scholarly journals Genetic and Molecular Studies on Om, a Locus Controlling Mouse Preimplantation Development

1996 ◽  
Vol 45 (1-2) ◽  
pp. 3-14 ◽  
Author(s):  
M. Cohen-Tannoudj ◽  
P. Balducci ◽  
C. Kress ◽  
V. Richoux-Duranthon ◽  
J.P. Renard ◽  
...  

Several lines of evidence have accumulated in recent years indicating that nuclear cytoplasmic interactions play an important role in the formation and fate of the developing mouse embryo. Early nuclear transplantation experiments indicated that the ability of nuclei to direct cleavage after transfer into enucleated zygotes falls abruptly with nuclei from more advanced preimplantation stages [1]. Transcriptional activation of the nuclei, which occurs during the second cell cycle probably precludes the reprogramming of nuclei from later cleavage stages [2]. Thus, when an 8-cell nucleus is transferred to an enucleated zygote, such a reconstituted zygote is blocked at the 2-cell stage. However, when identical 8-cell nuclei were transferred into both blastomeres of enucleated 2-cell embryos, they were able to support development to the blastocyst stage and even gave rise to live offspring [2-4]. This indicated the importance of the cytoplasmic environment for the ability of the incoming nucleus to support development. It should be noted that in these experiments, the nuclear cytoplasmic ratio was also an important factor in determining the development of the reconstituted embryos [2]. Similar observations were also made when monitoring the development of haploid embryos [5]. In another study, Latham and Solter [6] examined the ability of androgenones, obtained by replacing the female pronucleus of a zygote by the male pronucleus, to develop to the blastocyst stage. Androgenones generated from C57B1/6 eggs were found to be much more competent to give rise to blastocysts than were DBA/2 androgenones. However, when androgenones were constructed from (DBA/2×C57B1/6)F1, zygotes (genetic constitution of the embryos will hereafter be indicated with the female parent coming first followed by the male parent), by replacing the DBA/2 female pronucleus with a C57B1/6 pronucleus, they also developed poorly. This was not simply due to the lack of some component in DBA/2 cytoplasm, since the impaired development was also observed when C57B1/6 male pronuclei from pairs of (DBA/2×C57B1/6) F1, were transferred to an enucleated C57B1/6 egg.

1995 ◽  
Vol 7 (5) ◽  
pp. 1217 ◽  
Author(s):  
F Delhaise ◽  
FJ Ectors ◽  
Roover R de ◽  
F Ectors ◽  
F Dessy

The developmental potential of nuclei of bovine gonial cells was investigated by nuclear transfer. Gonial cells were collected from male fetuses at about 175 days post coitum (p.c.). They were fused with enucleated oocytes; reconstituted embryos were cultured in vitro for 7 days. Embryos reaching the compacted morula or blastocyst stage were either fixed for cell counting or transferred into recipients. Out of 115 oocyte-gonia fusions, 101 (87.8%) gave rise to cleaved embryos at Day 3 and 26 (22.6%) had reached the 8-cell stage. At Day 7, 1 (1%) developed to the morula stage and 5 (4%) reached the blastocyst stage. Three blastocysts were fixed and showed normal cell numbers (135; 90; 76 cells). Three blastocysts and one morula were transferred in four recipients; two recipients were pregnant at Day 21 but only one was positive at Day 35 p.c.; this last one aborted around Day 40 p.c. No conceptus was collected. These results indicate that gonial cell nuclei can be partially reprogrammed; they are able to develop into blastocysts and to initiate gestation. However, more experiments will be necessary to prove the nuclear totipotency of bovine gonial cells.


