Factors affecting cellular mosaicism in the expression of a lacZ transgene in two-cell stage mouse embryos

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
Keyword(s):  
Mouse Embryos ◽  
Cell Stage ◽  
Factors Affecting ◽  
Variable Expressivity ◽  
Preimplantation Stage ◽  
Lacz Activity ◽  
Variable Gene ◽  
Transgene Locus ◽  
Dna Methylation Analysis

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.

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.

Abnormal development of pre-implantation mouse embryos grown in vitro with [3H]thymidine

Development ◽  
1973 ◽  
Vol 29 (3) ◽  
pp. 601-615
Author(s):  
M. H. L. Snow
Keyword(s):  
Specific Activity ◽  
Inner Cell Mass ◽  
Cell Damage ◽  
Cell Mass ◽  
Cell Number ◽  
Mouse Embryos ◽  
Abnormal Development ◽  
Tritium Concentration ◽  
Cell Stage

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.

DEVELOPMENT OF EMBRYONIC STRUCTURES FROM ISOLATED MOUSE BLASTOMERES

1976 ◽  
Vol 56 (1) ◽  
pp. 33-36 ◽  
Author(s):  
P. S. FISER ◽  
J. W. MACPHERSON
Keyword(s):  
Mouse Embryos ◽  
Cell Stage ◽  
Potential Development

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.

171 THE EFFECT OF TRICHOSTATIN A ON THE DEVELOPMENT AND THE GLOBAL GENE EXPRESSION PATTERNS IN MOUSE EMBRYOS DEVELOPING IN VITRO

2008 ◽  
Vol 20 (1) ◽  
pp. 165
Author(s):  
X. S. Cui ◽  
X. Y. Li ◽  
T. Kim ◽  
N.-H. Kim
Keyword(s):  
Gene Expression ◽  
Trichostatin A ◽  
Expression Profiles ◽  
Expression Patterns ◽  
Gene Expression Profiles ◽  
Mouse Embryos ◽  
Differentially Expressed ◽  
Gene Expression Patterns ◽  
Cell Stage

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.

Potential of two-cell mouse embryos to develop to term despite partial damage after cryopreservation

1995 ◽  
Vol 29 (3) ◽  
pp. 320-326 ◽  
Author(s):  
Th. Rülicke ◽  
P. Autenried
Keyword(s):  
Inner Cell Mass ◽  
Cell Mass ◽  
Blastocyst Stage ◽  
Mouse Embryos ◽  
Cell Stage ◽  
Freeze Thaw ◽  
Foster Mothers ◽  
Vital Stains ◽  
Partial Damage

Approximately 18% of cryopreserved 2-cell mouse embryos of 26 different batches showed various degrees of morphological damage after the freeze-thaw process. Normal and damaged morphology were assessed by light microscopy and the ability of an embryo to develop in vitro to a blastocyst, or to develop to term, after transfer to foster mothers. Using vital stains such as Fluorescein-diacetate (FDA) and 4',6-Diamidino-2-Phenylindole (DAPI) it was found that in approximately 82% of the cases, both of the 2 blastomeres of the cryopreserved embryos survived the freeze-thaw process; in 10% only one cell survived the process; and in 8% none survived. Normally, only intact 2-cell embryos are considered for transfer. Here it was shown that over 60% of the partially damaged embryos developed in vitro to the blastocyst stage and, of those, 26% developed to term after transfer to suitable foster mothers. Although the inner cell mass (ICM) appeared to remain smaller during culture after the transfer of partially damaged 2-cell stage embryos, no difference during gestation period was found compared with intact embryos.

scholarly journals 37DEVELOPMENTAL POTENTIAL OF CLONE CELLS IN MURINE CLONE-FERTILIZED AGGREGATION CHIMERAS

2004 ◽  
Vol 16 (2) ◽  
pp. 141
Author(s):  
S. Eckardt ◽  
N.A. Leu ◽  
K.J. McLaughlin
Keyword(s):  
Early Stage ◽  
Cumulus Cell ◽  
Blastocyst Stage ◽  
Wild Type ◽  
Cell Stage ◽  
Developmental Potential ◽  
Preimplantation Stage ◽  
Transgenic Embryos ◽  
Clone Cells

