scholarly journals Gene expression in the mouse preimplantation embryo

Reproduction ◽  
2003 ◽  
pp. 457-468 ◽  
Author(s):  
JA Stanton ◽  
AB Macgregor ◽  
DP Green
Keyword(s):  
Gene Expression ◽  
Preimplantation Embryo ◽  
Inner Cell Mass ◽  
Cell Mass ◽  
Preimplantation Development ◽  
National Institutes Of Health ◽  
Cell Stage ◽  
Cdna Sequences ◽  
Starting Point ◽  
Mouse Preimplantation Embryo

Mouse preimplantation development represents a tightly controlled programme of gene expression and cell division, which starts with the fertilized egg and ends with implantation of the blastocyst approximately 4.5 days later. Spatial and temporal differences in gene expression underpin establishment of axes at the two-cell stage and development of the trophectoderm and inner cell mass after embryo compaction at the eight-cell stage. Approximately 15 700 mouse genes expressed during preimplantation development have been identified from cDNA sequences deposited in the UniGene database of the National Institutes of Health. This inventory of preimplantation genes is the starting point for identifying signalling modules that function in preimplantation development.

scholarly journals Localization of nitric oxide synthase activity in unfertilized oocytes and fertilized embryos during preimplantation development in mice

Reproduction ◽  
2001 ◽  
pp. 957-963 ◽  
Author(s):  
A Nishikimi ◽  
T Matsukawa ◽  
K Hoshino ◽  
S Ikeda ◽  
Y Kira ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Nitric Oxide Synthase ◽  
Inner Cell Mass ◽  
Cell Mass ◽  
Preimplantation Development ◽  
Cell Stage ◽  
Nos Inhibitors ◽  
Development In Vitro ◽  
Oxide Synthase

Changes in the activities of nitric oxide synthase (NOS) during embryonic development, and the distribution of endothelial nitric oxide synthase (eNOS) and inducible nitric oxide synthase (iNOS) isoforms were examined in unfertilized mouse oocytes at the second meiotic metaphase (MII) stage and in fertilized mouse embryos during preimplantation development. In addition, the effects of NOS inhibitors on mouse preimplantation development in vitro were investigated. The activities of NOS in MII oocytes and fertilized embryos during the preimplantation period were determined by NADPH-diaphorase staining. Although NOS activity was detected in unfertilized MII oocytes, the intensity of staining was much weaker than that of fertilized embryos at the one-cell stage. There was a decrease in NOS activity in embryos from the four-cell to the eight-cell stage; however, NOS activity increased again in embryos at the morula stage, particularly in the inner cell population. In the expanded blastocysts, staining was confined to the inner cell mass. Immuno-cytochemical staining showed that eNOS and iNOS were expressed in the cytoplasm of oocytes and embryos during the preimplantation period, and eNOS was also distributed in the nuclei of the embryos. When one-cell embryos were treated with 1 mmol N(omega)-nitro-L-arginine methyl ester (L-NAME) l(-1), their development in vitro was arrested at the two-cell stage. This inhibition of development was overcome by the addition of 1 mmol L-arginine l(-1) to the medium. These observations indicate that nitric oxide plays an important role as a diffusible regulator of cell proliferation and differentiation, especially at the developmental transition from the two-cell to the four-cell stage during preimplantation development of mice.

142 DYNAMICS OF Tet FAMILY DURING PRE-IMPLANTATION DEVELOPMENT OF PORCINE EMBRYOS

2012 ◽  
Vol 24 (1) ◽  
pp. 183 ◽  
Author(s):  
J. Teson ◽  
K. Lee ◽  
L. Spate ◽  
R. S. Prather
Keyword(s):  
Gene Expression ◽  
Embryo Development ◽  
Expression Profile ◽  
Inner Cell Mass ◽  
Cell Mass ◽  
Blastocyst Stage ◽  
Dna Demethylation ◽  
Dimensional Structure ◽  
Cell Stage ◽  
Donor Cells

