title: Production of functional small interfering RNAs by an amino-terminal deletion mutant of human Dicer.
abstract: Although RNA interference (RNAi) functions as a potent antiviral innate-immune response in plants and invertebrates, mammalian somatic cells appear incapable of mounting an RNAi response and few, if any, small interfering RNAs (siRNAs) can be detected. To examine why siRNA production is inefficient, we have generated double-knockout human cells lacking both Dicer and protein kinase RNA-activated. Using these cells, which tolerate double-stranded RNA expression, we show that a mutant form of human Dicer lacking the amino-terminal helicase domain can process double-stranded RNAs to produce high levels of siRNAs that are readily detectable by Northern blot, are loaded into RNA-induced silencing complexes, and can effectively and specifically inhibit the expression of cognate mRNAs. Remarkably, overexpression of this mutant Dicer, but not wild-type Dicer, also resulted in a partial inhibition of Influenza A virus-but not poliovirus-replication in human cells.
authors.affiliation: Department of Molecular Genetics & Microbiology, Center for Virology, Duke University Medical Center, Durham, NC 27710.
authors.forename: Edward M
authors.initials: EM
authors.lastname: Kennedy
authors.affiliation: Department of Molecular Genetics & Microbiology, Center for Virology, Duke University Medical Center, Durham, NC 27710.
authors.forename: Adam W
authors.initials: AW
authors.lastname: Whisnant
authors.affiliation: Department of Molecular Genetics & Microbiology, Center for Virology, Duke University Medical Center, Durham, NC 27710.
authors.forename: Anand V R
authors.initials: AV
authors.lastname: Kornepati
authors.affiliation: Department of Molecular Genetics & Microbiology, Center for Virology, Duke University Medical Center, Durham, NC 27710.
authors.forename: Joy B
authors.initials: JB
authors.lastname: Marshall
authors.affiliation: Department of Molecular Genetics & Microbiology, Center for Virology, Duke University Medical Center, Durham, NC 27710.
authors.forename: Hal P
authors.initials: HP
authors.lastname: Bogerd
authors.affiliation: Department of Molecular Genetics & Microbiology, Center for Virology, Duke University Medical Center, Durham, NC 27710 bryan.cullen@duke.edu.
authors.forename: Bryan R
authors.initials: BR
authors.lastname: Cullen
mesh_terms: D057809:HEK293 Cells; D006801:Humans; D034741:RNA, Small Interfering / Q000502:physiology*; D012367:RNA, Viral / Q000235:genetics; D043244:Ribonuclease III / Q000737:chemistry / Q000235:genetics*; D017384:Sequence Deletion
chemical_list: D034741:RNA, Small Interfering; D012367:RNA, Viral; D043244:Ribonuclease III
keywords: Dicer; RNA interference; innate immunity; microRNAs; small interfering RNAs