FUNCTION AND EXPRESSION OF LYB 2/CD72

LyB-2是一种B淋巴细胞系特异性的细胞表面糖蛋白 在早期B细胞前体上表达直至成熟B细胞阶段。 在终末分化为浆细胞时表达丧失。 LYB-2 似乎在B细胞增殖和活化中起重要作用， 并且可以是淋巴因子或生长因子的受体。 的主要目标 该项目将确定参与的分子机制， 调节Lyb-2的表达，并进一步探讨 蛋白质。 Lyb-2蛋白的结构会更好 通过B细胞和转染子的免疫沉淀研究表征。 将产生一组对Lyb-2特异的单克隆抗体， 将检测它们对B细胞的功能作用。 结构和 将确定该基因的序列。 表达的水平 该基因在不同的细胞类型和B的不同阶段受到调节 细胞发育将被检查，并涉及分子机制 Lyb-2表达的谱系和阶段特异性将被 测定 这些研究将开始于组织培养细胞， 来自Lyb-2基因的正确表达所必需的序列 (i.e.,与Lyb-2蛋白和mRNA表达模式相同）。 将确定转染细胞中的报告基因。 潜在 调控区域也将通过分析基因来确定， 表达Lyb-2的细胞中DNA酶超敏位点的差异， 相比之下，没有细胞。 识别序列的重要性将 通过位点特异性诱变证实。 Lyb-2监管将是 在转基因小鼠中检测。 这些研究的目的是确定 使用其自身的Lyb-2正确表达所必需的序列 控制序列，以及不适当表达的后果， 蛋白质是由使用其他基因的控制区而产生的，例如 免疫球蛋白、T细胞受体和β-肌动蛋白。 例如将 使用免疫球蛋白在B谱系细胞中持续表达LyB-2 启动子和增强子，导致缺乏或适当的B细胞分化， 抗体分泌细胞 这种持续的表达是否会导致B细胞 肿瘤？ 类似地，如果Lyb-2是生长因子或淋巴因子受体， 在T细胞或其他不合适的细胞上的表达是否会导致肿瘤 由于持续的增长刺激，？ 这些研究应 增强我们对B细胞正常调控机制的理解 增殖和分化以及这些细胞中的异常， 在B细胞肿瘤和自身免疫性疾病中观察到的途径。

Lyb-2 is a B lymphocyte lineage-specific cell surface glycoprotein expressed on early B cell precursors through the stage of mature B cells. Expression is lost upon terminal differentiation into plasma cells. Lyb-2 appears to play an important role in B cell proliferation and activation, and may be a receptor for a lymphokine or growth factor. The major goal of this project will be to define the molecular mechanisms involved in the regulation of expression of Lyb-2 and to further explore the function of the protein. The structure of the Lyb-2 protein will be better characterized by immunoprecipitation studies of B cells and transfectants. A panel of monoclonal antibodies specific for Lyb-2 will be generated and their functional effects upon B cells will be examined. The structure and sequence of he gene will be determined. The level at which expression of the gene is regulated in different cell types and at different stages of B cell development will be examined, and the molecular mechanisms involved int he lineage and stage specificity of expression Lyb-2 will be determined. These studies will begin in tissue culture cells, where the sequence from the Lyb-2 gene that are necessary for proper expression (i.e., the same pattern of expression as Lyb-2 protein and mRNA) of a reporter gene in transfected cells will be determined. Potential regulatory regions will also be identified by analyzing the gene for differences in DNAse hypersensitive sites in cells that express Lyb-2 as compared to cells that do not. The importance of identified sequences will be confirmed by site-specific mutagenesis. Lyb-2 regulation will then be examined in transgenic mice. The aim of these studies is to determine both the sequences necessary for proper expression of Lyb-2 using its own control sequences, and the consequences of inappropriate expression of the protein resulting from use of control regions of other genes, such as immunoglobulins, T cell receptor and beta-actin. For example, will continued expression of Lyb-2 in B lineage cells, using an immunoglobulin promoter and enhancer, lead to lack or proper B cell differentiation in to antibody-secreting cells? Will such continued expression lead to B cell tumors? Similarly, if Lyb-2 is a growth factor or lymphokine receptor, will expression on T cells or other inappropriate cells lead to tumor development because of continued growth stimulation? These studies should enhance our understanding of the normal mechanisms of control of B cell proliferation and differentiation as well as the abnormalities in these pathways that are observed in B cell neoplastic and autoimmune diseases.