An in situ transgenic enzyme marker for the midgestation mouse embryo and the visualization of inner cell mass clones during early organogenesis

Development ◽  
1989 ◽  
Vol 106 (1) ◽  
pp. 37-46 ◽  
Author(s):  
R.S. Beddington ◽  
J. Morgernstern ◽  
H. Land ◽  
A. Hogan
Keyword(s):  
Cell Fate ◽  
Inner Cell Mass ◽  
Cell Mass ◽  
Early Organogenesis ◽  
Transgenic Mouse Strain ◽  
Transgenic Cells ◽  
Actin Promoter ◽  
Cell Autonomy ◽  
Lac Z

In order to study the deployment of cells during gastrulation and early organogenesis, it is necessary to have an in situ cell marker which can be used to follow cell fate. To create such a marker a transgenic mouse strain, designated Tg(Act-lac Z)-1, which carries 6 copies of the Escherichia coli lac Z gene under the control of the rat beta-actin promoter, was made by pronuclear injection of DNA. Staining early postimplantation hemizygous mouse conceptuses, during gastrulation and early organogenesis, for beta-galactosidase activity shows that lac Z expression is ubiquitous and constitutive in all epiblast derivatives of the 10th day conceptus. No activity is seen in trophectoderm and primitive endoderm derivatives. Postimplantation grafts of [3H]thymidine-labelled transgenic cells establish the cell autonomy of this transgenic marker. Preliminary observations on the distribution of inner cell mass (ICM) descendant clones, identified in situ in midgestation conceptuses, confirm the pluripotency of individual ICM cells. The implications regarding patterns of cell growth in nascent fetal primordia are discussed.

scholarly journals Cell fate clusters in ICM organoids arise from cell fate heredity and division: a modelling approach

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Tim Liebisch ◽  
Armin Drusko ◽  
Biena Mathew ◽  
Ernst H. K. Stelzer ◽  
Sabine C. Fischer ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Cell Division ◽  
Cell Fate ◽  
Inner Cell Mass ◽  
Cell Mass ◽  
Cell Lineage ◽  
Cell Fate Decision ◽  
Cell Fate Decisions ◽  
Chemical Signalling ◽  
Fate Decision

AbstractDuring the mammalian preimplantation phase, cells undergo two subsequent cell fate decisions. During the first decision, the trophectoderm and the inner cell mass are formed. Subsequently, the inner cell mass segregates into the epiblast and the primitive endoderm. Inner cell mass organoids represent an experimental model system, mimicking the second cell fate decision. It has been shown that cells of the same fate tend to cluster stronger than expected for random cell fate decisions. Three major processes are hypothesised to contribute to the cell fate arrangements: (1) chemical signalling; (2) cell sorting; and (3) cell proliferation. In order to quantify the influence of cell proliferation on the observed cell lineage type clustering, we developed an agent-based model accounting for mechanical cell–cell interaction, i.e. adhesion and repulsion, cell division, stochastic cell fate decision and cell fate heredity. The model supports the hypothesis that initial cell fate acquisition is a stochastically driven process, taking place in the early development of inner cell mass organoids. Further, we show that the observed neighbourhood structures can emerge solely due to cell fate heredity during cell division.

scholarly journals p38-MAPK mediated rRNA processing and translation regulation enables PrE differentiation during mouse blastocyst maturation

2020 ◽  
Author(s):  
Pablo Bora ◽  
Lenka Gahurova ◽  
Tomáš Mašek ◽  
Andrea Hauserova ◽  
David Potěšil ◽  
...  
Keyword(s):  
Cell Fate ◽  
P38 Mapk ◽  
Ribosomal Proteins ◽  
De Novo ◽  
Inner Cell Mass ◽  
Cell Mass ◽  
Translation Regulation ◽  
Placental Development ◽  
Mapk Activity ◽  
Live Embryo

