scholarly journals Lineage allocation and asymmetries in the early mouse embryo

2003 ◽  
Vol 358 (1436) ◽  
pp. 1341-1349 ◽  
Author(s):  
Janet Rossant ◽  
Claire Chazaud ◽  
Yojiro Yamanaka

The mouse blastocyst, at the time of implantation, has three distinct cell lineages: epiblast (EPI), trophoblast and primitive endoderm (PE). Interactions between these three lineages and their directional growth and migration are critical for establishing the initial asymmetries that result in anterior–posterior patterning of the embryo proper. We have re–investigated the timing of specification of the three lineages in relation to the differential allocation of progeny of the first two blastomeres to the embryonic versus abembryonic axis of the blastocyst. We find that the majority of cells of the inner cell mass (ICM) are specified to be EPI or PE by the mid 3.5 day blastocyst and that this is associated with localized expression of GATA–6 in the ICM. We propose a model for molecular specification of the blastocyst lineages in which a combination of cell division order, signal transduction differences between inner and outer cells and segregation of key transcription factors can produce a blastocyst in which all three lineages are normally set up in an ordered, lineage–dependent manner, but which can also reconstruct a blastocyst when division order or cell interactions are disturbed.

2003 ◽  
Vol 23 (12) ◽  
pp. 4307-4318 ◽  
Author(s):  
William S. Mohan ◽  
Elisabeth Scheer ◽  
Olivia Wendling ◽  
Daniel Metzger ◽  
Làszlò Tora

ABSTRACT TAF10 (formerly TAFII30), is a component of TFIID and the TATA box-binding protein (TBP)-free TAF-containing complexes (TFTC/PCAF/STAGA). To investigate the physiological function of TAF10, we disrupted its gene in mice by using a Cre recombinase/LoxP strategy. Interestingly, no TAF10−/− animals were born from intercrosses of TAF10+/− mice, indicating that TAF10 is required for embryogenesis. TAF10−/− embryos developed to the blastocyst stage, implanted, but died shortly after ca. 5.5 days postcoitus. Surprisingly, trophoblast cells from TAF10−/− blastocysts were viable, whereas inner cell mass cells failed to survive, highlighting that TAF10 is not generally required for transcription in all cells. TAF10-deficient cells express normal levels of TBP and TAFs other than TAF10 but contain only partially formed TFIID, are endocycle arrested, and have undetectable levels of transcription. Thus, our results demonstrate that TAF10 is required for TFIID stability, cell cycle progression, and transcription in the early mouse embryo.


Development ◽  
2021 ◽  
Author(s):  
Esther Jeong Yoon Kim ◽  
Lydia Sorokin ◽  
Takashi Hiiragi

Development entails patterned emergence of diverse cell types within the embryo. In mammals, cells positioned inside the embryo give rise to the inner cell mass (ICM) that eventually forms the embryo proper. Yet the molecular basis of how these cells recognise their ‘inside’ position to instruct their fate is unknown. Here we show that provision of extracellular matrix (ECM) to isolated embryonic cells induces ICM specification and alters subsequent spatial arrangement between epiblast (EPI) and primitive endoderm (PrE) cells that emerge within the ICM. Notably, this effect is dependent on integrin β1 activity and involves apical to basal conversion of cell polarity. We demonstrate that ECM-integrin activity is sufficient for ‘inside’ positional signalling and it is required for proper EPI/PrE patterning. Our findings thus highlight the significance of ECM-integrin adhesion in enabling position-sensing by cells to achieve tissue patterning.


2002 ◽  
Vol 78 ◽  
pp. S283
Author(s):  
Navid Esfandiari ◽  
Tommaso Falcone ◽  
Ashok Agarwal ◽  
Ramadan A Saleh ◽  
Marjan Attaran ◽  
...  

