Dummy RNA Blocking of Plant Target DNA Methylation
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Solution Overview
Problem
Existing technologies lack a convenient and rapid method to inhibit methylation of target DNA in plants, particularly for directing demethylation without relying on recombinant technology.
Innovation Solution
Inhibiting the binding of scaffold RNA produced by transcription of target DNA with an siRNA-AGO4 complex using a short dummy RNA, which is complementary to the siRNA or scaffold RNA, in an RNA-directed DNA methylation mechanism, thereby preventing DRM2 recruitment and DNA methylation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If dCAS-fused TET1 is used to direct demethylation, then specific demethylation can be achieved, but the process becomes complex and time-consuming due to recombinant technology requirements
Solution Approach 1:
The invention uses a dummy RNA that copies the sequence of the target scaffold RNA to compete for binding with siRNA-AGO4 complex. This simple sequence-copying approach achieves specific demethylation without requiring complex recombinant protein engineering, thus resolving the contradiction between specificity and complexity
Solution Approach 2:
The dummy RNA acts as an intermediary molecule that mediates the demethylation process by competing with the scaffold RNA for siRNA-AGO4 binding. This intermediary approach simplifies the system by replacing complex recombinant proteins with a simple RNA molecule that can be easily introduced into plants
2Reliability
If conventional epigenetic control methods are used, then gene expression regulation is maintained, but the ability to rapidly and conveniently manipulate methylation is insufficient
Solution Approach 1:
The invention introduces dummy RNA sequences beforehand that are complementary to scaffold RNA. When siRNA-AGO4 complex forms, it is preemptively captured by the dummy RNA before it can bind to scaffold RNA and recruit DRM2 for methylation. This preliminary blocking action enables rapid control of methylation status without waiting for complex cellular processes
Solution Approach 2:
The system dynamically controls methylation status by introducing or removing dummy RNA. The methylation state is not fixed but can be rapidly switched between methylated and demethylated states depending on the presence of dummy RNA, providing both stability when needed and rapid manipulability when required
3Quantity of substance
If scaffold RNA binding with siRNA-AGO4 complex is allowed to proceed, then RNA-directed DNA methylation occurs, but specific inhibition of target DNA methylation cannot be achieved
Solution Approach 1:
The dummy RNA is designed with sequence specificity targeting only the scaffold RNA of interest. This local specificity ensures that only the target DNA region undergoes demethylation while other regions maintain their normal methylation status, achieving precise spatial control over methylation inhibition
Solution Approach 2:
The dummy RNA is introduced in excess to ensure complete competition with scaffold RNA for siRNA-AGO4 binding. This excessive action guarantees that all siRNA-AGO4 complexes are captured by dummy RNA, completely preventing scaffold RNA from recruiting DRM2 and achieving thorough inhibition of target DNA methylation
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
This approach allows for specific and rapid control of transcriptional gene silencing, enabling the production of plants with desired traits and increased accumulation of functional components.
Implementation Method 1
the short dummy RNA comprises i) a sequence complementary to the siRNA incorporated in the siRNA-AGO4 complex, or ii) a sequence complementary to the scaffold RNA
Data Source
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AI summary
According to the present invention, methylation of a target DNA in a plant is suppressed quickly and easily without using recombinant technology, and a plant having desired traits is thereby created. In an RNA-directed DNA methylation mechanism, binding between scaffold RNA produced by transcription of the target DNA and an siRNA-AGO4 complex is inhibited.