Asagi K, Oka T, Arao K, Suzuki I, Thakur M K, Izumi K, Natori Y
Department of Nutrition, University of Tokushima School of Medicine, Kuramoto, Japan.
Nephron. 1998;79(1):80-90. doi: 10.1159/000044996.
We have recently reported the presence of a novel perchloric acid soluble protein in rat liver (PSP1) that inhibits cell-free protein synthesis in a rabbit reticulocyte system. While studying the perchloric acid soluble proteins from different tissues of rats, we found that the kidney protein cross-reacted with antibody against the PSP1. In this investigation, we have purified a perchloric acid soluble protein from the rat kidney and studied its characterization and expression. The protein extracted from the postmitochondrial supernatant fraction with 5% perchloric acid was purified by ammonium sulfate fractionation and CM-Sephadex chromatography. By immunoscreening with the rabbit antisera against the PSP1, we detected a cDNA that contained an open reading frame of 411 bp, encoding a 137 amino-acid protein with a molecular mass of 14,149 daltons. The deduced amino acid sequence was completely identical with that of PSP1 from rat liver. The perchloric acid soluble protein from rat kidney (K-PSP1) also inhibited cell-free protein synthesis in the rabbit reticulocyte lysate system in a different manner than RNase A. Immunohistochemistry showed that the expression of K-PSP1 increased from fetal 17th day to postnatal 4th week, and it remained almost the same until the 7th week of postnatal age. Furthermore, the expression of K-PSP1 in the kidney of the nephrotic rat model was shown to be differentiation dependent. On the other hand, the expression of K-PSP1 in renal tumor cells was downregulated as compared with intact tissue. These results suggest that the expression of K-PSP1 is regulated in a differentiation-dependent manner in the kidney.
我们最近报道了大鼠肝脏中一种新型的高氯酸可溶性蛋白（PSP1），它在兔网织红细胞系统中抑制无细胞蛋白质合成。在研究大鼠不同组织的高氯酸可溶性蛋白时，我们发现肾脏蛋白与抗PSP1抗体发生交叉反应。在本研究中，我们从大鼠肾脏中纯化了一种高氯酸可溶性蛋白，并对其特性和表达进行了研究。用5%高氯酸从线粒体后上清液组分中提取的蛋白，通过硫酸铵分级分离和CM-葡聚糖凝胶层析进行纯化。通过用抗PSP1的兔抗血清进行免疫筛选，我们检测到一个包含411 bp开放阅读框的cDNA，编码一个分子量为14,149道尔顿的137个氨基酸的蛋白。推导的氨基酸序列与大鼠肝脏中的PSP1完全相同。大鼠肾脏中的高氯酸可溶性蛋白（K-PSP1）在兔网织红细胞裂解液系统中也以不同于核糖核酸酶A的方式抑制无细胞蛋白质合成。免疫组织化学显示，K-PSP1的表达从胎儿第17天到出生后第4周增加，并且在出生后第7周之前几乎保持不变。此外，肾病大鼠模型肾脏中K-PSP1的表达显示出分化依赖性。另一方面，与完整组织相比，肾肿瘤细胞中K-PSP1的表达下调。这些结果表明，K-PSP1在肾脏中的表达以分化依赖性方式受到调节。
