Several cloned animals have been produced using somatic cell nuclear transfer (SCNT) and have interested in producing the transgenic cloned animals to date. But still its efficiency was low due to a number of reasons, such as sub-optimal culture condition, aberrant gene expression and nuclear reprogramming. The purpose of this study was to analyze gene expression pattern in in vitro fertilized (IVF) or SCNT pre-implantation embryos. IVF- or SCNT-embryos were cultured in media supplemented with different proteins (FBS and BSA) or energy sources (glucose or fructose). Blastocysts from IVF or SCNT were analyzed using semi-quantitative RT-PCR in terms of developmentor metabolic-related genes. Culture medium supplemented different proteins or energy sources had affected on the expression of developmental or metabolic genes in the SCNT blastocysts.

We investigated the microtubule dynamics, including the inheritance of donor centrosomes and the mitotic spindle assembly occurring during the first mitosis of somatic cell nuclear transfer (SCNT) embryos in pigs. SCNT embryos were fixed 15 min and 1 h after fusion in order to assess the inheritance pattern of the donor centrosome. The distribution and dynamic of the centrosome and microtubule during the first mitotic phase of SCNT embryos were also evaluated. The frequency of embryos evidencing γ‐gtubulin spots (centrosome) was 93.2% in the SCNT embryos 15 min after fusion. In the majority of the SCNT embryos (61.5%), however, no centrosome was observed 1 h after fusion. The frequency of the embryos with no or abnormal mitotic spindles 20 h after fusion was 19.6%. The γ‐gtubulin spots were detected near the nuclei of somatic cells regardless of cell cycle phase, whereas γ‐g tubulin spots in the SCNT embryos were observed only during the inter‐ganaphase transition. These results showed that the donor centrosome is inherited into the SCNT embryos, but failed to assemble the normal mitotic spindles during first mitotic phase in some SCNT embryos.

We attempted to control the maturation promoting factor (MPF) activity and investigated the subsequent reprogramming of bovine somatic cell nuclear transfer (SCNT) embryos. Serum‐starved adult skin fibroblasts were fused to enucleated oocytes treated with 2.5 mM caffeine or 150 μM roscovitine. The MPF activity, nuclear remodeling patterns, chromosome constitutions and development of SCNT embryos were evaluated. Methylated DNA of embryos was detected at various developmental stages. The MPF activity was increased by caffeine treatment or reduced by roscovitine treatment (p<0.05). Blastocyst development was higher in the caffeine‐treated groups (27.6%) than that of the roscovitine‐treated group (8.3%, p<0.05). There was no difference in the apoptotic cell index among the three groups. However, the mean cell number of blastocysts was increased in the caffeine‐treated group (p<0.05). Higher methylation levels were observed in the Day 3 embryos of the roscovitine‐treated group (50.8%), whereas lower methylation levels were noted at Day 5 in the caffeine‐treated group (12.5%, p<0.05). These results reveal that the increase in MPF activity via a caffeine‐treatment creates a more suitable condition for nuclear reprogramming after SCNT.

Pluripotent embryonic stem (ES) cells isolated from inner cell mass (ICM) of blastocyst-stage embryos are capable of differentiating into various cell lineages and demonstrate germ-line transmission in experimentally produced chimeras. These cells have a great potential as tools for transgenic animal production, screening of newly-developed drugs, and cell therapy. Miniature pigs, selectively bred pigs for small size, offer several advantages over large breed pigs in biomedical research including human disease model and xenotransplantation. In the present study, factors affecting primary culture of somatic cell nuclear transfer blastocysts from miniature pigs for isolation of ES cells were investigated. Formation of primary colonies occurred only on STO cells in human ES medium. In contrast, no ICM outgrowth was observed on mouse embryonic fibroblasts (MEF) in porcine ES medium. Plating intact blastocysts and isolated ICM resulted in comparable attachment on feeder layer and primary colony formation. After subculture of ES-like colonies, two putative ES cell lines were isolated. Colonies of putative ES cells morphologically resembled murine ES cells. These cells were maintained in culture up to three passages, but lost by spontaneous differentiation. The present study demonstrates factors involved in the early stage of nuclear transfer ES cell isolation in miniature pigs. However, long-term maintenance and characterization of nuclear transfer ES cells in miniature pigs are remained to be done in further studies.

