BRONCHIAL SECRETIONS: PHYSICAL & CHEMICAL STUDIES

粘蛋白糖蛋白（粘蛋白），粘膜层的主要成分 保护和润滑哺乳动物的呼吸道， 上皮细胞排列在管腔和粘膜下腺体中。 这些细胞 在慢性阻塞性肺疾病中， 疾病 关于引发或引发的机制或因素知之甚少。 调节化生和增生，尽管最近 提出粘蛋白基因转录的起始是由 大鼠气道中的浆液细胞是导致杯状的主要事件， 粘液细胞化生和分泌过多（1）。 目前的证据 表明几种粘蛋白基因在气道中表达， 肠子 我们推测，特定的粘蛋白质是更多的 在气道疾病中高度表达（可能通过特定的气道细胞） 气道粘蛋白基因家族的不同成员 为特定的糖基转移酶提供独特的底物。 我们研究计划的长期目标是阐明 健康和疾病中的气道粘蛋白。 我们最近发现 并鉴定了一个编码TBM的cDNA克隆， 气管支气管粘蛋白似乎是气道特异性的。 具体 本提案的目的是：[1]识别和描述全长 编码TBM的cDNA克隆，并描述相似性和差异 与其他粘蛋白联系起来。 [2]阐明 粘蛋白基因的细胞和组织特异性 和北方印迹分析，并确定是否表达 特定的粘蛋白基因在气道疾病中受到影响。 [3]分离和 表征用于TBM的基因组DNA。 编码TBM的cDNA克隆 将用于探测基因组文库。 TBM基因组克隆将被 通过染色体定位、限制性酶切图谱、S1图谱 和外显子/内含子边界的序列分析。[4]到 研究TBM基因的表达和调控。 我们将 确定TBM基因的转录活性。 如果事实证明 转录活性，基因组克隆的启动子序列 将研究目标[3]中确定的监管要素， 启动子缺失构建体。

Mucin glycoproteins (mucins), the major components of the mucosal layer that protects and lubricates mammalian airways, are secreted by epithelial cells lining the lumen and submucosal glands. These cells and glands exhibit hyperplasia in chronic obstructive pulmonary diseases. Little is known about the mechanism or factors initiating or regulating metaplasia and hyperplasia, although it has recently been proposed that initiation of transcription of mucin protein genes by serous cells in rat airways is a primary event leading to goblet and mucous cell metaplasia and hypersecretion (1). Current evidence indicates that several mucin genes are expressed both in the airways and intestine. We speculate that the specific mucin proteins are more highly expressed in airway diseases (perhaps by specific airway cells) and that different members of the airway mucin protein gene family provide unique substrates for specific glycosyltransferases. The long term objective of our research program is to elucidate the role of airway mucins in health and in diseases. We have recently identified and characterized a cDNA clone that encodes TBM, a human tracheobronchial mucin that appears to be airway-specific. The specific aims of this proposal are: [1] To identify and characterize full length cDNA clones encoding TBM and to delineate similarities and differences to other mucins as such information becomes available. [2] To elucidate the cell and tissue specificity of mucin genes by in situ hybridization and Northern blot analysis and determine whether the expression of specific mucin genes is affected in airway diseases. [3] To isolate and characterize genomic DNA for TBM. The cDNA clone that encodes for TBM will be used to probe genomic libraries. TBM genomic clones will be characterized by chromosomal location, restriction mapping, S1 mapping, and by sequence analysis of the exon/intron boundaries. [4] To investigate expression and regulation of the TBM gene. We will determine the transcriptional activity of the TBM gene. Should it prove transcriptionally active, the promoter sequences of the genomic clones identified in aim [3] will be studied for regulatory elements using promoter deletion constructs.