Chang H W, Watson J C, Jacobs B L
Department of Microbiology, Arizona State University, Tempe 85287-2701.
Proc Natl Acad Sci U S A. 1992 Jun 1;89(11):4825-9. doi: 10.1073/pnas.89.11.4825.
A vaccinia virus-encoded double-stranded RNA-binding protein, p25, has been previously implicated in inhibition of the interferon-induced, double-stranded RNA-activated protein kinase. In this study, we have identified the vaccinia viral gene (WR strain) that encodes p25. Amino acid sequence analysis of a chymotryptic fragment of p25 revealed a close match to the vaccinia virus (Copenhagen strain) E3L gene. The WR strain E3L gene was cloned and expressed either in COS-1 cells or in rabbit reticulocyte lysates in vitro. A M(r) 25,000 polypeptide that could bind to poly(rI).poly(rC)-agarose and that reacted with p25-specific antiserum was produced in each case. In addition, COS cells expressing E3L gene products inhibited activation of the double-stranded RNA-activated protein kinase in extracts from interferon-treated cells. Removal of E3L-encoded products by adsorption with anti-p25 antiserum resulted in loss of kinase inhibitory activity. These results demonstrate that the vaccinia virus E3L gene encodes p25 and that the products of the E3L gene have kinase inhibitory activity. Comparison of the deduced amino acid sequence of the E3L gene products with the protein sequence data base revealed a region closely related to the human interferon-induced, double-stranded RNA-activated protein kinase.
一种痘苗病毒编码的双链RNA结合蛋白p25，先前已被证明与抑制干扰素诱导的双链RNA激活蛋白激酶有关。在本研究中，我们鉴定了编码p25的痘苗病毒基因（WR株）。对p25胰凝乳蛋白酶消化片段的氨基酸序列分析显示，它与痘苗病毒（哥本哈根株）E3L基因高度匹配。将WR株E3L基因克隆并在COS-1细胞或兔网织红细胞裂解物中进行体外表达。在每种情况下，都产生了一种分子量为25,000的多肽，它能与聚（rI）·聚（rC）-琼脂糖结合，并与p25特异性抗血清发生反应。此外，表达E3L基因产物的COS细胞抑制了干扰素处理细胞提取物中双链RNA激活蛋白激酶的激活。用抗p25抗血清吸附去除E3L编码产物导致激酶抑制活性丧失。这些结果表明，痘苗病毒E3L基因编码p25，且E3L基因产物具有激酶抑制活性。将E3L基因产物的推导氨基酸序列与蛋白质序列数据库进行比较，发现了一个与人干扰素诱导的双链RNA激活蛋白激酶密切相关的区域。
