Sex-Linked Differences in Developmental Potential of Single Blastomeres from in vitro-Fertilized 2-Cell Stage Mouse Embryos

1995 ◽  
Vol 44 (2) ◽  
pp. 4-8 ◽  
Author(s):  
Eimei Sato ◽  
Meiwei Xian ◽  
Ruby P.A. Valdivia ◽  
Yutaka Toyoda
2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Marino Maemura ◽  
Hiroaki Taketsuru ◽  
Yuki Nakajima ◽  
Ruiqi Shao ◽  
Ayaka Kakihara ◽  
...  

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.


Development ◽  
1987 ◽  
Vol 101 (2) ◽  
pp. 403-408
Author(s):  
E.T. Mystkowska ◽  
W. Sawicki

2-cell mouse embryos were treated in vitro with a 2 h pulse of phorbol myristate acetate (PMA) at 32nd, 38th and 50th h after hCG, then chased in culture for up to 46 h. Embryos were fixed at various time intervals of chasing, then stained and inspected. Some embryos were carefully inspected with a video recording system, every 1.44s and the cell divisions (cytokinesis) as well as formation of large, single blastomeres, each from two smaller ones, were recorded. PMA pulse let to the suppression of cell divisions. The rate of the suppression was time dependent: with a delay of 0–1, 12 and 18 h between the PMA pulse and time of scheduled cell division about 99, 87 and 44% of 2-cell embryos remained at this stage of development, for at least 10 h, respectively, and 90, 58 and 12% of their blastomeres revealed binuclearity. Since we found that PMA-mediated formation of binuclearity was not the effect of cell fusions, it was assumed that the inhibition of cytokinesis preceded by karyokinesis was responsible for binuclearity. PMA effect on cell divisions was reversible. PMA-treated embryos revealed formation of large, single blastomeres, each from two smaller ones. If cell division appeared after PMA pulse, in about 52% of 3- to 6-cell embryos, the large blastomere formation was recorded in the course of the subsequent 38 h. Large blastomere formation was concluded to be the result of either cell fusion or reversion of incompleted cytokinesis brought about by PMA.


Cells ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 3111
Author(s):  
Po-Yu Lin ◽  
Denny Yang ◽  
Chi-Hsuan Chuang ◽  
Hsuan Lin ◽  
Wei-Ju Chen ◽  
...  

The developmental potential within pluripotent cells in the canonical model is restricted to embryonic tissues, whereas totipotent cells can differentiate into both embryonic and extraembryonic tissues. Currently, the ability to culture in vitro totipotent cells possessing molecular and functional features like those of an early embryo in vivo has been a challenge. Recently, it was reported that treatment with a single spliceosome inhibitor, pladienolide B (plaB), can successfully reprogram mouse pluripotent stem cells into totipotent blastomere-like cells (TBLCs) in vitro. The TBLCs exhibited totipotency transcriptionally and acquired expanded developmental potential with the ability to yield various embryonic and extraembryonic tissues that may be employed as novel mouse developmental cell models. However, it is disputed whether TBLCs are ‘true’ totipotent stem cells equivalent to in vivo two-cell stage embryos. To address this question, single-cell RNA sequencing was applied to TBLCs and cells from early mouse embryonic developmental stages and the data were integrated using canonical correlation analyses. Differential expression analyses were performed between TBLCs and multi-embryonic cell stages to identify differentially expressed genes. Remarkably, a subpopulation within the TBLCs population expressed a high level of the totipotent-related genes Zscan4s and displayed transcriptomic features similar to mouse two-cell stage embryonic cells. This study underscores the subtle differences between in vitro derived TBLCs and in vivo mouse early developmental cell stages at the single-cell transcriptomic level. Our study has identified a new experimental model for stem cell biology, namely ‘cluster 3’, as a subpopulation of TBLCs that can be molecularly defined as near totipotent cells.


Zygote ◽  
2002 ◽  
Vol 10 (1) ◽  
pp. 73-78 ◽  
Author(s):  
Maurizio Zuccotti ◽  
Rubén H. Ponce ◽  
Michele Boiani ◽  
Stefano Guizzardi ◽  
Paolo Govoni ◽  
...  

