REARRANGEMENT AND REGULATION OF IMMUNOGLOBULIN GENES

免疫球蛋白基因表达需要重排和轻重排 B细胞发育过程中的链基因片段，带来启动子 元素进入增强子元素的附近。这件事的重点是 建议继续研究控制免疫球蛋白基因重排的事件 并且在B细胞个体发育早期表达，在小鼠和人类中都是如此。这 包括调节生殖系转录的元件的特征 以及它们在靶向基因片段中的潜在作用 重新编排。Kappa内含子和3‘端的发育激活 增强剂将通过转基因小鼠研究进行检验。具体的角色 内含子增强子的作用将通过检查 A-MuLV转化的正常重排细胞系中的增强子缺失 Kappa基因，以及用于产生转基因小鼠的ES细胞。这个 组成kappa内含子的结构和功能成分 将通过定义序列和蛋白质-DNA相互作用来研究增强子 在模型细胞中有助于转录激活和抑制的基因 文化体系。这包括克隆一种新颖的、可诱导的因子 绑定增强器中的区域，以及定义 所有序列主题的空间排列，有助于完整 增强剂活性。位于核心内含子增强子两侧并起作用的序列 作为增强剂活性的消音器，将被描述为。许多这样的 研究将包括直接比较老鼠和人类的增强剂 组织和职能。最后，一项正在进行的合作研究将是 维持对T细胞依赖、重链增强子介导的研究 抑制小鼠杂交瘤中IgE的表达。

Immunoglobulin gene expression requires rearrangement of heavy and light chain gene segments during B cell development, that brings promoter elements into the proximity of enhancer elements. The focus of this proposal is to continue to study events that control Ig gene rearrangement and expression early in B cell ontogeny, in both mouse and human. This includes characterization of elements which regulate germline transcription of the kappa locus, and their potential role in targeting gene segments for rearrangement. The developmental activation of the kappa intron and 3' enhancers will be examined by transgenic mouse studies. The specific role of the intron enhancer will be determined by examining the effects of enhancer deletion in A-MuLV transformed cell lines that normally rearrange kappa genes, and ES cells used to generate genetically altered mice. The structural and functional components that comprise the kappa intron enhancer will be studied by defining sequences and protein-DNA interactions that contribute to transcriptional activation and suppression in model cell culture systems. This includes cloning a novel, inducible factor that binds a region in the enhancer, as well as defining requirements for spatial arrangements of all the sequence motifs that contribute to full enhancer activity. Sequences that flank the core intron enhancer and act as silencers of enhancer activity will be characterized. A number of these studies will involve direct comparisons of mouse and human enhancer organization and function. Finally, an ongoing collaborative study will be maintained to study the T cell dependent, heavy chain enhancer-mediated suppression of IgE expression in murine hybridomas.