Sticky overhangs enhance siRNA-mediated gene silencing.
siRNA delivery to cells offers a convenient and powerful means of gene silencing that bypasses several barriers met by gene delivery. However, nonviral vectors, and especially polymers, form looser complexes with siRNA than with plasmid DNA. As a consequence, exchange of siRNA for larger polymeric anions such as proteoglycans found outside cells and at their surface may occur and lower delivery. We show here that making siRNAs "gene-like," via short complementary A(5-8)/T(5-8) 3' overhangs, increases complex stability, and hence RNase protection and gene silencing in vitro up to 10-fold. After decomplexation in the cytoplasm, sticky siRNA (ssiRNA) concatemers fall apart. ssiRNAs are therefore not inducing antiviral responses, as shown by the absence of IFN-beta production. Finally, transfection experiments in the mouse lung show that ssiRNA should be particularly suited to silencing with linear polyethylenimine in vivo.
Bolcato-Bellemin
Anne-Laure
AL
Polyplus-Transfection, Bioparc, Boulevard Sebastien Brant, 67400 Illkirch, France.
Bonnet
Marie-Elise
ME
Creusat
Gaëlle
G
Erbacher
Patrick
P
Behr
Jean-Paul
JP
D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D005260:Female; D005456:Fluorescent Dyes; D017930:Genes, Reporter; D005821:Genetic Techniques; D005822:Genetic Vectors; D006025:Glycosaminoglycans; D006367:HeLa Cells; D006801:Humans; D008055:Lipids; D008156:Luciferases / Q000235:genetics; D008168:Lung / Q000378:metabolism; D051379:Mice; D041681:NIH 3T3 Cells; D011094:Polyethyleneimine; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000008:administration & dosage / Q000737:chemistry* / Q000235:genetics*; D012260:Ribonucleases; D014162:Transfection
D005456:Fluorescent Dyes; D006025:Glycosaminoglycans; D008055:Lipids; D034741:RNA, Small Interfering; D011094:Polyethyleneimine; D008156:Luciferases; D012260:Ribonucleases