《细胞分化与基因表达调控》.ppt

Cell differentiation and Cancer cells Cell differentiation Cell differentiation occurs in multicellular organisms 2. Why a fertilized egg can develop into different cells: Gene differentiated express 4. House-keeping genes and luxury genes 5. Transdifferentiation: From one type of cell into another type Cell totipotency (细胞全能性) 1. Plant cells 2. Animal cloning— Stem cell and its differentiation potential 1. What is a stem cell ? 2. Where to get the stem cells? 3. Types of stem cells: differentiation potential 4.Why do researchers study stem cells ? 5. Stem cell plasticity Cancer:  Cells proliferate uncontrollably 1. The biology characteristics of cancer 2. The causes of cancer 3. Caner: As a result of the accumulation of mutation and natural selection (1) Proto-oncogens: Gain-of-function mutations (2) Tumor suppressor genes: Loss-of-function mutations Remember, you are only an expert from things done in the past. There are no experts from things that will happen in the future. Dr. Folkman (5) Lose Contact inhibition in vitro Carcinogenic chemicals and UV DNA and RNA tumor viruses Alter the genome SV40, Adenovirus HIV Benign tumor Malignant tumor Normal cell Cancer-inducing mutation genes Proto-oncogenes Tumor-suppressor genes ?癌基因（oncogenes）：v-onc and c-onc 抑癌基因（tumor-suppressor gene）Rb p53 特 点 原癌基因 抑癌基因 基因属性 细胞增殖必需 细胞分化必需 致癌方式 基因突变激活、异常表达 基因缺失或失活 Rous(1910)发现鸡的致癌RNA病毒； 1963年发现RSV突变株： tsRSV 鸡成纤维细胞 40C 37C 细胞正常 病毒正常繁殖 细胞癌变 病毒正常繁殖 tdRSV 鸡成纤维细胞 40C 37C 细胞正常 细胞正常 病毒正常繁殖 病毒正常繁殖 v-oncogene tdRSV3’端缺失1500－2000bp; 不影响病毒复制，但影响细胞转化 1976年发现，正常鸡细胞核DNA中，具有与V-onc的同源序列，称正常细胞中的同源序列为原癌基因（protooncogene）,或C-oncogene. v-onc和c-onc的关系：c-onc来自v-onc. 理由如下: 1、v-onc对病毒复制和生存都是不必要的；而c-onc对细胞重要功能和活动不可缺少；提示c-onc是进化中保存下来的细胞重要结构元件。 2、发现的30种c-onc是依靠病毒的v-onc探针找到的；并不是所有c-onc都有对应的同源v-onc。 3、v-sr