INHIBITION OF FORMATION OF REV-RRE COMPLEX BY PYRONIN-Y

The interaction of pyronin Y, an RNA intercalating drug, with the binding of Rev protein from human immunodeficiency virus type 1 (HIV-1) to Rev-responsive element (RRE)-containing env RNA was studied. In gel retardation assays, recombinant Rev protein tightly bound to in vitro transcribed RRE RNA. Nitrocellulose-filter-binding studies revealed a dissociation constant of almost-equal-to (1-2) = 10(-10)M (Pfeifer et al., 1991). Pyronin Y efficiently suppressed formation of the Rev-RRE complex. At a concentration of 1 mug ml-1, complex formation was almost completely inhibited. Electron microscopy showed that Rev oligomerizes in the presence of RRE-containing RNA with the formation of short rod-like structures or long filaments, depending on the length of the transcript. Assembly of Rev protein along RRE-containing RNAs was abolished after addition of pyronin Y. Thus pyronin Y represents the first compound described to inhibit Rev-RRE complex formation.