Well the article is about nonsense mediated decay and how the pre-termination codon recognition is mediated by a competition between 3′ UTR associated factors that stimulate or antagonize the recruitment of the Upf complex. It was proposed that mRNA’s with long 3′ UTRs can evade NMD through the recruitment of proteins to the 3′ UTR that antagonize NMD. A mechanism of recruiting these factors could be through sequence-specific binding to a sequence element in the 3′ UTR. By using the transgenes in the article we are suppose to design an experiment to detect these 3′ UTR sequence elements. One of the transgenes in the article is beta globin with adenovirus major late intron inserted in. I just don’t understand what tests would be used in order to determine the sequence elements that recruit factors within the 3′ UTR. Does that clear up the question?