SREs are enriched in Smaug-bound mRNAs and those that are translationally repressed by Smaug. Multiple linear regression was used to simultaneously assess the contribution of various stem-loop structures to Smaug binding and Smaug-mediated translational repression. Smaug binding was quantified using the fold enrichment in Smaug RIPs compared to control RIPs and Smaug-mediated translational repression was quantified by comparing the TI in smaug-mutant versus wild-type embryos. The structures tested in (A) included a consensus SRE with the loop sequence CNGGN0-4 while the other sequences tested carried the indicated changes in invariant positions of the loop that are predicted to reduce or block Smaug binding. The structures tested in (B) included all possible nucleotides in the second position of the loop. The structures tested in (C) included all possible nucleotides in the position that immediately precedes the loop. The structures tested in (D) included loops matching the CNGGN0-4 consensus where the loop size varied from four to eight nucleotides. Error bars indicate standard error of the mean.