Mutational analysis of individual sequence motifs with the three cis-regulatory elements. Note that in constructs 1 and 2 the seed mutations were generated in the context of a mutation in redundantly acting elements because it is only in such a “sensitized” construct that loss of an individual element would have an effect (see Fig. 4). The C deletion in construct 2 (testing the seed match in site A) is not a complete 25-bp deletion, but a CAAAUU motif deletion, which mimics the complete 25-bp deletion. Also note that compared to all other constructs in this article, construct 5 defines the most minimal changes that lead to a complete loss of die-1 3′UTR regulation, namely, the loss of two 6-bp motifs of the same sequence. For explanation of symbols, see the Figure 3 legend.
