scholarly journals Functional full-term placentas formed from parthenogenetic embryos using serial nuclear transfer

Development ◽  
2010 ◽  
Vol 137 (17) ◽  
pp. 2841-2847 ◽  
Author(s):  
T. Hikichi ◽  
H. Ohta ◽  
S. Wakayama ◽  
T. Wakayama
2005 ◽  
Vol 17 (2) ◽  
pp. 181 ◽  
Author(s):  
D. Sage ◽  
P. Hassel ◽  
B. Petersen ◽  
W. Mysegades ◽  
P. Westermann ◽  
...  

Porcine nuclear transfer (NT) is an inefficient process and it is necessary to use as many as 120 NT embryos for each foster mother to obtain small litters of live piglets. In these experiments, we evaluated the effects of culture atmosphere and medium on the development of NT embryos by monitoring blastocyst rate and cell number of Day 6 blastocysts. Age matched IVF and parthenogenetic embryos were also evaluated for comparison. For all experiments a pool of oocytes was aspirated from ovaries collected in a local abattoir. Following aspiration, oocytes were allowed to mature for 40 h in North Carolina State University (NCSU)-37 medium (supplemented with cAMP and hCG/eCG for the first 22 h). After removal of the cumulus cells, denuded oocytes with polar bodies were selected for NT, enucleated, fused with fetal fibroblasts, and sequentially activated electrically and chemically by 3 h of treatment with 6-dimethylaminopurine (6-DMAP). A second group of oocytes from the same denuded pool were maintained in TL-HEPES medium and activated in parallel with the NT group to produce parthenogenetic embryos. A third group was fertilized with frozen-thawed epididymal semen and co-cultured for ∼12 h to give IVF embryos. All three treatment groups were subdivided into a control subgroup and an experimental subgroup. In the first experiment, we compared the effects of atmosphere (20% vs. 5% oxygen) on in vitro embryonic development in NCSU-23 medium. In the second experiment, we used only the 5% oxygen concentration and compared different culture media. One subgroup was maintained in standard NCSU-23 medium and the second subgroup was cultured in a two-step system for the first 58 h in modified NCSU-23 (without glucose but supplemented with 2.0 mM lactate and 0.2 mM pyruvate), followed by addition of glucose to give a final concentration of 5.55 mM. Data were statistically analyzed by analysis of variance and chi square test. Blastocyst rate and mean cell number in all three embryo groups were improved under 5% oxygen. The most dramatic effect was observed in the NT group, in which the blastocyst rate increased significantly (P < 0.001) from 6.7% ± 5.9 (n = 279) to 19.6% ± 8.9 (n = 250) and mean cell number increased from 17.7 ± 12.1 to 25.8 ± 10.3 cells per blastocyst. With 5% oxygen there was also an increase of blastocyst rates and mean cell numbers in both IVF and parthenogenetic groups. In the second experiment, blastocyst rate for NT embryos increased significantly (P < 0.05) from 21.8% ± 7.6 (n = 242) in conventional NCSU-23 to 31.5% ± 11.0 (n = 271) in the modified system whereas there was almost no difference in the mean cell number of both groups (29.2 ± 4.3 vs. 31.5 ± 5.3). In the groups of IVF and parthenogenetic embryos no difference was found. These results indicate that both the reduced oxygen and the modified culture medium are important for pre-implantation development of porcine nuclear transfer embryos.


2010 ◽  
Vol 12 (2) ◽  
pp. 203-211 ◽  
Author(s):  
Li-Ying Sung ◽  
Ching-Chien Chang ◽  
Tomokazu Amano ◽  
Chih-Jen Lin ◽  
Misa Amano ◽  
...  

2006 ◽  
Vol 18 (2) ◽  
pp. 124 ◽  
Author(s):  
F. Du ◽  
J. Xu ◽  
S. Gao ◽  
L. Y. Sung ◽  
D. Stone ◽  
...  