2021 ◽  
Author(s):  
Esther J.Y. Kim ◽  
Lydia Sorokin ◽  
Takashi Hiiragi

Development entails patterned emergence of diverse cell types within the embryo. In mammals, cells positioned inside the embryo gives rise to the inner cell mass (ICM) that eventually forms the embryo proper. Yet the molecular basis of how these cells recognise their inside position to instruct their fate is unknown. Here we show that cells perceive their position through extracellular matrix (ECM) and integrin-mediated adhesion. Provision of ECM to isolated embryonic cells induces ICM specification and alters subsequent spatial arrangement between epiblast (EPI) and primitive endoderm (PrE) cells that emerge within the ICM. Notably, this effect is dependent on integrin β 1 activity and involves apical to basal conversion of cell polarity. We demonstrate that ECM-integrin activity is sufficient for inside positional signalling and it is required for proper sorting of EPI/PrE cells. Our findings thus highlight the significance of ECM-integrin adhesion in enabling position-sensing by cells to achieve tissue patterning.


1993 ◽  
Vol 120 (1) ◽  
pp. 235-243 ◽  
Author(s):  
A van de Stolpe ◽  
M Karperien ◽  
C W Löwik ◽  
H Jüppner ◽  
G V Segre ◽  
...  

Parathyroid hormone related peptide (PTHrP), first identified in tumors from patients with the syndrome of "Humoral Hypercalcemia of Malignancy," can replace parathyroid hormone (PTH) in activating the PTH-receptor in responsive cells. Although PTHrP expression is widespread in various adult and fetal tissues, its normal biological function is as yet unknown. We have examined the possible role of PTHrP and the PTH/PTHrP-receptor in early mouse embryo development. Using F9 embryonal carcinoma (EC) cells and ES-5 embryonic stem (ES) cells as in vitro models, we demonstrate that during the differentiation of these cells towards primitive and parietal endoderm-like phenotypes, PTH/PTHrP-receptor mRNA is induced. This phenomenon is correlated with the appearance of functional adenylate cyclase coupled PTH/PTHrP-receptors. These receptors are the mouse homologues of the recently cloned rat bone and opossum kidney PTH/PTHrP-receptors. Addition of exogenous PTH or PTHrP to RA-treated EC or ES cells is an efficient replacement for dBcAMP in inducing full parietal endoderm differentiation. Endogenous PTHrP is detectable at very low levels in undifferentiated EC and ES cells, and is upregulated in their primitive and parietal endoderm-like derivatives as assessed by immunofluorescence. Using confocal laser scanning microscopy on preimplantation mouse embryos, PTHrP is detected from the late morula stage onwards in developing trophectoderm cells, but not in inner cell mass cells. In blastocyst stages PTHrP is in addition found in the first endoderm derivatives of the inner cell mass. Together these results indicate that the PTH/PTHrP-receptor signalling system serves as a para- or autocrine mechanism for parietal endoderm differentiation in the early mouse embryo, thus constituting the earliest hormone receptor system involved in embryogenesis defined to date.


Development ◽  
1993 ◽  
Vol 118 (4) ◽  
pp. 1353-1361
Author(s):  
J.M. Baltz ◽  
J.D. Biggers ◽  
C. Lechene

Most cell types are relatively impermeant to H+ and are able to regulate their intracellular pH by means of plasma membrane proteins, which transport H+ or bicarbonate across the membrane in response to perturbations of intracellular pH. Mouse preimplantation embryos at the 2-cell stage, however, do not appear to possess specific pH-regulatory mechanisms for relieving acidosis. They are, instead, highly permeable to H+, so that the intracellular pH in the acid and neutral range is determined by the electrochemical equilibrium of H+ across the plasma membrane. When intracellular pH is perturbed, the rate of the ensuing H+ flux across the plasma membrane is determined by the H+ electrochemical gradient: its dependence on external K+ concentration indicates probable dependence on membrane potential and the rate depends on the H+ concentration gradient across the membrane. The large permeability at the 2-cell stage is absent or greatly diminished in the trophectoderm of blastocysts, but still present in the inner cell mass. Thus, the permeability to H+ appears to be developmentally regulated.


eLife ◽  
2017 ◽  
Vol 6 ◽  
Author(s):  
Eszter Posfai ◽  
Sophie Petropoulos ◽  
Flavia Regina Oliveira de Barros ◽  
John Paul Schell ◽  
Igor Jurisica ◽  
...  

