The P{UAS-mCherry.mir-276a.sponge.V2} and P{UAS-mCherry.mir-276b.sponge.V2} constructs target mir-276a-3P and mir-276b-3P respectively. However, because the only difference between mir-276a-3P and mir-276b-3P is at position 10, and position 10 is in the sponge bulge (not complementary to the miRNA), both sponges target both miRNAs.

Twenty miRNA binding sites with mismatches at positions 9-12 (creating a "Sponge", designed to sequester miRNAs and thus knocking-down endogenous miRNA activity) are placed in the 3'UTR of mCherry under the control of 10 Gal4 UAS binding sites.