FIGURE 2.

Streptavidin pull-down of enzymatically biotinylated RNAs. 5′-Labeled RNA N₂₂ was biotinylated with E. coli PAP, and body-labeled RNA₁₆₀₀ was biotinylated with φ29 DNA polymerase. Both were purified and applied to streptavidin Sepharose beads or, as a control, to the same beads blocked with biotin (for details, see Materials and Methods). After two rounds of washing, radioactivity on the beads and all previously collected fractions was measured by liquid scintillation and plotted as the percentage of input. (fth) Flowthrough, supernatant of pelleted beads.