In both murine and porcine preimplantation stage clones, mosaicism in gene expression has been observed, indicating variation in transcription of some genes between cells of the individual clone (Boiani M et al., 2002 Genes Dev. 16, 1209–1219; Park KW et al., 2002 Biol. Reprod. 66, 1001–1005). This observation raises the question as to whether all blastomeres within one early-stage clone are equivalent, or whether there are differences in developmental potential. To address this, we aggregated preimplantation-stage clone embryos with fertilized embryos and assessed contribution of Oct4-GFP expressing cells of clone origin in blastocysts and in vitro outgrowths. In normal embryos, the Oct4-GFP transgene is expressed during preimplantation stages and reflects expression of Oct4 protein. Mouse cumulus cell clones were produced from cells transgenic for Oct4-GFP (Szabó PE et al., 2002 Mech. Dev. 115, 157–160) as described (Boiani M et al., 2002 Genes Dev. 16, 1209–1219). Four-cell-stage clones and synchronous fertilized non-transgenic embryos were aggregated in micro-wells after removal of the zona pellucida using acid Tyrode’s solution. Aggregates were cultured to the blastocyst stage in -MEM supplemented with bovine serum albumin (0.4% w/v). All control chimeras produced from four-cell-stage fertilized non-transgenic and Oct4-GFP transgenic embryos formed blastocysts, and 15 of 20 had GFP-expressing cells. The majority of clone-wild-type aggregates developed to the blastocyst stage (35/40); however, contribution of GFP-expressing cells was observed in fewer blastocysts compared to controls (12/35; P&lt;0.05). Contribution of GFP expressing clone cells to the ICM varied between 30% and 100% of cells as determined by subjective evaluation of GFP fluorescence overlaying bright-field images. During in vitro outgrowth formation of synchronous aggregation chimeras of clone and wild-type embryos, maintenance of clone contribution to the ICM mound was observed, but at a lower frequency (12% v. 34% at the blastocyst stage). The results suggest that aggregation with fertilized cells does not provide benefit to clone blastomeres during preimplantation stages. Possibly, clone blastomeres may not be competitive with wild-type blastomeres, or are developmentally asynchronous, which will be tested using asynchronous chimeras.

Effect of medium conditioned with rat hepatoma BRL cells on ‘2-cell block’ of random-bred mouse embryos cultured in vitro

Zygote ◽  
2009 ◽  
Vol 17 (2) ◽  
pp. 169-174 ◽  
Author(s):  
Masayuki Kobayashi ◽  
Yoshinori Terawaki ◽  
Koichi Saito ◽  
Kano Kasuga ◽  
Ikuo Kojima
Keyword(s):  
Specific Inhibitor ◽  
Reversed Phase ◽  
Mouse Embryos ◽  
Mouse Strains ◽  
Pcr Analysis ◽  
Cell Block ◽  
Cell Stage ◽  
B Subunit ◽  
Rat Hepatoma

SummaryThe phenomenon of developmental arrest at the 2-cell stage of zygotes obtained from certain mouse strains during in vitro culture is known as the 2-cell block. The effect of conditioned medium (CM) with rat hepatoma BRL cells on the 2-cell block of CD-1 mouse zygotes was investigated in comparison with that of CM with rat hepatoma Reuber H-35 cells. In control medium with EDTA, 75.4% of 2-cell embryos developed to the 4- to 8-cell stages. In the same conditions, the BRL Mr <10000 fraction inhibited the development of 2-cell embryos to the 4- to 8-cell stages (57.7%), although the inhibition by this fraction was weaker than by the Reuber Mr <10000 fraction (19.8%). As a result of reversed-phase column chromatography, a 2-cell stage specific inhibitor of the cleavage of mouse embryos (Fr.B-25), which separated into the Mr <10000 fraction of the Reuber CM, was detected at a low level in the BRL Mr <10000 fraction. On the other hand, the Mr >10000 fraction of BRL CM accelerated the development of the embryos (90.3%). This beneficial effect was also evident even in the absence of EDTA. RT-PCR analysis revealed that mRNAs encoding the β-A or β-B subunit of activins (Mr ~29000), which are well characterized cytokines that act as releasers of the 2-cell block, were expressed in BRL cells. These results indicate that BRL cells synthesize Fr.B-25 at low levels, and that activins contained in the BRL CM probably contributed to overcoming the 2-cell block of CD-1 zygotes cultured in vitro.

Open-pulled straw (OPS) vitrification of in vitro fertilised mouse embryos at various stages

2008 ◽  
Vol 56 (2) ◽  
pp. 245-253 ◽  
Author(s):  
Chang-Liang Yan ◽  
Qi-En Yang ◽  
Guang-Bin Zhou ◽  
Yun-Peng Hou ◽  
Xue-Ming Zhao ◽  
...  
Keyword(s):  
Survival Rate ◽  
Developmental Stages ◽  
Developmental Rate ◽  
Blastocyst Stage ◽  
Significant Loss ◽  
Mouse Embryos ◽  
Cell Stage ◽  
Fresh Embryos

The present study was designed to investigate the cryotolerance of in vitro fertilised (IVF) mouse embryos at various preimplantation developmental stages. IVF mouse embryos were vitrified by the open-pulled straw (OPS) method. After warming, embryos were morphologically evaluated and assessed by their development to blastocysts, hatched blastocysts or term. The results showed that a high proportion (93.3–100.0%) of vitrified embryos at all developmental stages were morphologically normal after recovery. The developmental rate of vitrified 1-cell embryos to blastocyst (40.0%) or hatched blastocyst (32.7%) or term (9.3%) was significantly lower than that from other stages (P < 0.05). Vitrified embryos from 2-cell to early blastocyst stage showed similar blastocyst (71.8–89.5%) and hatched blastocyst rates (61.1–69.6%) and could develop to term without a significant loss of survival compared with those of fresh embryos (P > 0.05). Vitrified 2-cell embryos showed the highest survival rate in vivo (50.6%, 88/174), compared with that from other stages (9.3–30.5%, P < 0.05). The data demonstrate that the OPS method is suitable for the cryopreservation of IVF mouse embryos from 2-cell stage to early blastocyst stage without a significant loss of survival. Embryos at the 2-cell stage had the best tolerance for cryopreservation in the present study.