The objective of this study was to examine the effect of eCG and various concentrations (20, 40, and 80 ) of porcine FSH on nuclear maturation and intracellular glutathione (GSH) level of oocytes, and embryonic development after parthenogenetic activation (PA) and somatic cell nuclear transfer (SCNT) in pigs. Immature pig oocytes were matured in TCM-199 supplemented with porcine follicular fluid, cysteine, pyruvate, EGF, insulin, and hormones (10 IU/ml hCG and 10 IU/ml eCG or FSH) for the first 22 h and then further cultured in hormone-tree medium for an additional 22 h. Nuclear maturation of oocytes () was not influencem foreCG and various concentrations FSH. Embryonic development to the cleavage stage () and mean number of cells in blastocyst ( cells) after PA were not altered but blastocyst formation e-treignificaddlor(p<0.05) improvem forthe supplementation eith 80 FSHr(64%) compared to 47%, io8%, iand 47% in oocytes that were treated with eCG, 20,i and 40 FSH,i numectivelo. In SCNT, fusion () of cell-cytoplast couplets and siosequent embryo cleavage () were not influencem fordifferent gonadotropins but blastocyst formation tended to increase forthe supplementation eith 80 FSHr(25% vs. ). Our nuults demonstrated that oocyte maturation and embryonic development after PA and SCNT e-frinfluencem fortype of gcem fortype of gits concentration. In this study, supplementation of maturation medium eith 80 FSHrimproved preimplantation development of PA and SCNT pig embryos, probably by increasing intracellular GSH concentration of matured oocytes.

The objective of this study was to examine the effect of macromolecule in a maturation medium on nuclear maturation, intracellular glutathione (GSH) level of oocytes, and embryonic development after parthenogenetic activation (PA) and somatic cell nuclear transfer (SCNT) in pigs. Immature pig oocytes were cultured in maturation medium that was supplemented with each polyvinyl alcohol (PVA), pig follicular fluid (pFF) or newborn calf serum (NBCS) during the first 22 h and the second 22 h. Oocyte maturation was not influenced by the source of macromolecules during in vitro maturation (IVM). Embryo cleavage and cell number in blastocyst after PA was altered by the source of macromolecule but no difference was observed in blastocyst formation among treatments. Oocytes matured in PVA-PVA medium showed lower rates of oocyte-cell fusion (70.4% vs. 7782%) and embryo cleavage (75% vs. 8690%) after SCNT than those matured in other media but blastocyst formation was not altered (1327%) by different macromolecules. pFF added to IVM medium significantly increased the intracellular GSH level of oocytes compared to PVA and NBCS, particularly when pFF was supplemented during the first 22 h of IVM. Our results demonstrate that source of macromolecule in IVM medium influences developmental competence of oocytes after PA and SCNT, and that pFF supplementation during the early period (first 22 h) of IVM increases intracellular GSH level of oocytes.

