CHARACTERIZATION OF THE CDNA-ENCODING HUMAN NUCLEOPHOSMIN AND STUDIES OF ITS ROLE IN NORMAL AND ABNORMAL GROWTH
CHARACTERIZATION OF THE CDNA-ENCODING HUMAN NUCLEOPHOSMIN AND STUDIES OF ITS ROLE IN NORMAL AND ABNORMAL GROWTH
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DOI：
10.1021/bi00429a017
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发表时间：
1989-02-07
期刊：
影响因子：
2.9
通讯作者：
CHAN, PK
中科院分区：
文献类型：
--
作者：
CHAN, WY;LIU, QR;CHAN, PK
用抗大鼠核磷蛋白的单抗筛选人胎盘c DNA文库，再用已证实的人核磷蛋白的部分基因作为探针，获得了编码人核磷蛋白(蛋白B23)的c DNA。该基因全长1311bp，编码294个氨基酸的蛋白质。编码的氨基酸序列与大鼠核磷蛋白(共138个氨基酸)的测序结果一致，从而证实了该基因的同源性。该序列最显著的特征是位于分子中间的酸性簇。该簇由26个Asp/Glu和1个Phe和Ala组成。人核磷蛋白与非洲爪哇核仁蛋白N38的序列同源性为64.3%。人核磷蛋白的N端130个氨基酸与非洲爪哇核蛋白的同源性也达到50%。以部分核磷蛋白基因为探针，对大鼠肝总RNA进行Northern杂交分析，均一的mRNA条带大小约为1.6kb。在肥大的大鼠肝脏和Novikoff肝癌中也有类似的观察。然而，与正常大鼠肝脏相比，Novikoff肝癌和肥大大鼠肝脏中的核磷蛋白mRNA的量分别高出50倍和5倍。斑点印迹分析还显示，三种类型的大鼠肝脏中的核磷蛋白mRNA的比例为：5：1。当蛋白质水平与免疫印迹分析比较时，Novikoff肝癌的核磷蛋白含量是正常肝的20倍，而肥大的大鼠肝脏中核磷蛋白的含量仅为正常肝的5倍左右。
A cDNA encoding human nucleophosmin (protein B23) was obtained by screening a human placental cDNA library in .lambda.gtll first with monclonal antibody to rat nucleophosmin and then with confirmed partial cDNA of human nucleophosmin as probes. The cDNA had 1311 bp with a coding sequence encoding a protein of 294 amino acids. The identity of the cDNA was confirmed by the presence of encoded amino acid sequences identical with those determined by sequencing pure rat nucleophosmin (a total of 138 amino acids). The most striking feature of the sequence is an acidic cluster located in the middle of the molecule. The cluster consists of 26 Asp/Glu and 1 Phe and Ala. Comparison of human nucleophosmin and Xenopus nucleolar protein NO38 shows 64.3% sequence identity. The N-terminal 130 amino acids of human nucleophosmin also bear 50% identity with that of Xenopus nucleoplasmin. Northern blot analysis of rat liver total RNA with a partial nucleophosmin cDNA as probe demonstrated a homogeneous mRNA band of about 1.6 kb. Similar observations were made in hypertrophic rat liver and Novikoff hepatoma. However, the quantity of nucleophosmin mRNA is 50- and 5-fold higher in Novikoff hepatoma and hypertrophic rat liver, respectively, when compared with normal rat liver. Dot blot analysis also showed a nucleophosmin mRNA ratio of 64:5:1 in the three types of rat liver. When the protein levels were compared with Western blot immunoassays, Novikoff hepatoma showed 20 times more nucleophosmin, while only about 5 times more nucleophosmin was observed in hypertrophic rat liver than in unstimulated normal liver.