CLONING AND SEQUENCE ANALYSES OF CDNAS FOR INTERFERON-INDUCED AND VIRUS-INDUCED HUMAN MX PROTEINS REVEAL THAT THEY CONTAIN PUTATIVE GUANINE NUCLEOTIDE-BINDING SITES - FUNCTIONAL-STUDY OF THE CORRESPONDING GENE PROMOTER
CLONING AND SEQUENCE ANALYSES OF CDNAS FOR INTERFERON-INDUCED AND VIRUS-INDUCED HUMAN MX PROTEINS REVEAL THAT THEY CONTAIN PUTATIVE GUANINE NUCLEOTIDE-BINDING SITES - FUNCTIONAL-STUDY OF THE CORRESPONDING GENE PROMOTER
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DOI：
10.1128/jvi.64.3.1171-1181.1990
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发表时间：
1990-03-01
影响因子：
5.4
通讯作者：
CONTENT, J
中科院分区：
文献类型：
--
作者：
HORISBERGER, MA;MCMASTER, GK;CONTENT, J
人类蛋白质 p78 在用 1 型干扰素或某些病毒处理的细胞中被诱导和积累。它是参与抵抗流感病毒的小鼠 Mx 蛋白的人类同源物。编码人 p78 的全长 cDNA 克隆被克隆并测序。它含有662个氨基酸的开放阅读框，对应于预测分子量为75,500的多肽，与纯化的天然p78蛋白在十二烷基硫酸钠凝胶上测定的78,000的Mr非常一致。该克隆基因在体外表达，其大小、等电点、抗原决定簇和 NH2 末端序列与天然 p78 蛋白相对应。克隆了第二个 cDNA，其编码 633 个氨基酸的蛋白质，与人 p78 有 63% 同源性。该 p78 蛋白在网织红细胞裂解物中翻译，与 p78 共享抗原决定簇。包含在假定的p78 mRNA帽位点上游的基因启动子区域内的假定的83个碱基对的5'调节区赋予人α干扰素(IFN-α)对猫报道基因的诱导性。 p78蛋白在用IFN-α处理的细胞中积累到高水平。相反，p78相关蛋白没有以可检测的水平表达。用 IFN-α 处理 24 小时后，二倍体细胞中 p78 水平的衰减率。比针对甲型流感病毒水泡性口炎病毒的抗病毒状态的衰减速度慢得多，这表明p78蛋白可能不参与抗病毒机制。此外，我们还发现这些蛋白以及同源小鼠 Mx 蛋白具有三个间距适当的共有元件，这是 GTP 结合蛋白的特征。
The human protein p78 is induced and accumulated in cells treated with type 1 interferon or with some viruses. It is the human homolog of the mouse Mx protein involved in resistance to influenze virus. A full-length cDNA clone encoding the human p78 was cloned and sequenced. It contained an open reading frame of 662 amino acids, corresponding to a polypeptide with a predicted molecular weight of 75,500, in good agreement with the Mr of 78,000 determined on sodium dodecyl sulfate gels for the purified natural p78 protein. The clone gene was expressed in vitro and corresponded in size, pI, antigenic determinant(s), and NH2 terminius sequence to the natural p78 protein. A second cDNA was cloned which encoded a 633-amino-acid protein sharing 63% homology with human p78. This p78-protein was translated in reticulocyte lysates where it shared an antigenic determinant(s) with p78. A putative 5'' regulatory region of 83 base pairs contained within the gene promoter region upstream of the presumed p78 mRNA cap site conferred human alpah interferon (IFN-.alpha.) inducibility to the cat reporter gene. The p78 protein accumulated to high levels in cells treated with IFN-.alpha.. In contrast, the p78-related protein was not expressed at detectable levels. The rate of decay of p78 levels in diploid cells after a 24-h treatment with IFN-.alpha. was much slower than the rate of decay of the antiviral state against influenza A virus vesicular stomatitis virus, suggesting that the p78 protein is probably not involved in an antiviral mechanism. Furthermore, we showed that these proteins, as well as the homologous mouse Mx protein, possess three consensus elements in proper spacing, characteristic of GTP-binding proteins.