Mouse antral oocytes can be classified in two different types termed SN or NSN oocytes, depending on the presence or absence, respectively, of a ring of Hoechst 33342-positive chromatin surrounding the nucleolus. The aim of the present study was to test the developmental competence to blastocyst of the two types of oocytes. Here we show that following isolation, classification and culture of cumulus-free antral oocytes, 14.7% and 74.5% of NSN and SN oocytes, respectively, reached the metaphase II stage. When fertilised and further cultured none of the metaphase II NSN oocytes developed beyond the 2-cell stage whilst 47.4% of the metaphase II SN oocytes reached the 4-cell stage and 18.4% developed to blastocyst. The findings reported in this paper may contribute to improved procedures of female gamete selection for in vitro fertilisation of humans and farm animals. Furthermore, the selection of oocytes with better developmental potential may be of interest for studies on nuclear/cytoplasm interaction, particularly in nuclear-transfer experiments.


Development ◽  
1987 ◽  
Vol 100 (2) ◽  
pp. 279-295 ◽  
Author(s):  
L. Dale ◽  
J.M. Slack

We have further analysed the roles of mesoderm induction and dorsalization in the formation of a regionally specified mesoderm in early embryos of Xenopus laevis. First, we have examined the regional specificity of mesoderm induction by isolating single blastomeres from the vegetalmost tier of the 32-cell embryo and combining each with a lineage-labelled (FDA) animal blastomere tier. Whereas dorsovegetal (D1) blastomeres induce ‘dorsal-type’ mesoderm (notochord and muscle), laterovegetal and ventrovegetal blastomeres (D2–4) induce either ‘intermediate-type’ (muscle, mesothelium, mesenchyme and blood) or ‘ventral-type’ (mesothelium, mesenchyme and blood) mesoderm. No significant difference in inductive specificity between blastomeres D2, 3 and 4 could be detected. We also show that laterovegetal and ventrovegetal blastomeres from early cleavage stages can have a dorsal inductive potency partially activated by operative procedures, resulting in the induction of intermediate-type mesoderm. Second, we have determined the state of specification of ventral blastomeres by isolating and culturing them in vitro between the 4-cell stage and the early gastrula stage. The majority of isolates from the ventral half of the embryo gave extreme ventral types of differentiation at all stages tested. Although a minority of cases formed intermediate-type and dorsal-type mesoderms we believe these to result from either errors in our assessment of the prospective DV axis or from an enhancement, provoked by microsurgery, of some dorsal inductive specificity. The results of induction and isolation experiments suggest that only two states of specification exist in the mesoderm of the pregastrula embryo, a dorsal type and a ventral type. Finally we have made a comprehensive series of combinations between different regions of the marginal zone using FDA to distinguish the components. We show that, in combination with dorsal-type mesoderm, ventral-type mesoderm becomes dorsalized to the level of intermediate-type mesoderm. Dorsal-type mesoderm is not ventralized in these combinations. Dorsalizing activity is confined to a restricted sector of the dorsal marginal zone, it is wider than the prospective notochord and seems to be graded from a high point at the dorsal midline. The results of these experiments strengthen the case for the three-signal model proposed previously, i.e. dorsal and ventral mesoderm inductions followed by dorsalization, as the simplest explanation capable of accounting for regional specification within the mesoderm of early Xenopus embryos.


