title: Comparison of RNAi efficiency mediated by tetracycline-responsive H1 and U6 promoter variants in mammalian cell lines.
abstract: Conditional expression of short hairpin RNAs (shRNAs) to knock down target genes is a powerful tool to study gene function. The most common inducible expression systems are based on tetracycline-regulated RNA polymerase III promoters. During the last years, several tetracycline-inducible U6 and H1 promoter variants have been reported in different experimental settings showing variable efficiencies. In this study, we compare the most common variants of these promoters in several mammalian cell lines. For all cell lines tested, we find that several inducible U6 and H1 promoters containing single tetracycline operator (tetO) sequences show high-transcriptional background in the non-induced state. Promoter variants containing two tetO sequences show tight suppression of transcription in the non-induced state, and high tet responsiveness and high gene knockdown efficiency upon induction in all cell lines tested. We report a variant of the H1 promoter containing two O2-type tetO sequences flanking the TATA box that shows little transcriptional background in the non-induced state and up to 90% target knockdown when the inducer molecule (dox-doxycycline) is added. This inducible system for RNAi-based gene silencing is a good candidate for use both in basic research on gene function and for potential therapeutic applications.
authors.affiliation: Department of Pediatrics, University Hospital of North-Norway, Tromsø, Norway.
authors.forename: Jørn R
authors.initials: JR
authors.lastname: Henriksen
authors.forename: Cecilie
authors.initials: C
authors.lastname: Løkke
authors.forename: Martin
authors.initials: M
authors.lastname: Hammerø
authors.forename: Dirk
authors.initials: D
authors.lastname: Geerts
authors.forename: Rogier
authors.initials: R
authors.lastname: Versteeg
authors.forename: Trond
authors.initials: T
authors.lastname: Flaegstad
authors.forename: Christer
authors.initials: C
authors.lastname: Einvik
mesh_terms: D001483:Base Sequence; D002460:Cell Line; D004318:Doxycycline / Q000494:pharmacology*; D005822:Genetic Vectors; D006801:Humans; D008969:Molecular Sequence Data; D009875:Operator Regions, Genetic; D011401:Promoter Regions, Genetic; D034622:RNA Interference; D012342:RNA, Small Nuclear / Q000235:genetics; D022661:RNA, Untranslated / Q000096:biosynthesis*; D012097:Repressor Proteins / Q000378:metabolism; D043262:Ribonuclease P / Q000235:genetics; D014158:Transcription, Genetic / Q000187:drug effects
chemical_list: D012342:RNA, Small Nuclear; D022661:RNA, Untranslated; D012097:Repressor Proteins; C405486:U6 small nuclear RNA; C034811:tetracycline resistance-encoding transposon repressor protein; D043262:Ribonuclease P; D004318:Doxycycline