小干涉RNA递送方法的研究

发布时间：2018-09-04 18:22

【摘要】：RNAi 是指同源双链 RNA 所引发的特异序列的转录后基因沉默现象。哺乳动物细胞中,小于 30bp 的小双链 RNA 可以避开干扰素反应并在哺乳动物细胞内引发基因沉默。在功能基因组研究、药物靶点筛选、病毒防治、肿瘤治疗等研究领域中,RNAi 都是一种非常有用的基因敲除方法,具有广泛的应用前景。现有的在真核细胞中的 RNAi 技术可以分为两大类:⑴ 通过各种方法在体外制备小干涉 RNA(small interfering RNA,siRNA)后直接将其递送到真核细胞中。 ⑵ 将表达产物在细胞内自发形成 siRNA 的 DNA 表达框递送到真核细胞中。而所有这些方法的实现都依赖于建立一种核酸递送系统,即一种能够有效包裹和传递外源的遗传物质进入特定类型细胞的高效、低毒的载体系统。核酸递送载体系统可以被分为生物载体(主要是指病毒载体)和非生物载体两大类。病毒载体有着感染细胞的天性,有一整套将自己的基因导入靶细胞的步骤。然而制备与生产的困难、细胞毒性、免疫原性以及包装外源基因的大小限制是病毒载体应用面对的主要障碍。非病毒类核酸递送系统往往是在生理条件下带正电荷的化合物,包括阳离子多聚物,阳离子脂质体等。它们通过电荷相互作用与阴性负荷的核酸相互作用并通过内吞作用进入到细胞内。它不需要面对病毒类载体的种种不利,制备简便,没有免疫原性。但是它们导入外源基因的效率远低于病毒类载体,如何提高效率和稳定性,保证安全性一直是研究关注的重点。
[Abstract]:RNAi refers to posttranscriptional gene silencing of specific sequences induced by homologous double stranded RNA. In mammalian cells, small double-stranded RNA smaller than 30bp can avoid interferon reaction and induce gene silencing in mammalian cells. RNAi is a very useful gene knockout method in the fields of functional genome research, drug target screening, virus prevention and treatment, tumor therapy and so on. The existing RNAi techniques in eukaryotic cells can be divided into two categories: 1: 1 is delivered directly to eukaryotic cells by a variety of methods to prepare small interfering RNA (small interfering RNA,siRNA in vitro. 2 the expressed products are spontaneously formed in the cells The DNA expression box of siRNA was delivered to eukaryotic cells. The realization of all these methods depends on the establishment of a nucleic acid delivery system, that is, a highly efficient and low toxic carrier system that can effectively encapsulate and transmit exogenous genetic material into specific types of cells. Nucleic acid delivery vector systems can be divided into biological carriers (mainly refers to virus vectors) and abiotic carriers. Viral vectors have the nature of infecting cells and a set of steps to transfer their genes to target cells. However, the difficulties of preparation and production, cytotoxicity, immunogenicity and the size limitation of packaging foreign genes are the main obstacles in the application of virus vectors. Non-viral nucleic acid delivery systems are often positive charge compounds under physiological conditions, including cationic polymers, cationic liposomes and so on. They interact with negative-loaded nucleic acids through charge interactions and enter the cell through endocytosis. It does not need to face the various disadvantages of viral vectors, easy to prepare, no immunogenicity. However, the efficiency of introducing foreign genes is much lower than that of virus-like vectors, so how to improve the efficiency and stability and ensure the safety has always been the focus of research.
【学位授予单位】：重庆医科大学
【学位级别】：博士
【学位授予年份】：2005
【分类号】：Q78

【共引文献】