scholarly journals Nuclear Transplantation of Mouse Inner Cell Mass and Trophectoderm Cells into Enucleated Two-Cell Embryos.

1998 ◽  
Vol 44 (1) ◽  
pp. 1-6 ◽  
Author(s):  
Yusuke SOTOMARU ◽  
Yoko KATO ◽  
Yukio TSUNODA
Keyword(s):  
Inner Cell Mass ◽  
Cell Mass ◽  
Nuclear Transplantation ◽  
Trophectoderm Cells

Interactions of blastomeres suggest changes in cell surface adhesiveness during the formation of inner cell mass and trophectoderm in the preimplantation mouse embryo

Development ◽  
1982 ◽  
Vol 70 (1) ◽  
pp. 133-152
Author(s):  
Susan J. Kimber ◽  
M. Azim ◽  
H. Surani ◽  
Sheila C. Barton
Keyword(s):  
Inner Cell Mass ◽  
Single Cells ◽  
Cell Mass ◽  
Cell Stage ◽  
Trophectoderm Cells ◽  
Adhesive Surface ◽  
Preimplantation Mouse Embryo ◽  
Divergent Differentiation ◽  
Preimplantation Mouse ◽  
The Difference

Whole 8-cell morulae can be aggregated with isolated inner cell masses from blastocysts. On examining semithin light microscope sections of such aggregates we found that cells of the morula changed shape and spread over the surface of the ICM, thus translocating it to the inside of the aggregate. Using single cells from 8-cell embryos in combination with single cells from other stage embryos or isolated ICMs we show that 1/8 blastomeres spread over other cells providing a suitably adhesive surface. The incidence of spreading is high with inner cells from 16-cell embryos (56 %) and 32-cell embryos (62%) and isolated inner cell masses (64%). In contrast, the incidence of spreading of 1/8 blastomeres is low over outer cells from 16-cell embryos (26%) and 32-cell embryos (13%). Blastomeres from 8-cell embryos do not spread over unfertilized 1-cell eggs, 1/2 or 1/4 cells or trophectoderm cells contaminating isolated ICMs. When 1/8 cells are aggregated in pairs they flatten on one another (equal spreading) as occurs at compaction in whole 8-cell embryos. However, if 1/8 is allowed to divide to 2/16 in culture one of the cells engulfs the other (51-62/ pairs). Based on the ideas of Holtfreter (1943) and Steinberg (1964,1978) these results are interpreted to indicate an increase in adhesiveness at the 8-cell stage as well as cytoskeletal mobilization. Following the 8-cell stage there is an increase in adhesiveness of inside cells while the outside cells decrease in adhesiveness. The difference in adhesiveness between inside and outside cells in late morulae is probably central to the divergent differentiation of (inner) ICM and (outer) trophectoderm cell populations.

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.

Nuclear transplantation of male primordial germ cells in the mouse

Development ◽  
1989 ◽  
Vol 107 (2) ◽  
pp. 407-411 ◽  
Author(s):  
Y. Tsunoda ◽  
T. Tokunaga ◽  
H. Imai ◽  
T. Uchida
Keyword(s):  
Germ Cells ◽  
Inner Cell Mass ◽  
Primordial Germ Cells ◽  
Cell Mass ◽  
Blastocyst Stage ◽  
Nuclear Transplantation ◽  
Embryonic Genome ◽  
Donor Nucleus ◽  
Implantation Sites ◽  
Genome Activation

We examined the developmental ability of enucleated eggs receiving embryonic nuclei and male primordial germ cells (PGCs) in the mouse. Reconstituted eggs developed into the blastocyst stage only when an earlier 2-cell nucleus was transplanted (36%) but very rarely if the donor nucleus was derived from a later 2-cell, 8-cell, or inner cell mass of a blastocyst (0–3%). 54–100%, 11–67%, 6–43% and 6–20% of enucleated eggs receiving male PGCs developed to 2-cell, 4-cell, 8-cell and blastocyst stage, respectively, in culture. The overall success rate when taking into account the total number of attempts at introducing germ cells was actually 0–6%. Live fetuses were not obtained after transfer of reconstituted eggs to recipients, although implantation sites were observed. The developmental ability of reconstituted eggs in relation to embryonic genome activation and genomic imprinting is discussed.

