Cysteine residues of the porcine reproductive and respiratory syndrome virus small envelope protein are non-essential for virus infectivity
Cysteine residues of the porcine reproductive and respiratory syndrome virus small envelope protein are non-essential for virus infectivity
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DOI：
10.1099/vir.0.81160-0
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发表时间：
2005-11-01
影响因子：
3.8
通讯作者：
Yoo, D
中科院分区：
文献类型：
--
作者：
Lee, C;Yoo, D
猪繁殖与呼吸综合征病毒(PRRSV)开放阅读框(ORF)2a含有一个小的内部ORF(2b)，编码一个73aa的蛋白质，称为E蛋白。E蛋白的功能目前尚不清楚。E蛋白在49和54位有两个半胱氨酸，这两个半胱氨酸在北美分离株中高度保守。本研究表明，E蛋白既不与自身同源二聚，也不与核衣壳(N)蛋白异源二聚。然而，Pull-down分析表明，E蛋白与自身或与N蛋白非共价相互作用。用感染性克隆测定E蛋白半胱氨酸残基对病毒复制的意义。每个半胱氨酸都被丝氨酸取代，突变被引入PRRSV的全长克隆中。将半胱氨酸突变克隆导入MARC-145细胞后，均能诱导PRRSV特异性细胞病变，并产生感染性子代病毒。这些数据表明，E蛋白中的半胱氨酸残基对北美型PRRSV的复制不是必需的。
Porcine reproductive and respiratory syndrome virus (PRRSV) open reading frame (ORF) 2a contains a small internal ORF (2b) capable of encoding a protein of 73 aa, termed E protein. The function of E protein is currently unknown. The E protein possesses two cysteines at positions 49 and 54 that are highly conserved among North American isolates. In the present study, it was shown that E protein did not homodimerize with itself nor did it heterodimerize with the nucleocapsid (N) protein. However, E protein was interactive non-covalently with itself or with the N protein as shown by pull-down assays. The significance of the E protein cysteine residues on virus replication was determined using an infectious clone. Each cysteine was substituted by serine and the mutations were introduced into a full-length clone of PRRSV. When transfected into Marc-145 cells, all cysteine mutant clones induced PRRSV-specific cytopathic effects and produced infectious progeny virus. The data indicate that cysteine residues in the E protein are not essential for replication of North American genotype PRRSV.