FACTORS AFFECTING SOMATIC MUTATION--FOCUS ON THE BRAIN

我们和其他人的工作强烈表明， 而不是环境中的外源诱变剂介导大多数生殖系 突变。内源性过程也可能产生大多数突变 与某些类型的癌症有关。然而，非分裂细胞，如 像神经元一样，不容易患上癌症。是否自发的躯体 突变对这些组织有什么重要影响吗长期 该项目的目的是测试细胞死亡的假设， 增加的自发体细胞突变是 使用新开发的转基因小鼠治疗神经退行性疾病 突变检测系统（Big Blue（TM））。大蓝老鼠携带E.杆菌 λ噬菌体序列内的lacI基因，其整合到 小鼠基因组。lacI基因的突变可以从小鼠中分离出来 基因组DNA与λ包装提取物一起孵育， E.杆菌使lacI基因突变产生蓝色斑块 可以被分离和分析。有了这个系统， 大脑五个区域的模式将被确定并进行比较 其他体细胞和生殖细胞的突变频率和模式 组织中该项目的具体目标是： 1)确定组织/细胞类型、性别、年龄或有丝分裂活动是否影响 小鼠的突变模式。 2)确定大脑的不同区域是否有不同的模式， 突变 3)确定具有以下缺陷的转基因小鼠的突变模式： DNA修复 4)确定转基因小鼠中的突变模式， 突变的和正常的超氧化物歧化酶1。 5)确定噬菌体整合位点和啮齿动物物种对 突变的模式

Our work and that of others strongly suggests that endogenous processes rather than exogenous mutagens in the environment mediate most germline mutations. Endogenous processes may also produce most of the mutations associated with certain types of cancer. However, non-dividing cells such as neurons, are no susceptible to cancer. Does spontaneous somatic mutation have any important consequences in these tissues? The long-term objective of this project is to test the hypothesis that cell death due to increased-spontaneous somatic mutation is an important substrate for neurodegenerative disorders by using a newly developed transgenic mouse mutation detection system (Big Blue (TM)). Big Blue mice carry the E. coli lacI gene within a lambda phage sequence which is integrated into the mouse genome. Mutations in the lacI gene can be isolated from mouse genomic DNA by incubation with lambda packaging extract and infection of E. coli. Mutations that inactivate the lacI gene produce blue plaques which can be isolated and analyzed. With this system, mutation frequencies and patterns will be determined for five regions of the brain and compared wi mutation frequencies and patterns of other somatic and germline tissues. The specific aims of the project are: 1) Determine if tissue/cell type, gender, age, or mitotic activity affect the pattern of mutation in mouse. 2) Determine if different regions of the brain have different patterns of mutation. 3) Determine the pattern of mutation in transgenic mice with defects in DNA repair. 4) Determine the pattern of mutation in transgenic mice with overexpressed mutated and norma superoxide dismutase 1. 5)Determine the effects of phage integration site and rodent species on the pattern of mutation.