title: A hormone receptor-based transactivator bridges different binary systems to precisely control spatial-temporal gene expression in Drosophila.
abstract: The GAL4/UAS gene expression system is a precise means of targeted gene expression employed to study biological phenomena in Drosophila. A modified GAL4/UAS system can be conditionally regulated using a temporal and regional gene expression targeting (TARGET) system that responds to heat shock induction. However heat shock-related temperature shifts sometimes cause unexpected physiological responses that confound behavioral analyses. We describe here the construction of a drug-inducible version of this system that takes advantage of tissue-specific GAL4 driver lines to yield either RU486-activated LexA-progesterone receptor chimeras (LexPR) or β-estradiol-activated LexA-estrogen receptor chimeras (XVE). Upon induction, these chimeras bind to a LexA operator (LexAop) and activate transgene expression. Using GFP expression as a marker for induction in fly brain cells, both approaches are capable of tightly and precisely modulating transgene expression in a temporal and dosage-dependent manner. Additionally, tissue-specific GAL4 drivers resulted in target gene expression that was restricted to those specific tissues. Constitutive expression of the active PKA catalytic subunit using these systems altered the sleep pattern of flies, demonstrating that both systems can regulate transgene expression that precisely mimics regulation that was previously engineered using the GeneSwitch/UAS system. Unlike the limited number of GeneSwitch drivers, this approach allows for the usage of the multitudinous, tissue-specific GAL4 lines for studying temporal gene regulation and tissue-specific gene expression. Together, these new inducible systems provide additional, highly valuable tools available to study gene function in Drosophila.
authors.affiliation: Graduate Institute of Biomedicine and Biomedical Technology, National Chi-Nan University, Nantou, Taiwan.
authors.forename: Shu-Yun
authors.initials: SY
authors.lastname: Kuo
authors.forename: Chiao-Hui
authors.initials: CH
authors.lastname: Tu
authors.forename: Ya-Ting
authors.initials: YT
authors.lastname: Hsu
authors.forename: Horng-Dar
authors.initials: HD
authors.lastname: Wang
authors.forename: Rong-Kun
authors.initials: RK
authors.lastname: Wen
authors.forename: Chen-Ta
authors.initials: CT
authors.lastname: Lin
authors.forename: Chia-Lin
authors.initials: CL
authors.lastname: Wu
authors.forename: Yu-Ting
authors.initials: YT
authors.lastname: Huang
authors.forename: Guan-Shieng
authors.initials: GS
authors.lastname: Huang
authors.forename: Tsuo-Hung
authors.initials: TH
authors.lastname: Lan
authors.forename: Tsai-Feng
authors.initials: TF
authors.lastname: Fu
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified; D001921:Brain / Q000166:cytology / Q000378:metabolism; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism; D004331:Drosophila melanogaster / Q000235:genetics / Q000378:metabolism; D005786:Gene Expression Regulation / Q000187:drug effects*; D018507:Gene Expression Regulation, Developmental; D018390:Gene Targeting; D049452:Green Fluorescent Proteins; D015735:Mifepristone / Q000494:pharmacology*; D009928:Organ Specificity / Q000235:genetics; D010641:Phenotype; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism
chemical_list: D029721:Drosophila Proteins; C557617:GAL4 protein, Drosophila; D014157:Transcription Factors; D049452:Green Fluorescent Proteins; D015735:Mifepristone