One of the key regulators of gene expression in mammals is DNA methylation. The Tet family (Tet1–3) is suggested to be involved in regulating the level of methylation by hydroxylating a methyl group from 5-methylcytosine to form 5-hydroxymethylcystosine. This hydroxylation alters the 3-dimensional structure of the DNA and results in altered gene expression. Previous studies conducted in the mouse have shown that Tet1 is important for inner cell mass specification by regulating the apparent level of methylation on a specific promoter region in blastocysts and Tet3 is related to the apparent paternal DNA demethylation after fertilization by hydroxylating the paternal genome. The objective of this study was to investigate the expression profile of the Tet family in porcine oocytes and pre-implantation-stage embryos derived from IVF and somatic cell nuclear transfer (SCNT). The RNA was isolated from donor cells, germinal vesicle (GV), MII and 2-cell and blastocyst stage embryos (20 oocytes or embryos per group). Levels of mRNA for each Tet gene were measured by quantitative real-time RT-PCR. The levels of each mRNA transcript were compared to YWHAG, a housekeeping gene that shows a constant level of expression throughout pre-implantation embryo development and normalized to the GV stage. The analysis was repeated with 3 biological replications and 2 experimental replications. Differences in gene expression were compared by ANOVA and P < 0.05 was considered significant. No difference was found in the levels of the Tet family members between GV and MII stage oocytes. Compared with GV stage oocytes, up-regulation of Tet3 at the 2-cell stage was detected in both IVF and SCNT embryos, 4.7 and 6.2 fold, respectively. A dramatic increase in Tet1 was also observed at the blastocyst stage in IVF and SCNT embryos when compared with the GV stage, 65.7 and 79.7 fold increases, respectively. Interestingly, the level of Tet3 was down-regulated in blastocyst embryos at a 25 or more fold decrease compared with GV. The level of Tet2 remained constant throughout embryo development. Embryos (2-cell and blastocyst) compared from IVF and SCNT showed no difference in Tet expression levels. Donor cells had significantly lower levels of Tet2 and Tet3 when compared with GV. Our results indicate that the Tet family shows a dynamic expression profile during porcine pre-implantation embryo development. High expression of Tet3 in 2-cell stage embryos suggests its importance during the post-activation demethylation process. The increase of Tet1 transcript in blastocysts suggests that Tet1 is involved in regulating the type of methylation at the blastocyst stage. These results are consistent with results from previous mouse studies. There was no misregulated expression of the Tet family in SCNT embryos compared with IVF embryos, thus indicating successful reprogramming of the Tet family after SCNT. Lower levels of Tet2 and Tet3 would indicate that Tet1 is important for maintaining type of methylation in donor cells. This is the first report on the profile of the Tet family during porcine pre-implantation embryo development and further studies are needed to clarify their role during this stage.

Desmosome biogenesis in the mouse preimplantation embryo

Development ◽  
1991 ◽  
Vol 112 (2) ◽  
pp. 527-539 ◽  
Author(s):  
T.P. Fleming ◽  
D.R. Garrod ◽  
A.J. Elsmore
Keyword(s):  
Preimplantation Embryo ◽  
Inner Cell Mass ◽  
Cell Mass ◽  
Cell Contact ◽  
Cell Stage ◽  
Linear Pattern ◽  
Cell Clusters ◽  
Membrane Contact Sites ◽  
Contact Sites ◽  
Membrane Contact

The molecular processes underlying the formation of the first desmosomes in the mouse early embryo have been examined by immunocytochemical and biochemical techniques using antibody probes recognising desmosomal proteins 1 and 2 (dp1 + 2, desmoplakins), dp3 (plakoglobin), desmosomal glycoprotein 1 (dg1, desmoglein) and dg2 + 3 (desmocollins). Immunofluorescence labelling of staged intact embryos and synchronised cell clusters indicates that dp1 + 2, dg1 and dg2 + 3 are first detectable on the lateral membrane contact sites between trophectoderm cells in early cavitating blastocysts, coincident with the onset of desmosome formation as seen in ultrastructural preparations. Membrane localisation of these antigens is predominantly punctate in appearance, occurs after division to the 32-cell stage and appears to be coincident with blastocoele formation since non-cavitated embryos/cell clusters of equivalent age/cell cycle are usually unlabelled. In contrast, dp3 is first detectable at the 32-cell stage at all internal membrane contact sites (including those with inner cell mass cells) in a continuous linear pattern, and appears in both cavitated and non-cavitated specimens. Subsequently during blastocyst expansion, dp3 localisation becomes punctate and restricted to trophectodermal membranes. Immunoprecipitation of desmosomal antigens following metabolic labelling indicates that synthesis of dp3 is underway from at least compaction in the 8-cell embryo, while dp1 + 2 synthesis is first evident in 16-cell morulae. Synthesis of dg1 and dg2 + 3 is not detectable until the early blastocyst stage. These results suggest that desmosome biogenesis in the preimplantation embryo might be regulated by transcription or translation of desmosomal glycoproteins and by maturational changes in the trophectoderm layer associated with blastocoele formation. The earlier expression and wider distribution of dp3 at cell contact areas may reflect non-desmosomal sites (eg, adherens junctions) for this protein and a possible role for dp3 in the development of intercellular junctions.

