苏州大学医学部基础医学与生物科学学院医学生物化学课件 第14章.pptVIP

基因重组和基因工程 Genetic Recombination and Genetic Engineering 第 一 节DNA的重组 DNA Recombination Holliday模型中，同源重组主要4个关键步骤 ①两个同源染色体DNA排列整齐 ②一个DNA的一条链断裂、并与另一个DNA对应的链连接，形成Holliday中间体 ③通过分支移动产生异源双链DNA ④Holliday中间体切开并修复，形成两个双链重组体DNA，分别为： Recombinant DNA technology has revolutionized the study of the gene. It is a newly technology based on well understanding the theories of gene transfer and recombination. There are three broad classes of recombination events. 1) Homologous recombination is recombination between two DNA molecules of similar sequence, occurring in all cells; occurs during meiosis and mitosis in eukaryotes. 2) Site-specific recombination is a type of genetic recombination that occurs only at specific sequences depending on an enzyme-mediated recognition. 3) Transposition recombination is the movement of a gene or a set of genes from one site in the genome to another. The bacterial gene transfer includes conjugation, transformation and transduction. Conjugation is DNA plasmid transfers from cell to cell by conjunct between cells or flagellum conjunct between bacteria. Transformation is the introduction of an exogenous DNA into a cell, which will acquire a new phenotype. Transduction is the transfer of genetic information from one cell to another by means of a viral vector. Covalent link between different DNA molecular is recombined in the course of conjugation, transformation, transduction and transposition. 第 二 节 重组DNA技术 相关概念 DNA克隆 工具酶 目的基因 基因载体 基本原理 重组DNA技术与医学的关系 DNA cloning: Recombinant DNA technique in which specific cDNAs or fragments of genomic DNA are inserted into a cloning vector, which then is incorporated into cultured host cells (e.g., E. coli cells) and maintained during growth of the host cells; also called gene cloning. （二）工具酶 限制性核酸内切酶 DNA聚合酶Ⅰ 逆转录酶 T4DNA连接酶 碱性磷酸酶 末端转移酶 Taq DNA聚合酶 Restriction enzyme (endonuclease): Any enzyme that recognizes and cleaves a specific short sequence, the restriction site, in double-stranded DNA