AbstractBackgroundp38-MAPKs are stress-activated kinases necessary for placental development and nutrient and oxygen transfer during murine post-implantation development. In preimplantation development, p38-MAPK activity is required for blastocyst formation. Additionally, we have previously reported its role in regulating specification of inner cell mass (ICM) towards primitive endoderm (PrE), although a comprehensive mechanistic understanding is currently limited. Adopting live embryo imaging, proteomic and transcriptomic approaches, we report experimental data that directly address this deficit.ResultsChemical inhibition of p38-MAPK activity during blastocyst maturation causes impaired blastocyst cavity expansion, most evident between the third and tenth hours post inhibition onset. We identify an overlapping minimal early blastocyst maturation window of p38-MAPKi inhibition (p38-MAPKi) sensitivity, that is sufficient to impair PrE cell fate by the late blastocyst (E4.5) stage. Comparative proteomic analyses reveal substantial downregulation of ribosomal proteins, the mRNA transcripts of which are also significantly upregulated. Ontological analysis of the differentially expressed transcriptome during this developmental period reveals “translation” related gene transcripts as being most significantly, yet transiently, affected by p38-MAPKi. Moreover, combined assays consistently report concomitant reductions in de novo translation that are associated with accumulation of unprocessed rRNA precursors. Using a phosphoproteomic approach, ± p38-MAPKi, we identified Mybpp1a, an rRNA transcription and processing regulator gene, as a potential p38-MAPK effector. We report that siRNA mediated clonal knockdown of Mybpp1a is associated with significantly diminished PrE contribution. Lastly, we show that defective PrE specification caused by p38-MAPKi (but not MEK/ERK signalling inhibition) can be partially rescued by activating the archetypal mTOR mediated translation regulatory pathway.ConclusionsActivated p38-MAPK controls blastocyst maturation in an early and distinctly transient developmental window by regulating gene functionalities related to translation, that creates a permissive environment for appropriate specification of ICM cell fate.

Specific expression of a retinoic acid-regulated, zinc-finger gene, Rex-1, in preimplantation embryos, trophoblast and spermatocytes

Development ◽  
1991 ◽  
Vol 113 (3) ◽  
pp. 815-824 ◽  
Author(s):  
M.B. Rogers ◽  
B.A. Hosler ◽  
L.J. Gudas
Keyword(s):  
Retinoic Acid ◽  
Germ Cell ◽  
Cell Fate ◽  
Zinc Finger ◽  
Zinc Finger Protein ◽  
Inner Cell Mass ◽  
Cell Mass ◽  
Embryonic Stem ◽  
Preimplantation Embryos ◽  
Specific Expression

We have previously isolated a cDNA clone for a gene whose expression is reduced by retinoic acid (RA) treatment of F9 embryonal carcinoma cells. The nucleotide sequence indicated that this gene, Rex-1, encodes a zinc-finger protein and thus may be a transcriptional regulator. The Rex-1 message level is high in two lines of embryonic stem cells (CCE and D3) and is reduced when D3 cells are induced to differentiate using four different growth conditions. As expected for a stem-cell-specific message, Rex-1 mRNA is present in the inner cell mass (ICM) of the day 4.5 mouse blastocyst. It is also present in the polar trophoblast of the blastocyst. One and two days later, Rex-1 message is found in the ectoplacental cone and extraembryonic ectoderm of the egg cylinder (trophoblast-derived tissues), but its abundance is much reduced in the embryonic ectoderm which is directly descended from the ICM. Rex-1 is expressed in the day 18 placenta (murine gestation is 18 days), a tissue which is largely derived from trophoblast. The only tested adult tissue that contains detectable amounts of Rex-1 mRNA is the testis. In situ hybridization and northern analyses of RNA from germ-cell-deficient mouse testis and stage-specific germ cell preparations suggest that Rex-1 expression is limited to spermatocytes (germ cells undergoing meiosis). These results suggest that Rex-1 is involved in trophoblast development and spermatogenesis, and is a useful marker for studies of early cell fate determination in the ICM.

