Figure 4: Secondary structures and thermodynamic stabilities of the two mRNA segments. The mRNA segments of the (a) Fluc gene (91 nt to 454 nt) and (b) RLuc gene (334 nt to 715 nt) were analyzed using an RNAfold program (http://bibiserv.techfak.uni-bielefeld.de/rnafold/). The 2D structures and the entropy assigned to each nucleotide are shown. The siRNA binding sites are indicated by heavy lines.