@article{mbs:/content/journal/jgv/10.1099/vir.0.81160-0, author = "Lee, Changhee and Yoo, Dongwan", title = "Cysteine residues of the porcine reproductive and respiratory syndrome virus small envelope protein are non-essential for virus infectivity", journal= "Journal of General Virology", year = "2005", volume = "86", number = "11", pages = "3091-3096", doi = "https://doi.org/10.1099/vir.0.81160-0", url = "https://www.microbiologyresearch.org/content/journal/jgv/10.1099/vir.0.81160-0", publisher = "Microbiology Society", issn = "1465-2099", type = "Journal Article", abstract = "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.", }