Trophectodermal processes regulate the expression of totipotency within the inner cell mass of the mouse expanding blastocyst

Development ◽  
1984 ◽  
Vol 84 (1) ◽  
pp. 63-90
Author(s):  
Tom P. Fleming ◽  
Paul D. Warren ◽  
Julia C. Chisholm ◽  
Martin H. Johnson
Keyword(s):  
Inner Cell Mass ◽  
Cell Mass ◽  
Central Area ◽  
Ultrastructural Changes ◽  
Trophectoderm Cells ◽  
Junctional Complexes ◽  
Secondary Lysosomes ◽  
Cytoplasmic Processes ◽  
Cellular Cover

Mouse blastocysts, aged 0, 2, 6 and 12 h from the onset of cavitation, were examined by transmission (TEM) and scanning (SEM) electron microscopy. In TEM sections, trophectoderm cells (TE) differed morphologically from those of the inner cell mass (ICM) by their flattened shape, paler cytosol staining and polarized disposition of both junctional complexes (apicolateral) and intracellular secondary lysosomes (SL; basal). Throughout this period of development, cytoplasmic processes, characterized by abundant SLs, cover approximately 80 % of the juxtacoelic face of the ICM. These processes are shown to be derived from the basal surface of TE cells intermediately placed between polar and mural regions. In SEM preparations of the juxtacoelic ICM surface, revealed by ‘cracking open’ blastocysts, the processes appear as tongue-shaped, centripetally oriented structures which terminate collectively at a central area on the ICM surface. The potential of cultured ICMs to generate TE was demonstrated following their immunosurgical isolation from blastocysts aged up to 12 h post cavitation and by examining the sequence of ultrastructural changes associated with TE generation by ICMs from 2 h blastocysts. In contrast, the juxtacoelic cells of similarly aged ICMs observed in situ in ultrasections of intact embryos showed little or no evidence of totipotency expression as judged by the absence of TE characteristics. Since TE expression within presumptive ICM cells is thought to be generated by an asymmetry of cell contacts (Johnson & Ziomek, 1983), we propose that the juxtacoelic TE processes, by providing a cellular cover to the ICM, function in suppressing the expression in situ of ICM totipotency.

Stem cell defects in parthenogenetic peri-implantation embryos

Development ◽  
1995 ◽  
Vol 121 (7) ◽  
pp. 2069-2077
Author(s):  
E.D. Newman-Smith ◽  
Z. Werb
Keyword(s):  
Stem Cells ◽  
Growth Factor ◽  
Inner Cell Mass ◽  
Cell Mass ◽  
Cell Types ◽  
Insulin Like Growth Factor ◽  
Embryonic Antigen ◽  
Parietal Endoderm

Mouse embryos containing only maternal chromosomes (parthenotes) develop abnormally in vivo, usually failing at the peri-implantation stage. We have analyzed the development of parthenote embryos by using an inner cell mass (ICM) outgrowth assay that mimics peri-implantation development. ICMs from normal embryos maintained undifferentiated stem cells positive for stage-specific embryonic antigen-1 and Rex-1 while differentiating into a variety of cell types, including visceral endoderm-like cells and parietal endoderm cells. In contrast, ICMs from parthenotes failed to maintain undifferentiated stem cells and differentiated almost exclusively into parietal endoderm. This suggests that parthenote ICMs have a defect that leads to differentiation, rather than maintenance, of the stem cells, and a defect that leads to a parietal endoderm fate for the stem cells. To test the hypothesis that the ICM population is not maintained owing to a lack of proliferation of the stem cells, we investigated whether mitogenic agents were able to maintain the ICM population in parthenotes. When parthenote blastocysts were supplied with the insulin-like growth factor-1 receptor (Igf-1r) and insulin-like growth factor-2 (Igf-2), two genes not detectable in parthenote blastocysts by in situ hybridization, the ICM population was maintained. Similarly, culture of parthenote blastocysts in medium conditioned by embryonic fibroblasts and supplemented with the maternal factor leukemia inhibitory factor maintained the ICM population. However, once this growth factor-rich medium was removed, the parthenote ICM cells still differentiated predominantly into parietal endoderm.(ABSTRACT TRUNCATED AT 250 WORDS)

Isolation of the murine cyclin B2 cDNA and characterization of the lineage and temporal specificity of expression of the B1 and B2 cyclins during oogenesis, spermatogenesis and early embryogenesis

