RESUMEN
Host factors are required for efficient HIV-1 replication. To identify these factors, genome-wide RNA interference screening was performed using a human T cell line. In the present study, we assessed whether eukaryotic translation initiation factor 4A isoform 2 (eIF4A2), a DEAD-box protein identified in our screen, is necessary for efficient HIV-1 replication. Exploiting MT4C5 cells depleted of eIF4A2 by stable expression of eIF4A2-specific short-hairpin RNA (shRNA) using a lentiviral system, we found that depletion of eIF4A2 markedly inhibited the infection of a replication-competent reporter HIV-1. eIF4A2 depletion reduced the efficiency of viral cDNA synthesis with virion entry into target cells being unaffected. Depletion of eIF4A2 also inhibited HIV-1 spreading infection in a knockdown level-dependent manner. These results suggest that HIV-1 requires eIF4A2 for optimal replication in human T cells.
Asunto(s)
Factor 4A Eucariótico de Iniciación/metabolismo , Infecciones por VIH/enzimología , VIH-1/fisiología , Interacciones Huésped-Patógeno , Replicación Viral , Linfocitos T CD4-Positivos/enzimología , Linfocitos T CD4-Positivos/virología , Línea Celular , ADN Viral/biosíntesis , Factor 4A Eucariótico de Iniciación/química , Factor 4A Eucariótico de Iniciación/deficiencia , Factor 4A Eucariótico de Iniciación/genética , Silenciador del Gen , Infecciones por VIH/virología , Humanos , ARN Interferente Pequeño/genéticaRESUMEN
Infectious bursal disease (IBD) is an acute, highly contagious, and immunosuppressive avian disease caused by IBD virus (IBDV). Although an interaction between eukaryotic translational initiation factor 4AII (eIF4AII) of the host and viral protein 1 (VP1), the RNA-dependent RNA polymerase (RdRp) of IBDV, has been established, the underlying effects of this interaction on IBDV and the molecular mechanism remain unclear. We here report that interaction of the host eIF4AII with VP1 inhibits the RNA polymerase activity of IBDV to reduce its replication in host cells. We found that ectopically expressed eIF4AII markedly inhibited IBDV growth in DF1 cells, and knockdown of eIF4AII by small interfering RNA significantly enhanced viral replication in CEF cells. Furthermore, IBDV infection led to an increase in host eIF4AII expression, suggesting a feedback mechanism between the host and virus infection both in vitro and in vivo, which further confirmed the involvement of the host eIF4AII in the IBDV life cycle. Thus, via the interaction with VP1, eIF4AII plays a critical role in the IBDV life cycle, by inhibiting viral RNA polymerase activity, leading to a reduction of IBDV replication in cells.