Vitrification of biopsied mouse embryos

2005 ◽  
Vol 53 (1) ◽  
pp. 103-112 ◽  
Author(s):  
B. Baranyai ◽  
Sz. Bodó ◽  
◽  
Keyword(s):  
Solid Surface ◽  
Birth Rate ◽  
Subsequent Development ◽  
Blastocyst Stage ◽  
Mouse Embryos ◽  
The Novel ◽  
Cell Stage ◽  
Cryopreservation Protocol

Solid surface vitrification (SSV) was compared with in-straw vitrification for cryopreservation of biopsied mouse embryos. Eight-cell stage embryos were zona drilled and one blastomere was removed. Developed morulae or blastocysts were vitrified in microdrop (35% EG + 5% PVP + 0.4 M trehalose) or in straw (7.0 M EG + 0.5 M sucrose). Following recovery, embryos were cultivated in vi tro or transferred into recipients. Cryopreservation had an effect not only on the survival of biopsied embryos but also on their subsequent development in vitro. Cryosurvival of biopsied morulae vitrified in straw was significantly inferior to SSV. The post-warm development of biopsied and non-biopsied morulae was delayed on Day 3.5 and 4.5 in both vitrification groups. A delay in development was observed on Day 5.5 among vitrified non-biopsied blastocysts. The percentage of pups born from biopsied morulae or blastocysts following cryopreservation did not differ from that of the control. No significant differences could be detected between methods within and between embryonic stages in terms of birth rate. The birth rate of biopsied embryos vitrified in straw was significantly lower compared to the non-biopsied embryos. The novel cryopreservation protocol of SSV proved to be effective for cryopreservation of morula- and blastocyst-stage biopsied embryos.

scholarly journals 166MOUSE EMBRYONIC DEVELOPMENT FROM ONE-CELL STAGE TO BLASTOCYST, UTILIZING KSOM SUPPLEMENTED WITH AMINO ACIDS IN A MICROCHANNEL DEVICE

2004 ◽  
Vol 16 (2) ◽  
pp. 205
Author(s):  
P.H.C. Lopes ◽  
S.A. Malusky ◽  
A.S. Lima ◽  
D.J. Beebe ◽  
M.B. Wheeler
Keyword(s):  
Amino Acids ◽  
Embryonic Development ◽  
Mouse Strain ◽  
Mouse Embryos ◽  
Type I ◽  
Alternative Technique ◽  
Cell Stage ◽  
Mammalian Embryos ◽  
Microchannel Device

Great efforts have been made to improve in vitro culture for enhancement of embryonic development. However, in vitro development of mammalian embryos still remains a challenge for the scientific community. Recently, the use of microfluidic culture devices, as an alternative technique compared to the standard drop, has allowed mammalian embryos to develop to the hatched blastocyst stage. With the use of a different medium, mouse strain, and microchannel device than previously reported (Raty S et al., 2001 Theriogenology 55, 241 abst), this study was undertaken to determine if a microchannel device fabricated from borosilicate and poly-dimethylsiloxane would support development of mouse embryos from one-cell to blastocyst, as an alternative to standard microdrop culture. Mice (F1 inbred C57BL/6CRL X SJL) from 3 to 8 weeks old were superovulated with 5IU of PMSG and 5IU of hCG. The female SJL strain of the mice has demonstrated low reproductive performance. One-cell embryos were collected in M2 medium (Sigma, St. Louis, MO, USA.). For each treatment, 240 embryos in 24 replicates were cultured. Groups of 10 embryos were cultured in the microchannel device using 500μL of KSOM with amino acids (MR-106-D, Speciality Media, Phillipsburg, NJ, USA.); no additional supplements were added. Groups of 10 embryos were cultured in standard microdrops (control) using 30μL of the same medium covered with mineral oil. Embryos were cultured in a 100% humidified, 5% CO2 in air atmosphere at 37°C for 96h. Embryos were allocated to the control treatment or the microchannel device treatment using a randomized block design. The percentage of embryos at each stage of development was evaluated at 24-h intervals. The stage of embryo development at each observation was analyzed by ANOVA using the general linear model in SAS (PROC GLM, type I sum of squares). Blastocyst development in the microchannel device was not different when compared to results obtained in the standard drop. The percentage of blastocysts developing, when analyzed from one-cell stage, was 29±5% for the control and 26±6% for the microchannel. The percentage of blastocysts, when analyzed from cleavage, was 35±5% for the standard drop and 31±7% for the microchannel device. The results obtained are encouraging, when considering the non-optimized medium and mouse strain utilized in this experiment. In conclusion, the results show the microchannel device may be considered an alternative technique for use in embryo culture as it supports development of mouse embryos from one-cell stage to blastocyst.

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