Development ◽  
1987 ◽  
Vol 101 (4) ◽  
pp. 915-923 ◽  
Author(s):  
S.K. Howlett ◽  
S.C. Barton ◽  
M.A. Surani

We have investigated the development of reconstituted embryos in which enucleated 1- or 2-cell embryos received various advanced nuclei. Enucleated 1-cells developed to the blastocyst stage only when an early 2-cell donor nucleus was transferred but very rarely if the donor nucleus was derived from a late 2-cell, early 4-cell or mid 8-cell embryo. Although an 8-cell nucleus could only support development of an enucleated zygote to the 2-cell stage, it did express the hsp 68/70 X 10(3) Mr proteins that are characteristic of the first embryonic gene activity. These polypeptides were absent in enucleated zygotes that did not receive a donor nucleus. Moreover, an 8-cell nucleus transferred to an enucleated late 2-cell blastomere could also support preimplantation development provided that the nuclear:cytoplasmic ratio was maintained as in intact 2-cell blastomeres. 8-cell nuclei transferred to zygotes that retained at least one pronucleus were able to support development to the blastocyst stage provided that the pronucleus was both fully transcriptionally active and present beyond the late 1-cell stage. This study suggests an active and continued helper role of the resident pronucleus for the participation by an 8-cell nucleus in reconstituted eggs.


2008 ◽  
Vol 295 (4) ◽  
pp. E798-E809 ◽  
Author(s):  
Zhiming Han ◽  
Rita Vassena ◽  
Maggie M. Y. Chi ◽  
Santhi Potireddy ◽  
Miriam Sutovsky ◽  
...  

Cloned mouse embryos display a marked preference for glucose-containing culture medium, with enhanced development to the blastocyst stage in glucose-containing medium attributable mainly to an early beneficial effect during the first cell cycle. This early beneficial effect of glucose is not displayed by parthenogenetic, fertilized, or tetraploid nuclear transfer control embryos, indicating that it is specific to diploid clones. Precocious localization of the glucose transporter SLC2A1 to the cell surface, as well as increased expression of glucose transporters and increased uptake of glucose at the one- and two-cell stages, is also seen in cloned embryos. To examine the role of glucose in early cloned embryo development, we examined glucose metabolism and associated metabolites, as well as mitochondrial ultrastructure, distribution, and number. Clones prepared with cumulus cell nuclei displayed significantly enhanced glucose metabolism at the two-cell stage relative to parthenogenetic controls. Despite the increase in metabolism, ATP content was reduced in clones relative to parthenotes and fertilized controls. Clones at both stages displayed elevated concentrations of glycogen compared with parthenogenetic controls. There was no difference in the number of mitochondria, but clone mitochondria displayed ultrastructural alterations. Interestingly, glucose availability positively affected mitochondrial structure and localization. We conclude that cloned embryos may be severely compromised in terms of ATP-dependent processes during the first two cell cycles and that glucose may exert its early beneficial effects via positive effects on the mitochondria.


2007 ◽  
Vol 19 (1) ◽  
pp. 162
Author(s):  
T. Suzuki ◽  
N. Minami ◽  
H. Imai

Mammalian oocytes have the ability to confer totipotency to terminally differentiated somatic cell nuclei. Viable cloned animals have been produced by somatic cell nuclear transfer (NT) into oocytes in many mammalian species including mouse. However, the success rates of the production were quite low in all species. Many studies have measured differences in gene expression between NT and fertilized embryos in relatively advanced stages of development such as pre- and post-natal stages or the blastocyst stage. In the mouse, major zygotic gene activation (ZGA) occurs at the 2-cell stage after fertilization and leads to the transition of gene regulation from maternal control to embryonic control. Suppression of the ZGA by a transcription inhibitor was shown to decrease the viability of embryos, and causes developmental arrest at the 2-cell stage. An abnormal ZGA may therefore affect the viability of NT embryos and cause further abnormalities in later embryonic development. In the present study, we compared gene expression patterns using differential display RT-PCR (DDRT-PCR) between the NT and IVF embryos at the 2-cell stage to detect some abnormalities affecting later development of NT embryos. The developmental rate of NT embryos to blastocysts (32.9%) was significantly lower than that of IVF (92.7%) or PA (92.8%). In addition, the cell numbers of NT embryos at the blastocyst stage (39.5 � 2.6; n = 19) were less than those of IVF (66.8 � 2.1; n = 30) or PA embryos (48.2 � 2.1; n = 30). Using these embryos, we first identified 4 genes that were differentially expressed between NT and IVF embryos at the 2-cell stage. Among the identified genes, Inpp5b and Chst12 were up-regulated, and MuERV-L and Dnaja2 were down-regulated in the NT embryos compared with IVF embryos. Further analysis showed that the expression of zygotically activated genes such as Interferon-γ, Dub-1, Spz1, DD2106, and DD2111 were not properly activated in NT embryos, suggesting that the cellular process involved in the control of the zygotic genome activation is not appropriately regulated. These results indicate that abnormal gene expression has already occurred at the early stage of pre-implantation development as a failure of nuclear reprogramming.


