High efficiency inducible gene expression system based on activation of a chimeric transcription factor in transgenic pine.
Inducible gene expression systems are needed in functional genomics of tree species. A glucocorticoid-inducible gene expression system was established in a gymnosperm species Virginia pine (Pinus virginiana Mill.) through Agrobacterium tumefaciens-mediated genetic transformation. The results demonstrate that expression of the m-gfp5-ER reporter gene was tightly controlled and 0.1 microM of the glucocorticoid hormone triamcinolone was able to induce m-gfp5-ER expression in transgenic cells. Differential expression of gfp in transgenic cells induced by different concentrations of triamcinolone was observed and confirmed by Northern Blot analysis and by quantitative green fluorescence analyses with Laser Scanning Microscopy. In transgenic plantlets, triamcinolone was taken up efficiently by roots. Triamcinolone was able to induce m-gfp5-ER activity throughout the whole plant. The phenotype of transgenic plantlets was not affected 6 weeks after treatment with 0.1-10 microM triamcinolone. However, 6-week inductions with 100 microM triamcinolone caused growth retardation and developmental defects, as well as inhibition of root formation and elongation. With careful selection of transgenic lines, the inducible gene expression presented in this study could be a very valuable alternative for functional identification of novel genes in plants, especially in pine.
Tang
Wei
W
Department of Biology, Howell Science Complex, East Carolina University, Greenville, NC 27858-4353, USA. tangw@mail.ecu.edu
Newton
Ronald J
RJ
Charles
Thomas M
TM
D016960:Agrobacterium tumefaciens / Q000235:genetics; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D005786:Gene Expression Regulation / Q000235:genetics; D018506:Gene Expression Regulation, Plant / Q000187:drug effects / Q000235:genetics; D018014:Gene Transfer Techniques; D017930:Genes, Reporter / Q000187:drug effects / Q000235:genetics; D005822:Genetic Vectors / Q000235:genetics; D005938:Glucocorticoids / Q000494:pharmacology; D049452:Green Fluorescent Proteins / Q000235:genetics; D008855:Microscopy, Electron, Scanning; D010641:Phenotype; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000235:genetics; D028223:Pinus / Q000187:drug effects / Q000235:genetics* / Q000254:growth & development; D018517:Plant Roots / Q000187:drug effects / Q000254:growth & development; D018520:Plant Shoots / Q000187:drug effects / Q000235:genetics / Q000648:ultrastructure; D030821:Plants, Genetically Modified / Q000187:drug effects / Q000235:genetics* / Q000254:growth & development; D011993:Recombinant Fusion Proteins / Q000235:genetics*; D014157:Transcription Factors / Q000187:drug effects / Q000235:genetics*; D015533:Transcriptional Activation / Q000187:drug effects / Q000235:genetics; D014170:Transformation, Genetic / Q000235:genetics*; D014221:Triamcinolone / Q000494:pharmacology
D005938:Glucocorticoids; D011993:Recombinant Fusion Proteins; D014157:Transcription Factors; D049452:Green Fluorescent Proteins; D014221:Triamcinolone; D017853:Phosphotransferases (Alcohol Group Acceptor); C063242:hygromycin-B kinase