GENE REGULATION OF HUMAN LEUKOCYTE RECEPTOR CD11/CD18

CD 11/CD 18（白细胞粘附分子LFA- 1，CR 3和p150，95）是一种免疫调节剂， 三种表面膜糖蛋白异二聚体家族， 在白细胞粘附功能中起重要作用。每一个α亚单位 CD 11与一个共同的β亚基（CD 18）非共价连接。这些 糖蛋白是异二聚体受体大家族的成员 （整合素）介导特定的细胞-细胞和细胞-基质相互作用， 其包括人血小板gplIb/IIIa和纤连蛋白受体， 位置特异性抗原。CD 11/CD 18复合物介导 关键的白色血细胞功能（例如趋化性，吞噬作用， 与内皮细胞的聚集和粘附以及跨内皮细胞的迁移）。 体外和体内。几种疾病状态，先天性或获得性， 以这些基因产物的异常表达为特征。继承 缺乏这些糖蛋白的表面表达倾向于 威胁人类生命的细菌感染。表达不足 中央淋巴瘤表面的这些粘附分子可能有助于 他们的白血病转变以及他们逃避免疫 监视 另一方面，CD 11/CD 18的表面表达增加 一方面，如在糖尿病患者的单核细胞或粒细胞中所见， 血液透析可能分别有助于血管和血液动力学 和肺部并发症。此外，某些 结构和发育特征使研究基因调控的 CD 11/CD 18高度相关。高同源性CD 11基因的表达 以组织和细胞特异性方式发生，并对 分化和环境刺激。非同源的CD 18基因是 伴随着相同的刺激，导致独特的， 同源CD 11亚基的细胞特异性表达，从而提供 一个研究顺式和反式作用元件协同进化的理想系统 结构上不相关的基因。我们建议分析结构， 定位控制组织特异性的顺式作用遗传元件， CD 11b和CD 18基因的可诱导表达。基因结构将是 通过限制性酶切图谱和DNA测序来阐明。顺式 将通过基因转移鉴定调控基因元件， 定点诱变。 阐明这些组织的结构 基因及其转录调控机制的研究 应该有助于理解遗传性疾病的发病机制， CD 11/CD 18缺陷和细胞粘附改变的分子基础 其他常见疾病。这些研究也将为一些人提供战斗。 参与组织特异性和诱导性表达的机制 在不同但功能相关的基因分化期间， 将为进一步研究奠定基础，以确定负责的 因素生成的数据还应允许比较 整合素相关基因的进化、调控和功能 家人

CD11/CD18 (leukocyte adhesion molecules LFA- 1, CR3 and p150,95) is a family of three surface membrane glycoprotein heterodimers which serves crucial roles in leukocyte adhesion functions. Each of the alpha subunits (CD11) is noncovalently linked to a common beta subunit (CD18). These glycoproteins are members of a larger family of heterodimeric receptors (Integrins) mediating specific cell-cell & cell-matrix interactions, which include human platelet gplIb/IIIa and fibronectin receptors and position-specific antigens in Drosophila. CDll/CD18 complex mediates crucial white blood cell functions (e.g. chemotaxis, phagocytosis, aggregation & adhesion to and migration across endothelial cells) both in vitro and in vivo. Several disease states, congenital or acquired, are characterized by abnormal expression of these gene products. Inherited lack of surface expression of these glycoproteins predisposes to life-threatening bacterial infections in humans. Deficient expression of these adhesion molecules on the surface of cent lymphomas may contribute to their leukemic transition as well as their escape from immune surveillance. Increased surface expression of CD11/CD18 on the other hand, as seen in diabetic monocytes or granulocytes from patients during hemodialysis may contribute respectively to the vascular and hemodynamic and pulmonary complications of these diseases. In addition, certain structural and developmental features make studies of gene regulation of CD11/CD18 highly relevant. Expression of the highly homologous CD11 genes occurs in a tissue- and cell-specific manner and responds distinctly to differentiation and environmental stimuli. The nonhomologous CD18 gene is concomitantly expressed by the same stimuli that result in the unique and cell-specific expression of the homologous CD11 subunits thus providing an ideal system for studying coevolution of cis and transacting elements in structurally unrelated genes. We propose to analyze the structure and locate cis-acting genetic elements controlling tissue-specific and inducible expression of CD11b and CD18 genes. Gene structure will be elucidated by restriction mapping and DNA sequencing. Cis-acting regulatory gene elements will be identified by gene transfer and site-directed mutagenesis. Elucidation of the organization of these genes and of the mechanisms involved in their transcriptional regulation should be instrumental in understanding the pathogenesis of inherited CD11/CD18 deficiency and the molecular basis for altered cell adhesion in other common disease states. These studies would also shed fight on some of the mechanisms involved in tissue-specific and inducible expression during differentiation of distinct but functionally related genes and will lay the ground work for further studies to identify the responsible factors. The generated data should also permit comparisons of the evolution, regulation and function of the related genes in the integrin family.