scholarly journals Ring1B is crucial for the regulation of developmental control genes and PRC1 proteins but not X inactivation in embryonic cells

2007 ◽  
Vol 178 (2) ◽  
pp. 219-229 ◽  
Author(s):  
Martin Leeb ◽  
Anton Wutz
Keyword(s):  
Es Cells ◽  
Embryonic Stem ◽  
Ring Finger ◽  
X Inactivation ◽  
Polycomb Group ◽  
Histone H2a ◽  
Embryonic Cells ◽  
Differentiation Potential ◽  
Developmental Control ◽  
Protein Levels

The Polycomb group (PcG) gene Ring1B has been implicated in the repression of developmental control genes and X inactivation and is essential for embryogenesis. Ring1B protein contains a RING finger domain and functions as an E3 ubiquitin ligase that is crucial for the monoubiquitination of histone H2A (H2AK119ub1). Here, we study the function of Ring1B in mouse embryonic stem (ES) cells. The deletion of Ring1B causes the loss of several PcG proteins, showing an unanticipated function in the regulation of PcG protein levels. Derepression of lineage genes and an aberrant differentiation potential is observed in Ring1B-deficient ES cells. Despite a crucial function of Ring1B in establishing the chromosome-wide ubiquitination of histone H2A lysine 119 (H2AK119ub1) upon Xist expression in ES cells, the initiation of silencing by Xist is independent of Ring1B. Other chromatin marks associated with the initiation of X inactivation are not affected in Ring1B-deficient cells, suggesting compensation for the loss of Ring1B in X inactivation in contrast to the repression of lineage genes.

scholarly journals Differential control of retrovirus silencing in embryonic cells by proteasomal regulation of the ZFP809 retroviral repressor

2017 ◽  
Vol 114 (6) ◽  
pp. E922-E930 ◽  
Author(s):  
Cheng Wang ◽  
Stephen P. Goff
Keyword(s):  
Zinc Finger Protein ◽  
Es Cells ◽  
Embryonic Stem ◽  
Degradation Pathway ◽  
Embryonic Cells ◽  
Polyubiquitin Chains ◽  
Protein Levels ◽  
Differentiated Cells ◽  
C Terminus ◽  
Differential Control

Replication of the murine leukemia viruses is strongly suppressed in mouse embryonic stem (ES) cells. Proviral DNAs are formed normally but are then silenced by a large complex bound to DNA by the ES cell-specific zinc-finger protein ZFP809. We show here that ZFP809 expression is not regulated by transcription but rather by protein turnover: ZFP809 protein is stable in embryonic cells but highly unstable in differentiated cells. The protein is heavily modified by the accumulation of polyubiquitin chains in differentiated cells and stabilized by the proteasome inhibitor MG132. A short sequence of amino acids at the C terminus of ZFP809, including a single lysine residue (K391), is required for the rapid turnover of the protein. The silencing cofactor TRIM28 was found to promote the degradation of ZFP809 in differentiated cells. These findings suggest that the stem cell state is established not only by an unusual transcriptional profile but also by unusual regulation of protein levels through the proteasomal degradation pathway.

scholarly journals PCGF6-PRC1 suppresses premature differentiation of mouse embryonic stem cells by regulating germ cell-related genes

eLife ◽  
2017 ◽  
Vol 6 ◽  
Author(s):  
Mitsuhiro Endoh ◽  
Takaho A Endo ◽  
Jun Shinga ◽  
Katsuhiko Hayashi ◽  
Anca Farcas ◽  
...  
Keyword(s):  
Stem Cells ◽  
Embryonic Stem Cells ◽  
Germ Cell ◽  
Target Genes ◽  
Embryonic Stem ◽  
Ring Finger ◽  
Mouse Embryonic Stem Cells ◽  
Polycomb Group ◽  
Histone H2a ◽  
Cell Growth And Viability

