Production of transgenic cashmere goat embryos expressing red fluorescent protein and containing IGF1 hair-follicle-cell specific expression cassette by somatic cell nuclear transfer.
ABSTRACT In the present study, cashmere goat fetal fibroblasts were transfected with pCDsR-KI, a hair-follicle-cell specific expression vector for insulin-like growth factor 1 (IGF1) that contains two markers for selection (red fluorescent protein gene and neomycin resistant gene). The transgenic fibroblasts cell lines were obtained after G418 selection. Prior to the somatic cell nuclear transfer (SCNT), the maturation rate of caprine cumulus oocytes complexes (COCs) was optimized to an in vitro maturation time of 18 h. Parthenogenetic ooctyes were used as a model to investigate the effect of two activation methods, one with calcium ionophore IA23187 plus 6-DMAP and the other with ethanol plus 6-DMAP. The cleavage rates after 48 h were respectively 88.7% and 86.4%, with no significant difference (P>0.05). There was no significant difference between the cleavage rate and the blastocyst rate in two different media (SO-Faa and CR1aa; 86.3% vs 83.9%, P>0.05 and 23.1% vs 17.2%, P>0.05). The fusion rate of a 190 V/mm group (62.4%) was significantly higher than 130 V/mm (32.8%) and 200 V/mm (42.9%), groups (P>0.05). After transgenic somatic cell nuclear transfer (TSCNT) manipulation, 203 reconstructed embryos were obtained in which the cleavage rate after in vitro development (IVD) for 48 h was 79.3% (161/203). The blastocyst rate after IVD for 7 to 9 d was 15.3% (31/203). There were 17 embryos out of 31 strongly expressing red fluorescence. Two of the red fluorescent blastocysts were randomly selected to identify transgene by polymerase chain reaction. Both were positive. These results showed that: (i) RFP and Neo ( r ) genes were correctly expressed indicating that transgenic somatic cell lines and positive transgenic embryos were obtained; (ii) one more selection at the blastocyst stage was necessary although the donor cells were transgenic positive, because only partially transgenic embryos expressing red fluorescence were obtained; and (iii) through TSCNT manipulation and optimization, transgenic cashmere goat embryos expressing red fluorescence and containing an IGF1 expression cassette were obtained, which was sufficient for production of transgenic cashmere goats.
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ABSTRACT: Somatic cell nuclear transfer is used to generate genetic models for research and new, genetically modified livestock varieties. Goat fetal fibroblast cells (gFFCs) are the predominant nuclear donors in Cashmere goat transgenic cloning, but have disadvantages. We evaluated the potential of goat adipose-derived mesenchymal stem cells (gADSCs) and goat skeletal muscle-derived satellite cells (gMDSCs) for somatic cell nuclear transfer, evaluating their proliferation, pluripotency, transfection efficiency and capacity to support full term development of embryos after additive gene transfer or homologous recombination. gADSCs and gMDSCs were isolated by enzyme digestion and differentiated into neurocytes, myotube cells and insulin-producing cells. Neuron-specific enolase, fast muscle myosin and insulin expression were determined by immunohistochemistry. Following somatic cell nuclear transfer with donor cells derived from gADSCs, gMDSCs and gFFCs, transfection and cloning efficiencies were compared. Red fluorescent protein levels were determined by quantitative PCR and western blotting. 5-Methylcytosine, H4K5, H4K12 and H3K18 were determined immunohistochemically. gADSCs and gMDSCs were maintained in culture for up to 65 passages, whereas gFFCs could be passaged barely more than 15 times. gADSCs and gMDSCs had higher fluorescent colony forming efficiency and greater convergence (20%) and cleavage (10%) rates than gFFCs, and exhibited differing H4K5 histone modification patterns after somatic cell nuclear transfer and in vitro cultivation. After transfection with a pDsRed2-1 expression plasmid, the integrated exogenous genes did not influence the pluripotency of gADSCs-pDsRed2-1 or gMDSCs-pDsRed2-1. DsRed2 mRNA expression by cloned embryos derived from gADSCs-pDsRed2-1 or gMDSCs-pDsRed2-1 was more than twice that of gFFCs-pDsRed2-1 embryos (P<0.01). Pregnancy rates of gADSCs-pDsRed2-1 and gMDSCs-pDsRed2-1 recipients were higher than those of gFFCs-pDsRed2-1 recipients (P<0.01). With their high proliferative capacity and transfection efficiency, gADSCs and gMDSCs are a valuable cell source for breeding new, genetically modified varieties of livestock by somatic cell nuclear transfer.PLoS ONE 01/2014; 9(4):e93583. · 3.53 Impact Factor
