ACCESSORY CELL ACTIVATION OF THE IMMUNE RESPONSE

免疫反应的辅助细胞激活

• 批准号: 6633088
• 负责人: PHILIP E AURON
• 金额: $ 20.7万
• 依托单位: UNIVERSITY OF PITTSBURGH AT PITTSBURGH
• 依托单位国家: 美国
• 财政年份: 1995
• 资助国家: 美国
• 起止时间: 1995-08-25 至 2005-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6633088
• 关键词: antigen presenting cell; cell differentiation; cytomegalovirus; gene induction /repression; gene mutation; genetic enhancer element; genetic promoter element; human T cell lymphotropic virus type 1; interleukin 1; interleukin 6; leukocyte activation /transformation; lipopolysaccharides; molecular cloning; monocyte; simian virus 40; tissue /cell culture; transcription factor

Monocytes express at least two different classes of cell-type specific genes. One class, exemplified gy the M-CSF receptor gene, c-fms, is constitutively expressed and dependent upon the differentiated state. Another class, represented by the IL-1beta gene (il1b), is also generally monocyte-specific, but is only expressed immediately in response to a stimulation event that parallels the conversion of the resting monocyte to the activated monocyte/macrophage. Investigation of the il1b regulation mechanisms have revealed two distinct and separable regions of the gene that correspond to each of the two criteria, a cell type specific 143bp basal promoter and a signal-responsive upstream enhancer. The enhancer function depends upon the cooperative function of several broadly expressed signal-responsive transcription factors (e.g., C/EBPbeta, CREB, c-Jun, and NF- kappaB), including a novel STAT-like factor, whereas the 71 bp basal promoter appears to depend upon binding of one molecule of the mono-myeloid factor Spi-1/PU.1 (Spi-1), a factor that plays a central key role in monocyte development and cell type-specific gene expression. The functional interaction between the basal promoter and an enhancer requires a critical additional 73bp element that requires the binding of an additional Spi-1 molecule. This element is not required for enhancer-independent activity in the presence of IE2, a cytomegalovirus protein. IE2 appears to interact directly with the Spi-1 ETS domain. This region is found in all ETS proteins and mediates associations with a broad range of other proteins, modulating function in both partners. The object of this proposal is to elucidate the mechanism by which Spi-1 interacts with other proteins and integrates enhancer function into the core promoter and to attempt to clone the novel STAT-like factor that is activated in response to LPS, IL-1, and IL-6.

单核细胞表达至少两种不同类别的细胞类型特异性基因。 一类，例如M-CSF受体基因c-fms，是组成型表达的并且依赖于分化状态。 另一类以 IL-1beta 基因 (il1b) 为代表，通常也是单核细胞特异性的，但仅在响应刺激事件时立即表达，该刺激事件与静息单核细胞转化为激活的单核细胞/巨噬细胞平行。 对 il1b 调节机制的研究揭示了该基因的两个不同且可分离的区域，分别对应于两个标准：细胞类型特异性 143bp 基础启动子和信号响应上游增强子。 增强子功能取决于几种广泛表达的信号响应转录因子（例如 C/EBPbeta、CREB、c-Jun 和 NF-kappaB）的协同功能，包括一种新型 STAT 样因子，而 71 bp 基础启动子似乎取决于单髓细胞因子 Spi-1/PU.1 (Spi-1) 的一个分子的结合，该因子在 在单核细胞发育和细胞类型特异性基因表达中发挥核心作用。 基础启动子和增强子之间的功能相互作用需要一个关键的额外 73bp 元件，该元件需要结合额外的 Spi-1 分子。 在巨细胞病毒蛋白 IE2 存在的情况下，该元件不是增强子依赖性活性所必需的。 IE2 似乎直接与 Spi-1 ETS 域交互。 该区域存在于所有 ETS 蛋白中，并介导与多种其他蛋白的关联，调节双方的功能。 本提案的目的是阐明 Spi-1 与其他蛋白质相互作用并将增强子功能整合到核心启动子中的机制，并尝试克隆响应 LPS、IL-1 和 IL-6 而激活的新型 STAT 样因子。