title: N-linked glycosylation of GP5 of porcine reproductive and respiratory syndrome virus is critically important for virus replication in vivo.
abstract: It has been proposed that the N-linked glycan addition at certain sites in GP5 of porcine reproductive and respiratory syndrome virus (PRRSV) is important for production of infectious viruses and viral infectivity. However, such specific N-linked glycosylation sites do not exist in some field PRRSV isolates. This implies that the existence of GP5-associated glycan per se is not vital to the virus life cycle. In this study, we found that mutation of individual glycosylation sites at N30, N35, N44, and N51 in GP5 did not affect virus infectivity in cultured cells. However, the mutants carrying multiple mutations at N-linked glycosylation sites in GP5 had significantly reduced virus yields compared with the wild-type (wt) virus. As a result, no viremia and antibody response were detected in piglets that were injected with a mutant without all N-linked glycans in GP5. These results suggest that the N-linked glycosylation of GP5 is critically important for virus replication in vivo. The study also showed that removal of N44-linked glycan from GP5 increased the sensitivity of mutant virus to convalescent-phase serum samples but did not elicit a high-level neutralizing antibody response to wt PRRSV. The results obtained from the present study have made significant contributions to better understanding the importance of glycosylation of GP5 in the biology of PRRSV.
authors: Department of Swine Infectious Diseases, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, China.
authors: Zuzhang
authors: Z
authors: Wei
authors: Tao
authors: T
authors: Lin
authors: Lichang
authors: L
authors: Sun
authors: Yanhua
authors: Y
authors: Li
authors: Xiaoming
authors: X
authors: Wang
authors: Fei
authors: F
authors: Gao
authors: Runxia
authors: R
authors: Liu
authors: Chunyan
authors: C
authors: Chen
authors: Guangzhi
authors: G
authors: Tong
authors: Shishan
authors: S
authors: Yuan
mesh_terms: D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D000818:Animals; D057134:Antibodies, Neutralizing / Q000097:blood; D000914:Antibodies, Viral / Q000097:blood; D001483:Base Sequence; D001665:Binding Sites / Q000235:genetics; D002460:Cell Line; D004279:DNA, Viral / Q000235:genetics; D006031:Glycosylation; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D019318:Porcine Reproductive and Respiratory Syndrome / Q000276:immunology / Q000821:virology; D019316:Porcine respiratory and reproductive syndrome virus / Q000235:genetics / Q000276:immunology / Q000502:physiology*; D013552:Swine; D014759:Viral Envelope Proteins / Q000737:chemistry* / Q000235:genetics / Q000276:immunology / Q000502:physiology*; D014779:Virus Replication / Q000235:genetics / Q000502:physiology
chemical_list: D057134:Antibodies, Neutralizing; D000914:Antibodies, Viral; D004279:DNA, Viral; D014759:Viral Envelope Proteins; C114789:glycoprotein 5, PRRSV