REGULATION OF TRYPTASE EXPRESSION IN MAST CELLS

小鼠肥大细胞（MC）表达三种同源的胰蛋白酶（命名为mMCP-6、mMCP-7和mMCP-11），其基因聚集在染色体17上。mMCP-6和mMCP-7协同作用，差异性地调节中性粒细胞和嗜酸性粒细胞向炎症部位的外渗。在MC介导的炎症反应期间，mMCP还在组织中的凝块形成和纤维蛋白原/整合素依赖性细胞应答的调节中起重要作用。由于它们在先天性和适应性免疫中的重要性，MC胰蛋白酶在许多水平上受到调节。然而，转录和转录后机制似乎是MC控制它们表达的胰蛋白酶的主要方式。最近在过敏和哮喘患者血液中鉴定出含有大量类胰蛋白酶的细胞表明，迫切需要了解这些蛋白酶在正常和病理情况下是如何调节的。因此，项目1的长期目标是了解MC如何在分子水平上控制编码同源但功能不同的类胰蛋白酶的转录本的稳态水平。具体目标1的目标是阐明为什么类胰蛋白酶基因是成簇的基因聚集在17号染色体上。在这些研究中，将评估基因甲基化和组蛋白活化在类胰蛋白酶表达中的作用。具体目标2的目标是确定三种类胰蛋白酶基因的转录是如何差异调节的。在这些研究中，将确定调节每个基因转录的顺式作用元件和反式作用因子。将确定控制元件是否调节培养基因的基因座。具体目标3的目标是了解MC用于控制的两种非常不同的转录后机制。细胞中功能性和非功能性转录物的稳态水平。在这些研究中，将鉴定三种类胰蛋白酶转录物中的顺式作用元件和MC中的反式作用RNA结合蛋白，它们共同控制每种类胰蛋白酶转录物的稳定性。

Mouse mast cells (MC) express three homologous tryptases (designated mMCP-6, mMCP-7, and mMCP-11), whose genes are clustered on chromosome 17. mMCP-6 and mMCP-7 work in concert to differentially regulated the extravasation of neutrophils and eosinophils into inflammatory sites. mMCP also plays an important role in the regulation of clot formation and fibrinogen/integrin-dependent cellular responses in tissue during MC-mediated inflammatory reactions. Because of their importance in innate and adaptive immunity, MC tryptases are regulated at a number of levels. Nevertheless, transcriptional and post-transcriptional mechanisms appear to be the major ways MC control which tryptases they express. The recent identification of cells that contain substantial amounts of tryptase in the blood of patients with allergy and asthma indicates the urgent need contain substantial amounts of tryptase in the blood of patients with allergy and asthma indicates the urgent need to understand how these proteases are regulated in normal and pathologic circumstances. Thus, the long-term objective of Project 1 is to understand the molecular level how MC control the steady-state levels of the transcripts that encode homologous, but functionally distinct, tryptases. The goal of Specific Aim 1 is to elucidate why the tryptase genes are clustered genes are clustered on chromosome 17. In these studies, the role of gene methylation and histone activation in tryptase expression will be evaluated. The goal of Specific Aim 2 is to determine how transcription of the three tryptase genes is differentially regulated. In these studies, the cis-acting elements and trans-acting factors that regulate the transcription of each gene will be identified. Whether or not a locus a control element regulates of the cultured genes will be determined. The goal of Specific Aim 3 is to understand the two very different post-transcription mechanisms the MC uses to control. the steady-state levels of functional and non-functional transcripts in cells. In these studies, the cis-acting elements in the three tryptase transcripts and the trans-acting RNA-binding proteins in the MC that work together to control the stability of each tryptase transcript will be identified.