부산대학교 도서관

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.molbiopara.2005.08.009 Byline: Sam Alsford, Taemi Kawahara, Lucy Glover, David Horn Keywords: Bloodstream-form; Functional genomics; GFP; Leaky; Position effect; RNAi; Transfection; T7 RNA polymerase Abstract: In Trypanosoma brucei, RNA interference (RNAi) and recombinant protein expression are established as powerful approaches for functional genomics, particularly when combined with inducible expression. The favoured methods involve exploiting homologous recombination to target expression cassettes to a chromosome sub-set to establish stable cell lines. Unfortunately, bloodstream-form cells, those that cause disease in mammals, exhibit low efficiency stable transfection. Current expression systems can also exhibit other undesirable features, including variable position effects and leaky, inducible expression. We have developed systems in bloodstream-form cells that alleviate these problems. Using constructs for RNAi and expression of (GFP) tagged proteins, we target a (hyg) tagged ribosomal RNA (RRNA) locus which circumvents position effects and allows increased targeting efficiency. We also report a compatible double-inducible system for tight regulation of highly toxic products. This system exploits a new inducible RRNA promoter to drive T7 RNA polymerase (T7RNAP) transcription which then drives expression from inducible T7 promoters. The developments described should facilitate functional analysis and increased throughput. Author Affiliation: London School of Hygiene & Tropical Medicine, Department of Infections and Tropical Diseases, Keppel Street, London WC1E 7HT, UK Article History: Received 27 June 2005; Revised 9 August 2005; Accepted 11 August 2005