Transgenic Goats Produced by Germ Cell Transplantation

描述（由申请人提供）：本提案的目的是优化用于生产转基因山羊的雄性生殖细胞转染和移植方法。转基因山羊奶是一种安全、丰富、成本效益高的重组人生物药物生产来源。GTC Biotherapeutics（原Genzyme Transgenics Corp.）有将近二十几个商业转基因项目正在开发中。然而，即使是用于产生转基因创始者（第一代）山羊的最先进的方法仍然相对低效和昂贵。 已经在啮齿动物中开发了用于将遗传修饰的雄性生殖细胞移植到受体雄性中并使这些动物交配以产生转基因后代的方法。一个类似的系统在猪身上取得了一些早期的成功，初步研究表明它在山羊身上也是可行的。 现在我们建议：1）优化富集供体生殖细胞制备物的方法; 2）优化体外将转基因构建体转染到这些供体细胞中的方法;和3）证实山羊中的同源生殖细胞移植导致产生携带转基因的形态正常的活动精子。如果这种方法成功，它将提高效率并降低产生创始动物的成本，这是转基因生产过程中关键的早期步骤。

DESCRIPTION (provided by applicant): The objective of this proposal is to optimize methods of male germ cell transfection and transplantation for use in producing transgenic goats. The milk of transgenic goats is a safe, abundant and cost effective production source for recombinant human biopharmaceuticals. GTC Biotherapeutics (formerly Genzyme Transgenics Corp.) has nearly two dozen commercial transgenic programs in development. However, even state-of-the-art methods for generating transgenic founder (first generation) goats remain relatively inefficient and expensive. Methods have been developed in rodents for transplanting genetically modified male germ cells into recipient males and mating these animals to produce transgenic offspring. A similar system has shown some early success in pigs, and preliminary studies suggest that it may be feasible in goats. Now we propose to: 1) optimize methods of enriching donor germ cell preparations; 2) optimize methods of transfecting transgene constructs into these donor cells in vitro; and 3) confirm that homologous germ cell transplantation in goats results in the production of morphologically normal, motile sperm carrying the transgene. If this approach is successful, it will increase the efficiency and reduce the cost of generating founder animals, which is a critical early step in the transgenic production process.