Inositol transport in mouse embryonic stem cells

2005 ◽  
Vol 17 (6) ◽  
pp. 633 ◽  
Author(s):  
B. D. Higgins ◽  
M. T. Kane

The uptake of myo-inositol by mouse embryonic stem (ES) cells was measured using [2-3H]myo-inositol. Uptake of myo-inositol by ES cells occurred in a mainly saturable, sodium-, time- and temperature-dependent manner, which was inhibited by glucose, phloridzin and ouabain. Self inhibition by inositol was much greater than inhibition by glucose indicating that transport was not occurring via a sodium-dependent glucose transporter. Uptake rate was much greater than efflux rate indicating a mainly unidirectional transport mechanism. Estimated kinetics parameters for sodium-dependent inositol uptake were a Km of 65.1 ± 11.8 μ mol L−1 and a Vmax of 5.0 ± 0.59 pmol μ g protein−1 h−1. Inositol uptake was also sensitive to osmolality; uptake increased in response to incubation in hypertonic medium indicating a possible role for inositol as an osmolyte in ES cells. These characteristics indicate that myo-inositol transport in mouse ES cells occurs by a sodium-dependent myo-inositol transporter protein.

2013 ◽  
Author(s):  
David A Turner ◽  
Jamie Trott ◽  
Penelope Hayward ◽  
Pau Rué ◽  
Alfonso Martinez Arias

Embryonic Stem cells derived from the epiblast tissue of the mammalian blastocyst retain the capability to differentiate into any adult cell type and are able to self-renew indefinitely under appropriate culture conditions. Despite the large amount of knowledge that we have accumulated to date about the regulation and control of self-renewal, efficient directed differentiation into specific tissues remains elusive. In this work, we have analysed in a systematic manner the interaction between the dynamics of loss of pluripotency and Activin/Nodal, BMP4 and Wnt signalling in fate assignment during the early stages of differentiation of mouse ES cells in culture. During the initial period of differentiation, cells exit from pluripotency and enter an Epi-like state. Following this transient stage, and under the influence of Activin/Nodal and BMP signalling, cells face a fate choice between differentiating into neuroectoderm and contributing to Primitive Streak fates. We find that Wnt signalling does not suppress neural development as previously thought and that it aids both fates in a context dependent manner. Our results suggest that as cells exit pluripotency they are endowed with a primary neuroectodermal fate and that the potency to become endomesodermal rises with time. We suggest that this situation translates into a ?race for fates? in which the neuroectodermal fate has an advantage.


Genetics ◽  
2004 ◽  
Vol 166 (2) ◽  
pp. 895-899 ◽  
Author(s):  
Koichi Kawakami ◽  
Tetsuo Noda

Abstract The Tol2 transposable element of the Japanese medaka fish belongs to the hAT family of transposons including hobo of Drosophila, Ac of maize, and Tam3 of snapdragon. To date, Tol2 is the only natural transposon in vertebrates that has ever been shown to encode a fully functional transposase. It has not been known, however, whether Tol2 can transpose in vertebrates other than fish. We report here transposition of Tol2 in mouse embryonic stem (ES) cells. We constructed a transposon donor plasmid containing a nonautonomous Tol2 element with the neomycin resistance gene and a helper plasmid capable of expressing the transposase and introduced the donor plasmid with various amounts of the helper plasmid by electroporation into mouse ES cells. The number of G418-resistant ES colonies increased as the amount of helper plasmid was increased, in a dose-dependent manner, indicating that the transposase activity elevated the integration efficiency. These G418-resistant ES colonies were cloned and the structure of the junction of the integrated Tol2 element and the genomic DNA was analyzed by inverse PCR. In those clones, Tol2 was surrounded by mouse genomic sequences and an 8-bp direct repeat was created adjacent to both ends of Tol2, indicating that Tol2 was integrated in the genome through transposition. The Tol2 transposon system is thus active in mouse as well as in fish. We propose that it should be used as a genetic tool to develop novel gene transfer, transgenesis, and mutagenesis methods in mammals.


