title: A doubly inducible system for RNA interference and rapid RNAi plasmid construction in Trypanosoma brucei.
abstract: The most rapid method for the generation of conditional mutants in Trypanosoma brucei is the use of RNA interference. A single copy of the target sequence is cloned between two opposing T7 promoters bearing tet operators, and the resulting plasmid is integrated into the genome of cells expressing both the tet repressor and T7 RNA polymerase. Upon addition of tetracycline, double-stranded RNA is synthesised from the two T7 promoters. Unfortunately, repression of T7 promoter activity may sometimes be insufficient to prevent expression of toxic amounts of double-stranded RNA. We describe here cell lines in which the expression of T7 polymerase is under tetracycline control, and show that regulation of polymerase expression can modulate transcription from a constitutive T7 promoter. In addition we describe a construct containing two copies of the tn10 Tet repressor for easy creation of repressor-expressing trypanosomes, and an RNA interference vector which allows "TA" cloning of unmodified PCR products and blue/white selection.
authors.affiliation: Zentrum für Molekulare Biologie der Universität Heidelberg, ZMBH, Im Neuenheimer Feld 282, D-69120 Heidelberg, Germany.
authors.forename: Vincent P
authors.initials: VP
authors.lastname: Alibu
authors.forename: Lilian
authors.initials: L
authors.lastname: Storm
authors.forename: Simon
authors.initials: S
authors.lastname: Haile
authors.forename: Christine
authors.initials: C
authors.lastname: Clayton
authors.forename: David
authors.initials: D
authors.lastname: Horn
mesh_terms: D000818:Animals; D004259:DNA-Directed DNA Polymerase / Q000235:genetics / Q000378:metabolism; D017125:Genes, Protozoan; D005822:Genetic Vectors / Q000235:genetics; D008562:Membrane Glycoproteins / Q000235:genetics; D010957:Plasmids / Q000235:genetics*; D011401:Promoter Regions, Genetic; D015800:Protozoan Proteins / Q000235:genetics; D034622:RNA Interference; D011995:Recombination, Genetic; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism; D013752:Tetracycline / Q000494:pharmacology; D014346:Trypanosoma brucei brucei / Q000235:genetics* / Q000378:metabolism
chemical_list: D008562:Membrane Glycoproteins; D015800:Protozoan Proteins; D012097:Repressor Proteins; C053277:procyclic acidic repetitive protein, Trypanosoma; C034811:tetracycline resistance-encoding transposon repressor protein; C034970:bacteriophage T7 induced DNA polymerase; D004259:DNA-Directed DNA Polymerase; D013752:Tetracycline