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. ***
