Nuclear transfer of M-phase ferret fibroblasts synchronized with the microtubule inhibitor demecolcine

Cell cycle analysis and interspecies nuclear transfer of cat cells treated with chemical inhibitors

This study investigated the effect of chemical inhibitors on the cell-cycle synchronisation in cat fibroblast cells and evaluated the development of interspecies embryos reconstructed from cat donor cells and enucleated bovine oocytes. Cat fibroblast cells were treated with 15 μg/mL roscovitine or 0.05 μg/mL deme-colcine prior to cell cycle analysis and nuclear transfer. The percentage of cat fibroblast cells arrested at the G0/G1 phase in the roscovitine group was similar to that in the control group without any treatment. The percentage of cells arrested at the G2/M phase was significantly higher in the demecolcine group than in the control group. The fusion rate of interspecies couplets was significantly greater in the roscovitine group than in the control group. Most embryos stopped the development at the 2- or 4-cell stage, and none developed into blastocysts. Chemical inhibitor-induced donor cell cycle synchronisation did not overcome developmental arrest in interspecies cloned embryos.

Effect of dimethyl sulfoxide on cell cycle synchronization of goldfish caudal fin derived fibroblasts cells

Several studies have previously been conducted regarding cell cycle synchronization in mammalian somatic cells. However, limited work has been performed on the control of cell cycle stages in the somatic cells of fish. The aim of this study was to determine the cell cycle arresting effects of several dimethyl sulfoxide (DMSO) concentrations for different times on different cell cycle stages of goldfish caudal fin-derived fibroblasts. Results demonstrated that the cycling cells or control group (68.29%) yields significantly higher (p < 0.05) arrest in G0/G1 phase compared with the group treated for 24 h with different concentrations (0.5%, 1.0% or 1.5%) of DMSO (64.88%, 65.70%, 64.22% respectively). The cell cycle synchronization in the treatment of cells with 1.0% DMSO at 48 h (81.14%) was significantly higher than that in the groups treated for 24 h (76.82%) and the control group (77.90%). Observations showed that treatment of DMSO resulted in an increase in the proportion of cells at G0/G1 phase for 48 h of culture. However, high levels of apoptotic cells can be detected after 48 h of culture treated with 1% concentration of DMSO.

Effect of serum starvation and chemical inhibitors on cell cycle synchronization of canine dermal fibroblasts

The cell cycle stage of donor cells and the method of cell cycle synchronization are important factors influencing the success of somatic cell nuclear transfer. In this study, we examined the effects of serum starvation, culture to confluence, and treatment with chemical inhibitors (roscovitine, aphidicolin, and colchicine) on cell cycle characteristics of canine dermal fibroblast cells. The effect of the various methods of cell cycle synchronization was determined by flow cytometry. Short periods of serum starvation (24-72 h) increased (P<0.05) the proportion of cells at the G0/G1 phase (88.4-90.9%) as compared to the control group (73.6%). A similar increase in the percentage of G0/G1 (P<0.05) cells were obtained in the culture to confluency group (91.8%). Treatment with various concentrations of roscovitine did not increase the proportion of G0/G1 cells; conversely, at concentrations of 30 and 45 microM, it increased (P<0.05) the percentage of cells that underwent apoptosis. The use of aphidicolin led to increase percentages of cells at the S phase in a dose-dependent manner, without increasing apoptosis. Colchicine, at a concentration of 0.1 microg/mL, increased the proportion of cells at the G2/M phase (38.5%, P<0.05); conversely, it decreased the proportions of G0/G1 cells (51.4%, P<0.05). Concentrations of colchicines >0.1 microg/mL did not increase the percentage of G2/M phase cells. The effects of chemical inhibitors were fully reversible; their removal led to a rapid progression in the cell cycle. In conclusion, canine dermal fibroblasts were effectively synchronized at various stages of the cell cycle, which could have benefits for somatic cell nuclear transfer in this species.

Adeno-associated virus-targeted disruption of the CFTR gene in cloned ferrets

Somatic cell gene targeting combined with nuclear transfer cloning presents tremendous potential for the creation of new, large-animal models of human diseases. Mouse disease models often fail to reproduce human phenotypes, underscoring the need for the generation and study of alternative disease models. Mice deficient for CFTR have been poor models for cystic fibrosis (CF), lacking many aspects of human CF lung disease. In this study, we describe the production of a CFTR gene-deficient model in the domestic ferret using recombinant adeno-associated virus-mediated gene targeting in fibroblasts, followed by nuclear transfer cloning. As part of this approach, we developed a somatic cell rejuvenation protocol using serial nuclear transfer to produce live CFTR-deficient clones from senescent gene-targeted fibroblasts. We transferred 472 reconstructed embryos into 11 recipient jills and obtained 8 healthy male ferret clones heterozygous for a disruption in exon 10 of the CFTR gene. To our knowledge, this study represents the first description of genetically engineered ferrets and describes an approach that may be of substantial utility in modeling not only CF, but also other genetic diseases.

Cloned ferrets produced by somatic cell nuclear transfer

Somatic cell nuclear transfer (SCNT) offers great potential for developing better animal models of human disease. The domestic ferret (Mustela putorius furo) is an ideal animal model for influenza infections and potentially other human respiratory diseases such as cystic fibrosis, where mouse models have failed to reproduce the human disease phenotype. Here, we report the successful production of live cloned, reproductively competent, ferrets using species-specific SCNT methodologies. Critical to developing a successful SCNT protocol for the ferret was the finding that hormonal treatment, normally used for superovulation, adversely affected the developmental potential of recipient oocytes. The onset of Oct4 expression was delayed and incomplete in parthenogenetically activated oocytes collected from hormone-treated females relative to oocytes collected from females naturally mated with vasectomized males. Stimulation induced by mating and in vitro oocyte maturation produced the optimal oocyte recipient for SCNT. Although nuclear injection and cell fusion produced mid-term fetuses at equivalent rates (approximately 3-4%), only cell fusion gave rise to healthy surviving clones. Single cell fusion rates and the efficiency of SCNT were also enhanced by placing two somatic cells into the perivitelline space. These species-specific modifications facilitated the birth of live, healthy, and fertile cloned ferrets. The development of microsatellite genotyping for domestic ferrets confirmed that ferret clones were genetically derived from their respective somatic cells and unrelated to their surrogate mother. With this technology, it is now feasible to begin generating genetically defined ferrets for studying transmissible and inherited human lung diseases. Cloning of the domestic ferret may also aid in recovery and conservation of the endangered black-footed ferret and European mink.