Murakumo Y, Ide H, Itoh H, Tomita M, Kobayashi T, Maruyama H, Horii Y, Nawa Y
Department of Parasitology, Miyazaki Medical College, Japan.
Biochem J. 1995 Aug 1;309 ( Pt 3)(Pt 3):921-6. doi: 10.1042/bj3090921.
By using the combination of reverse-transcription PCR and rapid amplification of cDNA ends methods, a cDNA encoding mast cell tryptase was successfully cloned from the small intestine of Mongolian gerbil, Meriones unguiculatus, infected with Nippostrongylus brasiliensis. The cDNA was 1219 bp long including 810 bp of an open reading frame. Based on the deduced amino acid sequences of known mast cell tryptases of other species, the gerbil mast cell tryptase (gMCT) was highly similar to mouse mast cell protease (mMCP)-7, and seems to be translated as a prepro-enzyme with 25 amino acids of signal and activation peptides and 245 amino acids of mature enzyme. The gMCT mRNA was preferentially transcribed in the intestinal mucosa and to a far lesser extent in the connective tissue such as skin and tongue. Moreover, kinetic study after infection revealed that the amount of gMCT mRNA in the small intestine correlated well with the degree of intestinal mastocytosis. Throughout the course of infection, enzyme-histochemically detectable tryptase activity was limited to mucosal mast cells. Since mucosal mast cells of other rodents, including mice and rats, do not express tryptases, this is the first report of rodent mast cell tryptase expressed in the intestinal mucosa.
通过结合逆转录聚合酶链反应和cDNA末端快速扩增方法，成功地从感染巴西日圆线虫的长爪沙鼠小肠中克隆出编码肥大细胞类胰蛋白酶的cDNA。该cDNA长1219 bp，包含一个810 bp的开放阅读框。根据其他物种已知肥大细胞类胰蛋白酶的推导氨基酸序列，沙鼠肥大细胞类胰蛋白酶（gMCT）与小鼠肥大细胞蛋白酶（mMCP）-7高度相似，似乎被翻译为一种前体酶原，带有25个氨基酸的信号肽和激活肽以及245个氨基酸的成熟酶。gMCT mRNA优先在肠黏膜中转录，在皮肤和舌头等结缔组织中的转录程度要低得多。此外，感染后的动力学研究表明，小肠中gMCT mRNA的量与肠道肥大细胞增多症的程度密切相关。在整个感染过程中，酶组织化学可检测到的类胰蛋白酶活性仅限于黏膜肥大细胞。由于包括小鼠和大鼠在内的其他啮齿动物的黏膜肥大细胞不表达类胰蛋白酶，这是关于啮齿动物肥大细胞类胰蛋白酶在肠黏膜中表达的首次报道。