The ring finger protein PCGF6 (polycomb group ring finger 6) interacts with RING1A/B and E2F6 associated factors to form a non-canonical PRC1 (polycomb repressive complex 1) known as PCGF6-PRC1. Here, we demonstrate that PCGF6-PRC1 plays a role in repressing a subset of PRC1 target genes by recruiting RING1B and mediating downstream mono-ubiquitination of histone H2A. PCGF6-PRC1 bound loci are highly enriched for promoters of germ cell-related genes in mouse embryonic stem cells (ESCs). Conditional ablation of Pcgf6 in ESCs leads to robust de-repression of such germ cell-related genes, in turn affecting cell growth and viability. We also find a role for PCGF6 in pre- and peri-implantation mouse embryonic development. We further show that a heterodimer of the transcription factors MAX and MGA recruits PCGF6 to target loci. PCGF6 thus links sequence specific target recognition by the MAX/MGA complex to PRC1-dependent transcriptional silencing of germ cell-specific genes in pluripotent stem cells.

scholarly journals Dynamic Relocalization of Histone Macroh2a1 from Centrosomes to Inactive X Chromosomes during X Inactivation

2000 ◽  
Vol 150 (5) ◽  
pp. 1189-1198 ◽  
Author(s):  
Theodore P. Rasmussen ◽  
Mary-Ann Mastrangelo ◽  
Amir Eden ◽  
John R. Pehrson ◽  
Rudolf Jaenisch
Keyword(s):  
Es Cells ◽  
Embryonic Stem ◽  
X Inactivation ◽  
Cell Fractionation ◽  
Histone H2a ◽  
X Chromosomes ◽  
Male And Female ◽  
Terminal Domain ◽  
Xist Rna ◽  
Domain Of Unknown Function

Histone variant macroH2A1 (macroH2A1) contains an NH2-terminal domain that is highly similar to core histone H2A and a larger COOH-terminal domain of unknown function. MacroH2A1 is expressed at similar levels in male and female embryonic stem (ES) cells and adult tissues, but a portion of total macroH2A1 protein localizes to the inactive X chromosomes (Xi) of differentiated female cells in concentrations called macrochromatin bodies. Here, we show that centrosomes of undifferentiated male and female ES cells harbor a substantial store of macroH2A1 as a nonchromatin-associated pool. Greater than 95% of centrosomes from undifferentiated ES cells contain macroH2A1. Cell fractionation experiments confirmed that macroH2A1 resides at a pericentrosomal location in close proximity to the known centrosomal proteins γ-tubulin and Skp1. Retention of macroH2A1 at centrosomes was partially labile in the presence of nocodazole suggesting that intact microtubules are necessary for accumulation of macroH2A1 at centrosomes. Upon differentiation of female ES cells, Xist RNA expression became upregulated and monoallelic as judged by fluorescent in situ hybridization, but early Xist signals lacked associated macroH2A1. Xi acquired macroH2A1 soon thereafter as indicated by the colocalization of Xist RNA and macroH2A1. Accumulation of macroH2A1 on X chromosomes occurred with a corresponding loss of centrosomal macroH2A1. Our results define a sequence for the loading of macroH2A1 on the Xi and place this event in the context of differentiation and Xist expression. Furthermore, these results suggest a role for the centrosome in the X inactivation process.

scholarly journals Epigenetic Regulation of Mesenchymal Stem Cells: A Focus on Osteogenic and Adipogenic Differentiation

2011 ◽  
Vol 2011 ◽  
pp. 1-18 ◽  
Author(s):  
Chad M. Teven ◽  
Xing Liu ◽  
Ning Hu ◽  
Ni Tang ◽  
Stephanie H. Kim ◽  
...  
Keyword(s):  
Stem Cells ◽  
Mesenchymal Stem Cells ◽  
Epigenetic Regulation ◽  
Adult Stem Cells ◽  
Es Cells ◽  
Adipogenic Differentiation ◽  
Embryonic Stem ◽  
Cell Types ◽  
Differentiation Potential ◽  
Msc Differentiation