Development ◽  
1993 ◽  
Vol 118 (1) ◽  
pp. 229-240 ◽  
Author(s):  
D.L. Chapman ◽  
D.J. Wolgemuth
Keyword(s):  
Germ Cell ◽  
Germ Cells ◽  
Northern Blot ◽  
Inner Cell Mass ◽  
Cell Mass ◽  
Cell Development ◽  
Early Embryogenesis ◽  
Northern Blot Hybridization ◽  
Germ Cell Development

A cDNA encoding the murine cyclin B2 (cycB2) was isolated from an adult mouse testis cDNA library as part of studies designed to identify cyclins involved in murine germ cell development. This cycB2 cDNA was then used to examine the pattern of cycB2 expression during male and female germ cell development and in early embryogenesis, and to compare this expression with the previously characterized expression of cycB1. A single 1.7 kb cycB2 transcript was detected by northern blot hybridization analysis of total RNA isolated from midgestation embryos and various adult tissues. Northern blot and in situ hybridization analyses revealed that cycB2 expression in the testis was most abundant in the germ cells, specifically in pachytene spermatocytes. This is in contrast to the highest levels of expression of cycB1 being present in early spermatids. In situ analysis of the ovary revealed cycB2 transcripts in both germ cells and somatic cells, specifically in the oocytes and granulosa cells of growing and mature follicles. The pattern of cycB1 and cycB2 expression in ovulated and fertilized eggs was also examined. While the steady state level of cycB1 and cycB2 signal remained constant in oocytes and ovulated eggs, signal of both appeared to decrease following fertilization. In addition, both cycB1 and cycB2 transcripts were detected in the cells of the inner cell mass and the trophectoderm of the blastocyst. These results demonstrate that there are lineage- and developmental-specific differences in the pattern of the B cyclins in mammalian germ cells, in contrast to the co-expression of B cyclins in the early conceptus.

102. THE EFFECT OF INSULIN ON EMBRYONIC STEM CELL PROGENITOR CELLS IN THE MOUSE BLASTOCYST

2009 ◽  
Vol 21 (9) ◽  
pp. 21
Author(s):  
J. M. Campbell ◽  
I. Vassiliev ◽  
M. B. Nottle ◽  
M. Lane
Keyword(s):  
Progenitor Cells ◽  
Cell Fate ◽  
Culture Medium ◽  
Inner Cell Mass ◽  
Cell Mass ◽  
Embryonic Stem ◽  
Cell Number ◽  
Human Embryos ◽  
Cell Stage ◽  
Stage Of Development

Human ESCs are produced from embryos donated at the mid-stage of pre-implantation development. This cryostorage reduced viability. However, it has been shown that this can be improved by the addition of growth factors to culture medium. The aim of the present study was to examine whether the addition of insulin to embryo culture medium from the 8-cell stage of development increases the number of ES cell progenitor cells in the epiblast in a mouse model. In vivo produced mouse zygotes (C57Bl6 strain) were cultured in G1 medium for 48h to the 8-cell stage, followed by culture in G2 supplemented with insulin (0, 0.17, 1.7 and 1700pM) for 68h, at 37 o C , in 5% O2, 6%CO2, 89% N2 . The number of cells in the inner cell mass (ICM) and epiblast was determined by immunohistochemical staining for Oct4 and Nanog. ICM cells express Oct4, epiblast cells express both Oct4 and Nanog. The addition of insulin at the concentrations examined did not increase the ICM. However, at 1.7pM insulin increased the number of epiblast cells (6.6±0.5 cells vs 4.1±0.5, P=0.001) in the ICM, which increased the proportion of the ICM that was epiblast (38.9±3.7% compared to 25.8±3.4% in the control P=0.01). This indicates that the increase in the epiblast is brought about by a shift in cell fate as opposed to an increase in cell division. The effect of insulin on the proportion of cells in the epiblast was investigated using inhibitors of phosphoinositide3-kinase (PI3K) (LY294002, 50µM); one of insulin's main second messengers, and p53 (pifithrin-α, 30µg/ml); a pro-apoptotic protein inactivated by PI3K. Inhibition of PI3K eliminated the increase caused by insulin (4.5±0.3 cells versus 2.2±0.3 cells, P<0.001), while inhibition of p53 increased the epiblast cell number compared to the control (7.1±0.8 and 4.1±0.7 respectively P=0.001). This study shows that insulin increases epiblast cell number through the activation of PI3K and the inhibition of p53, and may be a strategy for improving ESC isolation from human embryos.

