Loop-Ended dsRNA Structures for Efficient Gene Silencing
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Solution Overview
Problem
Conventional dsRNA molecules for RNA interference in animal cells, particularly those formed by annealing single-stranded sense and antisense RNAs or self-complementary RNAs, face inefficiencies in processing and target gene silencing, with processed siRNAs from the loop end of hairpin RNAs being less effective.
Innovation Solution
The development of loop-ended dsRNA (ledRNA) molecules, which are easily synthesized and form efficient dsRNA structures, inducing gene silencing in eukaryotic cells, including those applied topically to plant leaves, with specific sense and antisense ribonucleotide sequences capable of hybridizing to target RNA molecules.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional dsRNA molecules are formed by annealing single-stranded sense and antisense RNAs or from self-complementary RNAs, then the dsRNA structure is formed, but the processing efficiency and gene silencing effectiveness are reduced
Solution Approach 1:
The dsRNA molecule is divided into two separate single-stranded RNA components (sense and antisense) that are covalently linked through a linking ribonucleotide sequence. This segmentation allows each component to be independently designed and optimized, with the sense strand containing a 5' leader sequence and the antisense strand containing a 3' trailer sequence, thereby improving processing efficiency and gene silencing effectiveness
Solution Approach 2:
A linking ribonucleotide sequence acts as an intermediary element covalently connecting the sense and antisense RNA components. This intermediary linkage enables the formation of a stable dsRNA structure while allowing proper processing by cellular enzymes, resolving the contradiction between structural formation and processing efficiency
2Reliability
If long hairpin RNAs are used to induce RNAi, then gene silencing is achieved, but the siRNA processing starts from the loop end resulting in less abundant siRNAs
Solution Approach 1:
Instead of using a traditional hairpin structure where processing starts from the loop end, the invention inverts the design by creating a linear dsRNA structure with covalently linked sense and antisense strands. The sense strand is oriented with its 5' end at one terminus and the antisense strand with its 3' end at the other terminus, allowing Dicer processing to start from the 5' end of the sense strand and generate siRNAs in the correct orientation with higher abundance
Solution Approach 2:
The dsRNA structure employs asymmetric design where the sense and antisense strands are covalently linked in a specific orientation (sense 5' to antisense 3' direction). This asymmetric configuration ensures that Dicer processes the dsRNA from the correct end, generating functional siRNAs with proper polarity and increased abundance compared to symmetric hairpin structures
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
LedRNA molecules facilitate efficient gene silencing by readily forming dsRNA structures and producing short interfering RNAs, effectively reducing target gene expression in eukaryotic cells, including plants.
Implementation Method 1
the first antisense ribonucleotide sequence hybridises with the first sense ribonucleotide sequence in the RNA molecule
Implementation Method 2
the second sense ribonucleotide sequence hybridises with the second antisense ribonucleotide sequence in the RNA molecule
Data Source
AI summary
The present invention relates to new double stranded RNA (dsRNA) structures and their use in gene silencing.