From essential to beneficial: glycoprotein D loses importance for replication of bovine herpesvirus 1 in cell culture

• Published in: Journal of Virology Vol. 71; no. 1; pp. 25 - 33
• Main Authors: Schroder, C. (Federal Research Centre for Virus Diseases of Animals , Insel Riens, Germany.), Linde, G, Fehler, F, Keil, G.M
• Format: Journal Article
• Language: English
• Published: United States American Society for Microbiology 01.01.1997
• Subjects: Animals; BOVIN; Cattle; Cell Line; COMPOSICION QUIMICA; COMPOSITION CHIMIQUE; CULTIVO DE CELULAS; CULTURE DE CELLULE; GANADO BOVINO; Gene Deletion; Genetic Variation; GLICOPROTEINAS; GLYCOPROTEINE; Herpesvirus 1, Bovine - isolation & purification; Herpesvirus 1, Bovine - metabolism; Herpesvirus 1, Bovine - physiology; HERPESVIRUS BOVIN; HERPESVIRUS BOVINO; INFECCION; INFECTION; MUTANT; MUTANTES; Open Reading Frames; Point Mutation; RECOMBINACION; RECOMBINAISON; REIN; RINONES; Viral Proteins - genetics; Viral Proteins - metabolism; Virus Replication
• ISSN: 0022-538X; 1098-5514
• DOI: 10.1128/jvi.71.1.25-33.1997

Glycoprotein D (gD) of bovine herpesvirus 1 (BHV-1) teas been shown to be an essential component of virions involved in virus entry. gD expression in infected cells is also required for direct cell-to-cell spread. Therefore, BHV-1 gD functions are identical in these aspects to those of herpes simplex virus 1 (HSV-1) gD. In contrast, the gD homolog of pseudorabies virus (PrV), although essential for penetration, is not necessary for direct cell-to-cell spread. Cocultivation of cells infected with phenotypically gD-complemented gD-mutant BHV-1/80-221 with noncomplementing cells resulted in the isolation of the cell-to-cell-spreading gD-negative mutant ctcs+BHV-1/80-221, which was present in the gD-null BHV-1 stocks. ctcs+BHV-1/80-221 could be propagated only by mixing infected with uninfected cells, and virions released into the culture medium were noninfectious. Marker rescue experiments revealed that a single point mutation in the first position of codon 450 of the glycoprotein H open reading frame, resulting in a glycine-to-tryptophan exchange, enabled complementation of the gD function for cell-to-cell spread. After about 40 continuous passages of ctcs+BHV-1/80-221-infected cells with noninfected cells, the plaque morphology in the cultures started to change from roundish to comet shaped. Cells from such plaques produced infectious gD- virus, named gD-infBHV-1, which entered cells much more slowly than wild-type BHV-1. In contrast, integration of the gD gene into the genomes of gD-infBHV-1 and ctcs+BHV-1/80-221 resulted in recombinants with accelerated penetration in comparison to wild-type virions. In summary, our results demonstrate that under selective conditions, the function of BHV-1 gD for direct cell-to-cell spread and entry into cells can be compensated for by mutations in other viral (glyco)proteins, leading to the hypothesis that gD is involved in formation of penetration-mediating complexes in the viral envelope of which gH is a component