The segregation of the trophectoderm (TE) from the inner cell mass (ICM) in the mouse blastocyst is determined by position-dependent Hippo signaling. However, the window of responsiveness to Hippo signaling, the exact timing of lineage commitment and the overall relationship between cell commitment and global gene expression changes are still unclear. Single-cell RNA sequencing during lineage segregation revealed that the TE transcriptional profile stabilizes earlier than the ICM and prior to blastocyst formation. Using quantitative Cdx2-eGFP expression as a readout of Hippo signaling activity, we assessed the experimental potential of individual blastomeres based on their level of Cdx2-eGFP expression and correlated potential with gene expression dynamics. We find that TE specification and commitment coincide and occur at the time of transcriptional stabilization, whereas ICM cells still retain the ability to regenerate TE up to the early blastocyst stage. Plasticity of both lineages is coincident with their window of sensitivity to Hippo signaling.


Development ◽  
1979 ◽  
Vol 54 (1) ◽  
pp. 263-275
Author(s):  
Stephen J. Gaunt ◽  
Virginia E. Papaioannou

Mouse embryonal carcinoma (EC) cells form permeable junctions at their homotypic cell-to-cell contacts which permit intercellular exchange of metabolites (metabolic co-operation). Hooper & Slack (1977) showed how this exchange could be detected by autoradiography as the transfer of [3H]nucleotides between PCI3 (a pluripotential EC line) and PCI 3- TG8 (a variant of PC13 which is deficient in hypoxanthine guanine phosphoribosyltransferase). We now show that cells taken from several different tissues of early mouse embryos, that is, from the morula, the inner cell mass of the blastocyst, and the endoderm, mesoderm and embryonic ectoderm of the 8th day egg cylinder, are able to serve as donors of [3H] ucleotides to PC13TG8. In contrast, trophectodermal cells of cultured blastocysts, and the trophectodermal derivatives in the 8th day egg cylinder, that is, extra-embryonic ectoderm and ectoplacental cone cells, showed little or no metabolic co-operation with PC13TG8. With reference to some common properties of EC and embryonic cells, we suggest how our findings may provide insight into cell-to-cell interactions in the early mouse embryo.


2003 ◽  
Vol 358 (1436) ◽  
pp. 1403-1409 ◽  
Author(s):  
Wolf Reik ◽  
Fatima Santos ◽  
Kohzoh Mitsuya ◽  
Hugh Morgan ◽  
Wendy Dean

Epigenetic asymmetry between parental genomes and embryonic lineages exists at the earliest stages of mammalian development. The maternal genome in the zygote is highly methylated in both its DNA and its histones and most imprinted genes have maternal germline methylation imprints. The paternal genome is rapidly remodelled with protamine removal, addition of acetylated histones, and rapid demethylation of DNA before replication. A minority of imprinted genes have paternal germline methylation imprints. Methylation and chromatin reprogramming continues during cleavage divisions, but at the blastocyst stage lineage commitment to inner cell mass (ICM) or trophectoderm (TE) fate is accompanied by a dramatic increase in DNA and histone methylation, predominantly in the ICM. This may set up major epigenetic differences between embryonic and extraembryonic tissues, including in X–chromosome inactivation and perhaps imprinting. Maintaining epigenetic asymmetry appears important for development as asymmetry is lost in cloned embryos, most of which have developmental defects, and in particular an imbalance between extraembryonic and embryonic tissue development.


eLife ◽  
2018 ◽  
Vol 7 ◽  
Author(s):  
Jan J Zylicz ◽  
Maud Borensztein ◽  
Frederick CK Wong ◽  
Yun Huang ◽  
Caroline Lee ◽  
...  

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.


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