Adjoining Ethylene Binding Elements Enhance EIN3 Affinity
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Solution Overview
Problem
The role of ethylene binding sequence (EBS) architecture in the functioning of the ETHYLENE INSENSITIVE3 (EIN3) transcription factor has not been investigated on a whole-genome level, limiting our understanding of ethylene-mediated gene expression in plants.
Innovation Solution
A recombinant nucleic acid construct comprising two or more directly adjoining ethylene binding sequences (EBS) of a specific formula, operably linked to a core promoter and optionally other regulatory elements, to modulate gene expression in response to ethylene.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single EBS sequence is used for EIN3 binding, then the binding affinity is moderate, but the sensitivity and specificity of ethylene detection are insufficient
Solution Approach 1:
The patent divides the EBS binding site into multiple discrete sequences (at least two separate EBS sequences) that can be individually optimized and positioned. This segmentation allows each EBS to contribute independently to EIN3 binding, enhancing overall detection sensitivity while maintaining manageable sequence complexity through modular design
Solution Approach 2:
The patent combines multiple EBS sequences into a single promoter region to create a composite binding site with enhanced affinity and specificity for EIN3. By merging multiple binding elements that recognize the same transcription factor, the system achieves superior ethylene detection sensitivity compared to single EBS constructs
2Reliability
If multiple EBS sequences are used to enhance ethylene detection sensitivity, then the binding affinity increases, but the construct complexity increases
Solution Approach 1:
The patent applies local quality by positioning multiple EBS sequences at specific locations within the promoter region (e.g., upstream of the core promoter at defined distances). This spatial arrangement optimizes EIN3 binding efficiency and ethylene-responsive gene activation while maintaining a structured, predictable construct design that manages complexity
Solution Approach 2:
The patent systematically varies parameters such as the number of EBS sequences (at least two), their spacing distances (e.g., 1-20 bp apart), and their positional arrangement relative to the core promoter. These parameter optimizations enhance detection reliability while providing a framework for designing constructs with controlled complexity based on specific application needs
3Strength
If EBS sequences are placed closer together to enhance binding, then the affinity increases, but the risk of non-specific transcription factor binding increases
Solution Approach 1:
The patent uses at least two EBS sequences positioned in close proximity (1-20 bp apart), which creates an excessive or enhanced binding signal that significantly strengthens EIN3 affinity. This partial repetition of binding elements ensures strong specific binding while the close spacing creates a distinctive pattern that reduces non-specific transcription factor interference
Data Source
AI summary
Provided is a recombinant nucleic acid construct comprising a sequence of Formula I (SEQ ID NO:48): X—N1—N2—N3—N4—N5—N6—N7—N8—N9—N10—N11—Y as an ethylene binding sequence (EBS). Tandems of two or more directly adjoining EBS are also described, and may be included in an expression cassette useful for modulating the expression of a nucleic acid of interest in a plant in response to plant hormone ethylene.