2017 ◽  
Vol 29 (9) ◽  
pp. 1868 ◽  
Author(s):  
Jean-Marc Lelièvre ◽  
Nathalie Peynot ◽  
Sylvie Ruffini ◽  
Ludivine Laffont ◽  
Daniel Le Bourhis ◽  
...  

In in vitro-produced (IVP) bovine embryos, a burst in transcriptional activation of the embryonic genome (EGA) occurs at the 8–16-cell stage. To examine transcriptional regulation prior to EGA, notably in response to heat stress, we asked (1) whether the spontaneous expression of a luciferase transgene that is driven by the minimal mouse heat-shock protein 1b (hspa1b) gene promoter paralleled that of HSPA1A during EGA in IVP bovine embryo and (2) whether expression of the endogenous heat-inducible iHSPA group member HSPA1A gene and the hspa1b/luciferase transgene were induced by heat stress (HS) prior to EGA. Using two culture systems, we showed that luciferase activity levels rose during the 40-h long EGA-associated cell cycle. In contrast, iHSPA proteins were abundant in matured oocytes and in blastomeres from the two-cell to the 16-cell stages. However, normalised results detected a rise in the level of HSPA1A and luciferase mRNA during EGA, when transcription was required for their protein expression. Prior to EGA, HS-induced premature luciferase activity and transgene expression were clearly inhibited. We could not, however, establish whether this was also true for HSPA1A expression because of the decay of the abundant maternal transcripts prior to EGA. In bovine embryos, heat-induced expression of hspa1b/luciferase, and most likely of HSPA1A, was therefore strictly dependent on EGA. The level of the heat-shock transcription factor 1 molecules that were found in cell nuclei during embryonic development correlated better with the embryo’s capacity for heat-shock response than with EGA-associated gene expression.


2013 ◽  
Vol 25 (1) ◽  
pp. 169
Author(s):  
Y. H. Nam ◽  
Y. Jeon ◽  
S. A. Cheong ◽  
S. S. Kwak ◽  
S. H. Hyun

