Fig. 1. Domain structure and expression of human Dicer. (A) Schematic illustration of the domain structure of the human Dicer protein. (B) Polyhistidine-tagged human Dicer protein was expressed in a baculovirus-based system, partially purified by Ni²⁺-affinity chromatography, and analyzed by SDS–PAGE followed by western blotting with anti-Dicer antibody or pre-immune serum, or Coomassie Blue staining. A preparation from mock-infected Sf9 cells was used as a control.