Stem cells are characterized by their capability to self-renew and terminally differentiate into multiple cell types. Somatic or adult stem cells have a finite self-renewal capacity and are lineage-restricted. The use of adult stem cells for therapeutic purposes has been a topic of recent interest given the ethical considerations associated with embryonic stem (ES) cells. Mesenchymal stem cells (MSCs) are adult stem cells that can differentiate into osteogenic, adipogenic, chondrogenic, or myogenic lineages. Owing to their ease of isolation and unique characteristics, MSCs have been widely regarded as potential candidates for tissue engineering and repair. While various signaling molecules important to MSC differentiation have been identified, our complete understanding of this process is lacking. Recent investigations focused on the role of epigenetic regulation in lineage-specific differentiation of MSCs have shown that unique patterns of DNA methylation and histone modifications play an important role in the induction of MSC differentiation toward specific lineages. Nevertheless, MSC epigenetic profiles reflect a more restricted differentiation potential as compared to ES cells. Here we review the effect of epigenetic modifications on MSC multipotency and differentiation, with a focus on osteogenic and adipogenic differentiation. We also highlight clinical applications of MSC epigenetics and nuclear reprogramming.

The responsiveness of embryonic stem cells to alpha and beta interferons provides the basis of an inducible expression system for analysis of developmental control genes

1993 ◽  
Vol 13 (12) ◽  
pp. 7971-7976
Author(s):  
L M Whyatt ◽  
A Düwel ◽  
A G Smith ◽  
P D Rathjen
Keyword(s):  
Gene Expression ◽  
Inner Cell Mass ◽  
Es Cells ◽  
Expression System ◽  
Cell Mass ◽  
Embryonic Stem ◽  
Expression Vectors ◽  
Developmental Control ◽  
Developmental Potential

Embryonic stem (ES) cells, derived from the inner cell mass of the preimplantation mouse embryo, are used increasingly as an experimental tool for the investigation of early mammalian development. The differentiation of these cells in vitro can be used as an assay for factors that regulate early developmental decisions in the embryo, while the effects of altered gene expression during early embryogenesis can be analyzed in chimeric mice generated from modified ES cells. The experimental versatility of ES cells would be significantly increased by the development of systems which allow precise control of heterologous gene expression. In this paper, we report that ES cells are responsive to alpha and beta interferons (IFNs). This property has been exploited for the development of inducible ES cell expression vectors, using the promoter of the human IFN-inducible gene, 6-16. The properties of these vectors have been analyzed in both transiently and stably transfected ES cells. Expression was minimal or absent in unstimulated ES cells, could be stimulated up to 100-fold by treatment of the cells with IFN, and increased in linear fashion with increasing levels of IFN. High levels of induced expression were maintained for extended periods of time in the continuous presence of the inducing signal or following a 12-h pulse with IFN. Treatment of ES cells with IFN did not affect their growth or differentiation in vitro or compromise their developmental potential. This combination of features makes the 6-16-based expression vectors suitable for the functional analysis of developmental control control genes in ES cells.

Production of chimeras by blastocyst and morula injection of targeted ES cells

1999 ◽  
Author(s):  
Virginia Papaioannou ◽  
Randall Johnson
Keyword(s):  
Stem Cells ◽  
Gene Targeting ◽  
Es Cells ◽  
Embryonic Stem ◽  
Embryonic Cells ◽  
Cell Potential ◽  
Teratocarcinoma Cell ◽  
Normal Manner ◽  
Mammalian Embryos

