Pigs are considered as ideal donors for xenotransplantation because they have many physiological and anatomical characteristics similar to human beings. However, antibody-mediated immunity, which includes both natural and induced antibody responses, is a major challenge for the success of pig-to-primate xenotransplantation. Various genetic modification methods help to tailor pigs to be appropriate donors for xenotransplantation. In this study, we applied transcription activator-like effector nuclease (TALEN) to knock out the porcine α-1, 3-galactosyltransferase gene GGTA1, which encodes Gal epitopes that induce hyperacute immune rejection in pig-to-human xenotransplantation. Meanwhile, human leukocyte antigen-G5 gene HLA-G5, which acts as an immunosuppressive factor, was co-transfected with TALEN into porcine fetal fibroblasts. The cell colonies of GGTA1 biallelic knockout with positive transgene for HLA-G5 were chosen as nuclear donors to generate genetic modified piglets through a single round of somatic cell nuclear transfer. As a result, we successfully obtained 20 modified piglets that were positive for GGTA1 knockout (GTKO) and half of them expressed the HLA-G5 protein. Gal epitopes on the cell membrane of GTKO/HLA-G5 piglets were completely absent. Western blotting and immunofluorescence showed that HLA-G5 was expressed in the modified piglets. Functionally, the fibroblasts from the GTKO/HLA-G5 piglets showed enhanced resistance to complement-mediated lysis ability compared with those from GTKO-only or wild-type pigs. These results indicate that the GTKO/HLA-G5 pigs could be a valuable donor model to facilitate laboratory studies and clinics for xenotransplantation.
Animals ; Animals, Genetically Modified ; Gene Knockout Techniques ; HLA Antigens ; Humans ; Nuclear Transfer Techniques ; Swine ; Transplantation, Heterologous

Somatic cell cloning (nuclear transfer) is a technique through which the nucleus (DNA) of a somatic cell is transferred into an enucleated oocyte for the generation of a new individual, genetically identical to the somatic cell donor. It could be applied for the enhancement of reproduction rate and the improvement of food products involving quality, yield and nutrition. In recent years, the United States, Japan and Europe as well as other countries announced that meat and milk products made from cloned cattle are safe for human consumption. Yet, cloned animals are faced with a wide range of health problems, with a high death rate and a high incidence of disease. The precise causal mechanisms for the low efficiency of cloning remain unclear. Is it safe that any products from cloned animals were allowed into the food supply? This review focuses on the security of meat, milk and products from cloned cattle based on the available data.
Animals ; Cattle ; Cloning, Organism ; Consumer Product Safety ; Dairy Products ; Female ; Meat Products ; Nuclear Transfer Techniques

Cell reprogramming is a progress in which the memory of a mature cell is erased and then the cell develops novel phenotype and function; ultimately, the fate of the cell changes. Cell reprogramming usually occurs at genes expression levels that no genomic DNA sequence change will be involved. By changing the programs of the genetic expressions of cells in terms of space and time, cell reprogramming alters the differentiation of cells and thus produces the required cells. Further research on cells reprogramming will elucidate the mechanisms that govern the cell development, and thus provides more information of the sources of seed cells used for regeneration medicine. More cells differentiated from many terminally differentiated cells will be obtained, which is extremely important for the understanding of molecular differentiation and for the development of cell replacement therapy. This article summarizes the classification, influencing factors, approaches and latest advances of cells reprogramming.
Animals ; Cell Dedifferentiation ; genetics ; Cell Differentiation ; genetics ; Cellular Reprogramming ; Gene Expression ; Humans ; Nuclear Transfer Techniques

Pregnancy ; Female ; Humans ; Placenta ; Nuclear Transfer Techniques ; Embryo, Mammalian ; Cell Nucleus

Embryonic stem (ES) cells have the unique capacity to proliferate extensively and maintain the potential to differentiate into advanced derivatives of all three primary germ layers. ES cell lines can also be generated from human blastocyst embryos and are considered promising donor sources for cell transplantation therapies for diseases such as juvenile diabetes, Parkinson's disease, and heart failure. However, as for organ transplants, tissue rejection remains a significant concern for ES cell transplantation. Another concern is the use of human embryos. One possible means to avoid these issues is by reprogramming the nuclei of differentiated cells to ES cell-like, pluripotent cells. This review discusses the potential of these strategies to generate tailor-made pluripotent stem cells and the role of transcription factors in the reprogramming process.
Cell Culture Techniques ; Cell Differentiation ; physiology ; Cells, Cultured ; Cellular Reprogramming ; Humans ; Nuclear Transfer Techniques ; Pluripotent Stem Cells ; cytology

The Spindle-view, a specialized instrument for observing spindle image, was applied to observe the meiotic spindles of vitro matured porcine oocytes at 36, 42, 44, 48h, and enucleation from porcine, comparing to the previously methods (McGrath-Solter's method and two-step-squeezing method) in the enucleated. The results showed that: (1) there was no noticeable differences at vicinity of spindle images and 1st polar body among in vitro matured porcine oocytes at 40-48 h under the instrument; (2) Spindle-view is suitable for the observation of meiotic spindles of matured oocytes and enucleation from porcine; the modified Spindle-view method for enucleation is significantly better than McGrath-Solter' s method and two-step-squeezing method in the enucleated rates (95.5%, 42.1%, 74.2%, P < 0.0l) of absolutely removing nuclei matter; (3) the spindle images could be used to monitor the oocyte qualities.
Animals ; Cell Nucleus ; ultrastructure ; Cells, Cultured ; Cytological Techniques ; Female ; Nuclear Transfer Techniques ; Oocytes ; cytology ; Spindle Apparatus ; ultrastructure ; Swine

