This work was undertaken in order to study the developmental competence of nuclear transfer cat embryo with fetal fibroblast and adult skin fibroblast as donor nuclei. Oocytes wererecovered by mincing the ovaries in Hepes-buffered TCM199 and selected the cumulus oocyte complexes (COCs) with compact cumulus cell mass and dark. Homogenous ooplasm were cultured for maturation in TCM199 + 10% fetal bovine serum (FBS) for 12 hours and used as a source of recipient cytoplast for exogenous somatic nuclei. In Experiment 1, we evaluated the effect donor cell types on the reconstruction and development of cloned embryos. Fusion, first cleavage and blastocyst developmental rate was not different between fetal fibroblast and adult skin cell (71.2 vs. 66.8; 71.0 vs. 57.6; 4.0 vs. 6.1 %, P<0.05). In Experiment 2, cloned embryos were surgically transferred into the oviducts of recipient queens. One of seven recipient queens was delivered naturally 2healthy cloned cats and 1 stillborn from fetal fibroblast cell of male origin after 65 days embryo transfer. One of three recipient queens was delivered naturally 1 healthy cloned cat from adult skin cell of female after 65 days embryo transfer. The cloned cats showed genotypes identical to the donor cell lines, indicating that adult somatic cells can be used for feline cloning.

The present study was conducted for the production of transgenic cloned cows by somatic cell nuclear transfer (SCNT) that secrete human prourokinase into milk. To establish an efficient production system for bovine transgenic SCNT embryos, the offset was examined of various conditions of donor cells including cell type, size, and passage number on the developmental competence of transgenic SCNT embryos. An expression plasmid far human prourokinase (pbeta-ProU) was constructed by inserting a bovine beta-casein promoter, a green fluorescent protein (GFP) marker gene, and a human prourokinase target gene into a pcDNA3 plasmid. Three types of bovine somatic cells including two adult cells (cumulus cells and ear fibroblasts) and fetal fibroblasts were prepared and transfected using a lipid-meidated method. In Experiment 1, developmental competence and rates of GFP expression in bovine transgenic SCNT embryos reconstructed with cumulus cells were significantly higher than those from fetal and ear fibroblasts. In Experiment 2, the effect of cellular senescence in early (2 to 4) and late (8 to 12) passages was investigated. No significant differences in the development of transgenic SCNT embryos were observed. In Experient 3, different sizes of GFP-expressing transfected cumulus cells [large (>30 ) or small cell (<30 )] were used for SCNT. A significant improvement in embryo development and GFP expression was observed when small cumulus cells were used for SCNT. Taken together, these results demonstrate that (1) adult somatic cells could serve as donor cells in transgenic SCNT embryo production and cumulus cells with small size at early passage were the optimal cell type, and (2) transgenic SCNT embryos derived from adult somatic cells have embryonic development potential.