Figure 7

Targeting of STAT3-3′UTR by 27 nt-siRNAs is reminiscent of miR targeting. (A) The biogenesis of 27 nt-ncRNA is still enigmatic. This figure shows secondary structure simulations of the different tandem repeats exhibiting regular extended stem-loops. (B) The expression of luciferase containing the STAT3 wild-type (wt) 3′-UTR target motif is significantly reduced when compared with luciferase containing a mutated putative STAT3 3′-UTR recognition motif (mut). (C) Phylogenetic analyses show that the intronic 27 nt-ncRNA motif is conserved in numerous primate species within the NOS3 gene. Analyses of the corresponding putative STAT3 recognition motifs in those primates suggest a putatively conserved miR recognition mechanism in Catarrhini, whereas less support is given for Platyrrhini and Tarsidae. No evidence for the 27 nt-ncRNA motif was found in species other than primates.