| 摘要 |
A gene expression system for controllable expression of ethylene response in a plant cell includes an activation cassette comprising a DNA-binding domain that recognizes a response element; an ecdysone receptor ligand binding domain; and an activation domain; and a target cassette comprising an inducible promoter, which comprises, in operative association, the response element and a minimal promoter responsive to the activation domain. The inducible promoter controls the expression of a nucleic acid sequence that encodes a selected regulatory protein that modifies sensitivity to ethylene of certain signal proteins in the plant. Interaction among the components of the activation cassette and target cassette, when in a plant cell, in the presence of an inducing composition, increases expression of the selected regulatory protein, and in turn decreases expression and accumulation of the signal protein in the plant, thereby and decreasing ethylene sensitivity in the plant cell. This increase in the expression of the regulatory protein, particularly in the presence of ethylene, is controlled by the timing, the concentration and the duration of the application of the inducing composition. Transgenic plant cells, tissues, organs and entire plants are provided, which in the presence of the inducing composition control ethylene sensitivity. Ethylene sensitivity and/or ethylene production in such transgenic plants and tissues may be controlled for purposes of manipulating ripening, flower senescence and other ethylene sensitive functions of the plant. |
| 主权项 |
1. A gene expression system for controllably inhibiting the accumulation in a plant cell of ethylene inducible proteins comprising:
an activation cassette comprising, under control of a constitutive G10-90 promoter and in operative association therewith, (a) a GAL 4 DNA-binding domain (DBD) that recognizes a response element comprising five copies of GAL4 response element; (b) an ecdysone receptor ligand binding domain (EcRLBD); and (c) a VP16 activation domain (AD) which is activated in the presence of an inducing composition; and a target cassette comprising (d) an inducible promoter comprising, in operative association, the five copies of the GAL 4 response element to which the DBD of (a) binds and the minimal 35 S promoter responsive to activation of the VP16 AD, the inducible promoter controlling expression of (e) a nucleic acid sequence that encodes an ETP1 or ETP2 protein; said activation cassette and the target cassette in operative association to enable interaction, when in a plant cell, with an inducing composition, to controllably increase expression of the ETP1 or ETP2 protein to inhibit the accumulation of the EIN2 gene product in the plant in the presence of ethylene, the inhibition of said accumulation in EIN2 protein expression controllable by the timing, the concentration, and the duration of the application of the inducing composition. |
