Production Of Human Lysozme Gene-Targeting Cells For Nuclear Transfer

Gene targeting, also known as gene knock-out and knock-in, carrying the foreign genes by homologous recombination vectorduring cells mitosis. The site-specific aimed gene gets integration into the genome of target cells, and under certain conditions, present the expression . Gene targeting technology is a modified organisms genetic information fixed-point techniques, it is based on technology of embryonic stem cell and homologous recombination , and promote the further development of related disciplines. Gene targeting will be widely used in gene function, development of animal models of human diseases and the economic improvement of animal genetic material and so on .Transgenic breeding for disease resistance technology is based on animal embryo manipulation techniques and transgenic technology, disease genes by knockout or knock resistance gene, so that animals were obtained the characteristics of esistance to certain drugs. In this experiment, human lysozyme gene targeting vector, based on the human lysozyme gene site-specific integration into bovine ?-casein protein in the second exon, and then genetically modified cells as nuclear donor cells by nuclear transfer experiments to produce transgenic cows with human lysozyme gene. When lactating , the expression of human lysozyme are followed by milk secreting to make the cows get disease-fighting properties.Gene targeted primary cells for nuclear transfer shows a higher effectiveness of production transgene animal than pronuclear injection in ruminant, but the primary cells is a challenge to be subjected to the drug selection followed by transfection,especially for transcriptionally silent gene as the targeted gene. Therefore few reports are present about the transcriptionally silent gene-targeting event in livestock. Here we successfully establish a transcriptionally silent gene-targeting procedure that human lysozyme gene was knocked in the bovineβ-casein gene and production of the trasgenic cells for nuclear transfer. So this study gives a new strategy for production of transcriptionally silent gene-targeting cells for nuclear transfer.