Transgenic/knockout (KO) rabbits can serve as an excellent animal model for human cardiovascular diseases (CVD) and other diseases. However, the production of transgenic/KO rabbits is hindered by low efficiency of traditional DNA microinjection and the unavailability of embryonic stem cell lines. An alternative approach is to produce transgenic/KO rabbits by somatic cell nuclear transfer (SCNT) using genetically modified somatic cells as nuclear donors. Our initial objective of the study was to prove the feasibility of cloning rabbits by SCNT because rabbit is a difficult species to be cloned. Rabbit oocytes were flushed from the oviducts of superovulated donors treated with the regime of follicle-stimulating hormone (FSH) and human choriani gonadotropin (hCG). Cumulus cells were then denuded from the oocytes by incubation in 0.5% hyaluronidase and pipetting. Oocyte enucleation was conducted in M199 + 10% fetal bovine serum (FBS) and confirmed by fluorescence microscopy. Cumulus cells used for nuclear donors were prepared from fresh cumulus-oocytes complexes. The donor nucleus was transferred into a recipient oocyte by either cell fusion or direct nuclear injection method. In the cell fusion method, a small donor cell with the diameter approximately 15–19 µm was transferred into the perivitelline space of an enucleated oocyte; subsequently the somatic cell-cytoplast pair was fused by applying three direct current pulses at 3.2 kV/cm for a duration of 20 µs/pulse. In the direct nuclear injection method, a mechanically lysed donor cell was injected into oocyte cytoplasm with the aid of a piezo-drill system. Fused embryos or injected oocytes were activated by the same electrical stimulation regime described above, and subsequently cultured in M199 + 10% FBS containing 2.0 mM 6-dimethylaminopurine (DMAP) and 5 µg/mL cycloheximide for 2 h. For the in vitro study, cloned embryos were cultured in B2 medium plus 2.5% FBS for 5 days (initiation of activation = day 0) at 38.5°C in 5% CO2 humidified air. For the in vivo study, cloned embryos were cultured for 20–22 h in vitro before transfer into pseudopregnant rabbit recipients. Pregnancy was monitored by palpation and/or ultrasound on Days 14–16 post embryo transfer (ET). The results (Table 1) show that the donor nuclei-introducing rate was higher with nuclear direct injection than with the cell fusion method (P < 0.05). There were no significant differences among subsequent cleavage and development to morula and blastocysts between both methods, although the development rates of cloned embryos via electrically mediated fusion were higher than those derived from the injection group. One recipient in the injection group (1/6, 17%) and six recipients in the fusion group (6/16, 38%) were diagnosed as pregnant. From the fusion group, one full-term but stillborn and one live and healthy clone rabbit were delivered on Days 33 and 31 post-ET, respectively. To our knowledge, this is the second report of full term development of cloned rabbit by somatic nuclear transfer cloning. Our further study is to clone live rabbit offspring with modified transgenic/KO somatic cell lines. Table 1. In vitro development of rabbit cloned embryos with cumulus cells as nuclear donors This work was supported by NIH/NCRR-SBIR grant: 1R43RR020261–11.


2006 ◽  
Vol 18 (2) ◽  
pp. 132
Author(s):  
W. A. King ◽  
B.-G. Jeon ◽  
D. H. Betts

