Figure 5.

(A) HspBP1 interacts with RNA in vivo and in vitro. PolyA-RNA binding was evaluated as described in detail [47]. HeLa cells were incubated with vehicle (EtOH, ethanol) or 2mM DEM for 4 hours and extracts were prepared. Starting material (ST), flow through (Ft), wash (W) and material eluted from oligo(dt)-cellulose (E) was analyzed by Western blotting. HspBP1 associated with polyA-RNA under control (EtOH) and stress (DEM) conditions. HuR provided a positive control. (B) Purified HspBP1 binds RNA homopolymers in vitro. Control and homopolymer resins were incubated with purified HspBP1. Starting material (St), unbound, heparin and 1 M NaCl wash fractions, as well as bound material were examined by Western blotting with antibodies against HspBP1. All lanes for each filter were on the same blot.