chap five gene transfer课件.pptVIP

Chapter 5 transfer the aim gene into the receptor cell Section one receptor cell 受体细胞：可摄取外源DNA并使其稳定维持的细胞，具有应用价值或理论价值。 又称宿主细胞或寄主细胞， The qualification for the cell to be receptor cell： It is Easy to be transferred with recombination DNA. The recombination DNA can exist in the cell stably. Easy to select the recombinant(重组体)。 Genetic characters of the cells are stable,the cells can be cultured easily. safe，without pathogenicity,could not pollute the environment. Without proteinase or it’s content is very low, so the protein expressed from the foreign gene can accumulate 遗传密码的应用无明显偏奇性。 有较好的转译后加工机制（真核基因）。 在理论和实践上有较高的价值。 一、procaryote cell 1、advantages of using procaryote cell as receptor cell： procaryote cells have no cell wall which consist of firm cellulose, so the foreign DNA can be transferred easily There is no nuclear membrane, chromosome DNA do not combine with protein, so the foreign DNA can recombine with chromosome DNA easily. . In procaryote cells, the genome is simple without mitochondria（线粒体） and plastid(质体) genome, it is easy to analyze the genetic characters of the foreign gene. Procaryote is a kind of single cell organism, it is easy to form consistent cell group, the cell grows quickly，the experiment can be repeated in a short time. 2、 disadvantages of using procaryote cell as receptor cell ： Without the protein folding system of eukaryote cell，many genes from eukaryote can not form special structure after gene expression Without the protein modification system, the protein can not be glycosylated and phosphorylated(糖基化、磷酸化). The proteinase in E.coli. can hydrolyze the protein which structure is not correct, so the protein expressed is not stable. 3、E.coli. 大肠杆菌 研究最多，应用最广。 优点：繁殖快，培养简单，代谢易于控制。 缺点：有内毒素 4、hay bacillus 枯草杆菌 优势： 基因表达产物可高效分泌到培养基中，简化蛋白的提取和加工。 真核生物的重组蛋白被分泌后便具有天然构象和生物活性。 无内毒素，安全。 同样具有大肠杆菌的优点。 二、fungi cell 真菌是低等真核生物，具有转录后加工和翻译后蛋白修饰功能 Microzyme(酵母菌) is usually used as receptor cell, it is a kind of single cell fungi and can propagate asexually