Development ◽  
1995 ◽  
Vol 121 (9) ◽  
pp. 2853-2859 ◽  
Author(s):  
A. Weng ◽  
T. Magnuson ◽  
U. Storb

A murine transgene, HRD, is methylated only when carried in certain inbred strain backgrounds. A locus on distal chromosome 4, Ssm1 (strain-specific modifier), controls this phenomenon. In order to characterize the activity of Ssm1, we have investigated developmental acquisition of methylation over the transgene. Analysis of postimplantation embryos revealed that strain-specific methylation is initiated prior to embryonic day (E) 6.5. Strain-specific transgene methylation is all-or-none in pattern and occurs exclusively in the primitive ectoderm lineage. A strain-independent pattern of partial methylation occurs in the primitive endoderm and trophectoderm lineages. To examine earlier stages, embryonic stem (ES) cells were derived from E3.5 blastocysts and examined for transgene methylation before and after differentiation. Though the transgene had already acquired some methylation in undifferentiated ES cells, differentiation induced further, de novo methylation in a strain-dependent manner. Analysis of methylation in ES cultures suggests that the transgene and endogenous genes (such as immunoglobulin genes) are synchronously methylated during early development. These results are interpreted in the context of a model in which Ssm1-like modifier genes produce alterations in chromatin structure during and/or shortly after implantation, thereby marking target loci for de novo methylation with the rest of the genome during gastrulation.


PLoS ONE ◽  
2021 ◽  
Vol 16 (7) ◽  
pp. e0254447
Author(s):  
Marcos Francia ◽  
Martin Stortz ◽  
Camila Vazquez Echegaray ◽  
Camila Oses ◽  
Paula Verneri ◽  
...  

Akt/PKB is a kinase involved in the regulation of a wide variety of cell processes. Its activity is modulated by diverse post-translational modifications (PTMs). Particularly, conjugation of the small ubiquitin-related modifier (SUMO) to this kinase impacts on multiple cellular functions, such as proliferation and splicing. In embryonic stem (ES) cells, this kinase is key for pluripotency maintenance. Among other functions, Akt is known to promote the expression of Nanog, a central pluripotency transcription factor (TF). However, the relevance of this specific PTM of Akt has not been previously analyzed in this context. In this work, we study the effect of Akt1 variants with differential SUMOylation susceptibility on the expression of Nanog. Our results demonstrate that both, the Akt1 capability of being modified by SUMO conjugation and a functional SUMO conjugase activity are required to induce Nanog gene expression. Likewise, we found that the common oncogenic E17K Akt1 mutant affected Nanog expression in ES cells also in a SUMOylatability dependent manner. Interestingly, this outcome takes places in ES cells but not in a non-pluripotent heterologous system, suggesting the presence of a crucial factor for this induction in ES cells. Remarkably, the two major candidate factors to mediate this induction, GSK3-β and Tbx3, are non-essential players of this effect, suggesting a complex mechanism probably involving non-canonical pathways. Furthermore, we found that Akt1 subcellular distribution does not depend on its SUMOylatability, indicating that Akt localization has no influence on the effect on Nanog, and that besides the membrane localization of E17K Akt mutant, SUMOylation is also required for its hyperactivity. Our results highlight the impact of SUMO conjugation in the function of a kinase relevant for a plethora of cellular processes, including the control of a key pluripotency TF.


2000 ◽  
Vol 113 (1) ◽  
pp. 5-10 ◽  
Author(s):  
M.F. Pera ◽  
B. Reubinoff ◽  
A. Trounson

Embryonic stem (ES) cells are cells derived from the early embryo that can be propagated indefinitely in the primitive undifferentiated state while remaining pluripotent; they share these properties with embryonic germ (EG) cells. Candidate ES and EG cell lines from the human blastocyst and embryonic gonad can differentiate into multiple types of somatic cell. The phenotype of the blastocyst-derived cell lines is very similar to that of monkey ES cells and pluripotent human embryonal carcinoma cells, but differs from that of mouse ES cells or the human germ-cell-derived stem cells. Although our understanding of the control of growth and differentiation of human ES cells is quite limited, it is clear that the development of these cell lines will have a widespread impact on biomedical research.


2021 ◽  
pp. 21-37
Author(s):  
Jonathan Slack

‘Embryonic stem cells’ focuses on embryonic stem (ES) cells, which are grown in tissue culture from the inner cell mass of a mammalian blastocyst-stage embryo. Human ES cells offer a potential route to making the kinds of cells needed for cell therapy. ES cells were originally prepared from mouse embryos. Although somewhat different, cells grown from inner cell masses of human embryos share many properties with mouse ES cells, such as being able to grow without limit and to generate differentiated cell types. Mouse ES cells have so far been of greater practical importance than those of humans because they have enabled a substantial research industry based on the creation of genetically modified mice.


