Infectious bronchitis virus E protein is targeted to the Golgi complex and directs release of virus-like particles
Infectious bronchitis virus E protein is targeted to the Golgi complex and directs release of virus-like particles
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DOI：
10.1128/jvi.74.9.4319-4326.2000
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发表时间：
2000-05-01
影响因子：
5.4
通讯作者：
Machamer, CE
中科院分区：
文献类型：
--
作者：
Corse, E;Machamer, CE
冠状病毒E蛋白是一种特征不明确的小包膜蛋白，在病毒体中以低水平存在。我们感兴趣的是E在传染性支气管炎病毒（IBV）膜蛋白的细胞内靶向的作用。我们制备了IBV E蛋白的cDNA克隆和E蛋白的抗体，以研究其在无病毒感染的情况下的细胞生物学特性。结果表明，IBVE是一个完整的膜蛋白，抗原表位特异性抗体显示，IBVE的C端位于胞质，N端移位。IBVE的短腔N端含有一个N-糖基化的共有位点，但该位点未被利用。当使用重组牛痘病毒表达时，IBV E蛋白以低水平从细胞中释放出来，形成可沉降颗粒，其密度与冠状病毒粒子的密度相似。当存在时，IBV M蛋白被掺入这些颗粒中。间接免疫荧光显微镜显示E定位于瞬时表达IBV E的细胞中的高尔基复合体，当与IBV M共表达时，无论是从cDNA还是在IBV感染中，这两种蛋白质都共定位于高尔基膜，靠近冠状病毒出芽位点。因此，尽管IBVE在病毒体中以低水平存在，但在病毒装配位点附近的感染细胞中显然以高水平表达。
The coronavirus E protein is a poorly characterized small envelope protein present in low levels in virions. We are interested in the role of E in the intracellular targeting of infectious bronchitis virus (IBV) membrane proteins. We generated a cDNA clone of IBV E and antibodies to the E protein to study its cell biological properties in the absence of virus infection. We show that IBV E is an integral membrane protein when expressed in cells from cDNA, Epitope-specific antibodies revealed that the C terminus of IBV E is cytoplasmic and the N terminus is translocated, The short luminal N terminus of IBV E contains a consensus site for N-linked glycosylation, but the site is not used. When expressed using recombinant vaccinia virus, the IBV E protein is released from cells at low levels in sedimentable particles that have a density similar to that of coronavirus virions. The IBV M protein is incorporated into these particles when present. Indirect immunofluorescence microscopy showed that E is localized to the Golgi complex in cells transiently expressing IBV E, When coexpressed with IBV M, both from cDNA and in IBV infection, the two proteins are colocalized in Golgi membranes, near the coronavirus budding site. Thus, even though IBV E is present at low levels in virions, it is apparently expressed at high levels in infected cells near the site of virus assembly.