Sulfonylurea-Responsive Repressors for Plant Gene Control
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Solution Overview
Problem
The tetracycline operon system has had limited use in plants due to issues with antibiotic inducers that are sensitive to light, necessitating a more effective method for regulating gene expression in response to sulfonylurea compounds.
Innovation Solution
Development of sulfonylurea-responsive repressors that specifically bind to operators, regulated by sulfonylurea compounds, allowing for tight control of gene expression in plants and other organisms, including the use of modified TetR proteins with enhanced activity on compounds like chlorsulfuron and ethametsulfuron.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the tetracycline operon system is used to regulate gene expression, then gene expression control is achieved, but the system has limited use in plants due to light sensitivity of antibiotic inducers
Solution Approach 1:
The patent modifies the ligand binding domain of the TetR repressor protein through amino acid substitutions (e.g., F57L, F188C, C189S) to change its ligand specificity from tetracycline to sulfonylurea compounds. This parameter change in molecular recognition enables the system to respond to herbicides instead of antibiotics, resolving the light sensitivity issue while maintaining gene expression control functionality in plants
Solution Approach 2:
The patent creates a modified version of the TetR repressor system that copies the fundamental mechanism of tetracycline-induced gene regulation but replaces the inducer molecule with sulfonylurea compounds. This copying approach preserves the reliable gene expression control while eliminating the harmful light sensitivity associated with antibiotic inducers
2Measurement precision
If modified TetR proteins are used to enhance activity on sulfonylurea compounds, then regulatory specificity is improved, but protein structure complexity increases
Solution Approach 1:
The patent applies local quality changes by introducing specific amino acid substitutions only in the ligand binding domain (LBD) of the TetR protein, while leaving the DNA-binding domain and overall protein architecture intact. This localized modification approach achieves high regulatory specificity for sulfonylurea compounds without requiring complete restructuring of the entire protein, thus limiting the increase in overall complexity
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The sulfonylurea-responsive repressors provide a robust and specific regulatory mechanism for gene expression in plants, enabling precise control of transgenes and potential applications in agricultural biotechnology, such as herbicide resistance and trait management.
Implementation Method 1
isolated sulfonylurea-responsive repressors (SuRs) that specifically bind to operator sequences
Data Source
AI summary
Compositions and methods relating to the use of sulfonylurea-responsive repressors are provided. Compositions include polypeptides that specifically bind to an operator, wherein the specific binding is regulated by a sulfonylurea compound. Compositions also include polynucleotides encoding the polypeptides as well as constructs, vectors, prokaryotic and eukaryotic cells, and eukaryotic organisms including plants and seeds comprising the polynucleotide, and/or produced by the methods. Also provided are methods to provide a sulfonylurea-responsive repressor to a cell or organism, and to regulate expression of a polynucleotide of interest in a cell or organism, including a plant or plant cell.