Haemoglobin expression in in vivo murine preimplantation embryos suggests a role in oxygen-regulated gene expression

2019 ◽  
Vol 31 (4) ◽  
pp. 724 ◽  
Author(s):  
M. Lim ◽  
H. M. Brown ◽  
K. L. Kind ◽  
J. Breen ◽  
M. R. Anastasi ◽  
...  
Keyword(s):  
Gene Expression ◽  
Glucose Transporter ◽  
Preimplantation Embryo ◽  
Inner Cell Mass ◽  
Cell Mass ◽  
Specific Effect ◽  
Blastocyst Stage ◽  
High Expression ◽  
Preimplantation Embryos ◽  
Regulated Gene Expression

Haemoglobin expression is not restricted to erythroid cells. We investigated the gene expression of the haemoglobin subunits haemoglobin, alpha adult chain 1 (Hba-a1) and haemoglobin, beta (Hbb), 2,3-bisphosphoglycerate mutase (Bpgm) and the oxygen-regulated genes BCL2/adenovirus E1B interacting protein 3 (Bnip3), solute carrier family 2 (facilitated glucose transporter), member 1 (Slc2a1) and N-myc downstream regulated gene 1 (Ndrg1) in the murine preimplantation embryo, comparing invivo to invitro gene expression. Relatively high levels of Hba-a1 and Hbb were expressed invivo from the 2-cell to blastocyst stage; in contrast, little or no expression occurred invitro. We hypothesised that the presence of haemoglobin invivo creates a low oxygen environment to induce oxygen-regulated gene expression, supported by high expression of Slc2a1 and Ndrg1 in invivo relative to invitro embryos. In addition, analysis of an invitro-derived human embryo gene expression public dataset revealed low expression of haemoglobin subunit alpha (HBA) and HBB, and high expression of BPGM. To explore whether there was a developmental stage-specific effect of haemoglobin, we added exogenous haemoglobin either up to the 4-cell stage or throughout development to the blastocyst stage, but observed no difference in blastocyst rate or the inner cell mass to trophectoderm cell ratio. We conclude that haemoglobin in the invivo preimplantation embryo raises an interesting premise of potential mechanisms for oxygen regulation, which may influence oxygen-regulated gene expression.

The effect of extracellular matrix molecules on mouse preimplantation embryo development in vitro

2002 ◽  
Vol 14 (7) ◽  
pp. 443 ◽  
Author(s):  
F. Figueiredo ◽  
G. M. Jones ◽  
G. A. Thouas ◽  
A. O. Trounson
Keyword(s):  
Culture Medium ◽  
Preimplantation Embryo ◽  
Inner Cell Mass ◽  
Culture Media ◽  
Cell Mass ◽  
Sulfate Proteoglycan ◽  
Preimplantation Embryo Development ◽  
Cell Numbers ◽  
Mouse Preimplantation Embryo

The extracellular matrix (ECM) molecules, laminin (LN), chondroitin sulfate (CS), fibronectin (FN), hyaluronic acid (HA), mucin (MUC) and heparan sulfate proteoglycan (HS), were investigated as supplements to culture medium to improve the in vitro development of mouse 1-cell zygotes to blastocysts. Development was also compared with that in medium supplemented with bovine serum albumin (BSA) to determine the potential for ECM molecules as suitable alternatives to serum albumin in culture medium. Supplementation of sequential culture media with LN at all concentrations examined failed to result in more than 70% of zygotes developing to blastocysts; therefore, LN was considered unsuitable as a replacement for BSA and was not examined further. The optimal concentration of the remaining ECM molecules was used to supplement sequential culture media and the effect on blastocyst quality was assessed by determining the differential cell numbers of blastocysts grown in BSA-supplemented medium. Development to blastocyst was similar, regardless of the macromolecule used. The number of inner cell mass cells was significantly higher in HS-supplemented medium compared with controls. Trophectoderm cell numbers were similar to control values for all ECM molecules examined except CS for which there were fewer trophectoderm cells. It is concluded that ECM molecules, FN, HA, MUC and HS may be used as substitutes for serum protein supplementation of culture media EG0/G2 for mouse preimplantation embryo development. Heparan sulfate proteoglycan increases inner cell mass numbers and this may be due to interactions with the growth factors fibroblast growth factor 4 (FGF-4) and granulocyte–macrophage colony-stimulating factor.