The ability of mammalian embryos to incorporate foreign cells and develop as chimeras has been exploited for a variety of purposes including the elucidation of cell lineages, the investigation of cell potential, the perpetuation of mutations produced in embryonic stem (ES) cells by gene targeting, and the subsequent analysis of these mutations. The extent of contribution of the foreign cells depends on their developmental synchrony with the host embryo and their mitotic and developmental potential, which may be severely restricted if the cells bear mutations. If the goal in making chimeras is the transmission of a mutation produced by gene targeting to the next generation, the mutant ES cells must have the capacity to undergo meiosis and gametogenesis. Cells from two different mammalian embryos were first combined experimentally to produce a composite animal, dubbed a chimera, nearly four decades ago. Pairs of cleaving, pre-implantation embryos were mechanically associated in vitro until they aggregated together to make single large morulae; these in turn resulted in chimeric offspring (1). Genetic markers were used to distinguish the contributions of the two embryos in these animals. Since then, various methods for making chimeras have been explored to address different types of questions (2). In 1972 it was reported that highly asynchronous embryonic cells, which had been cultured in vitro, could contribute to chimeras upon re-introduction into pre-implantation embryos (3). Not long afterward, several groups working with teratocarcinomas, tumours derived from germ cells of the gonad, discovered that stem cells from these tumours, known as embryonal carcinoma cells, could contribute to an embryo if introduced into pre-implantation stages (4-6). It appeared that the undifferentiated stem cells of the tumour had enough features in common with early embryonic cells that they could respond to the embryonic environment, differentiating in a normal manner, even after long periods in vitro. Their embryonic potential was limited, however, and many teratocarcinoma cell lines made only meagre contributions to the developing fetus or even produced tumours in chimeras (7). Either their derivation from tumours or their extended sojourn in vitro rendered these cells so dissimilar from early embryonic cells that they rarely, if ever, had full embryonic potential.

scholarly journals Cell stemness is maintained upon concurrent expression of RB and the mitochondrial ribosomal protein S18-2

2020 ◽  
Vol 117 (27) ◽  
pp. 15673-15683
Author(s):  
Muhammad Mushtaq ◽  
Larysa Kovalevska ◽  
Suhas Darekar ◽  
Alexandra Abramsson ◽  
Henrik Zetterberg ◽  
...  
Keyword(s):  
Stem Cell ◽  
Ribosomal Protein ◽  
Severe Combined Immunodeficiency ◽  
Ectopic Expression ◽  
Embryonic Stem ◽  
Ring Finger ◽  
Histone H2a ◽  
Mitochondrial Ribosomal Protein ◽  
Primary Mouse

Stemness encompasses the capability of a cell for self-renewal and differentiation. The stem cell maintains a balance between proliferation, quiescence, and regeneration via interactions with the microenvironment. Previously, we showed that ectopic expression of the mitochondrial ribosomal protein S18-2 (MRPS18-2) led to immortalization of primary fibroblasts, accompanied by induction of an embryonic stem cell (ESC) phenotype. Moreover, we demonstrated interaction between S18-2 and the retinoblastoma-associated protein (RB) and hypothesized that the simultaneous expression of RB and S18-2 is essential for maintaining cell stemness. Here, we experimentally investigated the role of S18-2 in cell stemness and differentiation. Concurrent expression of RB and S18-2 resulted in immortalization ofRb1−/−primary mouse embryonic fibroblasts and in aggressive tumor growth in severe combined immunodeficiency mice. These cells, which express both RB and S18-2 at high levels, exhibited the potential to differentiate into various lineages in vitro, including osteogenic, chondrogenic, and adipogenic lineages. Mechanistically, S18-2 formed a multimeric protein complex with prohibitin and the ring finger protein 2 (RNF2). This molecular complex increased the monoubiquitination of histone H2ALys119, a characteristic trait of ESCs, by enhanced E3-ligase activity of RNF2. Furthermore, we found enrichment of KLF4 at theS18-2promoter region and that theS18-2expression is positively correlated withKLF4levels. Importantly, knockdown of S18-2 in zebrafish larvae led to embryonic lethality. Collectively, our findings suggest an important role for S18-2 in cell stemness and differentiation and potentially also in cancerogenesis.

