GENETIC REGULATION OF LYMPHOID DIFFERENTIATION ANTIGENS

HLA-II类细胞表面分子在细胞凋亡中具有重要作用， 参与免疫反应的相互作用，以及II类特异性等位基因 抗原似乎赋予某些疾病的易感性，可能是通过 因为他们的免疫功能。 HLA II类基因在一个 复杂的方式，组成型表达，诱导表达，或没有 表达，这取决于检查的细胞类型及其阶段。 分化 本申请提出了各种分子和遗传学方法， 研究II类基因调控的方法。 HLA的体细胞杂种 II类表达和非表达以及诱导型细胞类型和突变体 将以各种组合进行，以通过互补分析来定义 II类表达所通过的因子、途径或亚基的数量 调控 实验室的初步证据表明， 是II类基因的反式正调控因子， 转录。该提案的一个主要目的是描述 II类表达的假定调节因子，及其表达的位点和方式， 行动上 将开发用于拟议的交互调节器的测定， 这是一个可以描述的调节器。 低水平的孤立突变体 将研究单个II类基因mRNA的表达，以确定 损伤是转录的。 II类转录缺陷基因和 它们所来源的正常基因将被克隆。 的能力 调节分子与正常和转录缺陷的 将确定突变基因和诱导DNA酶I超敏反应的能力。 具有转录损伤的突变基因的基因组克隆将被 部分测序以绘制受影响的核苷酸位置。 另 本申请的主要目标是克隆编码II类的基因 反式调节子，以确定其基因产物如何运作，并 绘制它结合到HLA II类基因中或周围的序列。

HLA Class II cell surface molecules have important roles in cell interactions involved in immune responses, and specific alleles of Class II antigens appear to confer susceptibility to certain diseases, probably by virtue of their immune functions. HLA Class II genes are regulated in a complex manner, being constitutively expressed, inducibly expressed, or not expressed, depending on the cell type examined and its stage of differentiation. This application proposes various molecular and genetic approaches to study Class II gene regulation. Somatic cell hybrids of HLA Class II expressing and non-expressing and inducible cell types and mutants will be made in various combinations to define by complementation analysis the number of factors, pathways or subunits by which Class II expression is regulation. Preliminary evidence from this laboratory suggests that their is a transactive positive regulator of Class II genes which acts transcriptionally. A major aim of this proposal is to characterize the putative regulator of Class II expression, and its site and mode of action. Assays for the proposed transactive regulator will be developed so that the regulator can be characterized. Isolated mutants with low levels of a single Class II gene mRNA will be studied to determine whether the lesions are transcriptional. Transcription defective Class II genes and the normal genes from which they derived will be cloned. The ability of the regulatory molecule to bind to the normal and transcription-defective mutant genes and to induce DNase I hypersensitivity will be determined. Genomic clones of mutant genes with transcriptional lesions will be partially sequenced to map the affected nucleotide positions. The other major goal of this application is to clone the gene coding for the Class II transactive regulator, to determine how its gene product operates, and to map the sequences it binds in to or around HLA Class II genes.