document: oligos with a branched structure.17 In particular, various sequences of siRNA can easily be incorporated into the branch of the pRNA-3WJ motifs via bottom-up self-assembly, which could be processed intracellularly by dicer for multigene silencing. In addition, the RNA backbones with 2’-fluorine, 2’-O-methyl or 2’-amine modifications of U and C nucleotides render the RNAs resistant to RNase degradation or hydrolysis, enhancing their in vivo half-life while retaining authentic functions of the