Probing features of RNA 1/(MS2)2 important for p53 recognition. (A) The primary insert sequence of RNA 1/(MS2)2 is not recognized by p53 in a different structural context (1h/(MS2)2). (Left) Predicted secondary structure of hybrid RNA 1h/(MS2)2 with MS2 recognition sequences shown in gray. The unique sequence from RNA 1/(MS2)2 is highlighted in red. (Right) Yeast three-hybrid growth assay for HIS3 expression on selective medium containing a gradient of 0–35 mM 3-AT and β-galactosidase assay. Two independent transformants of each strain are shown. (B) Role for a predicted three-way RNA junction in p53 recognition depends on context. (C) Presentation of a single MS2 sequence cannot increase p53 recognition of the primary sequence for RNA 1d/(MS2)2.