Somatic cell nuclear transfer (SCNT) is considered to be a critical tool for propagating valuable animals. To determine the productivity calves resulting from embryos derived with different culture media, enucleated oocytes matured in vitro were reconstructed with fetal fibroblasts, fused, and activated. The cloned embryos were cultured in modified synthetic oviduct fluid (mSOF) or a chemically defined medium (CDM) and developmental competence was monitored. After 7 days of culturing, the blastocysts were transferred into the uterine horn of estrus-synchronized recipients. SCNT embryos that were cultured in mSOF or CDM developed to the blastocysts stages at similar rates (26.6% vs. 22.5%, respectively). A total of 67 preimplantational stage embryos were transferred into 34 recipients and six cloned calves were born by caesarean section, or assisted or natural delivery. Survival of transferred blastocysts to live cloned calves in the mSOF and the CDM was 18.5% (to recipients), 9.6% (to blastocysts) and 42.9% (to recipients), 20.0% (to blastocysts), respectively. DNA analysis showed that all cloned calves were genetically identical to the donor cells. These results demonstrate that SCNT embryos cultured in CDM showed higher viability as judged by survival of the calves that came to term compared to blastocysts derived from mSOF cultures.
Animals ; Blastocyst/physiology ; *Cattle ; Cloning, Organism/methods/*veterinary ; Culture Media/chemistry ; Embryo Culture Techniques ; Embryo Transfer ; Embryonic Development ; Female ; Fertilization in Vitro/*veterinary ; Nuclear Transfer Techniques/*veterinary ; Pregnancy

To knock out β-lactoglobulin (BLG) gene and insert human lactoferrin (hLF) coding sequence at BLG locus of goat, the transcription activator-like effector nucleases (TALEN) mediated recombination was used to edit the BLG gene of goat fetal fibroblast, then as donor cells for somatic cell nuclear transfer. We designed a pair of specific plasmid TALEN-3-L/R for goat BLG exon III recognition sites, and BLC14-TK vector containing a negative selection gene HSV-TK, was used for the knock in of hLF gene. TALENs plasmids were transfected into the goat fetal fibroblast cells, and the cells were screened three days by 2 μg/mL puromycin. DNA cleavage activities of cells were verified by PCR amplification and DNA production sequencing. Then, targeting vector BLC14-TK and plasmids TALEN-3-L/R were co-transfected into goat fetal fibroblasts, both 700 μg/mL G418 and 2 μg/mL GCV were simultaneously used to screen G418-resistant cells. Detections of integration and recombination were implemented to obtain cells with hLF gene site-specific integration. We chose targeting cells as donor cells for somatic cell nuclear transfer. The mutagenicity of TALEN-3-L/R was between 25% and 30%. A total of 335 reconstructed embryos with 6 BLG-/hLF+ targeting cell lines were transferred into 16 recipient goats. There were 9 pregnancies confirmed by ultrasound on day 30 to 35 (pregnancy rate of 39.1%), and one of 50-day-old fetus with BLG-/hLF+ was achieved. These results provide the basis for hLF gene knock-in at BLG locus of goat and cultivating transgenic goat of low allergens and rich hLF in the milk.
Animals ; Animals, Genetically Modified ; genetics ; Female ; Fibroblasts ; Gene Knock-In Techniques ; Gene Knockout Techniques ; Goats ; genetics ; Humans ; Lactoferrin ; genetics ; Lactoglobulins ; genetics ; Milk ; chemistry ; Nuclear Transfer Techniques ; Plasmids ; Pregnancy ; Transfection

The level of P4 at the time of embryo transfer (ET) is important. P4 concentrations and numbers of corpora lutea for 126 recipients were evaluated. Nuclear transfer embryos were transferred into 126 surrogates. 11 maintained their pregnancy until full-term delivery, 17 miscarried, and implantation failed in 98 animals. P4 levels in the full-term group were significantly different from those of the pigs that aborted or in which implantation failed (p < 0.05). However, the numbers of corpora lutea were not significantly different. These findings indicate that the concentration of progesterone can be an important factor for successful ET in pigs.
Animals ; Corpus Luteum/*physiology ; Embryo Transfer/*veterinary ; Embryo, Mammalian/*physiology ; Female ; Nuclear Transfer Techniques ; Pregnancy ; *Pregnancy Rate ; Progesterone/*blood ; Retrospective Studies ; Sus scrofa/*physiology

To optimize program of bovine somatic nuclear transfer, we used two different enucleation procedures (by Spindle-view system & Hoechst 33342 staining), two different procedures to introduce donor nuclei (by ooplasm microinjection & electrofusion), and three different group electrofusion parameters (group 1: 1.9 kV/cm, 10 micros, two; group 2: 1.5 kV/cm, 25 micros, two; group 3: 0.6 kV/cm, 100 micros, one) to reconstruct bovine cloned embryos. The cleavation rates and blastocyst development rates of cloned embryos were used to assess the efficiency of different operational procedure. Finally, the best combination of operational procedure, that the spindle-viewer system was used for oocytes enucleating, and donor cell was electrofused into ooplasm by electrical pulse (1.9 kV/cm, 10 micros, two) to reconstruct bovine cloned embryos. Then the excellent blastocysts were transferred to fosters for producing cloned cattle 80 high-quality cloned blastocysts were transferred into 33 fosters, two cloned calves were produced. According to the results, the optimized program could be used to produce cloned cattle.
Animals ; Cattle ; Cell Nucleus ; physiology ; Cloning, Organism ; veterinary ; Embryo Transfer ; methods ; Embryo, Mammalian ; cytology ; physiology ; Female ; Microinjections ; Nuclear Transfer Techniques ; veterinary ; Oocytes ; cytology ; physiology