Defects in the allocation of cells to the inner cell mass and trophectoderm of parthenogenetic mouse blastocysts

1996 ◽  
Vol 8 (8) ◽  
pp. 1193 ◽  
Author(s):  
B Mognetti ◽  
D Sakkas
Keyword(s):  
Inner Cell Mass ◽  
Cell Mass ◽  
Substantial Reduction ◽  
Cell Lineage ◽  
Blastocyst Stage ◽  
Trophectoderm Cells ◽  
Parthenogenetic Development ◽  
Preimplantation Stage ◽  
Parthenogenetic Mouse Embryos ◽  
Parthenogenetic Embryos

Diploid parthenogenetic mouse embryos (which possess two maternally-derived genomes) can develop only as far as the 25-somite stage when transferred in utero and exhibit a substantial reduction in trophoblast tissue. The loss of cultured parthenogenetic embryos during postimplantation indicates that a defect in cell lineage may be evident as early as the blastocyst stage. The possibility that a defect may already be reflected at the preimplantation stage was investigated by examining the allocation of cells to the trophectoderm (trophoblast progenitor cells) and the inner cell mass of haploid and diploid parthenogenetic mouse blastocysts. Utilizing a differential labelling technique for counting cells, diploid parthenogenetic blastocysts were found to have fewer inner cell mass cells and trophectoderm cells than their haploid counterparts and normal blastocysts. In addition, both haploid and diploid parthenogenetic blastocysts had a lower inner cell mass: trophectoderm ratio than normal blastocysts. Thus, the relatively poor development of the trophectoderm lineage at the postimplantation stage is not reflected by a reduction in its allotment of cells at its first appearance. Nevertheless, the findings indicate that parthenogenetic development is already compromised at the blastocyst stage, and provide evidence that the expression of imprinted genes has significance for the development of the embryo at the preimplantation stage.

scholarly journals Sex differences in response of the bovine embryo to colony-stimulating factor 2

Reproduction ◽  
2016 ◽  
Vol 152 (6) ◽  
pp. 645-654 ◽  
Author(s):  
Luiz G B Siqueira ◽  
Peter J Hansen
Keyword(s):  
Gene Expression ◽  
Inner Cell Mass ◽  
Cell Mass ◽  
Transcript Abundance ◽  
Bovine Embryo ◽  
Sexually Dimorphic ◽  
Dependent Manner ◽  
Trophectoderm Cells ◽  
Gene Assay

We tested whether gene expression of the bovine morula is modified by CSF2 in a sex-dependent manner and if sex determines the effect of CSF2 on competence of embryos to become blastocysts. Embryos were produced in vitro using X- or Y-sorted semen and treated at Day 5 of culture with 10 ng/mL bovine CSF2 or control. In experiment 1, morulae were collected at Day 6 and biological replicates (n = 8) were evaluated for transcript abundance of 90 genes by RT-qPCR using the Fluidigm Delta Gene assay. Expression of more than one-third (33 of 90) of genes examined was affected by sex. The effect of CSF2 on gene expression was modified by sex (P < 0.05) for five genes (DDX3Y/DDX3X-like, NANOG, MYF6, POU5F1 and RIPK3) and tended (P < 0.10) to be modified by sex for five other genes (DAPK1, HOXA5, PPP2R3A, PTEN and TNFSF8). In experiment 2, embryos were treated at Day 5 with control or CSF2 and blastocysts were collected at Day 7 for immunolabeling to determine the number of inner cell mass (ICM) and trophectoderm (TE) cells. CSF2 increased the percent of putative zygotes that became blastocysts for females, but did not affect the development of males. There was no effect of CSF2 or interaction of CSF2 with sex on the total number of blastomeres in blastocysts or in the number of inner cell mass or trophectoderm cells. In conclusion, CSF2 exerted divergent responses on gene expression and development of female and male embryos. These results are evidence of sexually dimorphic responses of the preimplantation embryo to this embryokine.

