KSRP and PTBP2 are present in the same complexes with the F1 region of the 3′-UTR of Pgk2 mRNA. RNA gel shifts were performed with testis extracts as in (Figure 2B). (A) Lane 1, transcript F1 without testis extract; lane 2, transcript F1 with extract; lane 3, transcript F1 with extract and anti-PTBP2; lane 4, transcript F1 with extract, anti-PTBP2 and anti-KSRP. The position of one complex shifted by each antibody is shown by an arrow. (B) Recombinant t-KSRP and recombinant PTBP2 (1 µg) interact and form complexes with F1 RNA containing both proteins. Lane 1, transcript F1 without testis extract; lane 2, transcript F1 t-KSRP; lane 3, transcript F1 with PTBP2; lane 4, transcript F1 with PTBP2 and KSRP; lane 5, transcript F1 with PTBP2, t-KSRP and anti-KSRP (Abnova, Taiwan); lane 6, transcript F1 with PTBP2, t-KSRP and anti-PTBP2 (Abnova).