title: Porcine reproductive and respiratory syndrome virus ORF5a protein is essential for virus viability.
abstract: It has been shown that ORF5a protein in EAV is important but not essential for virus infectivity. In this study, we found that RNA changes in the overlapping region (1-104 nucleotide, nt) between ORF5 and ORF5a introduced by codon-optimized GP5 was lethal for virus viability, suggesting that the nt changes or amino acid (aa) mutations in the GP5 or ORF5a protein did not permit the production of infectious virus. Furthermore, inactivation of ORF5a expression in the context of type 1 (pSHE) and type 2 (pAJXM and pAPRRS) full-length PRRSV cDNA clones was lethal for the production of infectious virus, while viable PRRSV could be recovered by expressing ORF5a protein in trans, suggesting that ORF5a protein was essential for virus viability. Finally, ORF5a protein could be putatively extended to 63 aas by inactivation of the downstream stop codon candidates, thereby demonstrating that the C-terminus of ORF5a may be variable.
authors.affiliation: College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, PR China.
authors.forename: Lichang
authors.initials: L
authors.lastname: Sun
authors.forename: Yanhua
authors.initials: Y
authors.lastname: Li
authors.forename: Runxia
authors.initials: R
authors.lastname: Liu
authors.forename: Xiaomin
authors.initials: X
authors.lastname: Wang
authors.forename: Fei
authors.initials: F
authors.lastname: Gao
authors.forename: Tao
authors.initials: T
authors.lastname: Lin
authors.forename: Ting
authors.initials: T
authors.lastname: Huang
authors.forename: Huochun
authors.initials: H
authors.lastname: Yao
authors.forename: Guangzhi
authors.initials: G
authors.lastname: Tong
authors.forename: Hongjie
authors.initials: H
authors.lastname: Fan
authors.forename: Zuzhang
authors.initials: Z
authors.lastname: Wei
authors.forename: Shishan
authors.initials: S
authors.lastname: Yuan
mesh_terms: D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D003062:Codon; D006224:Cricetinae; D015967:Gene Expression Regulation, Viral; D055786:Gene Knockout Techniques; D023061:Gene Order; D005804:Genes, Lethal; D050296:Microbial Viability / Q000235:genetics*; D008969:Molecular Sequence Data; D009154:Mutation; D019316:Porcine respiratory and reproductive syndrome virus / Q000235:genetics* / Q000378:metabolism; D016415:Sequence Alignment; D014759:Viral Envelope Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism
chemical_list: D003062:Codon; D014759:Viral Envelope Proteins; C114789:glycoprotein 5, PRRSV