Dominant Negative KRPI Mutants for Crop Yield Enhancement
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Solution Overview
Problem
Current methods for modifying crop characteristics, such as increasing crop yields or seed size, are limited by the inefficiencies of post-transcriptional gene silencing technologies and the lack of commercially available transgenic crops with enhanced yield or seed size.
Innovation Solution
Development of variant plant cyclin-dependent kinase inhibitor (CKI) polypeptides with modified binding affinity for CDK proteins, which act as dominant negative antagonists to wild-type CKI function, allowing for accelerated cell cycle progression and increased cell proliferation when expressed in plants.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If post-transcriptional gene silencing (PTGS) is used to modify crop characteristics, then gene expression can be suppressed, but the efficiency is low and the technology is transient
Solution Approach 1:
Instead of using PTGS to suppress gene expression (the conventional approach), the patent inverts the strategy by using dominant negative mutants that actively interfere with protein function. The mutant KRPI protein binds to cyclin-CDK complexes and prevents their activity, achieving more reliable and lasting effects than PTGS.
Solution Approach 2:
The patent modifies the protein function by changing the amino acid sequence parameters of the KRPI protein. Specific amino acid substitutions (e.g., at positions 151, 153, 149, 164, 165) create dominant negative variants with altered binding affinity and functional properties, enabling more effective and stable gene modification.
2Reliability
If wild-type CKI proteins are expressed to inhibit CDK activity, then cell cycle progression is slowed, but crop yield and seed size are reduced
Solution Approach 1:
The patent applies local quality by creating KRPI variants with specific modifications only in the CDK binding region (amino acid positions 151, 153, 149, 164, 165), while maintaining the rest of the protein structure intact. This localized modification allows the protein to bind cyclin-CDK complexes with high affinity but prevents effective inhibition, thereby promoting cell cycle progression and increasing crop yield.
Solution Approach 2:
Instead of using wild-type CKI proteins that effectively inhibit CDK activity (which reduces yield), the patent uses dominant negative mutants that fail to inhibit CDK activity despite binding the complexes. This inversion of function allows maintaining CDK inhibition effectiveness while improving crop productivity.
3Adaptability or versatility
If multiple CKI genes are silenced simultaneously to achieve desired phenotype, then multiple characteristics can be modified, but the complexity and cost increase
Solution Approach 1:
The patent merges the functions of multiple CKI genes into a single dominant negative KRPI protein expression system. By expressing one mutant protein that interferes with multiple CDK-cyclin complexes, the system achieves the effect of silencing multiple genes simultaneously, thereby reducing technical complexity and cost while maintaining versatility.
Data Source
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AI summary
Disclosed are mutant CDK inhibitor (CKI) polypeptides having dominant negative antagonist activity against wild-type CKI proteins, as well as related compositions, including nucleic acids and vectors encoding the mutant CKI polypeptides and transformed host cells and transgenic plants comprising such nucleic acids and vectors. Also disclosed are related methods for using the mutant proteins to modulate cell division in cells, particularly plant cells.