Post-transcriptional Control of Immunoglobulin Expression

免疫球蛋白（Ig）重链基因转录终止和RNA加工的调控将在B细胞发育过程中进行研究。这项研究的长期目标是更好地理解控制这些事件的一般机制，并确定B细胞成熟过程中发生的发育调节变化的基础。前体RNA形成(s和(m) mRNA的调控替代加工不需要任何Ig基因特异性序列。相反，该基因的重要特征是它包含竞争性剪接和切割-聚腺苷酸化反应的信号。因此，参与这两个过程的一般因子的数量或活性必须在B细胞成熟过程中改变。与浆细胞相比，通过分析B细胞在缺乏poly(a)位点时的剪接选择，可以确定剪接是否在B细胞成熟过程中受到调节。一个体外剪接/聚腺苷酸化系统，将模仿在体内（基因特征）将被检查。成功地建立一个体外系统来研究其调控将为许多未来的实验提供基础。我们将检测已知的一般RNA加工调节因子在B细胞和浆细胞中的表达，以确定可能介导这种调节的因素；在B细胞和/或浆细胞中的过表达将进一步研究任何表达与加工变化相关的基因。这些实验结合起来，将提供一个更完整的RNA加工调控的图像，并应该开始识别在B细胞成熟过程中发生改变的反式作用RNA加工成分。为了研究转录终止及其调控，将稳定导入浆细胞和B细胞系的完整和修饰基因的转录通过核运行实验进行分析，以确定其终止区域。基因修饰将被设计来确定两个聚(A)位点、聚(A)位点强度和终止区域内的下游序列对整个终止过程的贡献。本研究通过比较单一细胞类型中的正常基因和修饰基因，将提供关于终止的一般过程的信息，并通过比较B细胞和浆细胞中的修饰基因，将研究这一过程中调控变化的基础。免疫球蛋白（Ig）重链基因的转录终止和RNA加工将在B细胞发育过程中进行检测。这项研究的长期目标是更好地理解控制这些事件的一般机制，并确定B细胞成熟过程中发生的发育调节变化的基础。＊＊＊

9507513 Peterson Regulated transcriptional termination and RNA processing of the immunoglobulin (Ig) heavy chain ( gene will be examined during B cell development. The long-term goal of this research is to better understand the general mechanisms governing these events as well as to determine the basis for the developmentally regulated changes that occur during B cell maturation. The regulated alternative processing of a ( precursor RNA to form (s and (m mRNA does not require any Ig gene-specific sequences. Instead, the important feature of this gene is that it contains signals for competing splice and cleavage-polyadenylation reactions. Thus, the amount or activity of a general factor(s) involved in these two processes must be altered during B cell maturation. It will be determined whether splicing is regulated during B cell maturation by analyzing alternative splice choices made in the absence of a poly(A) site in B cells as compared to plasma cells. An in vitro splicing/polyadenylation system that will mimic in vivo ( gene characteristics will be examined. Successfully establishing an in vitro system to study ( regulation would provide the basis for many future experiments. The expression of the known general RNA processing regulators in B cells and plasma cells will be examined to identify factors that potentially mediate the regulation; any whose expression correlates with ( processing changes will be studied further by over-expression in B cells and/or plasma cells. These experiments, taken together, will provide a more complete picture of ( processing regulation and should begin to identify the trans-acting RNA processing components that are altered during B cell maturation. To investigate transcriptional termination and its regulation, the transcription of intact and modified ( genes, stably introduced into plasma cell and B cell lines, will be analyzed by nuclear run-on experiments to identify their termination regions. Gene modifications will be designed to determine the contributio n that the two ( poly(A) sites, the poly(A) site strength, and the downstream sequences within the termination region make to the overall termination process. This study, by comparing normal and modified genes in a single cell type will provide information about the general process of termination and, by comparing the modified genes in both B cells and plasma cells, will examine the basis for regulatory changes in this process. %%% Regulated transcriptional termination and RNA processing of the immunoglobulin (Ig) heavy chain ( gene will be examined during B cell development. The long-term goal of this research is to better understand the general mechanisms governing these events as well as to determine the basis for the developmentally regulated changes that occur during B cell maturation. ***