Inhibition of chicken anaemia virus replication using multiple short-hairpin RNAs.

RNA interference is becoming a powerful tool in gene-specific silencing. New generation vaccines against many pathogens will attempt to incorporate these molecules. Here we report the efficient silencing of chicken anaemia virus (CAV) genes in vitro using short-hairpin RNAs (shRNAs) targeting the region of the CAV transcript encoding either viral protein (VP) 1, or overlapping sections of VP2/3 and VP1/2. The shRNAs were first validated against a EGFP-CAV fusion transcript reporter system and then against CAV grown in MDCC-MSB1 cells. The decrease in CAV replication was shown with a flow cytometry assay specific for VP3. Overall the results showed efficient silencing of CAV replication in tissue culture using shRNAs. It was also shown that the combination of three shRNAs being expressed from a single plasmid is less effective at silencing CAV replication than the most active shRNA alone.