Substitution 3A protein of foot-and-mouth disease virus of attenuated ZB strain rescued the viral replication and infection in bovine cells

Abstract The non-structural protein 3A of foot-and-mouth disease virus (FMDV) plays an important role in viral replication, virulence and determination of host range. Previously we identified genomic changes in gene encoding 3A protein between the attenuated ZBatt strain and its parental virulent strain during the attenuation process. However, the effects of changes in 3A protein on viral replication and infection of the rabbit-attenuated ZBatt virus during the attenuation process are poorly understood. In this study, a chimeric virus, rZBatt-3A, was constructed by introducing the 3A gene of virulent ZB virus into its attenuated vaccine ZB strain. Subsequently, the biological characteristics between rZBatt-3A and its parental virus (rZBatt) were compared. The relative expression level of four host cell proteins that interact with FMDV 3A were also analyzed. The results showed that the chimeric virus rZBatt-3A exhibited significantly different growth properties and plaque phenotypes from rZBatt in primary fetal bovine kidney (BK) cells. Cytopathic effect (CPE) of the rZBatt-3A was observed in BK cells with smaller plaque size, but CPE from the rZBatt could not be observed. The viral RNA replication was higher in rZBatt-3A-infected BK cells than in rZBatt-infected cells at 24 hpi (P