Characterization of an inducible promoter system in Catharanthus roseus hairy roots.
Transgenic hairy root cultures of Catharanthus roseus were established with a glucocorticoid-inducible promoter controlling the expression of green fluorescent protein (GFP), and GFP expression was characterized. The inducible system shows a tightly controlled, reversible, and dosage-dependent response to the glucocorticoid dexamethasone in C. roseus hairy roots. Full induction was noted after 12-18 h in the mature regions of the root tips and after 6 h in the meristem tissue. Upon removal of the inducing agent, GFP expression declined to undetectable levels in the mature tissues after 24 h and in the meristem after 48 h. Although no dosage-dependent response was noted in the meristem region, such a response was apparent in the mature region of the tip and verified by quantitative GFP analysis. The inducible promoter system allowed quantitative control of GFP expression between 0.01 and 10 microM dexamethasone with saturation occurring at higher levels. Using GFP as a model system allowed demonstration of the ability to control temporal and quantitative gene expression with the glucocorticoid-inducible promoter in transgenic C. roseus hairy roots.
Hughes
Erik H
EH
Department of Chemical Engineering, Rice University, PO Box 1892, Houston, Texas 77251, USA.
Hong
Seung-Beom
SB
Shanks
Jacqueline V
JV
San
Ka-Yiu
KY
Gibson
Susan I
SI
D030008:Catharanthus / Q000235:genetics*; D003907:Dexamethasone / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D005786:Gene Expression Regulation / Q000187:drug effects; D005938:Glucocorticoids / Q000494:pharmacology; D049452:Green Fluorescent Proteins; D008164:Luminescent Proteins / Q000032:analysis / Q000235:genetics; D018517:Plant Roots / Q000235:genetics; D030821:Plants, Genetically Modified; D011401:Promoter Regions, Genetic / Q000187:drug effects*; D015533:Transcriptional Activation / Q000187:drug effects
D005938:Glucocorticoids; D008164:Luminescent Proteins; D049452:Green Fluorescent Proteins; D003907:Dexamethasone