Abstract
Dicer proteins are involved in RNA silencing. They produce siRNAs and miRNAs, and, in animals, they interact with a dsRNA-binding protein (RDE-4 and R2D2). In Arabidopsis thaliana there are 4 members of the Dicer family and 5 members of the RDE-4/R2D2-like dsRNA-binding protein family. We have studied the biochemical properties of these eight gene products: four Arabidopsis Dicer-like proteins (DCL1-4) and four RDE-4/R2D2-like dsRNA-binding proteins (HYL1/DRB1, DRB2, DRB4 and DRB5). We have reported that DCL1, DCL3 and HYL1/DRB family proteins exhibit dsRNA-binding activity, DCL1, DCL4, HYL1/DRB1 and DRB4 localize in the nucleus, and HYL1/DRB family proteins bind to DCL family proteins. HYL1/DRB1 binds specifically to DCL1, and DRB4 most strongly binds to DCL4 in vitro. Here, we show that DRB4 interacts specifically with DCL4 in vivo by immunoprecipitation. The result suggest that a Dicer functions with a dsRNA-binding protein (HYL1/DRB family) in plant.
