GENETIC COMPLEXITY OF HLA CLASS II GENE REGULATION

人类主要组织相容性复合体II类基因的调控 表达是本提案中调查的主要焦点。 HLA II类抗原是一个多态性表面糖蛋白家族 主要在B淋巴细胞、巨噬细胞和活化的T细胞上表达。 这些抗原是识别外来或改变的 免疫系统的物质。 因此，研究这些调节 基因对于理解控制免疫系统的机制很重要 反应，更普遍地说，那些控制真核基因 表情 所提出的实验是以前工作的继续 表征源自HLA的B细胞系中的缺陷表达 II类阴性先天性免疫缺陷（以前称为裸淋巴细胞 综合征，BLS）患者。 使用插入诱变的策略， 逆转录病毒产生新的HLA II类阴性突变体的概述。 这种方法的目标是来自亲本的细胞系 BLS患者 因为家庭研究和早期的分析 实验室表明BLS是一种常染色体隐性遗传缺陷， 假设亲本细胞只包含一个完整的和功能性的 一个特定的调控基因的拷贝。 因此，前病毒的整合 野生型调节基因内或附近基因组应该影响其 表达和/或功能，导致较低或缺乏II类 表达允许选择突变细胞。联动 前病毒与假定的调节基因的结合将允许分离 基因组序列 随后，这些侧翼区域内的外显子 鉴定并用于分离cDNA克隆。 表征及 cDNA克隆的表达应该揭示了 这些调控基因。 除了促进对基本监管机制的理解外， 在免疫反应中，鉴定突变的调节基因 应该导致基因治疗和BLS患者的长期利益。 可能更重要的是对调控基因的分析 在自身免疫性疾病患者中， II类基因是经常发现的。此外， 在许多人类恶性肿瘤中的表达可能是通过调节 我们定义的基因可能是肿瘤进展的重要因素。 了解HLA II类调节基因的结构和功能 应该提供新的策略来改变HLA II类表达， 影响疾病的发展。

Regulation of HLA (human major histocompatibility complex) class II gene expression is the primary focus of investigation in this proposal. HLA Class II antigens are a family of polymorphic surface glycoproteins expressed primarily on B lymphocytes, macrophages, and activated T cells. These antigens are required for the recognition of foreign or altered substances by the immune system. Thus, study of the regulation of these genes is important in understanding the mechanisms that control an immune response and more generally, those that control eukaryotic gene expression. The proposed experiments are a continuation of previous work characterizing defective expression in B cell lines derived from HLA Class II negative congenital immunodeficiency (formerly Bare Lymphocyte Syndrome, BLS) patients. A strategy using insertional mutagenesis with retroviruses to generate new HLA class II negative mutants is outlined. The targets in this approach will be cell lines derived from the parents of BLS patients. Because family studies and earlier analyses from this laboratory indicate that BLS is an autosomal recessive defect, it is assumed that the parental cells contain only one intact and functional copy of a particular regulatory gene. Thus, integration of a proviral genome within or near that wild type regulatory gene should affect its expression and/or function, resulting in lower or absent class II expression allowing selection of the mutant cells. Linkage of the provirus to the putative regulatory gene will allow the isolation of genomic sequences. Subsequently, exons within these flanking regions identified and used to isolate cDNA clones. Characterization and expression of the cDNA clones should reveal clues to the function of these regulatory genes. In addition to promoting the understanding of basic regulatory mechanisms in the immune response, the identification of mutant regulatory genes should lead to gene therapy and long term benefit for BLS patients. Potentially even more important, will be an analysis of regulatory genes in patients with autoimmune diseases in which aberrant expression of HLA class II genes is often found. Furthermore, activation of HLA class II expression in many human malignancies perhaps through the regulatory genes we define may be a significant factor in tumor progression. Understanding the structure and function of HLA class II regulatory genes should provide new strategies to alter HLA class II expression and influence the development of disease.