Double-stranded RNA-binding protein 4 (DRB4) plays a role in RNA-mediated post-transcriptional gene silencing (PTGS). It assists DCL4 during biogenesis of trans-acting small interferring RNAs (ta-siRNAs) and is necessary for DCL4 activity. DRB4 is also involved in RNA silencing of RNA and DNA viruses.Alternative name: dsRNA-binding protein 4, DBR4