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ABSTRACT: The aim of this study was to develop a method for the in vitro separation and culture of Arbas Cashmere goat bone marrow stromal cells (gBMSCs). Arbas Cashmere gBMSCs were isolated and cultured in vitro and cell surface markers were identified immunohistochemically. The gBMSCs were differentiated into neurocytes and osteoblasts and the expression of neuron-specific enolase (NSE) and osteocalcin was identified by immunohistochemistry. The gBMSCs and gFFCs were compared for transient transfection efficiency and fluorescent colony forming efficiency with Arbas Cashmere goat fetal fibroblasts (gFFCs) as a control. pDsRed2-1 encodes DsRed2, a variant of the Discosoma sp. red fluorescent protein (DsRed). In addition, the coding sequence for DsRed2 contains a series of silent base-pair changes for higher expression in mammalian cells. Of the gBMSCs-pDsRed2-1, one fraction was tested for pluripotency, while the other fraction was manipulated using SCNT, and the in vitro growth status of transgenic embryos derived from gBMSCs-pDsRed2-1 and gFFCs-pDsRed2-1 was compared. The findings showed that gBMSCs were isolated and amplified to express CD29, CD44 and CD90 through adherent culture, with no marked signs of aging after multiple passages. Expression of NSE and osteocalcin by gBMSCs and gBMSCs-pDsRed2-1 was strongly induced by neuronal and osteogenic differentiation, while the integrated exogenous genes did not influence pluripotency (P > 0.05). The transient transfection efficiencies of gBMSCs and gFFCs after 48 h were not significantly different; however, the fluorescent colony forming efficiency of gBMSCs-pDsRed2-1 after G418 screening was approximately 13% higher than that of gFFCs-pDsRed2-1. The convergence and cleavage rates of cloned embryos derived from gBMSCs-pDsRed2-1 were higher than those derived from gFFCs-pDsRed2-1, while their 8-cell and blastocyst rates were similar. The red fluorescent protein expression levels were higher levels in transgenic embryos derived from gBMSCs-pDsRed2-1 compared to those derived from gFFCs-pDsRed2-1 (48.8% vs. 31.1%, respectively) (P < 0.01). Real-time quantitative PCR analysis showed that DsRed2-1 mRNA expression of cloned embryos derived from gBMSCs was 2.24 greater than that of embryos derived from gFFCs-pDsRed2-1 (P < 0.01). Similarly, Western blot analysis showed that DsRed2 protein expression of cloned embryos derived from gBMSCs-pDsRed2-1 was 1.29 greater than that of embryos derived from gFFCs-pDsRed2-1 (P < 0.01). In this study gBMSCs were also used for SCNT and shown to provide effective nuclear donor cells for breeding new genetically modified varieties of livestock.Theriogenology 01/2014; · 2.08 Impact Factor
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ABSTRACT: It has been 30 years since the first transgenic mouse was generated and 26 years since the first example of transferring the technology to livestock was published. While there was tremendous optimism in those initial years, with most convinced that genetically modified animals would play a significant role in agricultural production, that has not come to be. So at first sight one could conclude that this technology has, to a large extent, failed. On the contrary, it is believed that it has succeeded beyond our original expectations, and we are now at what is perhaps the most exciting time in the development and implementation of these technologies. The original goals, however, have drastically changed and it is now biomedical applications that are playing a central role in pushing both technical and scientific developments. The combination of advances in somatic cell nuclear transfer, the development of induced pluripotent stem cells and the completion of the sequencing of most livestock genomes ensures a bright and exciting future for this field, not only in livestock but also in companion animal species.Reproduction Fertility and Development 01/2011; 23(1):56-63. · 2.58 Impact Factor