In vitro differentiation of reprogrammed murine somatic cells into hepatic precursor cells

2008 ◽  
Vol 389 (7) ◽  
Author(s):  
Tobias Cantz ◽  
Martina Bleidißel ◽  
Martin Stehling ◽  
Hans R. Schöler
Keyword(s):  
Bone Marrow ◽  
Bone Marrow Cells ◽  
Es Cells ◽  
Marrow Cell ◽  
Somatic Cells ◽  
Embryonic Stem ◽  
Precursor Cells ◽  
Differentiation Potential ◽  
Teratoma Formation ◽  
Transplantation Experiments

Abstract Recently, a new approach to reprogram somatic cells into pluripotent stem cells was shown by fusion of somatic cells with embryonic stem (ES) cells, which results in a tetraploid karyotype. Normal hepatocytes are often polyploid, so we decided to investigate the differentiation potential of fusion hybrids into hepatic cells. We chose toxic milk mice (a model of Wilson's disease) and performed initial transplantation experiments using this potential cell therapy approach. Mononuclear bone marrow cells from Rosa26 mice were fused with OG2 (Oct4-GFP transgenic) ES cells. Unfused ES cells were eliminated by selection with G418 for OG2-Rosa26 hybrids and fusion-derived colonies could be subcloned. Using an endodermal differentiation protocol, hepatic precursor cells could be generated. After FACS depletion of contaminating Oct4-GFP-positive cells, the hepatic precursor cells were transplanted into immunosuppressed toxic milk mice by intrasplenic injection. However, five out of eight mice showed teratoma formation within 3–6 weeks after transplantation in the spleen and liver. In conclusion, a hepatic precursor cell type was achieved from mononuclear bone marrow cell-ES cell hybrids and preliminary transplantation experiments confirmed engraftment, but also showed teratoma formation, which needs to be excluded by using more stringent purification strategies.

scholarly journals Polycomb Group Proteins Ring1A/B Link Ubiquitylation of Histone H2A to Heritable Gene Silencing and X Inactivation

2004 ◽  
Vol 7 (5) ◽  
pp. 663-676 ◽  
Author(s):  
Mariana de Napoles ◽  
Jacqueline E. Mermoud ◽  
Rika Wakao ◽  
Y.Amy Tang ◽  
Mitusuhiro Endoh ◽  
...  
Keyword(s):  
Gene Silencing ◽  
X Inactivation ◽  
Polycomb Group ◽  
Polycomb Group Proteins ◽  
Histone H2a

scholarly journals Isolation, Characterization and Differentiation Potential of Chicken Spermatogonial Stem Cell Derived Embryoid Bodies

2016 ◽  
Vol 16 (1) ◽  
pp. 115-128 ◽  
Author(s):  
Thanh Luan Nguyen ◽  
Jae Gyu Yoo ◽  
Neelesh Sharma ◽  
Sung Woo Kim ◽  
Yong Jun Kang ◽  
...  
Keyword(s):  
Developmental Biology ◽  
Regenerative Medicine ◽  
Connexin 43 ◽  
Es Cells ◽  
Periodic Acid ◽  
Embryonic Stem ◽  
Embryoid Bodies ◽  
Significant Finding ◽  
Differentiation Potential

Abstract Human, murine and monkey spermatogonial stem cells (SSCs) have the capability to undergo self-renewal and differentiation into different body cell types in vitro, which are expected to serve as a powerful tool and resource for the developmental biology and regenerative medicine. We have successfully isolated and characterized the chicken SSCs from 3-day-old chicken testicular cells. The pluripotency was using Periodic Acid-Schiff (PAS ) staining or alkaline phosphatase staining, and antibodies to stage-specific embryonic antigens. In suspension culture conditions SSCs formed embryoid bodies (EBs) like embryonic stem (ES) cells. Subsequently EB differentiated into osteoblasts, adipocytes and most importantly into cardiomyocytes under induced differentiation conditions. The differentiation potential of EBs into cardiomyocyte-like cells was confirmed by using antibodies against sarcomeric α-actinin, cardiac troponin T and connexin 43. Cardiomyocytes-like cells were also confirmed by RT-PCR analysis for several cardiac cell genes like GATA-4, Nkx2-5, α-MHC, and ANF. We have successfully established an in vitro differentiation system for chicken SSCs into different body cells such as osteoblasts, adipocytes and cardiomyocytes. The most significant finding of this study is the differentiation potential of chicken SSCs into cardiomyocytes. Our findings may have implication in developmental biology and regenerative medicine by using chicken as the most potential animal model.

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