Somatic cell nuclear transfer (SCNT) has been utilized to study various genetic and epigenetic contributions of specific biomedical diseases and developmental events by using various donor cell types such as mature lymphocytes, brain tumor cells, and other unique genotypes. Previously, we produced cloned fetuses and offspring derived from SCNT of adult ear skin fibroblasts obtained from a sub-fertile cow harboring an X-autosome translocation as a model to study X-inactivation and chromosome dynamics during female meiosis. The aim of this study was to assess the cloning efficiency of the fibroblasts derived from a cloned calf with the X-autosome translocation t(Xp+;23q-) compared to the original adult fibroblast donor containing the same chromosome translocation. Primary cultures of cells were established in DMEM +15% fetal calf serum (FCS). To serve as nuclear donors, cells at 5-7 passages were cultured for 5 days until confluent. Oocytes matured for 18 h in TCM-199 with hormones were removed of their chromatin, and reconstructed by transfer of donor cells and fusion with two DC pulses (1.2 kV/cm, 15 �s), delivered by a BTX 2000 Electro Cell Minupulator (BTX, Inc., San Diego, CA, USA), in 0.28 M mannitol containing 0.01 mM MgCl2. After 1 h of fusion, the eggs were activated with 5.5 �M ionomycin for 5 min, followed by 11 �g/mL cyclohexamide for 5 h. The eggs were cultured for 9 days in L-SOF at 39�C in a humidified atmosphere of 5% CO2, 5% O2, 90% N2. Chi-square analysis revealed no significant (P > 0.05) differences in the rates of cleavage, blastocyst frequencies, and cell numbers between the 1st and 2nd generation cloned embryos. Cleavage rates were 87.4% and 85.4% for 1st and 2nd generation cloned embryos, respectively. The frequencies of blastocyst development and hatched blastocyst formation on Day 9 were 41.4% (91/220) and 38.7% (92/238), and 26.4% (58/220) and 22.7% (54/238) for the 1st and 2nd generation cloned embryos, respectively. The numbers of total cells and inner cell mass (ICM) cells of Day 9 blastocysts were 183 and 52, respectively, in the 1st generation embryos and 167 and 51 cells in the 2nd-generation cloned embryos. In summary, 2nd generation cloned embryos derived from fibroblasts of a cloned calf with an X-autosome translocated chromosome showed embryo development and cell numbers similar to those of the 1st generation clones. These results demonstrate that serial nuclear transfer does not improve the blastocyst development rate of cloned embryos containing the X-autosome translocation t(Xp+;23q-). This work was funded by OCAG, OMAF, and CRC.


Development ◽  
1995 ◽  
Vol 121 (4) ◽  
pp. 1123-1128 ◽  
Author(s):  
T. Kono ◽  
J. Carroll ◽  
K. Swann ◽  
D.G. Whittingham

During mammalian fertilization, the sperm triggers a series of intracellular Ca2+ oscillations which initiate oocyte activation and the formation of pronuclei. Oocyte activation can be induced artificially by a variety of chemical and physical stimuli which elevate intracellular calcium. We show that the transfer of nuclei from 1- and 2-cell-stage fertilized mouse embryos to unfertilized oocytes stimulates the completion of meiosis and the formation of pronuclei. Nuclei from embryos that had developed to the 4-cell stage did not stimulate meiotic resumption. The ability to cause oocyte activation was specific to nuclei transferred from fertilized embryos as nuclei from parthenogenetic embryos or cytoplasts from fertilized or parthenogenetic embryos did not induce activation. Nucleus-induced oocyte activation was associated with the generation of intracellular Ca2+ transients, which were seen after nuclear envelope breakdown of the transferred nuclei. Treatment of the oocyte with the intracellular Ca2+ chelator, BAPTA, prior to nuclear transfer inhibited intracellular Ca2+ transients and oocyte activation. The specific Ca(2+)-releasing activity of the nucleus was not caused by sperm-induced protein synthesis since similar activity was present in nuclei originating from embryos exposed to cycloheximide throughout fertilization. The specific ability of nuclei from fertilized embryos to stimulate Ca2+ transients and oocyte activation was also found in nuclei from embryos parthenogenetically activated by the injection of a partially purified cytosolic sperm factor. The results suggest that the fertilizing sperm introduces Ca(2+)-releasing activity which becomes associated with the nucleus of early mammalian embryos.


2006 ◽  
Vol 65 (2) ◽  
pp. 424-440 ◽  
Author(s):  
Vanessa J. Hall ◽  
Nancy T. Ruddock ◽  
Melissa A. Cooney ◽  
Natasha A. Korfiatis ◽  
R. Tayfur Tecirlioglu ◽  
...  

2003 ◽  
Vol 5 (2) ◽  
pp. 133-142 ◽  
Author(s):  
P. Holm ◽  
P.J. Booth ◽  
H. Callesen

2008 ◽  
Vol 10 (4) ◽  
pp. 429-434 ◽  
Author(s):  
Qinggang Meng ◽  
Minkang Wang ◽  
Claudia Ana Stanca ◽  
Szilard Bodo ◽  
Andras Dinnyes

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