Recently, great focus has been on the rescue of endangered animals through somatic cell nuclear transfer (SCNT). Because it is difficult to obtain the oocytes of endangered species, interspecies SCNT (iSCNT) methods have been attempted. Numerous iSCNT embryos have shown unsuccessful development due to aberrations in expression of housekeeping genes and genes dependent on the major embryonic genome activation (EGA). In particular, aberrant EGA may cause the arrest of nucleoli formation and developmental block in embryos. According to this concept, we performed raccoon iSCNT using porcine oocytes and analyzed iSCNT embryo development pattern and formation of nucleoli. Enucleated porcine oocytes were fused with raccoon fibroblasts by electrofusion. Cleavage and blastocyst formation were evaluated under a stereomicroscope at 48 and 168 h post-activation (hpa), respectively. To confirm the formation of nucleoli, which can be detected by C23 antibody labeling in many mammalian species, C23 immunocytochemistry was performed at 48 and 72 hpa. A total of 158 iSCNT embryos were cultured; 68.5% of the raccoon iSCNT embryos were cleaved at 48 hpa (1-cell stage: 9.7%; 2-cell stage: 14.4%; 4-cell stage: 34.1%; 6-cell stage: 12.7%; 8-cell stage: 7.3%; fragmented: 21.8%). But, the embryos seen as 5- to 8-cell stage did not have the same number of nuclei as their blastomere number. When raccoon iSCNT embryos were stained by Hoechst 33342, 5- to 8-blastomere raccoon iSCNT embryos had only 4 nuclei. The raccoon iSCNT embryos did not develop past the 4-cell stage and failed to form blastocysts. In the control group, 65.2% of pig SCNT embryos were cleaved at 48 hpa (1-cell stage: 8.0%; 2-cell stage: 4.2%; 4-cell stage: 23.6%; 6-cell stage: 13.6%; 8-cell stage: 23.8%; fragmented: 26.8%), and 10.0% of pig SCNT embryos developed to blastocysts. In raccoon iSCNT embryos, raccoon nuclei failed to form nucleoli at 48 and 72 hpa. By contrast, pig SCNT embryos showed 18.8 and 87.9% nucleoli formation at 48 and 72 hpa. Our results demonstrate that 4-cell-stage embryos of raccoon-porcine hybrid embryos may be produced by SCNT methods. The pig oocytes partly supported the remodeling and reprogramming of the raccoon somatic cell nuclei, but they were unable to support nucleoli formation. Moreover, aberrant nucleoli formation caused the unsuccessful development of raccoon SCNT embryos to the blastocyst stage. This work was supported by a grant from the Next Generation BioGreen 21 program (no. PJ008121012011), Rural Development Administration, Republic of Korea.


Reproduction ◽  
2004 ◽  
Vol 127 (2) ◽  
pp. 201-205 ◽  
Author(s):  
Cai-Xia Yang ◽  
Zhao-Hui Kou ◽  
Kai Wang ◽  
Yan Jiang ◽  
Wen-Wei Mao ◽  
...  

In cloned animals where somatic cell nuclei and oocytes are from the same or closely related species, the mitochondrial DNA (mtDNA) of the oocyte is dominantly inherited. However, in nuclear transfer (NT) embryos where nuclear donor and oocyte are from two distantly related species, the distribution of the mtDNA species is not known. Here we determined the levels of macaque and rabbit mtDNAs in macaque embryos reprogrammed by rabbit oocytes. Quantification using a real-time PCR method showed that both macaque and rabbit mtDNAs coexist in NT embryos at all preimplantation stages, with maternal mtDNA being dominant. Single NT embryos at the 1-cell stage immediately after fusion contained 2.6 × 104 copies of macaque mtDNA and 1.3 × 106 copies of rabbit mtDNA. Copy numbers of both mtDNA species did not change significantly from the 1-cell to the morula stages. In the single blastocyst, however, the number of rabbit mtDNA increased dramatically while macaque mtDNA decreased. The ratio of nuclear donor mtDNA to oocyte mtDNA dropped sharply from 2% at the 1-cell stage to 0.011% at the blastocyst stage. These results suggest that maternal mtDNA replicates after the morula stage.


Development ◽  
1976 ◽  
Vol 35 (1) ◽  
pp. 179-190
Author(s):  
Matthew H. Kaufman ◽  
Leo Sachs

The present experiments were undertaken to determine whether, in parthenogenesis, heterozygous embryos develop better than homozygous embryos. Such experiments may provide an approach to elucidating whether fertilized embryos develop better than parthenogenetic ones because of heterozygosity, or if the sperm provides another contribution necessary for complete embryonic development. The parthenogenetic embryos studied included uniform haploids after extrusion of the second polar body, mosaic haploids in which each blastomere contained a genetically different haploid nucleus, and heterozygous diploid mouse embryos. Eggs were activated and cultured in a chemically denned medium. About three times as many mosaic haploid or heterozygous diploid eggs developed beyond the 4-cell stage after 98–100 h and to the blastocyst stage after 120 h in culture, than uniform haploid eggs. This indicates that the development of parthenogenetic embryos is probably under genetic control and that there was a better development of the heterozygous embryos. Mosaic haploid embryos showed the same high frequency of development as heterozygous diploids. The results therefore indicate that heterozygosity provided a developmental advantage even when distributed between two genetically different clones of cells in the same embryo.


