FIGURE 5.

Effects of nucleolin and AUF1 on the exosomal degradation of ARE^bcl-2 transcripts in HeLa extracts. A, 5′-capped [³²P]ARE^bcl-2 (filled squares) and β-globin (filled triangles) transcripts were incubated in S100 HeLa cell extracts, and aliquots were removed at the times indicated. Recovery of RNA was assessed by electrophoresis on denaturing polyacrylamide gels and analyzed by phosphorimaging. Data are represented as a semilog plot of fraction of RNA remaining versus time of incubation in cell extracts. B, recombinant GST-nucleolin was incubated with ARE^bcl-2 prior to exposure to S100 extracts (gray circles). Filled squares correspond to decay in unsupplemented S100 extracts, and open circles to S100 supplemented with GST. Error bars for open circles are smaller than the symbol. C, ARE^bcl-2 transcripts were incubated in untreated S100 HeLa extracts (filled squares) or in S100 extracts pretreated with anti-AUF1 antibody (open squares). D, representative gel is shown in which ARE^bcl-2 transcripts were incubated in untreated S100 HeLa extracts or in AUF1-depleted extracts. Error bars for A–C indicate average of two to four experiments.