Sam68ΔC inhibits the association of 9 kb proviral mRNAs with PABP1. Cells were transfected with the proviral clone pHxBruR-/RI- in the absence (pcDNA) or presence of the various Sam68ΔC mutants. Cell lysates were prepared 48 h post-transfection and used in RIP assays. a) PABP1 western blot showing the input and immunoprecipitated (IP) protein using either rabbit IgG (R-IgG) or anti-PABP1 (PABP). b) RNase protection assays showing input and PABP1 immunoprecipitated (IP) HxBruR-/RI- RNAs. RNA was extracted from either rabbit IgG (R-IgG) or anti-PABP1 (PABP) precipitated samples and analyzed by RPA. c) Quantitation of RPA shown in (b). The amount of 9 kb HxBruR-/RI- mRNA relative to actin mRNA immunoprecipitated with anti-PABP1 compared to the input. The amount of 9 kb precipitated in the presence of pcDNA was set to 1.0. Error bars represent one standard deviation. Data was quantitated from 3 independent experiments. Asterisks indicate values significantly different (p-value < 0.01) from pcDNA.