2020 ◽  
Vol 6 (35) ◽  
pp. eabb5820 ◽  
Author(s):  
Zhiming Li ◽  
Xu Hua ◽  
Albert Serra-Cardona ◽  
Xiaowei Xu ◽  
Songlin Gan ◽  
...  

How parental histones, the carriers of epigenetic modifications, are deposited onto replicating DNA remains poorly understood. Here, we describe the eSPAN method (enrichment and sequencing of protein-associated nascent DNA) in mouse embryonic stem (ES) cells and use it to detect histone deposition onto replicating DNA strands with a relatively small number of cells. We show that DNA polymerase α (Pol α), which synthesizes short primers for DNA synthesis, binds histone H3-H4 preferentially. A Pol α mutant defective in histone binding in vitro impairs the transfer of parental H3-H4 to lagging strands in both yeast and mouse ES cells. Last, dysregulation of both coding genes and noncoding endogenous retroviruses is detected in mutant ES cells defective in parental histone transfer. Together, we report an efficient eSPAN method for analysis of DNA replication–linked processes in mouse ES cells and reveal the mechanism of Pol α in parental histone transfer.


Blood ◽  
2000 ◽  
Vol 95 (7) ◽  
pp. 2275-2283 ◽  
Author(s):  
Naoki Nakayama ◽  
Jae Lee ◽  
Laura Chiu

Abstract The totipotent mouse embryonic stem (ES) cell is known to differentiate into cells expressing the β-globin gene when stimulated with bone morphogenetic protein (BMP)-4. Here, we demonstrate that BMP-4 is essential for generating both erythro-myeloid colony-forming cells (CFCs) and lymphoid (B and NK) progenitor cells from ES cells and that vascular endothelial growth factor (VEGF) synergizes with BMP-4. The CD45+ myelomonocytic progenitors and Ter119+ erythroid cells began to be detected with 0.5 ng/mL BMP-4, and their levels plateaued at approximately 2 ng/mL. VEGF alone weakly elevated the CD34+ cell population though no lymphohematopoietic progenitors were induced. However, when combined with BMP-4, 2 to 20 ng/mL VEGF synergistically augmented the BMP-4-dependent generation of erythro-myeloid CFCs and lymphoid progenitors from ES cells, which were enriched in CD34+ CD31lo and CD34+CD45− cell populations, respectively, in a dose-dependent manner. Furthermore, during the 7 days of in vitro differentiation, BMP-4 was required within the first 4 days, whereas VEGF was functional after the action of BMP-4 (in the last 3 days). Thus, VEGF is a synergistic enhancer for the BMP-4-dependent differentiation processes, and it seems to be achieved by the ordered action of the 2 factors.


2003 ◽  
Vol 163 (5) ◽  
pp. 1873-1885 ◽  
Author(s):  
Charles Heilig ◽  
Frank Brosius ◽  
Brian Siu ◽  
Luis Concepcion ◽  
Richard Mortensen ◽  
...  

2005 ◽  
Vol 25 (9) ◽  
pp. 3431-3442 ◽  
Author(s):  
Yiduo Hu ◽  
Xincheng Lu ◽  
Ellen Barnes ◽  
Min Yan ◽  
Hua Lou ◽  
...  

ABSTRACT In eukaryotes, crossovers in mitotic cells can have deleterious consequences and therefore must be suppressed. Mutations in BLM give rise to Bloom syndrome, a disease that is characterized by an elevated rate of crossovers and increased cancer susceptibility. However, simple eukaryotes such as Saccharomyces cerevisiae have multiple pathways for suppressing crossovers, suggesting that mammals also have multiple pathways for controlling crossovers in their mitotic cells. We show here that in mouse embryonic stem (ES) cells, mutations in either the Bloom syndrome homologue (Blm) or the Recql5 genes result in a significant increase in the frequency of sister chromatid exchange (SCE), whereas deleting both Blm and Recql5 lead to an even higher frequency of SCE. These data indicate that Blm and Recql5 have nonredundant roles in suppressing crossovers in mouse ES cells. Furthermore, we show that mouse embryonic fibroblasts derived from Recql5 knockout mice also exhibit a significantly increased frequency of SCE compared with the corresponding wild-type control. Thus, this study identifies a previously unknown Recql5-dependent, Blm-independent pathway for suppressing crossovers during mitosis in mice.


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