Regulatory motifs in the 3'UTR of the human MID1 gene. (A) Sequences of ARE motifs 1–3 with surrounding AU-rich sequences. (B) UV-crosslink with protein lysate from HeLa cells and the ARE1 motif. Arrows indicate proteins that bound the ARE1 sense transcript with much higher affinity than the antisense negative control. (C) Western blot analyses of RNA-protein pulldowns with protein lysate from HeLa cells and the ARE1 motif. HuR and AUF1 are detected using specific antibodies.