Interaction in vitro; bait produced as a recombinant fusion protein in bacterial system; prey produced and labeled by in vitro transcription.

Imp binds to regions of grk RNA with Kd = 134 nM or higher, but not to bcd RNA (negative control).

Labeled grk RNA was incubated with purified Imp protein, then filtered through nitrocellulose in filter binding buffer. The amount of bound grk was determined by scintillation counting.

The grk-GST particles were pre-bound to resin and incubated with ovary extract.

Interaction in vitro; bait produced by in vitro transcription; prey derived from wild-type ovary extract.

GRNA chromatography: grk RNA containing a BoxB sequence of the λ phage was bound to a fusion of GST with the 21 residue N antiterminator peptide.