Development ◽  
1990 ◽  
Vol 108 (Supplement) ◽  
pp. 81-87 ◽  
Author(s):  
Charles Babinet ◽  
Véronique Richoux ◽  
Jean-Louis Guénet ◽  
Jean-Paul Renard

The DDK strain of mice has unusual genetic properties. When females of this strain are crossed to males of other strains, they generally exhibit a very low fertility, whereas reciprocal crosses are fully fertile as are the intrastrain crosses. The observed low fertility results from early embryonic lethality, the F1 embryos dying around the late morula–early blastocyst stage. Nuclear transplantation experiments between hybrid eggs of BALB/c and DDK strains has shown that failure of F1(DDK ♀× BALB/c♂) embryos to develop is not due to the combination per se of maternal (DDK) and paternal (BALB/c) genomes but rather to an incompatibility between paternal (BALB/c) genomic contribution and DDK cytoplasm. This incompatibility does not occur between a female BALB/c pronucleus and the DDK cytoplasm, suggesting the involvement of a differential imprinting of parental genomes. Introduction of cytoplasts isolated from DDK 1- to 8-cell embryos into BALB/c♀×BALB/c♂ or BALB/c♀×DDK♂ embryos of the corresponding developmental stage demonstrate that the cytoplasm of DDK embryos prevents the formation of normal blastocysts through a specific interaction with the paternal component of the BALB/c diploid nucleus. Genetic and molecular studies are underway to try and isolate the gene(s) responsible for the failure of (DDK♀×BALB/c♂)F1 embryos. These experiments should help in our understanding of nucleocytoplasmic interactions and the respective roles of parental genomes in early embryonic development.


Reproduction ◽  
2017 ◽  
Vol 154 (6) ◽  
pp. 859-866 ◽  
Author(s):  
Yoshiaki Tanabe ◽  
Hiroki Kuwayama ◽  
Sayaka Wakayama ◽  
Hiroaki Nagatomo ◽  
Masatoshi Ooga ◽  
...  

Recently, it has become possible to generate cloned mice using a somatic cell nucleus derived from not only F1 strains but also inbred strains. However, to date, all cloned mice have been generated using F1 mouse oocytes as the recipient cytoplasm. Here, we attempted to generate cloned mice from oocytes derived from the ICR-outbred mouse strain. Cumulus cell nuclei derived from BDF1 and ICR mouse strains were injected into enucleated oocytes of both strains to create four groups. Subsequently, the quality and developmental potential of the cloned embryos were examined. ICR oocytes were more susceptible to damage associated with nuclear injection than BDF1 oocytes, but their activation rate and several epigenetic markers of reconstructed cloned oocytes/embryos were similar to those of BDF1 oocytes. When cloned embryos were cultured for up to 4 days, those derived from ICR oocytes demonstrated a significantly decreased rate of development to the blastocyst stage, irrespective of the nuclear donor mouse strain. However, when cloned embryos derived from ICR oocytes were transferred to female recipients at the two-cell stage, healthy cloned offspring were obtained at a success rate similar to that using BDF1 oocytes. The ICR mouse strain is very popular for biological research and less expensive to establish than most other strains. Thus, the results of this study should promote the study of nuclear reprogramming not only by reducing the cost of experiments but also by allowing us to study the effect of oocyte cytoplasm by comparing it between strains.


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