scholarly journals Colony-Stimulating Factor 2 (CSF-2) Improves Development and Posttransfer Survival of Bovine Embryos Produced in Vitro

Endocrinology ◽  
2009 ◽  
Vol 150 (11) ◽  
pp. 5046-5054 ◽  
Author(s):  
Bárbara Loureiro ◽  
Luciano Bonilla ◽  
Jeremy Block ◽  
Justin M. Fear ◽  
Aline Q. S. Bonilla ◽  
...  
Keyword(s):  
Embryonic Development ◽  
Inner Cell Mass ◽  
Cell Mass ◽  
Colony Stimulating Factor ◽  
Bovine Embryos ◽  
Epigenetic Effects ◽  
Trophectoderm Cells ◽  
Stimulating Factor

In this study, we tested the role of colony-stimulating factor 2 (CSF2) as one of the regulatory molecules that mediate maternal effects on embryonic development during the preimplantation period. Our objective was to verify effects of CSF2 on blastocyst yield, determine posttransfer survival, and evaluate properties of the blastocyst formed after CSF2 treatment. In vitro, CSF2 increased the percentage of oocytes that became morulae and blastocysts. Blastocysts that were treated with CSF2 tended to have a greater number of inner cell mass cells and had a higher ratio of inner cell mass to trophectoderm cells. There was no effect of CSF2 on the incidence of apoptosis. Treatment with CSF2 from d 5 to 7 after insemination increased embryonic survival as indicated by improved pregnancy rate at d 30–35 of gestation. Moreover, treatment with CSF2 from either d 1–7 or 5–7 after insemination reduced pregnancy loss after d 30–35. Results indicate that treatment with CSF2 can affect embryonic development and enhance embryo competence for posttransfer survival. The fact that treatment with CSF2 during such a narrow window of development altered embryonic function much later in pregnancy suggests that CSF2 may exert epigenetic effects on the developing embryo that result in persistent changes in function during the embryonic and fetal periods of development.

scholarly journals PC7 and the related proteases Furin and Pace4 regulate E-cadherin function during blastocyst formation

2015 ◽  
Vol 210 (7) ◽  
pp. 1185-1197 ◽  
Author(s):  
Sylvain Bessonnard ◽  
Daniel Mesnard ◽  
Daniel B. Constam
Keyword(s):  
Cell Adhesion ◽  
Inner Cell Mass ◽  
Cell Mass ◽  
Cell Polarization ◽  
Hippo Signaling ◽  
Trophectoderm Cells ◽  
Mammalian Embryos ◽  
Lineage Decision ◽  
E Cadherin ◽  
Cell Cell

The first cell differentiation in mammalian embryos segregates polarized trophectoderm cells from an apolar inner cell mass (ICM). This lineage decision is specified in compacted morulae by cell polarization and adhesion acting on the Yes-associated protein in the Hippo signaling pathway, but the regulatory mechanisms are unclear. We show that morula compaction and ICM formation depend on PC7 and the related proprotein convertases (PCs) Furin and Pace4 and that these proteases jointly regulate cell–cell adhesion mediated by E-cadherin processing. We also mapped the spatiotemporal activity profiles of these proteases by live imaging of a transgenic reporter substrate in wild-type and PC mutant embryos. Differential inhibition by a common inhibitor revealed that all three PCs are active in inner and outer cells, but in partially nonoverlapping compartments. E-cadherin processing by multiple PCs emerges as a novel mechanism to modulate cell–cell adhesion and fate allocation.

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