Expression of the gap junction proteins connexin31 and connexin43 correlates with communication compartments in extraembryonic tissues and in the gastrulating mouse embryo, respectively

1996 ◽  
Vol 109 (1) ◽  
pp. 191-197
Author(s):  
E. Dahl ◽  
E. Winterhager ◽  
B. Reuss ◽  
O. Traub ◽  
A. Butterweck ◽  
...  

We have characterized the pattern of connexin expression in embryonic and extraembryonic tissues during early mouse development. In the preimplantation blastocyst, at 3.5 days post coitum (dpc), immunofluorescent signals specific for connexin31 and connexin43 proteins were present in both the inner cell mass and the trophectoderm, as shown by confocal laser scan microscopy. Immediately after implantation at 6.5 dpc, however, we find complete compartmentation of these two connexins: connexin31 mRNA and protein are expressed exclusively in cells derived from the trophectoderm lineage, whereas connexin43 mRNA and protein are detected in cells derived from the inner cell mass. This expression pattern of connexin31 and connexin43 is maintained at 7.5 dpc when the axial polarity of the mouse embryo is established. It correlates with the communication compartments in extraembryonic tissues and the gastrulating mouse embryo, respectively. The communication boundary between those compartments may be due to incompatibility of connexin31 and connexin43 hemichannels, which do not communicate with each other in cell culture.

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.


Development ◽  
1990 ◽  
Vol 109 (3) ◽  
pp. 655-665
Author(s):  
P. Savatier ◽  
J. Morgenstern ◽  
R.S. Beddington

Permissiveness to Moloney Murine Leukemia Virus (MoMuLV) expression was examined during preimplantation and early postimplantation development of the mouse embryo. Blastocysts and 8th, 9th and 10th day postimplantation embryos were infected in vitro with a MoMuLV-based retroviral vector expressing the lacZ gene driven off an internal rat beta-actin promoter. Beta-galactosidase-positive cells were identified in all embryonic tissues including inner cell mass, epiblast, mesoderm, endoderm and definitive ectoderm. In contrast, embryos infected with a MoMuLV-based vector expressing the lacZ gene driven off the viral LTR showed beta-galactosidase-positive cells only in mesoderm and definitive ectoderm. We conclude that permissiveness to transcriptional activity of the LTR is acquired immediately upon differentiation of epiblast during gastrulation of the mouse embryo.


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

Development ◽  
1993 ◽  
Vol 117 (2) ◽  
pp. 711-723 ◽  
Author(s):  
R.M. Albano ◽  
N. Groome ◽  
J.C. Smith

Members of the activin family have been suggested to act as mesoderm-inducing factors during early amphibian development. Little is known, however, about mesoderm formation in the mammalian embryo, and as one approach to investigating this we have studied activin expression during early mouse development. Activins are homo- or heterodimers of the beta A or beta B subunits of inhibin, itself a heterodimer consisting of one of the beta subunits together with an alpha subunit. Our results indicate that the oocyte contains mRNA encoding all three subunits, and antibody staining demonstrates the presence of both alpha and beta protein chains. From the fertilized egg stage onwards, alpha subunit protein cannot be detected, so the presence of beta subunits reflects the presence of activin rather than inhibin. Maternal levels of activin protein decline during early cleavage stages but increase, presumably due to zygotic transcription (see below), in the compacted morula. By 3.5 days, only the inner cell mass (ICM) cells of the blastocyst express activin, but at 4.5 days the situation is reversed; activin expression is confined to the trophectoderm. Using reverse transcription-PCR, neither beta A nor beta B mRNA was detectable at the two-cell stage but transcripts encoding both subunits were detectable at the morula stage, with beta B mRNA persisting into the blastocyst. We have also analyzed activin and inhibin expression in ES and EC cells. Consistent with the observation that activins are expressed in the ICM of 3.5-day blastocysts, we find high levels of beta A and beta B mRNA in all eight ES cell lines tested. F9 EC cells express only activin beta B, together with low levels of the inhibin alpha chain. When ES and EC cells are induced to differentiate, levels of activin fall dramatically. These results are consistent with a role for activins in mesoderm formation and other steps of early mouse development.


Author(s):  
Marc Lenburg ◽  
Rulang Jiang ◽  
Lengya Cheng ◽  
Laura Grabel

We are interested in defining the cell-cell and cell-matrix interactions that help direct the differentiation of extraembryonic endoderm in the peri-implantation mouse embryo. At the blastocyst stage the mouse embryo consists of an outer layer of trophectoderm surrounding the fluid-filled blastocoel cavity and an eccentrically located inner cell mass. On the free surface of the inner cell mass, facing the blastocoel cavity, a layer of primitive endoderm forms. Primitive endoderm then generates two distinct cell types; parietal endoderm (PE) which migrates along the inner surface of the trophectoderm and secretes large amounts of basement membrane components as well as tissue-type plasminogen activator (tPA), and visceral endoderm (VE), a columnar epithelial layer characterized by tight junctions, microvilli, and the synthesis and secretion of α-fetoprotein. As these events occur after implantation, we have turned to the F9 teratocarcinoma system as an in vitro model for examining the differentiation of these cell types. When F9 cells are treated in monolayer with retinoic acid plus cyclic-AMP, they differentiate into PE. In contrast, when F9 cells are treated in suspension with retinoic acid, they form embryoid bodies (EBs) which consist of an outer layer of VE and an inner core of undifferentiated stem cells. In addition, we have established that when VE containing embryoid bodies are plated on a fibronectin coated substrate, PE migrates onto the matrix and this interaction is inhibited by RGDS as well as antibodies directed against the β1 integrin subunit. This transition is accompanied by a significant increase in the level of tPA in the PE cells. Thus, the outgrowth system provides a spatially appropriate model for studying the differentiation and migration of PE from a VE precursor.


Development ◽  
2002 ◽  
Vol 129 (14) ◽  
pp. 3455-3468 ◽  
Author(s):  
Dominic P. Norris ◽  
Jane Brennan ◽  
Elizabeth K. Bikoff ◽  
Elizabeth J. Robertson

The TGFβ-related growth factor Nodal governs anteroposterior (AP) and left-right (LR) axis formation in the vertebrate embryo. A conserved intronic enhancer (ASE), containing binding sites for the fork head transcription factor Foxh1, modulates dynamic patterns of Nodal expression during early mouse development. This enhancer is responsible for early activation of Nodal expression in the epiblast and visceral endoderm, and at later stages governs asymmetric expression during LR axis formation. We demonstrate ASE activity is strictly Foxh1 dependent. Loss of this autoregulatory enhancer eliminates transcription in the visceral endoderm and decreases Nodal expression in the epiblast, but causes surprisingly discrete developmental abnormalities. Thus lowering the level of Nodal signaling in the epiblast disrupts both orientation of the AP axis and specification of the definitive endoderm. Targeted removal of the ASE also dramatically reduces left-sided Nodal expression, but the early events controlling LR axis specification are correctly initiated. However loss of the ASE disrupts Lefty2 (Leftb) expression and causes delayed Pitx2 expression leading to late onset, relatively minor LR patterning defects. The feedback loop is thus essential for maintenance of Nodal signals that selectively regulate target gene expression in a temporally and spatially controlled fashion in the mouse embryo.


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.


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