Primordial germ cells from chicken embryonic stem cells

描述(申请人提供)：在Origin Treeutics，我们已经获得了鸡胚胎干细胞(CES)，这种细胞可以在培养中保持较长时间，并对嵌合体中的体细胞组织做出广泛贡献，并对生殖系做出低水平的贡献。Origin的目标是利用这些CES细胞创造转基因鸡，在它们的鸡蛋中产生临床相关的药物蛋白。Origin已经建立了稳定转染构建长达160kb的ES细胞的常规程序，并与携带45kb转基因的ES细胞产生了嵌合体，该转基因编码产生人类单抗的重链和轻链成分。这种单抗仅在输卵管的管状腺细胞中表达，并被输出到蛋清中。为了最佳地生产蛋白质，需要完全转基因的鸡，这就需要强大的种系传播。近年来，从人和小鼠的胚胎干细胞中分离出了分化的体细胞。最近，也有来自小鼠胚胎干细胞的卵母细胞和精子。在鸡中，PGCs通过血管系统迁移到性腺。当在适当的时间注射外源PGCs时，可以在受体胚胎的种系中大量定植。为了获得强大的生殖系传播水平，该应用程序建议从胚胎干细胞中提取PGCs，并用体外获得的PGCs在性腺中定植。

DESCRIPTION(provided by applicant): At Origin Therapeutics we have derived chicken embryonic stem cells (cES) that can be maintained in culture for extended periods of time and contribute extensively to the somatic tissues in chimeras and at low levels to the germline. Origin's goal is to use these cES cells to create transgenic chickens producing clinically relevant pharmaceutical proteins in their eggs. Origin has established routine procedures for stable transfection of ES cells with constructs up to 160 kb and has produced chimeras with ES cells carrying a 45 kb transgene that encodes the production of the heavy and light chain components of a human monoclonal antibody. This monoclonal antibody is expressed exclusively in the tubular gland cells of the oviduct and is exported into egg white. For optimal production of proteins fully transgenic chickens are required necessitating robust germline transmission. In recent years differentiated somatic cells have been derived from human and murine ES cells. Most recently oocytes and sperm have also been derived from mouse ES cells. In the chicken PGCs migrate to the gonads through the vasculature. Exogenous PGCs, when injected at the appropriate time, can substantially colonize the germline of recipient embryos. To obtain robust levels of germline transmission this application proposes to derive PGCs from embryonic stem cells and to colonize the gonad with in vitro derived PGCs.