• Clinical and Experimental Reproductive Medicine
• /
• v.23 no.3
• /
• pp.293-301
• /
• 1996

In the present study, mouse follicular oocytes and 2-cell embryos(late -zygote stage embryos included) were cultured on the electric pad for electric stimulation in the culture incubator. In addition, follicular oocytes and embryos were tested for maturation and development under higher temperature condition($39^{\circ}C$).Mouse follicular oocyte maturation were not affected by anion electric stimulation and there is no significant difference in GBVD and MI between the control and experiment group after 4hr culture. In the embryo culture, it was found that more morula and blastocyst were found in the electric stimulation group rather than the control(96hr). This may seem to be caused with cytoplasmic $Ca^{2+}$ transient rise by electric stimulation(anion pad). On the other hand higher temperature incubation ($39^{\circ}C$) on the anion pad caused all the embryos degenerated within $12h{\sim}24hr$ culture. This was quite different from large animal embryos(bovine, pig, sheep), in which beneficial effect of high temperature incubation for oocyte maturation and embryo development were found.

• Journal of Animal Reproduction and Biotechnology
• /
• v.35 no.4
• /
• pp.323-328
• /
• 2020

Direct injection of genome editing tools such as CRISPR/Cas9 system into developing embryos has been widely used to generate genetically engineered pigs. The approach allows us to produce pigs carrying targeted modifications at high efficiency without having to apply somatic cell nuclear transfer. However, the targeted modifications during embryogenesis often result in mosaicism, which causes issues in phenotyping founder animals and establishing a group of pigs carrying intended modifications. This study was aimed to establish a genomic PCR and sequencing system of a single blastomere in the four-cell embryos to detect potential mosaicism. We performed genomic PCR in four individual blastomeres from four-cell embryos. We successfully amplified target genomic region from single blastomeres of 4-cell stage embryo by PCR. Sanger sequencing of the PCR amplicons obtained from the blastomeres suggested that PCR-based genotyping of single blastomere was a feasible method to determine mutation type generated by genome editing technology such as CRISPR/Cas9 in early stage embryos. In conclusion, we successfully genotyped single blastomeres in a single 4-cell stage embryo to detect potential mosaicism in porcine embryos. Our approach offers a simple platform that can be used to screen the prevalence of mosaicism from designed CRISPR/Cas9 systems.

• Korean Journal of Animal Reproduction
• /
• v.26 no.2
• /
• pp.87-94
• /
• 2002

This study was performed during the four seasons for the production of transgenic pigs containing the Cellulase Digest Gene. Purebred Landrace gilts and sows approximately 8∼15 months of age (n=126) were used for the collection of 1-cell zygotes for DNA microinjection and transfer. Retrospectively, estrus synchronization and superovulation schemes were evaluated to assess practicality fur zygote collection. Synchronization and superovulation procedures were used that cyclic gilts were synchronized with 20mg altrenogest (ALT) per day for 9 days after PG600 administration followed by superovulation with 1000 IU pregnant mares serum gonadotropin (PMSG) and 750IU human chorionic gonadotrophin (hCG). The cellulase digestion gene for microinjection is rat elasterase promoter (rEl) linked to CelD gene. After hormone treatment, 1,422 embryos were collected from 91 donors and 95.6% (1,359/1,422) embryos were in 1-cell stage which can be visualized the pronuclei for DNA microinjection. A total of 725 DNA microinjected embryos transferred into 35 recipients and produced 65 piglets from 13 litters. Pregnancy rate according to the number of transferred embryos to recipients was higher the group which received 21 to 24 embryos (50.0%) than other groups 20.0% in less and 33.3% in more. A tail tissue was collected from 65 piglets for biopsy. PCR screening was performed on each DNA sample using two separate sets of primers specific for the 5'- and 3'-flanking region of the rEl-CelD gene. Five of the 65 piglets (7.69%) were positive for the transgene. This study provide useful information regarding production of transgenic pig for bioreactor research.

• Journal of Embryo Transfer
• /
• v.30 no.4
• /
• pp.345-350
• /
• 2015

In the last 10 years, porcine somatic cell nuclear transfer to generate transgenic pig has been performed tremendous development with introduction and knockout of many genes. However, efficiency of porcine somatic cell nuclear transfer is still low and embryo transfer (ET) is one of important step for production efficiency. In porcine ET for production of transgenic cloned pig, we can consider many of points to increase production rates. In respect of seasonality and weather, porcine ET usually is not performed in summer and winter. Cloned transgenic embryos must be transferred into reproductive tracts of recipients where embryos are located after natural fertilization with similar estrous cycle. If cloned embryos with 2~4 cell stage are transferred, they must be transferred into oviducts in periovulatory stage. Number and deposition sites of transferred cloned embryos are important. And we must compare the methods of ET between surgical and non-surgical ones in respect of production efficiency. Sow recipients after natural estrus is most preferred recipients however its cost is must be considered. Here we will review many of current studies about porcine embryo transfer to increase production efficiency of transgenic pigs and strategies for further studies.