Development ◽  
1973 ◽  
Vol 29 (3) ◽  
pp. 601-615
Author(s):  
M. H. L. Snow

Mouse embryos were grown in vitro from the 2-cell stage to blastocysts in the presence of [3H]thymidine. Methyl-T-thymidine and thymidine-6-T(n) were used and both forms found to be lethal at concentrations above 0·1 μCi/ml. Both forms of [3H]Tdr at concentrations between 0·01 and 0·1 μCi/ml caused a highly significant (P < 0·001) reduction in blastocyst cell number. The reduction in cell number, which was positively correlated with specific activity and tritium concentration, was associated with cell damage typical of radiation damage caused by tritium disintegration. Thymidine-6-T(n) also significantly reduced the number of 2-cell embryos forming blastocysts whereas methyl-T-Tdr did not. This difference in effect is assumed to be caused by contamination of one form of [3H]Tdr with a by-product of the tritiation process. A study of the cleavage stages showed that almost all the reduction in cell numbers could be accounted for by selective cell death occurring at the 16-cell stage. Cells which survive that stage cleave at a normal rate. The cells that are most susceptible to [3H]Tdr damage were found to normally contribute to the inner cell mass. The [3H]Tdr-resistant cells form the trophoblast. It is possible to grow blastocysts in [3H]Tdr such that they contain no inner cell mass but are composed entirely of trophoblast. Comparatively short (12 h) incubation with [3H]Tdr at any stage prior to the 16-cell stage will cause this damage. Possible reasons for this differential effect are discussed, and also compared with damage caused by X-irradiation.


1992 ◽  
Vol 70 (10-11) ◽  
pp. 1097-1104 ◽  
Author(s):  
R. K. Kothary ◽  
N. D. Allen ◽  
S. C. Barton ◽  
M. L. Norris ◽  
M. A. H. Surani

In the present study, we have analysed the expression pattern of a lacZ transgene (CMZ12) in preimplantation stage mouse embryos. The transgene is expressed at the two-cell stage, where it shows cellular mosaicism due to variable expressivity. The variable gene expression indicates a partial penetrance of the transgene. The extent of variation in expression is influenced by the genetic background of the oocyte. DBA/2 and CFLP genetic backgrounds promote high expression of the transgene, while Balb/c, C57BL/6, DDK, and F1(C57BL/6 × CBA) genetic backgrounds give none or very little lacZ activity. In vitro culture of one-cell embryos to the two-cell stage induces the expression of lacZ in all strain backgrounds tested. The variation in CMZ12 expression is a transient phenomenon and does not affect later stage activity of the transgene. Nuclear transfer experiments and DNA methylation analysis suggests that a heritable modification of the transgene locus has not occurred.Key words: cellular mosaicism, lacZ transgene, mouse embryos, variable expressivity.


1976 ◽  
Vol 56 (1) ◽  
pp. 33-36 ◽  
Author(s):  
P. S. FISER ◽  
J. W. MACPHERSON

The potential development of blastomeres isolated from 255 mouse embryos in the 2-cell stage, 283 embryos in the 4-cell stage and 184 embryos in the 8-cell stage was compared. Results indicated that 44.6, 34.9 and 14.0% of these blastomeres, respectively, were capable of forming blastocysts in vitro. Transfers of cloned embryos into synchronized females was unsuccessful.


2007 ◽  
Vol 19 (1) ◽  
pp. 203 ◽  
Author(s):  
A. Aroyo ◽  
S. Yavin ◽  
Z. Roth ◽  
A. Arav

Heat stress is a major contributing factor to low fertility among dairy cattle, as reflected by the dramatic reduction in conception rate during the hot months. The effects of thermal stress on oocyte competence and embryonic development have been well documented. However, timing of embryonic cleavage, which may be considered a parameter for the identification of good-quality embryos, and its association with elevated temperatures have not been studied. Two experiments were performed to examine and characterize seasonal effects (i.e. thermal stress) on cleavage timing of bovine parthenogenetic embryos. Oocytes were aspirated from ovaries collected at the local abattoir in 2 seasons: cold (Dec–Apr) and hot (May–Nov). Matured oocytes were chemically activated (ionomycin followed by 6-DMAP) and cultured in vitro; cleavage timing to the 2- and 4-cell stages was observed and documented. The one-way ANOVA procedure was used for statistical analysis. In the first experiment (n = 5416 oocytes), cleavage was documented at specific time points during development post-activation. The peak in embryonic development to the 2-cell stage was earlier (22 to 27 vs. 27 to 40 h after activation) and the cleavage rate higher (39 vs. 21%; P < 0.0001) during the cold season relative to the hot season, respectively. Similarly, the peak in 4-cell-stage development was also observed earlier (46–52 vs. 52–70 h after activation) and corresponded with a higher proportion of developing embryos (33 vs. 21%; P < 0.0001) during the cold season as compared to the hot season, respectively. These results indicate that embryonic development is delayed and a lower proportion of embryos cleaved during the hot season. To better understand the delay in cleavage timing, a second experiment (n = 308 oocytes) was performed through two consecutive hot seasons. A time-lapse system (EmbryoGuard; IMT, Ltd., Ness-Ziona, Israel) was employed to collect accurate data on the first cleavage division, known to be indicative of embryo quality. The time-lapse system was pre-programmed to take photos at 1-h intervals such that culture dishes did not need to be removed from the incubator. Similar to the pattern noted for the hot season in the first experiment, a wide distribution of cleavage timing (18-40 h after activation) was observed. Further analysis revealed that embryos cleaved in 2 distinct waves: cleavage timing of the first wave (18 to 25 h after activation) was characterized by a time frame similar to that in the cold season, suggesting good-quality embryos; however, the second wave, from 27 to 40 h after activation, presented a delay in cleavage timing, suggesting that these late-cleaving embryos are of inferior quality. Taken together, the results of the 2 experiments lead to the assumption that oocytes harvested from lactating cows during the hot season are of reduced developmental potential, which may be explained, in part, by the pattern of 2 cleavage waves. Furthermore, cleavage timing appears to be a good indicator of embryo potential and may increase the chances of selecting better in vitro-derived embryos during the hot season for embryo transfer.


