Identification of histaminergic fiber in human lung

通过分析从编码功能性HDC的人HDC cDNA克隆（p-TN 2）的核苷酸序列推导的氨基酸序列，确定来自KU-812 F的HDC的一级结构。人HDC具有662个氨基酸（Mr 74，178），并且在氨基酸序列中显示出与大鼠和小鼠HDC序列85%的同源性。通过从HDC mRNA的体外翻译证明了人HDC的74 kDa早熟形式，这表明人HDC是后加工的。KU-817 F表达2.4-kb和3.4-kb HDC mRNA，其从HDC基因选择性剪接。在这些mRNA中，只有2.4-kb的mRNA编码功能性HDC。在包括肺和脑在内的人体组织中，评估了2.4-kb HDC mRNA的表达。HDC基因在正常人肺组织中表达较低或在IPF患者肺组织中不表达，而在支气管哮喘患者肺组织中表达明显增高，提示组胺的过度生成可能参与了支气管哮喘的发病过程。

The primary structure of HDC from KU-812F was determined by the analysis of the amino acid sequence deduced from the nucleotide sequence of the human HDC cDNA clone(p-TN2)encoding functional HDC. Human HDC has 662 amino acids(Mr 74,178)and shows 85% homology in amino acid sequence to the rat and mouse HDC sequences. 74kDa premature form of human HDC was demonstrated by in vitro translation from HDC mRNA,suggesting that human HDC is processed post-translationally. KU-817F expresses 2.4-kb and 3.4-kb HDC mRNA's which are alternatively spliced from the HDC gene. Among these mRNA's,only 2.4-kb mRNA encodes functional HDC.In human tissues including the lung and brain,the expression of 2.4-kb HDC mRNA was evaluated. While HDC gene expression was low in the lungs of normal individual,or not detected in the lungs from the patients with IPF,the HDC mRNA level was markedly increased in the lungs from the patients with bronchial asthma,suggesting that hyperproduction of histamine may be involved in the pathogenesis of bronchial asthma.