title: RNA interference in mammalian cells by chemically-modified RNA.
abstract: RNA interference (RNAi) is proving to be a robust and versatile technique for controlling gene expression in mammalian cells. To fully realize its potential in vivo, however, it may be necessary to introduce chemical modifications to optimize potency, stability, and pharmacokinetic properties. Here, we test the effects of chemical modifications on RNA stability and inhibition of gene expression. We find that RNA duplexes containing either phosphodiester or varying numbers of phosphorothioate linkages are remarkably stable during prolonged incubations in serum. Treatment of cells with RNA duplexes containing phosphorothioate linkages leads to selective inhibition of gene expression. RNAi also tolerates the introduction of 2'-deoxy-2'-fluorouridine or locked nucleic acid (LNA) nucleotides. Introduction of LNA nucleotides also substantially increases the thermal stability of modified RNA duplexes without compromising the efficiency of RNAi. These results suggest that inhibition of gene expression by RNAi is compatible with a broad spectrum of chemical modifications to the duplex, affording a wide range of useful options for probing the mechanism of RNAi and for improving RNA interference in vivo.
authors.affiliation: Department of Pharmacology, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas 75390, USA.
authors.forename: Dwaine A
authors.initials: DA
authors.lastname: Braasch
authors.forename: Susan
authors.initials: S
authors.lastname: Jensen
authors.forename: Yinghui
authors.initials: Y
authors.lastname: Liu
authors.forename: Kiran
authors.initials: K
authors.lastname: Kaur
authors.forename: Khalil
authors.initials: K
authors.lastname: Arar
authors.forename: Michael A
authors.initials: MA
authors.lastname: White
authors.forename: David R
authors.initials: DR
authors.lastname: Corey
mesh_terms: D015153:Blotting, Western; D051242:Caveolin 1; D022461:Caveolins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D017931:DNA Primers; D015870:Gene Expression; D020868:Gene Silencing; D006367:HeLa Cells; D006801:Humans; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014529:Uridine / Q000031:analogs & derivatives / Q000737:chemistry / Q000378:metabolism
chemical_list: D051242:Caveolin 1; D022461:Caveolins; D017931:DNA Primers; D034741:RNA, Small Interfering; D014529:Uridine