Three different amounts (150, 300 and 450 ng) of the TAV 2b protein purified from E. coli were each incubated with 4 ng of each of the [ 32 P]-labelled TAV RNA 3 transcripts in a binding buffer [50 mM Tris-HCl (pH 8.2), 10 mM MgCl 2 , 1 mM EDTA, 10% glycerol, 200 ng of yeast tRNA (Sigma), and 2 U of RNase inhibitor (Promega)] at 258C for 30 min (46) . After incubation, potential protein-RNA complexes were analysed via electrophoresis on a 4% non-denaturing polyacrylamide gel and detected by autoradiography.