title: Characterization and comparison of chicken U6 promoters for the expression of short hairpin RNAs.
abstract: RNA interference (RNAi) is a powerful method of sequence-specific gene knockdown that can be mediated by DNA-based expression of short hairpin RNA (shRNA) molecules. A number of vectors for expression of shRNA have been developed with promoters for a small group of RNA polymerase III (pol III) transcripts of either mouse or human origin. To advance the use of RNAi as a tool for functional genomic research and future development of specific therapeutics in the chicken species, we have developed shRNA expression vectors featuring chicken U6 small nuclear RNA (snRNA) promoters. These sequences were identified based on the presence of promoter element sequence motifs upstream of matching snRNA sequences that are characteristic of these types of pol III promoters. To develop suitable shRNA expression vectors specifically for chicken functional genomic RNAi applications, we compared the efficiency of each of these promoters to express shRNA molecules. Promoter activity was measured in the context of RNAi by targeting and silencing the reporter gene encoding the enhanced green fluorescent protein (EGFP). Plasmids containing one of four identified chicken U6 promoters gave a similar degree of knockdown in DF-1 cells (chicken); although, there was some variability in Vero cells (monkey). Because the chicken promoters were not stronger than the benchmark mouse U6 promoter, we suggest that the promoter sequence and structure is more important in determining efficiency in vitro rather than its species origin.
authors.affiliation: CSIRO Livestock Industries, Australian Animal Health Laboratory, Geelong, Australia.
authors.forename: Terry G
authors.initials: TG
authors.lastname: Wise
authors.forename: Darren J
authors.initials: DJ
authors.lastname: Schafer
authors.forename: Luke S
authors.initials: LS
authors.lastname: Lambeth
authors.forename: Scott G
authors.initials: SG
authors.lastname: Tyack
authors.forename: Matthew P
authors.initials: MP
authors.lastname: Bruce
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Moore
authors.forename: Tim J
authors.initials: TJ
authors.lastname: Doran
mesh_terms: D000818:Animals; D001483:Base Sequence; D002645:Chickens / Q000235:genetics*; D002522:Chlorocebus aethiops; D004258:DNA Polymerase III / Q000096:biosynthesis / Q000235:genetics; D049452:Green Fluorescent Proteins / Q000096:biosynthesis / Q000235:genetics; D051379:Mice; D008856:Microscopy, Fluorescence / Q000662:veterinary; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D034622:RNA Interference; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D034741:RNA, Small Interfering / Q000096:biosynthesis / Q000235:genetics*; D012342:RNA, Small Nuclear / Q000235:genetics*; D014162:Transfection / Q000662:veterinary; D014709:Vero Cells
chemical_list: D012333:RNA, Messenger; D034741:RNA, Small Interfering; D012342:RNA, Small Nuclear; C405486:U6 small nuclear RNA; C485184:enhanced green fluorescent protein; D049452:Green Fluorescent Proteins; D004258:DNA Polymerase III