Fig. 7. Binding of RKO ASHuR cells to transcripts from cyclins A and B1. (A) Quantitation of radioactive signals (sum of all bands, represented as the mean ± SEM from three independent experiments) from binding experiments similar to those shown in (B). (B) Repre sentative complexes forming between cytoplasmic lysates from synchronous populations of RKO zeo or ASHuR cells (prepared at the times indicated after serum stimulation), and radiolabeled cyclin A 3′ UTR (top) or cyclin B1 3′ UTR (bottom). Supershift analysis was carried out where indicated (+HuR); the arrowhead shows supershifted complexes.