Modified mRNA 5' UTR Elements for Leaky Scanning Control
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Solution Overview
Problem
Existing mRNA therapeutics face challenges in controlling and regulating translation to ensure the initiation of the desired therapeutic protein or peptide at the correct initiation codon, due to leaky scanning which can lead to the translation of aberrant or undesirable open reading frames.
Innovation Solution
The development of modified mRNAs (mmRNAs) with chemical and structural modifications, including GC-rich RNA elements and nucleotide modifications, to enhance translational regulation by increasing the residence time of the 43S pre-initiation complex at the initiation codon, promoting translation from the correct start site, and inhibiting leaky scanning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional mRNA is used without modifications, then the mRNA structure is simple and easy to manufacture, but leaky scanning occurs causing translation of aberrant open reading frames
Solution Approach 1:
The patent applies local quality by introducing specific GC-rich RNA elements at particular locations within the 5' UTR region. These localized modifications create strong secondary structures only where needed to prevent ribosomal scanning past the start codon, while leaving the rest of the mRNA structure relatively unchanged. This targeted approach improves translational fidelity without requiring complete redesign of the entire mRNA molecule.
Solution Approach 2:
The patent employs parameter changes by modifying the nucleotide sequence composition, specifically increasing GC content in the 5' UTR region. This parameter change (GC content) enables formation of stable secondary structures that regulate translation initiation. The modification transforms the local physical-chemical properties of the mRNA to achieve leaky scanning prevention without fundamentally altering the overall mRNA architecture.
2Reliability
If modifications are added to prevent leaky scanning, then translation fidelity improves, but the mRNA becomes more complex and harder to manufacture
Solution Approach 1:
The patent applies segmentation by dividing the mRNA into distinct functional regions: a 5' UTR containing GC-rich elements for translation regulation, a coding sequence for the therapeutic protein, and a 3' UTR. This segmented design allows the GC-rich elements to be synthesized separately and then ligated to the coding sequence, simplifying the manufacturing process compared to synthesizing the entire modified mRNA as a single continuous strand.
Solution Approach 2:
The patent uses an intermediary approach by employing GC-rich RNA elements as mediators between the 5' cap and the start codon. These elements act as translational regulators that facilitate correct initiation without requiring complex synthesis procedures. The GC-rich elements can be incorporated through standard molecular biology techniques, maintaining ease of manufacture while achieving the desired translational control.
3Productivity
If GC-rich RNA elements are introduced to increase residence time of 43S complex, then translation efficiency improves, but the mRNA structure becomes more complex
Solution Approach 1:
The patent applies merging by combining the GC-rich RNA elements with the existing 5' UTR sequence in a unified structure. Rather than adding completely separate and complex elements, the GC-rich sequences are integrated into the 5' UTR region, creating a cohesive structure that performs both translation regulation and maintains structural simplicity. This merging approach increases translation efficiency while minimizing additional structural complexity.
Data Source
AI summary
The present disclosure provides messenger RNAs (mRNAs) having chemical and/or structural modifications, including RNA elements and/or modified nucleotides, which provide a desired translational regulatory activity to the mRNA.