scholarly journals G9a regulates temporal preimplantation developmental program and lineage segregation in blastocyst

eLife ◽  
2018 ◽  
Vol 7 ◽  
Author(s):  
Jan J Zylicz ◽  
Maud Borensztein ◽  
Frederick CK Wong ◽  
Yun Huang ◽  
Caroline Lee ◽  
...  
Keyword(s):  
Cell Fate ◽  
Inner Cell Mass ◽  
Cell Mass ◽  
Blastocyst Stage ◽  
Vital Role ◽  
Mouse Development ◽  
Cell Stage ◽  
Developmental Progression ◽  
Early Mouse ◽  
The Impact

Early mouse development is regulated and accompanied by dynamic changes in chromatin modifications, including G9a-mediated histone H3 lysine 9 dimethylation (H3K9me2). Previously, we provided insights into its role in post-implantation development (Zylicz et al., 2015). Here we explore the impact of depleting the maternally inherited G9a in oocytes on development shortly after fertilisation. We show that G9a accumulates typically at 4 to 8 cell stage to promote timely repression of a subset of 4 cell stage-specific genes. Loss of maternal inheritance of G9a disrupts the gene regulatory network resulting in developmental delay and destabilisation of inner cell mass lineages by the late blastocyst stage. Our results indicate a vital role of this maternally inherited epigenetic regulator in creating conducive conditions for developmental progression and on cell fate choices.

scholarly journals Gata6, Nanog and Erk signaling control cell fate in the inner cell mass through a tristable regulatory network

Development ◽  
2014 ◽  
Vol 141 (19) ◽  
pp. 3637-3648 ◽  
Author(s):  
S. Bessonnard ◽  
L. De Mot ◽  
D. Gonze ◽  
M. Barriol ◽  
C. Dennis ◽  
...  
Keyword(s):  
Cell Fate ◽  
Regulatory Network ◽  
Inner Cell Mass ◽  
Control Cell ◽  
Cell Mass ◽  
Erk Signaling

scholarly journals Epigenetic Modification Affecting Expression of Cell Polarity and Cell Fate Genes to Regulate Lineage Specification in the Early Mouse Embryo

2010 ◽  
Vol 21 (15) ◽  
pp. 2649-2660 ◽  
Author(s):  
David-Emlyn Parfitt ◽  
Magdalena Zernicka-Goetz
Keyword(s):  
Cell Fate ◽  
Cell Polarity ◽  
Mouse Embryo ◽  
Inner Cell Mass ◽  
Epigenetic Modification ◽  
Cell Mass ◽  
Time Lapse ◽  
Cell Polarization ◽  
Asymmetric Divisions

Formation of inner and outer cells of the mouse embryo distinguishes pluripotent inner cell mass (ICM) from differentiating trophectoderm (TE). Carm1, which methylates histone H3R17 and R26, directs cells to ICM rather that TE. To understand the mechanism by which this epigenetic modification directs cell fate, we generated embryos with in vivo–labeled cells of different Carm1 levels, using time-lapse imaging to reveal dynamics of their behavior, and related this to cell polarization. This shows that Carm1 affects cell fate by promoting asymmetric divisions, that direct one daughter cell inside, and cell engulfment, where neighboring cells with lower Carm1 levels compete for outside positions. This is associated with changes to the expression pattern and spatial distribution of cell polarity proteins: Cells with higher Carm1 levels show reduced expression and apical localization of Par3 and a dramatic increase in expression of PKCII, antagonist of the apical protein aPKC. Expression and basolateral localization of the mouse Par1 homologue, EMK1, increases concomitantly. Increased Carm1 also reduces Cdx2 expression, a transcription factor key for TE differentiation. These results demonstrate how the extent of a specific epigenetic modification could affect expression of cell polarity and fate-determining genes to ensure lineage allocation in the mouse embryo.

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