Skip to Content
Merck
  • Enhancement of allele discrimination by introduction of nucleotide mismatches into siRNA in allele-specific gene silencing by RNAi.

Enhancement of allele discrimination by introduction of nucleotide mismatches into siRNA in allele-specific gene silencing by RNAi.

PloS one (2008-05-22)
Yusuke Ohnishi, Yoshiko Tamura, Mariko Yoshida, Katsushi Tokunaga, Hirohiko Hohjoh
ABSTRACT

Allele-specific gene silencing by RNA interference (RNAi) is therapeutically useful for specifically inhibiting the expression of disease-associated alleles without suppressing the expression of corresponding wild-type alleles. To realize such allele-specific RNAi (ASP-RNAi), the design and assessment of small interfering RNA (siRNA) duplexes conferring ASP-RNAi is vital; however, it is also difficult. In a previous study, we developed an assay system to assess ASP-RNAi with mutant and wild-type reporter alleles encoding the Photinus and Renilla luciferase genes. In line with experiments using the system, we realized that it is necessary and important to enhance allele discrimination between mutant and corresponding wild-type alleles. Here, we describe the improvement of ASP-RNAi against mutant alleles carrying single nucleotide variations by introducing base substitutions into siRNA sequences, where original variations are present in the central position. Artificially mismatched siRNAs or short-hairpin RNAs (shRNAs) against mutant alleles of the human Prion Protein (PRNP) gene, which appear to be associated with susceptibility to prion diseases, were examined using this assessment system. The data indicates that introduction of a one-base mismatch into the siRNAs and shRNAs was able to enhance discrimination between the mutant and wild-type alleles. Interestingly, the introduced mismatches that conferred marked improvement in ASP-RNAi, appeared to be largely present in the guide siRNA elements, corresponding to the 'seed region' of microRNAs. Due to the essential role of the 'seed region' of microRNAs in their association with target RNAs, it is conceivable that disruption of the base-pairing interactions in the corresponding seed region, as well as the central position (involved in cleavage of target RNAs), of guide siRNA elements could influence allele discrimination. In addition, we also suggest that nucleotide mismatches at the 3'-ends of sense-strand siRNA elements, which possibly increase the assembly of antisense-strand (guide) siRNAs into RNA-induced silencing complexes (RISCs), may enhance ASP-RNAi in the case of inert siRNA duplexes. Therefore, the data presented here suggest that structural modification of functional portions of an siRNA duplex by base substitution could greatly influence allele discrimination and gene silencing, thereby contributing to enhancement of ASP-RNAi.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
Fetal Bovine Serum, Australia origin, γ-irradiated, sterile-filtered, suitable for cell culture
Sigma-Aldrich
Fetal Bovine Serum, Australia origin, USDA approved, sterile-filtered, suitable for cell culture
Sigma-Aldrich
Fetal Bovine Serum, USA origin, suitable for cell culture
Sigma-Aldrich
Fetal Bovine Serum, USA origin, γ-irradiated by SER-TAIN process, sterile-filtered, suitable for cell culture
Sigma-Aldrich
Fetal Bovine Serum, USA origin, Heat Inactivated, sterile-filtered, suitable for cell culture
Sigma-Aldrich
Fetal Bovine Serum, non-USA origin, from USDA approved countries, Heat Inactivated, sterile-filtered, suitable for cell culture
Sigma-Aldrich
Fetal Bovine Serum, Australia origin, USDA approved, Heat Inactivated, suitable for cell culture
Sigma-Aldrich
Fetal Bovine Serum, non-USA origin, sterile-filtered, suitable for cell culture
Sigma-Aldrich
Fetal Bovine Serum, Australia origin, suitable for, USDA approved, sterile-filtered, suitable for cell culture, suitable for hybridoma
Sigma-Aldrich
Fetal Bovine Serum, USDA approved, sterile-filtered, suitable for cell culture
Sigma-Aldrich
Fetal Bovine Serum, Canada origin, sterile-filtered, suitable for cell culture
Sigma-Aldrich
Fetal Bovine Serum, USA origin, sterile-filtered, suitable for cell culture, suitable for hybridoma
Sigma-Aldrich
Fetal Bovine Serum, USA origin, Dialyzed by ultrafiltration against 0.15 M NaCl, sterile-filtered, suitable for cell culture
Sigma-Aldrich
Fetal Bovine Serum, USA origin, Heat Inactivated, sterile-filtered, suitable for cell culture, suitable for insect cell culture, suitable for hybridoma
Sigma-Aldrich
Fetal Bovine Serum, USA origin, Charcoal Stripped, sterile-filtered, suitable for cell culture
Sigma-Aldrich
Fetal Bovine Serum, Heat Inactivated, non-USA origin, sterile-filtered, suitable for cell culture
SAFC
Fetal Bovine Serum, Australia origin, γ-irradiated, suitable for cell culture, suitable for hybridoma