title: Alteration of Drosophila life span using conditional, tissue-specific expression of transgenes triggered by doxycyline or RU486/Mifepristone.
abstract: The conditional systems Tet-on and Geneswitch were compared and optimized for the tissue-specific expression of transgenes and manipulation of life span in adult Drosophila. Two versions of Tet-on system reverse-tetracycline-Trans-Activator (rtTA) were compared: the original rtTA, and rtTAM2-alt containing mutations designed to optimize regulation and expression. The rtTAM2-alt version gave less leaky expression of target constructs in the absence of doxycyline, however the absolute level of expression that could be achieved was less than that produced by rtTA, in contrast to a previous report. Existing UAS-rtTAM2-alt insertions were re-balanced, and combined with several tissue-general and tissue-specific GAL4 driver lines to yield tissue-specific, doxycyline-inducible transgene expression over three orders of magnitude. The Geneswitch (GS) system also had low background, but the absolute level of expression was low relative to Tet-on. Consequently, actin5C-GS multi-insert chromosomes were generated and higher-level expression was achieved without increased background. Moderate level over-expression of MnSOD has beneficial effects on life span. Here high-level over-expression of MnSOD was found to have toxic effects. In contrast, motor-neuron-specific over-expression of MnSOD had no detectable effect on life span. The results suggest that motor-neuron tissue is not the essential tissue for either MnSOD induced longevity or toxicity in adult males.
authors.affiliation: Molecular and Computational Biology Program, Department of Biological Sciences, University of Southern California, 1050 Childs Way, Room 201, Los Angeles, CA 90089-2910, USA.
authors.forename: Daniel
authors.initials: D
authors.lastname: Ford
authors.forename: Nicholas
authors.initials: N
authors.lastname: Hoe
authors.forename: Gary N
authors.initials: GN
authors.lastname: Landis
authors.forename: Kevin
authors.initials: K
authors.lastname: Tozer
authors.forename: Allan
authors.initials: A
authors.lastname: Luu
authors.forename: Deepak
authors.initials: D
authors.lastname: Bhole
authors.forename: Ananth
authors.initials: A
authors.lastname: Badrinath
authors.forename: John
authors.initials: J
authors.lastname: Tower
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified / Q000378:metabolism; D004318:Doxycycline / Q000494:pharmacology; D004331:Drosophila melanogaster / Q000187:drug effects / Q000235:genetics*; D005260:Female; D015870:Gene Expression / Q000187:drug effects; D005821:Genetic Techniques; D007763:Lac Operon / Q000187:drug effects; D008136:Longevity / Q000187:drug effects / Q000235:genetics*; D008297:Male; D015735:Mifepristone / Q000494:pharmacology; D009154:Mutation; D009420:Nervous System / Q000378:metabolism; D013482:Superoxide Dismutase / Q000235:genetics
chemical_list: D015735:Mifepristone; D013482:Superoxide Dismutase; D004318:Doxycycline