• Asian-Australasian Journal of Animal Sciences
• /
• v.28 no.11
• /
• pp.1565-1572
• /
• 2015

Porcine embryonic stem cells (pESCs) have become an advantageous experimental tool for developing therapeutic applications and producing transgenic animals. However, despite numerous reports of putative pESC lines, deriving validated pESC lines from embryos produced in vitro remains difficult. Here, we report that embryo aggregation was useful for deriving pESCs from in vitro-produced embryos. Blastocysts derived from embryo aggregation formed a larger number of colonies and maintained cell culture stability. Our derived cell lines demonstrated expression of pluripotent markers (alkaline phosphatase, Oct4, Sox2, and Nanog), an ability to form embryoid bodies, and the capacity to differentiate into the three germ layers. A cytogenetic analysis of these cells revealed that all lines derived from aggregated blastocysts had normal female and male karyotypes. These results demonstrate that embryo aggregation could be a useful technique to improve the efficiency of deriving ESCs from in vitro-fertilized pig embryos, studying early development, and deriving pluripotent ESCs in vitro in other mammals.

• Journal of Embryo Transfer
• /
• v.23 no.2
• /
• pp.101-108
• /
• 2008

This study investigated the developmental ability and gene expression of somatic cell nuclear transfer embryos using ear skin fibroblast cells derived from miniature pig. When miniature pig (m) and landrace pig (p) were used as donor cells, there were no differences in cleavage (79.2 vs. 78.2%) and blastocyst rates (27.4 vs. 29.7%). However, mNT blastocysts showed significantly higher apoptosis rate than that of pNT blastocysts (6.1 vs. 1.7%) (p<0.05). The number of nuclei in pNT blastosysts was significantly higher than that of mNT (35.8 vs. 29.3) (p<0.05). Blastocysts were analyzed using Realtime RT-PCR to determine the expression of Bax-${\alpha}$, Bcl-xl, H19, IGF2, IGF2r and Xist. Bax-${\alpha}$ was higher in mNT blastocyst than pNT blastocyst (p<0.05). There was no difference in Bcl-xl between two NT groups. Bax-${\alpha}$/Bcl-xl was, however, significantly higher in mNT blastocyst compared to pNT. The expression of imprinting genes were aberrant in blastocysts derived from NT compared to in vivo blastocysts. H19 and IGF2r were significantly lower in mNT blastocysts (p<0.05). The expression of IGF2 and Xist was similar in two NT groups. However, imprinting genes were expressed aberrantly in mNT compared to pNT blastocysts. The present results suggest that the NT between donor cells derived from miniature pig and recipient oocytes derived from crossbred pig might affect reprogramming of donor cell, resulting in high apoptosis and aberrant expression patterns of imprinting genes.

• Proceedings of the Korean Society of Embryo Transfer Conference
• /
• 2003.10a
• /
• pp.124-124
• /
• 2003

• Proceedings of the Korean Society of Embryo Transfer Conference
• /
• 2006.10a
• /
• pp.113-113
• /
• 2006

• Korean Journal of Animal Reproduction
• /
• v.14 no.3
• /
• pp.223-230
• /
• 1990

This experiment was carried out to investigate in vitro maturation rate of pig follicular oocytes cultured from 30 to 48hr in TCM 199 supplemented with gonadotropins(FSH, LH) and estradiol-17$\beta$ and in vitro fertilization with ejaculated sperm preincubated in BO medium containing 2mM caffein and development of IVF oocytes. The results obtained in this experiments were as follows ; 1. In addition of hormones, in vitro maturation rate of follicular oocyte increased gradually from 36hr and 74.47% at 48hr in addition of hormones, but there was no differences among in vitro maturation rates after 36hr of culture. 2. Penetration rate of pig oocytes matured in FSH＋LH＋E2 and FSH＋E2 was 71.8%, 71.0% and significantly increased by the addition of hormones. 3. Percentage of developed oocytes was 44.4% for oocytes matured in FSH＋LH＋E2-added medium and 48.7% for oocytes matured in FSH＋E2-added medium, respectively. 4. Two to 16 cells stage embryos were obtained only when pig oocytes matuerd in vitro in hormones-added medium and 72hr after IVF. 5. From present results, it is concluded that gonadotropins and estradiol17$\beta$ can enhance in vitro fertilization and subsequent development as well as in vitro maturation pig follicular oocytes.

• Proceedings of the KSAR Conference
• /
• 2004.06a
• /
• pp.217-217
• /
• 2004

The present study was conducted to investigate the developmental competency between male- and female-somatic cell derived nuclear-transferred porcine embryos, and the productive and survival efficiency of cloned male and female piglets. The potential of eggs receiving somatic cells to develop into blastocysts was not different among donor cells of different origins. (omitted)