scholarly journals Connexin trafficking and the control of gap junction assembly in mouse preimplantation embryos

Development ◽  
1993 ◽  
Vol 117 (4) ◽  
pp. 1355-1367 ◽  
Author(s):  
P.A. De Sousa ◽  
G. Valdimarsson ◽  
B.J. Nicholson ◽  
G.M. Kidder
Keyword(s):  
Gap Junction ◽  
Plasma Membranes ◽  
Inner Cell Mass ◽  
Cell Mass ◽  
Brefeldin A ◽  
Preimplantation Development ◽  
Preimplantation Embryos ◽  
Cell Fractionation ◽  
Cell Stage ◽  
Junction Protein

Gap junction assembly in the preimplantation mouse embryo is a temporally regulated event, beginning a few hours after the third cleavage during the morphogenetic event known as compaction. Recently, we demonstrated that both mRNA and protein corresponding to connexin43, a gap junction protein, accumulate through preimplantation development beginning at least as early as the 4-cell stage. Using an antibody raised against a synthetic C-terminal peptide of connexin43, this protein was shown to assemble into gap junction-like plaques beginning at compaction (G. Valdimarsson, P. A. De Sousa, E. C. Beyer, D. L. Paul and G. M. Kidder (1991). Molec. Reprod. Dev. 30, 18–26). The purpose of the present study was to follow the fate of nascent connexin43 during preimplantation development, from synthesis to plaque insertion, and to learn more about the control of gap junction assembly during compaction. Cell fractionation and reverse transcription-polymerase chain reaction were employed to show that connexin43 mRNA is in polyribosomes at the 4-cell stage, suggesting that synthesis of connexin43 begins at least one cell cycle in advance of when gap junctions first form. The fate of nascent connexin43 was then followed throughout preimplantation development by means of laser confocal microscopy, using two other peptide (C-terminal)-specific antibodies. As was reported previously, connexin43 could first be detected in gap junction-like plaques beginning in the 8-cell stage, at which time considerable intracellular immunoreactivity could be seen as well. Later, connexin43 becomes differentially distributed in the apposed plasma membranes of morulae and blastocysts: a zonular distribution predominates between outside blastomeres and trophectoderm cells whereas plaque-like localizations predominate between inside blastomeres and cells of the inner cell mass. The cytoplasmic immunoreactivity in morulae was deemed to be nascent connexin en route to the plasma membrane since it could be abolished by treatment with cycloheximide, and redistributed by treatment with monensin or brefeldin-A, known inhibitors of protein trafficking. Treatment of uncompacted 8-cell embryos with either monensin or brefeldin-A inhibited the appearance of gap junction-like structures and the onset of gap junctional coupling in a reversible manner. These data demonstrate that the regulated step in the onset of gap junction assembly during compaction is downstream of transcription and translation and involves mobilization of connexin43 through trafficking organelles to plasma membranes.

scholarly journals The absence of a Ca2+ signal during mouse egg activation can affect parthenogenetic preimplantation development, gene expression patterns, and blastocyst quality

Reproduction ◽  
2006 ◽  
Vol 132 (1) ◽  
pp. 45-57 ◽  
Author(s):  
N T Rogers ◽  
G Halet ◽  
Y Piao ◽  
J Carroll ◽  
M S H Ko ◽  
...  
Keyword(s):  
Gene Expression ◽  
Inner Cell Mass ◽  
Expression Patterns ◽  
Cell Mass ◽  
Blastocyst Stage ◽  
Distinct Pattern ◽  
Egg Activation ◽  
Cell Stage ◽  
Embryonic Genome ◽  
Genome Activation

