Kotani K, Kuroiwa A, Saito T, Matsuda Y, Koda T, Kijimoto-Ochiai S
Division of Molecular Immunology, Institute for Genetic Medicine, Hokkaido University, Kita-15 Nishi-7, Kitaku, Sapporo, 060-0815, Japan.
Biochem Biophys Res Commun. 2001 Aug 17;286(2):250-8. doi: 10.1006/bbrc.2001.5374.
We have totally sequenced a cytosolic sialidase [EC 3.2.1.18] by RT-PCR from the murine thymus (murine thymic sialidase, MTS) which has a 1844-base length (encoding 385 amino acids including two sialidase motifs) and is the longest cytosolic sialidase ever reported. MTS has high and relatively low homologies with those of mammalian cytosolic sialidases from the mouse brain (99%), rat (91%), and human skeletal muscle (75%), and those of the mouse lysosomal (47%) and membrane-bound (51%) sialidases, respectively. Chromosomal mapping, being the first report of mouse cytosolic sialidase gene, showed that the MTS gene is localized to the distal part of mouse chromosome 1D and to rat chromosome 9q36. RT-PCR with the site-specific primers revealed that the coding region was expressed in all organs tested, but expressions including the 5'-UTR were barely detectable except for in the upper-thymic fraction. Also, soluble sialidase activity in the thymus was the highest of these organs. There were mRNA instability signals and AT-rich regions in 143 bp of MTS 5'-end.
我们通过逆转录聚合酶链反应（RT-PCR）从鼠胸腺中对一种胞质唾液酸酶[EC 3.2.1.18]进行了全序列分析（鼠胸腺唾液酸酶，MTS），该酶长度为1844个碱基（编码385个氨基酸，包括两个唾液酸酶基序），是迄今报道的最长的胞质唾液酸酶。MTS与来自小鼠脑（99%）、大鼠（91%）和人类骨骼肌（75%）的哺乳动物胞质唾液酸酶，以及与小鼠溶酶体（47%）和膜结合（51%）唾液酸酶的同源性分别较高和较低。染色体定位是小鼠胞质唾液酸酶基因的首次报道，结果显示MTS基因定位于小鼠染色体1D的远端和大鼠染色体9q36。用位点特异性引物进行的RT-PCR显示，编码区在所有测试器官中均有表达，但除胸腺上部组分外，包括5'-非翻译区（5'-UTR）在内的表达几乎检测不到。此外，胸腺中的可溶性唾液酸酶活性在这些器官中是最高的。MTS 5'-端的143 bp中有mRNA不稳定信号和富含AT的区域。
