The open reading frame 3 of equine arteritis virus encodes an immunogenic glycosylated, integral membrane protein
The open reading frame 3 of equine arteritis virus encodes an immunogenic glycosylated, integral membrane protein
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DOI：
10.1006/viro.1999.9982
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发表时间：
1999-11-10
期刊：
影响因子：
3.7
通讯作者：
MacLachlan, NJ
中科院分区：
文献类型：
--
作者：
Hedges, JF;Balasuriya, UBR;MacLachlan, NJ
马动脉炎病毒（EAV）开放阅读框3（ORF 3）编码一种糖基化膜蛋白（GP 3），但其结构尚不清楚。在体外转录EAV的美国典型培养物保藏中心株的ORF 3，并且在有和没有犬微粒体膜的情况下体外翻译编码的GP 3蛋白。在无犬微粒体膜的体外翻译后，GP 3蛋白约为17 kDa，而在微粒体膜翻译后，糖基化形式为36-42 kDa的弥散带，表明GP 3蛋白广泛糖基化。去糖基化使GP 3蛋白质减少至约17 kDa，与在没有微粒体膜的情况下翻译的大小相同，表明信号序列未被切割。EAV GP 3蛋白是膜相关的，并且不作为可溶性蛋白释放，与其他一些动脉炎病毒的ORF 3编码的蛋白形成鲜明对比。GP 3蛋白在封闭的膜囊泡中受到蛋白酶消化的保护，这表明该蛋白延伸到膜囊泡中并通过N-末端信号序列、C-末端疏水结构域或两者锚定，但不跨越膜三次。缺乏C-末端跨膜结构域的GP 3蛋白保持膜结合，表明该末端不是必需的膜锚。来自持续感染EAV的种马和用经修饰的活EAV疫苗反复免疫的马的血清含有GP 3蛋白的特异性抗体。数据表明，GP 3蛋白是一种广泛糖基化的膜蛋白，在一些EAV感染期间具有免疫原性。(C)北京：科学出版社.
Open reading frame 3 (ORF 3) of equine arteritis virus (EAV) is predicted to encode a glycosylated membrane protein (GP3) that is uncharacterized. ORF 3 of the American Type Culture Collection strain of EAV was in vitro transcribed and the encoded GP3 protein was in vitro translated with and without canine microsomal membranes. The GP3 protein was approximately 17 kDa after in vitro translation without canine microsomal membranes whereas the glycosylated form, after translation with microsomal membranes, was a diffuse band of 36-42 kDa, indicating that the GP3 protein is extensively glycosylated. Deglycosylation reduced the GP3 protein to approximately 17 kDa, the same size as that translated without microsomal membranes, indicating that the signal sequence was not cleaved. The EAV GP3 protein was membrane associated and not released as a soluble protein, in marked contrast to the ORF 3-encoded proteins of some other arteriviruses. The GP3 protein was protected from protease digestion in closed membrane vesicles, suggesting that the protein extends into the membrane vesicles and is anchored by the N-terminal signal sequence, a C-terminal hydrophobic domain, or both, but does not span the membrane three times. A GP3 protein lacking the C-terminal transmembrane domain remained membrane associated, indicating that this terminus is not a necessary membrane anchor. Sera from stallions persistently infected with EAV and horses immunized repeatedly with the modified live EAV vaccine contained antibodies specific for the GP3 protein. The data indicate that the GP3 protein is an extensively glycosylated membrane protein that is immunogenic during some EAV infections. (C) 1999 Academic Press.