SOMATIC MUTATION OF AN ANTIBODY TRANSGENE

抗体转基因的体细胞突变

• 批准号: 2382590
• 负责人: ERIK SELSING
• 金额: $ 16.28万
• 依托单位: TUFTS UNIVERSITY BOSTON
• 依托单位国家: 美国
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-08-01 至 2000-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2382590
• 关键词: B lymphocyte; antibody formation; gene conversion; gene rearrangement; hybridomas; immunoglobulin genes; laboratory mouse; polymerase chain reaction; tissue /cell culture; transfection

During B Cell differentiation, antibody genes are diversified by a number of distinct mechanisms. At early stages of B-cell development, V(D)J recombination leads to an enormous diversity of lg V-region sequences among individual maturing B cells. During later, antigen-dependent, stages of B cell differentiation, another mechanisms, somatic hypermutation, gives rise to additional antibody diversity. Somatic hypermutation appears to be central in allowing the body to produce high-affinity antibody responses to protect against pathogens. On the other hand, somatic hypermutation has also been implicated in aberrantly activating oncogenes involved in tumorigenesis, and, in some B-cell leukemias, somatic hypermutation is apparently ongoing, leasing to tumor cell variations that can defeat therapies based on anti- idiotypic reagents. Very little is known about the molecular mechanisms that are involved in the somatic hypermutational process. We have recently found that sequence transfers which resemble gene conversion events can occur within a murine antibody H-chain transgene and that these sequence transfers correlate with the somatic hypermutation process. We now believe that gene conversion mechanisms could be a part of the somatic hypermutational mechanism. During the proposed project period, we wish to investigate the targeting and mechanism of transgene sequence transfers and determine the types of B cells that undergo sequence transfer events. We will also further investigate the relationships between the sequence transfer and somatic hypermutation processes. The goals of the current proposal are (1) to determine whether transgene sequence transfers occur by gene conversion or DNA recombination, (2) to investigate the effect of spacing on the frequency of transgene conversion between VDJ segments, (3) to localize and characterize those B cells which have undergone transgene conversion and investigate the correlation of transgene conversion and somatic hypermutation, and (4) to investigate sequence transfer among antibody V(D)J segments within the endogenous murine lgH locus. We expect that these studies will indicate whether gene conversion might have a role in the diversification of normal antibody genes and whether gene conversion is involved in the currently uncharacterized mechanism of somatic hypermutation. We hope that a more thorough understanding of the hypermutational process could lead to more effective approaches to treatment of some B cell cancers and to a fuller understanding of some steps of tumorigenesis.

在 B 细胞分化过程中，抗体基因通过以下方式多样化： 一些不同的机制。 B细胞的早期阶段 V(D)J 重组导致巨大的多样性 各个成熟B细胞之间的lg V区序列。 在后来的抗原依赖性 B 细胞分化阶段， 另一种机制，体细胞超突变，会产生额外的 抗体多样性。体细胞超突变似乎是其中的核心 允许身体产生高亲和力抗体反应 预防病原体。 另一方面，躯体 超突变也与异常激活有关 癌基因参与肿瘤发生，并且在某些 B 细胞中 白血病，体细胞超突变显然正在进行中，租赁给 肿瘤细胞变异可以击败基于抗的治疗 独特型试剂。 人们对分子的了解甚少 参与体细胞超突变的机制 过程。 我们最近发现序列转移 类似的基因转换事件可能发生在小鼠体内 抗体 H 链转基因以及这些序列转移 与体细胞超突变过程相关。 我们现在相信 基因转换机制可能是体细胞的一部分 超突变机制。 在拟议的项目期间， 我们希望研究转基因的靶向和机制 序列转移并确定经历的 B 细胞类型 序列传输事件。 我们还将进一步调查 序列转移与体细胞的关系 超突变过程。 当前提案的目标是 (1) 确定基因是否发生转基因序列转移 转换或 DNA 重组，(2) 研究效果 VDJ 之间转基因转化频率的间隔 片段，(3) 定位和表征那些具有 进行转基因转化并研究相关性 转基因转化和体细胞超突变，以及（4） 研究抗体 V(D)J 片段之间的序列转移 内源性小鼠lgH基因座内。 我们期望这些 研究将表明基因转换是否可能在 正常抗体基因的多样化以及是否基因 转换涉及目前未知的机制 体细胞超突变。 我们希望能够更彻底地 对超突变过程的理解可能会导致更多 治疗某些 B 细胞癌的有效方法 更全面地了解肿瘤发生的某些步骤。