Lack Of Interferon (IFN) Response To T7 Transcribed pppG (n)(n = 2,3)-shRNA

• Published in: Nucleosides, nucleotides & nucleic acids nucleotides & nucleic acids, 2007-06, Vol.26 (6-7), p.805-808
• Main Authors: Gondai, Takuma, Yamaguchi, Kazuya, Hashimoto, Kahoko, Miyano-Kurosaki, Naoko, Takaku, Hiroshi
• Format: Article
• Language: English
• Subjects: Base Sequence; DNA-Directed RNA Polymerases - metabolism; HeLa Cells; Humans; Interferons - biosynthesis; Luciferases; Molecular Sequence Data; Oligonucleotides - genetics; RNA, Messenger; RNA, Small Interfering - genetics; RNAi; shRNA; T7 RNA polymerase; Transcription, Genetic; type I interferon; Viral Proteins - metabolism
• ISSN: 1525-7770; 1532-2335
• DOI: 10.1080/15257770701503647

RNA interference (RNAi) mediated by siRNAs has proved to be a highly effective gene silencing mechanism with great potential for gene therapeutic applications. However, siRNA agents have been shown to exert non-target-related biological effects and toxicities, including immune stimulation. Specifically, siRNA synthesized from a T7 RNA polymerase system can trigger the potent induction of type I IFN in a variety of cells. The single-stranded RNA can also stimulate innate cytokine responses in mammals. We found that pppGn (n = 1-3), associated with the 5′ end of the shRNA produced from the T7 RNA polymerase system, did not induce detectable levels of IFN. The residual amount of G associated with the 5′-end of the transcript was proportional to the reduction of the interferon response. We describe a T7 pppGn (n = 1-3) shRNA synthesis system that alleviates the IFN response, which will facilitate the design of siRNAs while maintaining their full efficacy.