN) and TS cells, like ES cells, can dominantly reprogramme somatic cells (human lymphocytes), but that they initiate discrete and different lineage-specific gene expression programmes. Taken together, these results suggest that dynamic changes in chromatin organization occur within the developing blastocyst and that these epigenetic changes are important for cell specification and conveying lineage identity.


Differences in the epigenetic and reprogramming properties of pluripotent and extra-embryonic stem cells implicate chromatin remodelling as an important early event in the developing mouse embryo.

Santos J, Pereira CF, Di-Gregorio A, Spruce T, Alder O, Rodriguez T, Azuara V, Merkenschlager M, Fisher AG - Epigenetics Chromatin (2010)

Embryo-derived stem cell lines respectively express lineage-associated markers. (A) Brief schematic representation of mouse pre-implantation development and origin of lineage-derived stem cells. Embryonic stem (ES), trophectoderm stem (TS) and extra-embryonic endoderm (XEN) can be derived from the inner cell mass (yellow), trophectoderm (blue) and primitive endoderm (red) of mouse blastocysts. (B) Reverse transcription polymerase chain reaction expression analysis of ESOS25, TSB1 and XENIM8A1 cells lines. RNA was isolated and cDNA prepared from all three embryo-derived stem cell lines cells and analysed using primers for Oct4, Nanog, Sox2, Fgf4, Rex1, Cdx2, Eomes, Esrrb, Hand1, Gata4, Gata6, Foxa2, Hnf4 and Gapdh as a loading control. +/- indicates presence or absence of reverse transcriptase; H2O, water control.
© Copyright Policy - open-access
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC2821315&req=5

Figure 1: Embryo-derived stem cell lines respectively express lineage-associated markers. (A) Brief schematic representation of mouse pre-implantation development and origin of lineage-derived stem cells. Embryonic stem (ES), trophectoderm stem (TS) and extra-embryonic endoderm (XEN) can be derived from the inner cell mass (yellow), trophectoderm (blue) and primitive endoderm (red) of mouse blastocysts. (B) Reverse transcription polymerase chain reaction expression analysis of ESOS25, TSB1 and XENIM8A1 cells lines. RNA was isolated and cDNA prepared from all three embryo-derived stem cell lines cells and analysed using primers for Oct4, Nanog, Sox2, Fgf4, Rex1, Cdx2, Eomes, Esrrb, Hand1, Gata4, Gata6, Foxa2, Hnf4 and Gapdh as a loading control. +/- indicates presence or absence of reverse transcriptase; H2O, water control.
Mentions: Recently, data from two different sources has provided important insights into how lineage potential is regulated at the earliest stages of mammalian development. Studies comparing DNA methylation at gene promoters in embryonic stem (ES) versus trophectoderm stem (TS) cells, germ cells and fibroblasts identified novel factors that act as 'gatekeepers' for the specification of extra-embryonic tissue [17] and showed that epigenetic reprogramming, essential for the transmission of pluripotency, occurs within the germline prior to fertilization [18]. Another set of reports, in which the chromatin profile of ES cells, somatic stem cells and their differentiated progeny were contrasted, provided collective evidence that many developmental regulators genes in ES cells are primed for future expression, being marked with histone modifications associated with both active and repressed chromatin [19,20]. In this study we have examined the epigenetic status of other blastocyst-derived lineages required for the successful development of the early mammalian embryo, using stem cells lines isolated from the TE [21] and PrE [22] that self-renew and differentiate into defined extra embryonic tissues (Figure 1A). Our results demonstrate that, following lineage specification to the ICM, TE and PrE, there are predictable changes in the temporal replication and chromatin structure of lineage-determining genes, as reflected in the stem cell lines analysed here. We also show that extra-embryonic endoderm (XEN) and TS cells, like ES cells, can dominantly reprogramme somatic cells (human lymphocytes), but that they initiate discrete and different lineage-specific gene expression programmes. Taken together, these results suggest that dynamic changes in chromatin organization occur within the developing blastocyst and that these epigenetic changes are important for cell specification and conveying lineage identity.

Bottom Line: We found that many lineage-specific genes replicate early in ES, TS and XEN cells, which was consistent with a broadly 'accessible' chromatin that was reported previously for multiple ES cell lines.A comparative analysis of modified histones at the promoters of individual genes showed that in TS and ES cells many lineage-specific regulator genes are co-marked with modifications associated with active (H4ac, H3K4me2, H3K9ac) and repressive (H3K27me3) chromatin.Consistent with TS and XEN having a restricted developmental potential, we show that these cells selectively reprogramme somatic cells to induce the de novo expression of genes associated with extraembryonic differentiation.

View Article: PubMed Central - HTML - PubMed

Affiliation: Lymphocyte Development Group, MRC Clinical Sciences Centre, Imperial College School of Medicine, Hammersmith Campus, Du Cane Road, London W12 0NN, UK.

ABSTRACT

Background: During early mouse development, two extra-embryonic lineages form alongside the future embryo: the trophectoderm (TE) and the primitive endoderm (PrE). Epigenetic changes known to take place during these early stages include changes in DNA methylation and modified histones, as well as dynamic changes in gene expression.

Results: In order to understand the role and extent of chromatin-based changes for lineage commitment within the embryo, we examined the epigenetic profiles of mouse embryonic stem (ES), trophectoderm stem (TS) and extra-embryonic endoderm (XEN) stem cell lines that were derived from the inner cell mass (ICM), TE and PrE, respectively. As an initial indicator of the chromatin state, we assessed the replication timing of a cohort of genes in each cell type, based on data that expressed genes and acetylated chromatin domains, generally, replicate early in S-phase, whereas some silent genes, hypoacetylated or condensed chromatin tend to replicate later. We found that many lineage-specific genes replicate early in ES, TS and XEN cells, which was consistent with a broadly 'accessible' chromatin that was reported previously for multiple ES cell lines. Close inspection of these profiles revealed differences between ES, TS and XEN cells that were consistent with their differing lineage affiliations and developmental potential. A comparative analysis of modified histones at the promoters of individual genes showed that in TS and ES cells many lineage-specific regulator genes are co-marked with modifications associated with active (H4ac, H3K4me2, H3K9ac) and repressive (H3K27me3) chromatin. However, in XEN cells several of these genes were marked solely by repressive modifications (such as H3K27me3, H4K20me3). Consistent with TS and XEN having a restricted developmental potential, we show that these cells selectively reprogramme somatic cells to induce the de novo expression of genes associated with extraembryonic differentiation.

Conclusions: These data provide evidence that the diversification of defined embryonic and extra-embryonic lineages is accompanied by chromatin remodelling at specific loci. Stem cell lines from the ICM, TE and PrE can each dominantly reprogramme somatic cells but reset gene expression differently, reflecting their separate lineage identities and increasingly restricted developmental potentials.

No MeSH data available.


Related in: MedlinePlus