FIGURE 9.

DGCR8 binds heme in insect cells. A, electronic absorption spectrum of His₆-NC1 (human) expressed in Sf9 cells using baculovirus. His₆-NC1 was purified using Ni affinity chromatography followed by cation exchange chromatography. The image of a silver-stained SDS-polyacrylamide gel is shown. B, analytical size exclusion chromatogram of the His₆-NC1 sample used in A, with the silver-stained gel of the SEC fractions shown above. The peak indicated by the asterisk contains mainly nucleic acids. C, His₆-NC1 expressed in insect cells was used in reconstituted pri-miRNA processing assays. A pri-miR-30a fragment was uniformly labeled with α-³²P-UTP and was incubated with recombinant Drosha and NC1 at indicated concentrations. The reactions were analyzed using denaturing gel electrophoresis and autoradiography.