2008 ◽  
Vol 20 (1) ◽  
pp. 165
Author(s):  
X. S. Cui ◽  
X. Y. Li ◽  
T. Kim ◽  
N.-H. Kim

Trichostatin A (TSA) is an inhibitor of histone deacetylase and is able to alter gene expression patterns by interfering with the removal of acetyl groups from histones. The aim of this study was to determine the effect of TSA treatment on the development and gene expression patterns of mouse zygotes developing in vitro. The addition of 100 nm TSA to the culture medium did not affect the cleavage of mouse embryos (TSA treatment, 148/150 (99%) v. control, 107/107 (100%)); however, embryos that were treated with TSA arrested at the 2-cell stage (145/148, 98%). We estimated the number of nuclei in control and TSA-treated embryos by propidium iodide staining, taking into account the presence of any cells with two or more nuclei. At 62–63 h post-hCG stimulation, control zygotes had developed to the 4-cell stage and exhibited one nucleus in each blastomere, indicative of normal development. In contrast, we observed tetraploid nuclei in at least one blastomere in 20.8% (11/53) of the embryos that had been treated with TSA. At 28–29 h post-hCG stimulation (metaphase of the 1-cell stage), there was no difference in the mitotic index (as determined by analyzing the microtubule configuration) in the TSA group compared to the control group. At the 2-cell stage, however, we did not observe mitotic spindles and metaphase chromatin in embryos in the TSA treatment group compared to the controls. Interestingly, when embryos were cultured in TSA-free medium from 35 h post-hCG stimulation (S- or early G2-phase of the 2-cell stage) onward, almost all of them (47/50) developed to the blastocyst stage. In contrast, when embryos were cultured in TSA-free medium from 42 h post-hCG stimulation (middle G2-phase of the 2-cell stage) onward, they did not develop to the 4-cell stage. We used Illumina microarray technology to analyze the gene expression profiles in control and TSA-treated late 2-cell-stage embryos. Applied Biosystems Expression System software was used to extract assay signals and assay signal-to-noise ratio values from the microarray images. Our data showed that 897 genes were significantly (P < 0.05; 2-sample t-test) up- or down-regulated by TSA treatment compared to controls. Analysis using the PANTHER classification system (https://panther.appliedbiosystems.com) revealed that the 575 genes that were differentially expressed in the TSA group compared to the control were classified as being associated with putative biological processes or molecular function. Overall, in terms of putative biological processes, more nucleoside, nucleotide, and nucleic acid metabolism, protein metabolism and modification, signal transduction, developmental process, and cell cycle genes were differentially expressed between the TSA and control groups. In terms of putative molecular function, more nucleic acid-binding transcription factor and transferase genes were differentially expressed between the groups. The results collectively suggest that inhibition of histone acetylation in mouse embryos affects gene expression profiles at the time of zygotic genome activation, and this subsequently affects further development.


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