FIGURE 2.

Binding of nucleolin to fragments of ARE^bcl-2 RNA. A, schematic representation of the transcripts utilized in binding assays. Transcripts contained the full-length (136 nucleotides) ARE^bcl-2 or portions containing the two pentamers (P1 and P2) (70 nucleotides), one nonamer (N) (66 nucleotides), or both the pentamers and the nonamer (76 nucleotides = short). Thin line indicates vector sequences present in all transcripts; thick line or boxes indicate bcl-2 mRNA sequences. B, ³²P-ARE transcripts (25 nm) incubated in buffer alone or with purified recombinant Nuc-His (50, 100, 200, or 400 nm indicated by triangle above gel). The transcript used in each assay is indicated below the gel. Samples were separated on a 1.5% agarose gel, which was dried and analyzed by phosphorimaging.