A series of Ca2+ oscillations during mammalian fertilization is necessary and sufficient to stimulate meiotic resumption and pronuclear formation. It is not known how effectively development continues in the absence of the initial Ca2+ signal. We have triggered parthenogenetic egg activation with cycloheximide that causes no Ca2+ increase, with ethanol that causes a single large Ca2+ increase, or with Sr2+ that causes Ca2+ oscillations. Eggs were co-treated with cytochalasin D to make them diploid and they formed pronuclei and two-cell embryos at high rates with each activation treatment. However, far fewer of the embryos that were activated by cycloheximide reached the blastocyst stagecompared tothose activated by Sr2+ orethanol. Any cycloheximide-activated embryos that reached the blastocyst stage had a smaller inner cell mass number and a greater rate of apoptosis than Sr2+-activated embryos. The poor development of cycloheximide-activated embryos was due to the lack of Ca2+ increase because they developed to blastocyst stages at high rates when co-treated with Sr2+ or ethanol. Embryos activated by either Sr2+ or cycloheximide showed similar signs of initial embryonic genome activation (EGA) when measured using a reporter gene. However, microarray analysis of gene expression at the eight-cell stage showed that activation by Sr2+ leads to a distinct pattern of gene expression from that seen with embryos activated by cycloheximide. These data suggest that activation of mouse eggs in the absence of a Ca2+ signal does not affect initial parthenogenetic events, but can influence later gene expression and development.

Tracing the origin of the placental trophoblast cells in mouse embryo development†

2019 ◽  
Vol 102 (3) ◽  
pp. 598-606
Author(s):  
Shanshan Guo ◽  
Xiuhong Cui ◽  
Xiangxiang Jiang ◽  
Shuguang Duo ◽  
Shiwen Li ◽  
...  
Keyword(s):  
Gene Expression ◽  
Cell Fate ◽  
Inner Cell Mass ◽  
Expression Patterns ◽  
Cell Mass ◽  
Cell Fates ◽  
Cell Stage ◽  
Mouse Fetus ◽  
Cell Fate Decisions ◽  
Distinct Cell

Abstract The placenta, which originates from the trophectoderm (TE), is the first organ to form during mammalian embryogenesis. Recent studies based on bioinformatics analysis have revealed that heterogeneous gene expression initiates cell-fate decisions and directs two distinct cell fates by modulating the balance of pluripotency and differentiation as early as the four-cell stage. However, direct developmental evidence to support this is still lacking. To address at which stage the cell fate of the TE and inner cell mass (ICM) is determined, in this study, we administered a microinjection of Cre mRNA into a single blastomere of the mTmG mouse at different cleavage stages before implantation to examine the distributions of the descendants of the single-labeled cell in the mouse fetus and the placenta at E12.5. We found that the descendants of the labeled cells at the two-cell stage contributed to both the placenta and the fetus. Notably, the derivatives of the labeled cells at the four-cell stage fell into three categories: (1) distributed in both embryonic and extraembryonic lineages, (2) distributed only in mouse placental trophoblast layers, or (3) distributed only in the lineage derived from the ICM. In addition, these results fell in line with single-cell studies focusing on gene expression patterns that characterize particular lineages within the blastocyst. In conclusion, this study shows that the four-cell blastomeres differ in their individual developmental properties insofar as they contribute to either or both the ICM and trophoblast fate.

scholarly journals Totipotency of mouse zygotes extends to single blastomeres of embryos at the four-cell stage

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Marino Maemura ◽  
Hiroaki Taketsuru ◽  
Yuki Nakajima ◽  
Ruiqi Shao ◽  
Ayaka Kakihara ◽  
...  
Keyword(s):  
Inner Cell Mass ◽  
Cell Mass ◽  
Mouse Embryos ◽  
Primitive Endoderm ◽  
Cell Stage ◽  
Supportive Environment ◽  
Mouse Zygotes ◽  
Single Blastomeres ◽  
Multicellular Organisms

AbstractIn multicellular organisms, oocytes and sperm undergo fusion during fertilization and the resulting zygote gives rise to a new individual. The ability of zygotes to produce a fully formed individual from a single cell when placed in a supportive environment is known as totipotency. Given that totipotent cells are the source of all multicellular organisms, a better understanding of totipotency may have a wide-ranging impact on biology. The precise delineation of totipotent cells in mammals has remained elusive, however, although zygotes and single blastomeres of embryos at the two-cell stage have been thought to be the only totipotent cells in mice. We now show that a single blastomere of two- or four-cell mouse embryos can give rise to a fertile adult when placed in a uterus, even though blastomere isolation disturbs the transcriptome of derived embryos. Single blastomeres isolated from embryos at the eight-cell or morula stages and cultured in vitro manifested pronounced defects in the formation of epiblast and primitive endoderm by the inner cell mass and in the development of blastocysts, respectively. Our results thus indicate that totipotency of mouse zygotes extends to single blastomeres of embryos at the four-cell stage.

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