The aim of this study was to examine the microtubule distributions of somatic cell nuclear transfer (SCNT) and parthenogenetic porcine embryos. Porcine SCNT embryos were produced by fusion of serum-starved fetal fibroblast cells with enucleated oocytes. Reconstituted and mature oocytes were activated by electric pulses combined with 6-dimethlyaminopurine treatment. SCNT and parthenogenetic embryos were cultured in vitro for 6 days. Microtubule assembly of embryos was examined by confocal microscopy 1 hr and 20 hr after fusion or activation, respectively. The proportions of embryos developed to the blastocyst stage were 25.7% and 30.4% in SCNT and parthenogenetic embryos, respectively. The frequency of embryos showing β-tubulins was 81.8% in parthenogenetic embryos, whereas 31.3% in SCNT embryos 1 hr after activation or fusion. The frequency of the embryos underwent normal mitotic phase was low in SCNT embryos (40.6%) compared to that of parthenogenetic ones (59.7%) 20 hr after fusion or activation (p<0.05). The rate of SCNT embryos with an abnormal mitosis pattern is about twice compared to that of parthenogenetic ones. The spindle assembly and its distribution of SCNT embryos in the first mitotic phase were not different from those of parthenogenetic ones. The result shows that although microtubule distribution of porcine SCNT embryos shortly after fusion is different from parthenogenetic embryos, and the frequency of abnormal mitosis 20 hr after fusion or activation is slightly increased in SCNT embryos, microtubule distributions at the first mitotic phase are similar in both SCNT and parthenogenetic embryos.

Interspecies somatic cell nuclear transfer (iSCNT) is a valuable tool for studying the interactions between an oocyte and somatic nucleus. The object of this study was to investigate the developmental competence of in vitro‐matured porcine oocytes after transfer of the somatic cell nuclei of 2 different species (goat and rabbit). Porcine cumulus oocytes were obtained from the follicles of ovaries and matured in TCM‐199. The reconstructed embryos were electrically fused with 2 DC pulses of 1.1 kV/cm for 30 μs in 0.3 M mannitol medium. The activated cloned embryos were cultured in porcine zygote medium‐3 (PZM‐3), mSOF or RDH medium for 7 days. The blastocyst formation rate of the embryos reconstructed from goat or rabbit fetal fibroblasts was significantly lower than that of the embryos reconstructed from porcine fetal fibroblast cells. However, a significantly higher number of embryos reconstructed from goat or rabbit fetal fibroblasts cultured in mSOF or RDH, respectively, developed to the morular stage than those cultured in PZM‐3. These results suggest that goat and bovine fetal fibroblasts were less efficacious than porcine‐porcine cloned embryos and that culture condition could be an important factor in iSCNT. The lower developmental potential of goat‐porcine and porcine‐bovine cloned embryos may be due to incompatibility between the porcine oocyte cytoplasm and goat and bovine somatic nuclei.

This study was designed to investigate the effect of essential amino acids (EAA) and/or non-essential amino acids (NEAA) on the development of parthenogenetic and somatic cell nuclear transfer (SCNT) porcine embryos in vitro. To evaluate the timing of amino acids supplementation, activated oocytes were cultured in NCSU23-PVA with EAA, NEAA or NEAA+EAA (AAs) during specific periods as below: EAA, NEAA or AAs were supplemented during Day 0 to 6 (whole culture period: ALL), Day 2 to Day 6 (post-maternal embryonic transition period: POST-MET), Day 5 to Day 6 (post-compaction period: POST-CMP), Day 0 to Day 2 (pre-maternal embryonic transition period: PRE-MET), or Day 0 to Day 4 (post-compaction period: PRE-CMP). Supplementation of NEAA decreased cleavage rates in PRE-MET and PRE-CMP and also decreased blastocyst rates in POST-CMP. On the other hand, EAA significantly enhanced blastocyst formation rate in POST-MET and no detrimental effect on embryonic development in other groups. Interestingly, NEAA and EAA had synergistic effect when they were supplemented to the medium during whole culture period. Supplementation of AAs also enhanced SCNT porcine embryo development whereas BSA-free medium without AAs could not supported blastocyst formation of SCNT embryos. In conclusion, existence of EAA and NEAA in defined culture medium variously influences the development of parthenogenetic and SCNT porcine embryos, and their positive effect are only occurred when both EAA and NEAA are supplemented to the medium during whole culture period. Additionally, AAs supplementation enhances the blastocyst formation of SCNT porcine embryos when they are cultured in the defined condition.