A. GST pull-downs. They were performed with GST or GST.SIVNef and [35S]-labeled Gag, the frameshifted, protease negative fsSIVGagPR- and SIVp6*PR- peptides. Lanes 1, 4 and 7 represent 10% input for fsSIVGagPR-, SIVp6*PR- and SIVGag, respectively (boxed). Inputs for GST and GST.Nef are related to panel B. B. Reverted mutant SIVNef proteins restore the binding to SIVGagPol. GST pull-downs were performed with GST alone or GST.NefM8 and reverted GST.SIVNef and the Myc epitope-tagged fsSIVGagPR- proteins. Proteins were separated by 10% SDS-PAGE followed by western blotting with anti-Myc antibodies. Lane 1 represents 10% of the input for fsSIVGagPR-.