A chemical-regulated inducible RNAi system in plants.
Constitutive expression of an intron-containing self-complementary 'hairpin' RNA (ihpRNA) has recently been shown to efficiently silence target genes in transgenic plants. However, this technique cannot be applied to genes whose silencing may block plant regeneration or result in embryo lethality. To obviate these potential problems, we have used a chemical-inducible Cre/loxP (CLX) recombination system to trigger the expression of an intron-containing inverted-repeat RNA (RNAi) in plants. A detailed characterization of the inducible RNAi system in transgenic Arabidopsis thaliana and Nicotiana benthamiana plants demonstrated that this system is stringently controlled. Moreover, it can be used to induce silencing of both transgenes and endogenous genes at different developmental stages and at high efficiency and without any detectable secondary affects. In addition to inducing complete silencing, the RNAi can be produced at various times after germination to initiate and obtain different degrees of gene silencing. Upon induction, transgenic plants with genetic chimera were obtained as demonstrated by PCR analysis. Such chimeric plants may provide a useful system to study signaling mechanisms of gene silencing in Arabidopsis as well as other cases of long-distance signaling without grafting. The merits of using the inducible CLX system for RNAi expression are discussed.
Guo
Hui-Shan
HS
Laboratory of Molecular Cell Biology, Temasek Life Sciences Laboratory, National University of Singapore, 1 Research Link, 117604 Singapore.
Fei
Ji-Feng
JF
Xie
Qi
Q
Chua
Nam-Hai
NH
D017360:Arabidopsis / Q000235:genetics*; D049452:Green Fluorescent Proteins; D008164:Luminescent Proteins / Q000235:genetics / Q000378:metabolism; D010088:Oxidoreductases / Q000235:genetics / Q000378:metabolism; D030821:Plants, Genetically Modified; D034622:RNA Interference; D016337:RNA, Catalytic / Q000235:genetics / Q000378:metabolism; D018749:RNA, Plant / Q000235:genetics* / Q000378:metabolism; D014026:Nicotiana / Q000235:genetics* / Q000378:metabolism
D008164:Luminescent Proteins; D016337:RNA, Catalytic; D018749:RNA, Plant; C418481:hairpin ribozyme; D049452:Green Fluorescent Proteins; D010088:Oxidoreductases; C022398:phytoene dehydrogenase