AR mRNA associates with the MID1 complex. (A) Agarose gel showing RT-PCR products of AR or of two control genes (prefoldin 5, PFDN5; thymosin like 8, TMSL8). mRNA was isolated either from total cell lysate or after immunoprecipitation of the MID1 complex using lysates from MID1-FLAG overexpressing HeLa cells with an anti-FLAG antibody (IP-FLAG) or with unspecific IgGs (IP-IgG). (B) Schematic overview of five different regions on the AR mRNA: 5′ region: nucleotides (nt) 212–1224, poly(CAG): nt 1160–1446, intermediate sequence: nt 1390–2445, poly(GGY): nt 2382–2652, 3′ region: nt 2593–4123. (C) Detection of FLAG-MID1 on Western blots analyzing AR mRNA association to MID1. In vitro transcribed and biotin-labeled regions of AR mRNA were added to lysates of HeLa cells overexpressing MID1-FLAG. Streptavidin coated magnetic beads were used to isolate the RNA/protein complexes. Whole lysate served as control for presence of MID1 and antisense RNA or no RNA were used as negative controls.